Table of contents

The Symposium DISCRETE'08 on Prospects in the Physics of Discrete Symmetries was held at the Instituto de Física Corpuscular (IFIC) in Valencia, Spain from 11 to 16 December 2008. IFIC is a joint centre of the Consejo Superior de Investigaciones Científicas (CSIC) and the Universitat de València (UVEG).

The aim of the Symposium was to bring together experts on the field of Discrete Symmetries in order to discuss its prospects on the eve of the LHC era. The general state of the art for CP, T and CPT symmetries was reviewed and their interplay with Baryogenesis, Early Cosmology, Quantum Gravity, String Theory and the Dark Sector of the Universe was emphasised. Connections with physics beyond the Standard Model, in particular Supersymmetry, were investigated. Experimental implications in current and proposed facilities received particular attention.

The scientific programme consisted of 24 invited Plenary Talks and 93 contributions selected among the submitted papers. Young researchers, in particular, were encouraged to submit an abstract. The Special Lecture on ''CERN and the Future of Particle Physics'', given by the CERN Director General Rolf-Dieter Heuer to close the Symposium, was of particular relevance. On the last day of the Symposium, an open meeting took place between Professor Heuer and the Spanish community of particle physics.

The Symposium covered recent developments on the subject of Discrete Symmetries in the following topics:

• Quantum Vacuum

• Entanglement, Symmetrisation Principle

• CPT in Quantum Gravity and String Theory, Decoherence, Lorentz Violation

• Ultra-high-energy Messengers

• Time Reversal

• CP violation in the SM and beyond

• Neutrino Mass, Mixing and CP

• Baryogenesis, Leptogenesis

• Family Symmetries

• Supersymmetry and other searches

• Experimental Prospects: LHC, Super-B Factories, DAΦNE-2, Neutrino Beams

The excellence of most of the presentations during the Symposium was pointed out by many participants. The broad spectrum of topics under the guideline of Symmetry and Symmetry Breaking was an added value to the interest of such an event. The Symposium was attended by 160 participants, among which 63 from Spain, 77 coming from the rest of Europe, 10 from USA and 10 from the rest of the world.

The Symposium started with a welcome address by Dr Vasiliki Mitsou, Co-Chair of the Organising Committee, and Professor Francisco J Botella, Director of IFIC. The scientific plenary sessions started with a discussion on the search for Time Reversal Violation, independent of CP and/or CPT symmetries, by Helen Quinn. Related to this important subject, David Wark made a presentation of the state of the art in the measurement of Electric Dipole Moments. The status and prospects of CP-violation Experiments was reviewed by Tatsuya Nakada, whereas Andrzej Buras made a comprehensive discussion on the search for New Physics with Rare Decays and CP Violation. The implications for Cosmology were presented by Mikhail Shaposhnikov with a talk on Baryogenesis. The pending understanding of the Flavour Problem was discussed by Graham G Ross in his presentation on Family Symmetries. Going beyond the paradigm imposed by local quantum field theories, Nikolaos Mavromatos described the scenario of CPT Violation and Decoherence in Quantum Gravity. Antonio Di Domenico presented the status on the search for CPT Violation and Decoherence in the Neutral Kaon System and José L F Barbón covered the territory of Strings, Symmetry and Holography. The problem of the Quantum Vacuum was addessed by Mariano Quirós in his presentation on the nature of the Electroweak Higgs sector. In Cosmology, Pierre Binetruy treated the fascinating question of the possible concepts to explain the Dark Energy in the Universe. On the theme of High Energy Messengers from the Cosmos, Graciela Gelmini presented the solved and unsolved questions associated with the High Energy Cosmic Rays, Manel Martínez discussed methods to study Fundamental Physics with Cosmic Gamma Rays and Francis Halzen gave the present status of High Energy Neutrino Astronomy and the projects towards Km3-scale cosmic neutrino Underwater Detectors. On Neutrino Physics, Niki Saoulidou reviewed its present status and the experimental prospects, Peter Minkowski discussed the proposals to understand the Origin of Neutrino Mass and Apostolos Pilaftsis made a Little Review on the implications of global Lepton Number Violation with neutrino Majorana mass for Leptogenesis in the Universe. The interplay of Dark Matter studies with the search for SUSY at LHC was discussed by Antonio Masiero, whereas Athanasios Lahanas presented Dark Matter in the eye of CP-violating SUSY theory. On the Experimental Prospects frontier, André Rubbia discussed Underground Detectors for Particle and Astroparticle Science, Daniel Froidevaux gave a stimulating review on the Physics to be expected at LHC, Marcello A Giorgi examined the Future of SuperFlavour Factories as complementary to LHCb and Mats Lindroos presented the options for the Ultimate Neutrino Beam(s), able to discover and measure CP Violation in neutrino oscillations.

In the Parallel Sessions, the contributions selected for oral presentation during the Symposium were well balanced covering all aspects of Discrete Symmetries. They are reproduced in the present Proceedings distributed according to the various topic-specific sessions in which they were presented. The papers published here have, in addition, passed positively the refereeing system defined by the members of the Organising Committee of the DISCRETE'08 Symposium.

The DISCRETE'08 Symposium was the first in a series of biannual events on the general topic of Symmetries. The next symposium will be organised by the University of La Sapienza, Rome, Italy, in the autumn of 2010.

Valencia, April 2009

The Editors

J Bernabéu (IFIC Valencia) F J Botella (IFIC Valencia) N E Mavromatos (King's College London) V A Mitsou (IFIC Valencia)

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focussed on the latter, namely the violation of T-reversal invariance in particle physics theories.

The origin of the CP violation which created the matter in the universe is one of the enduring mysteries of fundamental physics. Particle electric dipole moments provide a sensitive probe of CP violation from new physics. The article describes past and future work being done at the ILL in Grenoble to search for an electric dipole moment of the neutron.

Symmetry plays a crucial role in constructing a theory which describes the building blocks of of the material and interactions between them. From the experimental observation of CP violation, existence of the third quark family had been revealed well before the second family was experimentally established. In this article, we recall the historical development of CP violation, and review the current important experimental results and prospects in near future. Then, it concludes with a general reflection.

After an overture and a non-technical exposition of the relevant theoretical framework, that together offer hopefully a grand picture of the present status of flavour physics, I will collect 20 Goals for this important field. Most of them could be reached already in the next decade. Taken together these goals could be considered as a systematic search for New Physics with the help of flavour- and CP-violating decays of K, D, B mesons and leptons. Also electric dipole moments and (g − 2)_μ play an important role in this program. In this context we will discuss very briefly several extensions of the Standard Model like models with Minimal Flavour Violation, general MSSM, Littlest Higgs Model with T parity and Randall-Sundrum models. This presentation is not meant to be a comprehensive review of flavour physics but rather a personal view on this fascinating field and an attempt to collect those routes that with the help of oncoming experiments should allow us to reach a much deeper understanding of flavour physics at very short distance scales.

We will discuss different mechanisms for baryogenesis with special emphasis to those of them that can be experimentally tested.

The hierarchical structure of quark and charged lepton masses and the small mixing angles in the quark sector is in stark contrast with the structure of neutrino masses and mixing angles. I discuss how these apparently disparate structure can be elegantly explained through an underlying discrete non-Abelian family symmetry.

In this brief review I discuss ways and tests of CPT-Violation in the context of quantum gravity theories with space-time foam vacua, which entail quantum decoherence of matter propagating in such backgrounds. I cover a wide variety of sensitive probes, ranging from cosmic neutrinos to meson factories. I pay particular emphasis on associating the latter with specific, probably unique ('smoking-gun'), effects of this type of CPT Violation, related to a modification of Einstein-Podolsky-Rosen (EPR) correlations in the entangled states of the relevant neutral mesons. I also present some semi-microscopic estimates of these latter effects, in the context of a specific string-inspired model of space-time foam ('D-particle foam').

The neutral kaon system offers a unique possibility to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The most recent limits on several kinds of possible CPT violation and decoherence mechanisms, which in some cases might be justified in a quantum gravity framework, are reviewed, including the latest results obtained by the KLOE experiment at the DAΦNE e⁺e^- collider. No deviation from the expectations of quantum mechanics and CPT symmetry is observed, while the precision of the measurements, in some cases, reaches the interesting Planck scale region.

We review some aspects of the information problem in black hole physics, from the point of view holographic ideas, and the AdS/CFT correspondence in particular.

In this talk I will first discuss the main features of electroweak symmetry breaking in the Standard Model and in particular I will focus on the Higgs sector responsible thereof. I will highlight the deficiencies of the Standard Model both from the experimental (Dark Matter, baryogenesis,...) and theoretical (ultraviolet sensitivity of the Higgs mass, unexplained flavor textures in the quark and lepton sectors, lack of unification of gauge couplings, strong CP problem,...) points of view which largely motivate extending it to Beyond the Standard Model scenarios. We then briefly review some of the scenarios which aim at solving some of the above problems. In particular we have discussed the minimal supersymmetric extension of the Standard Model, Little Higgs models, gauge-Higgs unification scenarios and the possibility of the Higgs living in a conformal sector (un-Higgs) as a solution to the hierarchy problem. In all cases we have focused on the electroweak sector of the models and the particular solution they offer to the Standard Model problems.

The acceleration of the expansion of the Universe which has been identified in recent years has deep connections with some of the most central issues in fundamental physics. At present, the most plausible explanation is some form of vacuum energy. The puzzle of vacuum energy is a central question which lies at the interface between quantum theory and general relativity. Solving it will presumably require to construct a quantum theory of gravity and a correspondingly consistent picture of spacetime. To account for the acceleration of the expansion, one may also think of a more dynamical form of energy, what is known as dark energy, or modifications of gravity. In what follows, we review the the basic models for dark energy and the difficulties encountered in each approach, as well as we discuss the vacuum energy problem.

I review here some of the physics we are learning and expect to learn in the near future through the observation of cosmic rays. The study of cosmic rays involves a combination of data from accelerators, ground arrays, atmospheric fluorescence detectors and balloon and satellite experiments. I will discuss the data of the Pierre Auger Observatory, PAMELA, ATIC and FST among other experiments.

The observation of the universe in the VHE gamma ray domain with the new generation of Cherenkov Telescopes is producing new measurements with a direct implication for cosmology. The present results and the future prospects will be discussed.

We discuss the status of the kilometer-scale neutrino detector IceCube and its low energy upgrade Deep Core and review its scientific potential for particle physics. We subsequently appraise IceCube's potential for revealing the enigmatic sources of cosmic rays. After all, this aspiration set the scale of the instrument. While only a smoking gun is missing for the case that the Galactic component of the cosmic ray spectrum originates in supernova remnants, the origin of the extragalactic component remains as inscrutable as ever. We speculate on the role of the nearby active galaxies Centaurus A and M87.

We will start with a brief overview of neutrino oscillation physics with emphasis on the remaining open questions. Next we will review the current status and prospects of experiments probing the 'solar' and 'atmospheric' neutrino mixing parameters. Finally, we will describe the status and prospects of near and longer term neutrino oscillation experiments aiming to study the 'cross' neutrino mixing parameters which, to date, are almost entirely unknown.

I propose to give an outline based on partial answers to questions beneath 'the origin of neutrino mass':

(a) building on the limiting uncurved structure of 1 time + 3 space dimensions, what is the full extent of space-time dimensions and their meaning in quantum gravity? (b) what is the origin and nature of spin-½ fermions? (c) if charge-like and orientation-like gaugeing is related, then what is the explanation for 3 colors and 3 families along the path of unification?

This is a brief review on the scenario of baryogenesis through leptogenesis. Leptogenesis is an appealing scenario that may relate the observed baryon asymmetry in the Universe to the low-energy neutrino data. In this review talk, particular emphasis is put on recent developments on the field, such as the flavourdynamics of leptogenesis and resonant leptogenesis near the electroweak phase transition. It is illustrated how these recent developments enable the modelling of phenomenologically predictive scenarios that can directly be tested at the LHC and indirectly in low-energy experiments of lepton-number and lepton-flavour violation.

Given that nucleosynthesis (BBN) provides the oldest available information we have on the evolution of the Universe, it is worthwhile exploring possible deviations from the standard Big Bang cosmology based on General Relativity in pre-BBN epochs. Non-GR pre-BBN cosmologies affect the evolution of the WIMP DM component, in particular determining relevant shifts on its freeze-out temperature. The impact of this new 'degree of freedom' in the discussion of naturalness of WIMPs in playing the role of DM is presented in the context of Scalr Tensor (ST) theories of gravity.

Supersymmetry provides ideal candidates for explaining the dark matter mystery of our universe. Compelling cold dark matter (CDM) candidates are the neutralino, gravitino and the superpartner of the elusive axion, the axino. The LSP neutralino is perhaps the best motivated candidate for CDM and the popular SUSY models can be in agreement with accelerator and WMAP data. Supersymmetric CP-violating phases, although phenomenologically and theoretically interesting, especially for baryogenesis scenarios, are tightly constrained by electric dipole moment (EDM) data. Two-loop renormalization group equation (RGE) running from the unification to the electroweak scale renormalizes the gaugino mass phases with important consequences for EDMs. In minimal CP-violating extensions of mSUGRA, with non-universal boundary conditions at the unification scale, EDMs and WMAP data can be sumiltaneously satisfied for large values of the phases in regions where neutralinos annihilate through a rapid Higgs resonance. These regions of the parameter space are accessible to LHC.

The current focus of the CERN program is the Large Hadron Collider (LHC), however, CERN is engaged in long baseline neutrino physics with the CNGS project and supports T2K as recognized CERN RE13, and for good reasons: a number of observed phenomena in high-energy physics and cosmology lack their resolution within the Standard Model of particle physics; these puzzles include the origin of neutrino masses, CP-violation in the leptonic sector, and baryon asymmetry of the Universe. They will only partially be addressed at LHC. A positive measurement of sin² 2θ₁₃ > 0.01 would certainly give a tremendous boost to neutrino physics by opening the possibility to study CP violation in the lepton sector and the determination of the neutrino mass hierarchy with upgraded conventional super-beams. These experiments (so called 'Phase II') require, in addition to an upgraded beam power, next generation very massive neutrino detectors with excellent energy resolution and high detection efficiency in a wide neutrino energy range, to cover 1st and 2nd oscillation maxima, and excellent particle identification and p⁰ background suppression. Two generations of large water Cherenkov detectors at Kamioka (Kamiokande and Super-Kamiokande) have been extremely successful. And there are good reasons to consider a third generation water Cherenkov detector with an order of magnitude larger mass than Super-Kamiokande for both non-accelerator (proton decay, supernovae,...) and accelerator-based physics. On the other hand, a very massive underground liquid Argon detector of about 100 kton could represent a credible alternative for the precision measurements of 'Phase II' and aim at significantly new results in neutrino astroparticle and non-accelerator-based particle physics (e.g. proton decay).

This review focuses on the expected performance of the ATLAS and CMS detectors at the CERN Large Hadron Collider (LHC), together with some of the highlights of the global commissioning work done in 2008 with basically fully operational detectors. A selection of early physics measurements, expected to be performed with the data taken in 2009/2010 is included for completion, together with a brief reminder of the ultimate physics potential of the LHC.

The status of the flavor physics is presented: the experimental achievements, the outstanding success of the CKM picture within the Standard Model and the flavor experiments presently running and in preparation. From now on the exploration beyond the Standard Model needs a global approach where single measurements coming from individual ad hoc experiments and a more wide set of results expected from multipurpose detectors running at the future Flavor Factories could add value complementary to the direct investigation at LHC. The perspective of the Flavor Factories of next generation, that are expected to be built and running within the next decade, is discussed, with a focus on the technical specific aspects of each individual project.

The advance in neutrino oscillation physics is driven by the availability of well characterized and high flux neutrino beams. The three present options for the next generation neutrino oscillation facility are super beams, neutrino factories and beta-beams. A super-beam is a very high intensity classical neutrino beam generated by protons impinging on a target where the neutrinos are generated by the secondary particles decaying in a tunnel down streams of the target. In a neutrino factory the neutrinos are generated from muons decaying in a storage ring with long straight sections pointing towards the detectors. In a beta-beam the neutrinos are also originating from decay in a storage ring but the decaying particles are radioactive ions rather than muons.

I will in this presentation review the three options and discuss the pros and cons of each. The present joint design effort for a future high intensity neutrino oscillation in Europe within a common EU supported design study, EURONU, will also be presented. The design study will explore the physics reach, the detectors, the feasibility, the safety issues and the cost for each of the options so that the the community can take a decision on what to build when the facilities presently under exploitation and construction have to be replaced.

With the start-up of the Large Hadron Collider, particle physics is entering into an exciting period of research and discovery with high prospects for exciting advances in our understanding of Nature. The results from the initial running at the LHC will provide the directions for the future of particle physics and as host to the LHC, CERN is in a unique position to play a key role in the future course of particle physics. Future major facilities in particle physics require the formation of collaborations on a global scale, and to this end organisational structures are being put in place to oversee such extended endeavours. This paper reviews the characteristic features of particle physics and analyses the routes to be taken for the future advancement of the field.

A summary of the latest results of Standard Model Higgs boson searches from CDF and DØ analyses using up to 3.0 fb^_1 of Tevatron data are reviewed. 95% C.L. upper limits on Higgs boson production are shown for Higgs masses ranging from 100 to 200 GeV.

In this paper we report on a summary of the most recent strategies developed to discover the Higgs boson with the ATLAS detector at the LHC. We cover both the Standard Model Higgs framework as well as its minimal supersymmetric extension. We review the main observable channels together with the experimental aspects more relevant for their observation.

One of the greatest challenges in High Energy Physics is the discovery of the Higgs boson which is responsible for the Standard Model particles mass generation. Below ∼150 GeV/c² the Higgs decay into two b-quarks, H → b dominates. The two quarks form a string which fragments, giving rise to hadronization in jets containing b-hadrons. The study is focused on the channel where the Higgs boson is produced in association with a gauge boson decaying leptonically H + W → b + lv and H + Z → b + ll and Higgs masses are in the range 115 − 140 GeV/c². The gauge bosons decay produces hard leptons quite often isolated from the b-jets. Hence an isolated lepton with high transverse momentum is required in order to reject the large QCD background.

The aim of this work is to explore the feasibility to observe Higgs-like particles at the LHCb experiment at CERN by exploiting the detector capabilities to identify b-jets.

In this work we study the Higgs sector in the minimal S₃ extension of the Standard Model. The S₃ extended Standard Model, which has three Higgs doublets fields that belong to the three-dimensional reducible representation of the permutation group S₃, has naturally new phenomena: there are several Higgs bosons, charged, neutral and pseuodscalar ones, and more than one potential minimum. We analyzed the stability of the minimal S3 invariant extension of the Higgs potential and show that at tree-level, the potential minimum preserving electric charge and CP symmetries, when it exists, is the global one.

We analyze a gauge-Higgs unification model which is based on a gauge theory defined on a six-dimensional spacetime with an S² extra-space. In our approach, we impose a symmetry condition for a gauge field and non-trivial boundary conditions of the S². We provide the scheme for constructing a four-dimensional theory from the six-dimensional gauge theory under these conditions. We then construct a concrete model based on an SO(12) gauge theory under the scheme. This model leads to a Standard-Model(-like) gauge theory which has gauge symmetry SU(3) × SU(2)_L × U(1)_Y (× U(1)²) and one generation of SM fermions, in four-dimensions. The Higgs sector of the model is also analyzed, and it is shown that the electroweak symmetry breaking and the prediction of W-boson and Higgs-boson masses are obtained.

Applying a novel non-perturbative functional method framework to a two-dimensional bosonic sigma model with tachyon, dilaton and graviton backgrounds we construct exact (non perturbative in the Regge slope α') inflationary solutions, consistent with world-sheet Weyl Invariance. The mechanism for inflation entails a (partial) 'alignment' between tachyon and dilaton backgrounds in the solution space. Some cosmological solutions which contain inflationary eras for a short period and interpolate between flat universes in the far past and far future are also discussed. These solutions are characterized by the absence of cosmological horizons, and therefore have well-defined scattering amplitudes. This makes them compatible with a perturbative string framework, and therefore it is these solutions that we consider as self-consistent in our approach. Within the context of the interpolating solutions, string production at the end of inflation (preheating) may also be studied. The advantage of our method is that the solutions are valid directly in four target-space-time dimensions, as a result of the non trivial dilaton configurations. Whether the model is phenomenologically realistic, with respect to its particle physics aspects, remains an open issue. This talk was based on work recently done with J. Alexandre and N. E. Mavromatos [1].

The Pauli exclusion principle (PEP) represents one of the basic principles of the modern physics. Even if there are no compelling reasons to doubt its validity, it still spurs a lively debate, because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. A new limit on the probability that PEP is violated by electrons was estabilished by the VIP (VIolation of the Pauli exclusion principle) Collaboration, using the method of searching for PEP forbidden atomic transitions in copper. The preliminary value, ½ β² <6 × 10^-29, represents an improvement of more than two orders of magnitude of the previous limit. The goal of VIP is to push this limit at the level of 10^-30.

The characterization of entanglement is a fundamental issue for Quantum Information Theory. But the definition of entanglement depends on the notion of locality, and thus on the tensor product structure of the state space of the composite system. This notion is affected by the presence of superselection rules that restrict the accessible Hilbert space to a direct sum of subspaces.

Indistinguishability of particles imposes one such restriction, namely to totally symmetric or totally antisymmetric states. The entanglement can in this case be defined with respect to partitions of modes in the second quantization formalism. For fermionic systems the Fock space of m modes is isomorphic to the space of m qubits, but the action of creation and annihilation operators is not local, due to their anticommutation.

Conservation of the parity of fermion number imposes another relevant superselection rule. It requires that local physical observables commute with the local parity operator.

Taking into account the considerations above, it is possible to define the set of separable states or equivalently the concept of entanglement for fermionic systems in a number of ways. Here we analyze systematically these possibilities and the relation among the various sets of separable states. We also discuss the behavior of the different classes when taking several copies of the state, as well as the characterization of the sets in terms of the usual criteria regarding the tensor product.

We show that a symmetry violation in particle physics is related to nonlocality of quantum mechanics. This adds a new puzzle to violation. Moreover, we discuss how the nonlocality may be tested in experiments and what more quantum features can be investigated in high energy physics.

We discuss an explicit realization of the dissipative dynamics anticipated in the proof of 't Hooft's existence theorem, which states that 'For any quantum system there exists at least one deterministic model that reproduces all its dynamics after prequantization'. – There is an energy-parity symmetry hidden in the Liouville equation, which mimics the Kaplan-Sundrum protective symmetry for the cosmological constant. This symmetry may be broken by the coarse-graining inherent in physics at scales much larger than the Planck length. We correspondingly modify classical ensemble theory by incorporating dissipative fluctuations (information loss) – which are caused by discrete spacetime continually 'measuring' matter. In this way, aspects of quantum mechanics, such as the von Neumann equation, including a Lindblad term, arise dynamically and expectations of observables agree with the Born rule. However, the resulting quantum coherence is accompanied by an intrinsic decoherence and continuous localization mechanism. Our proposal leads towards a theory that is linear and local at the quantum mechanical level, but the relation to the underlying classical degrees of freedom is nonlocal.

We apply non-extensive statistics, namely Tsallis statistics, on a case of supercritical string cosmology (SSC) as the one studied in [1] and obtain interesting cosmological modifications. At the beginning, we seek for the non-extensive corrections to the dilaton energy density and the off-shell (off-critical) terms and by using the set of dynamical equations of [1], we derive the modified evolution equation for the radiation energy density in a r.d.e. (radiation dominated era). This in fact is characterised by fractal ('exotic') scaling and this seems to be a generic result of our analysis. The modified Boltzmann equation was also considered, giving us the effects on dark matter candidates relic abundances of non-extensitivity besides the SSC effects. An effort to give a physical interpretation to the essential results of models such as the Tsallis statistical model has been done in collaboration with N. Mavromatos and S. Sarkar by using the D-particles foam model which is presented at the last part of this work.

In recent years, the breakdown of spacetime symmetries has been identified as a promising research field in the context of Planck-scale phenomenology. For example, various theoretical approaches to the quantum-gravity problem are known to accommodate minute violations of CPT invariance. This talk covers various topics within this research area. In particular, some mechanisms for spacetime-symmetry breaking as well as the Standard-Model Extension (SME) test framework will be reviewed; the connection between CPT and Lorentz invariance in quantum field theory will be exposed; and the a few experimental CPT tests with emphasis on matter–antimatter comparisons will be discussed.

Precision tests of the discrete symmetries T and CPT have been performed relying on large samples of clean events from e⁺e^- annihilations, which have been collected by the Belle and BABAR B-factories. In particular, large samples of coherently produced B-meson pairs have provided especially favorable conditions for testing the Standard Model predictions regarding indirect T and CPT violation in B-mixing. The most interesting and recent results are reported in the following.

Quantum gravity may involve models with stochastic fluctuations of the associated metric field, around some fixed background value. Such stochastic models of gravity may induce decoherence for matter propagating in such fluctuating space time. In most cases, this leads to fewer neutrinos of all active flavours being detected in a long baseline experiment as compared to three-flavour standard neutrino oscillations. We discuss the potential of the CNGS and J-PARC beams in constraining models of quantum-gravity induced decoherence using neutrino oscillations as a probe. We use as much as possible model-independent parameterizations, even though they are motivated by specific microscopic models, for fits to the expected experimental data which yield bounds on quantum-gravity decoherence parameters.

It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c = [1 ± (E/M_vQG1)] or [1 ± (E/M_vQG2)²], using data from supernova explosions and the OPERA long-baseline neutrino experiment.

The possible role of decoherence due to space-time foam is discussed within the context of two models, one based on string/brane theory. and the other based on properties of black hole horizons in general relativity. It is argued that the density matrix satisfies a dissipative master equation, primarily from the study of renormalization group flows in non-critical string theory. This interpretation of the zero mode of the Liouville field as time leads necessarily to the CPT operator being ill defined. One striking consequence is that the quantum mechanical correlations of pair states of neutral mesons produced in meson factories are changed from the usual EPR state. The magnitude of this departure from EPR correlations is characterised by a parameter ω. The predicted value of ω is very small or zero. However it is shown explicitly that the the non-vanishing of ω is only a feature of the model based on string/brane theory.

We present a model of gravity based on spontaneous Lorentz symmetry breaking. We start from a model with spontaneously broken symmetries for a massless 2-tensor with a linear kinetic term and a nonderivative potential, which is shown to be equivalent to linearized general relativity, with the Nambu-Goldstone (NG) bosons playing the role of the gravitons. We apply a bootstrap procedure to the model based on the principle of consistent coupling to the total energy energy-momentum tensor. Demanding consistent application of the bootstrap to the potential term severely restricts the form of the latter. Nevertheless, suitable potentials exists that permit stable vacua. It is shown that the resulting model is equivalent, at low energy, to General Relativity in a fixed gauge.

In this paper we first discuss the analysis regarding the role of Lorentz symmetry in the perturbative non-gravitational anomalies for a family of fermions, which has been recently performed in arXiv:0809.0184. The theory is assumed to be translational invariant, power-counting renormalizable and based on a local action, but is allowed to have general Lorentz violating operators, including those that break CPT. The main result is that Lorentz symmetry does not participate in the clash of symmetries that leads to the anomalies. Moreover, here we provide a simple semiclassical argument that shortly illustrates the origin of this fact.

We use the generalization of quantum theory for the case of non-Hermitian Hamiltonians with (C)PT symmetry to show how a classical cosmological model describes a smooth transition from ordinary dark energy to the phantom one. We consider the PT symmetric flat Friedmann model of two scalar fields with positive kinetic terms. The solution for the normal field is real while the solution for the second field is purely imaginary, realizing classically the 'phantom' behavior. The energy density and pressure happen to be real and the corresponding geometry is well-defined. The Lagrangian for the linear perturbations leads to positive energy densities for both the fields, so that the problem of stability does not arise. The phantom phase in the cosmological evolution appears to be transient and the Big Rip never occurs.

The Southern Pierre Auger Observatory is complete. Data have been taken since January 2004 while the array was being constructed, what amounts to more than 1 year of exposure with the full array. Results on the energy spectrum of UHECRs above 10¹⁸ eV measured with vertical and inclined showers are presented. Inclined showers are also used to search for ultra-high energy neutrinos, and a competitive limit on their diffuse flux for energies above ∼ 10¹⁷ eV has also been placed.

The Alpha Magnetic Spectrometer (AMS-02) on the International Space Station (ISS) is a large acceptance magnetic spectrometer aiming for high precision studies of cosmic rays in space. The experiment will address fundamental questions regarding primary antimatter and dark matter contents of the universe. In addition, the precise measurements of cosmic rays in a wide energy range will result in a greatly improved understanding of the cosmic ray propagation in the Galaxy. The detector is now in its final assembly stage at CERN (Geneva) and it will be shipped to KSC (Florida) for integration with the space shuttle Discovery before the end of 2009. The STS-134 mission, currently scheduled for launch in September 2010 will transport the experiment to the ISS where it will operate for a period of 3 to 5 years.

Very High Energy (VHE) gamma-ray astronomy is today a well established and successful discipline. Among the major imaging air Cherenkov telescopes in operation, MAGIC, a 17 m single dish telescope, has reached the lowest energy threshold. This unique feature has allowed the discovery of VHE gamma rays from 3C279, the farthest blazar detected in VHE, as well as the first observation of the VHE pulsed emission from the Crab pulsar. In addition a number of galactic and extra-galactic sources have been discovered or confirmed. Moreover, MAGIC has constrained limits of the quantum gravity mass scale, the extragalactic background light and gamma ray fluxes from dark matter annihilation. In 2009 a second 17 m telescope, MAGIC-II, will start operation. The stereoscopic observation mode will improve the angular and energy resolution, reducing the background at the same time. All this will improve the sensitivity of the instrument by more than a factor two.

The observation of high energy extraterrestrial neutrinos can be an invaluable source of information about the most energetic phenomena in the Universe. Neutrinos can shed light on the processes that accelerate charge particles in an incredibly wide range of energies both within and outside our Galaxy. They can also help to investigate the nature of the dark matter that pervades the Universe. The unique properties of the neutrino make it peerless as a cosmic messenger, enabling the study of dense and distant astrophysical objects at high energy. The experimental challenge, however, is enormous. Due to the weakly interacting nature of neutrinos and the expected low fluxes very large detectors are required.

In this paper we briefly review the neutrino telescopes under the Mediterranean Sea that are operating or in progress. The first line of the ANTARES telescope started to take data in March 2006 and the full 12-line detector was completed in May 2008. By January 2009 more than one thousand neutrino events had been reconstructed. Some of the results of ANTARES will be reviewed. The NESTOR and NEMO projects have made a lot of progress to demonstrate the feasibility of their proposed technological solutions. Finally, the project of a km³-scale telescope, KM3NeT, is rapidly progressing: a conceptual design report was published in 2008 and a technical design report is expected to be delivered by the end of 2009.

We add an energy-independent Hamiltonian to the standard flavour oscillation one. This kind of physics might appear in theories where neutrinos couple differently to a plausible non-zero torsion of the gravitational field or more dramatically in the presence of CPT-violating physics in the flavour oscillations. If this contribution exists, experiments at higher energies are more sensitive to their free parameters, and flavour conversion could be severely modified. We show that this new physics modifies the neutrino mixing angles and find expressions that relate the new, effective, angles to the standard oscillation parameters Δm²_ij, θ_ij and δ_{C P} and to the parameters in the new-physics Hamiltonian, within a three-neutrino formalism. We consider scenarios where the new parameters allow for extreme deviations of the expected neutrino flavour ratios at Earth from their standard values. We show that large departures of the standard flavour scenario are plausible, which would be a strong hint of the violation of a conserved symmetry.

Cosmological and astrophysical constraints on the mixings of sterile neutrinos are commonly much more stringent than the ones coming from laboratory searches. Within the standard cosmological picture, this mixing needs to be very small to prevent the cosmological overabundance of sterile neutrinos. We present here a scenario, based on a low reheating temperature T_RH << 100 MeV at the end of (the last episode of) inflation or entropy creation, and show that the production of sterile neutrinos becomes largely suppressed with respect to what happens in the standard framework. In this case, the dominant constraints come from laboratory measurements, which may render sterile neutrinos to be 'visible' in future experiments.

The KLOE experiment has concluded its data taking in March 2006, having acquired an integrated luminosity of 2.5 fb^_1 of e+e- collisions at the center of mass energy around the ø(1020) resonance. The complete data set includes a sample of 100 million η's produced through the radiative decay ø → ηγ and tagged by means of the monochromatic recoil photon. This huge amount of data allows to perform the first test of CP violation in η decays through the study of the rare η → π⁺π^-e⁺e channel, measuring the asymmetry between the π⁺π^- and the e⁺e^- decay planes in the η rest frame (_ϕ). Being this process flavor conserving, such an observation will point to unexpected mechanism of CP violation, thus providing an hint of new physics beyond the Standard Model. A study of the η→ π⁺π^-e⁺e^- decay based on a data sample of 1.7 fb^_1 will be presented. Electrons and pions are identified using both the time of flight to the calorimeter and the momentum of each track. Cuts on track momenta and on photon conversion on the beam pipe allow to significantly reduce the background, with a final 20% contamination. The analysis efficiency for the signal is 8%, dominated by geometrical acceptance. The final sample of about 1600 signal events, 100 times larger than today best measurement, is used to measure both the η→ π⁺π^-e⁺e^-(γ) branching fraction and the asymmetry _ϕ.

The KLOE experiment has provided precise measurements of the branching ratio of the main neutral and charged kaon decay modes, of the K_l and the K^± lifetimes, and of the K_l vector and scalar form factors. We present a description of the above measurements and an overall fit of all our data, with particular attention to correlations. These data provide the basis for the determination of the value of the CKM matrix element V_us and a test of the unitarity of the quark mixing matrix. In addition our first measurement of the charge asimmetry in K_S semileptonic decays, A_S, gaves us the possibility to contribute to the knowledge of () and testing the CPT symmetry through the Bell Steinberger relation.

In this paper the most recent Tevatron results concerning CP violation are reviewed. These are the measurements of direct CP asymmetry in the charmless two-body decays of B⁰, B⁰_s and A_b (performed by CDF), CP asymmetry in B⁺ → J/ψK* (performed by D0), the flavor-tagged measurement of B^0s semileptonic asymmetry, a^s_sl and the measurement of b_s in the decay B⁰_s→ J/ψϕ (performed by CDF and D0).

We begin with a brief presentation of the phenomenology of D⁰ − mixing. This is followed by a summary of experimental results in various final states. In particular, we will first describe the discovery of D⁰ − mixing by BaBar and Belle using two-body decay modes, and follow this with more recent studies in three-body decay modes. Finally, we will mention semileptonic searches for D⁰ − mixing and end with a summary of all experimental results.

An overview of the measurements of the Cabibbo-Kobayashi-Maskawa matrix elements at BABAR and Belle experiments is given in this talk. Recent results of |V_ub| and |V_cb| from exclusive and inclusive semileptonic B decays and of the ratio |V_td/V_ts| from radiative B decays are presented.

The NA62 experiment aims to measure the very rare kaon decay K⁺ → π⁺ν at the CERN SPS. The expected branching ratio has been recently estimated within the Standard Model to be (8.22 ± 0.84) × 10^-11. From the experimental side, 7 events has been found by E787/949 experiments at BNL providing a measurement of the branching ratio of (1.73^+1.15_-1.05) × 10^-10. The aim of NA62 is to collect ∼100 events in two years of data taking with a 10% background. A description of the setup and the R&D program is presented.

The LHCb experiment has been designed to perform precision measurements on CP asymmetries and rare decay searches of B mesons. The LHCb construction and installation has been finished early summer last year. The experiment is ready to exploit first data from CERN's Large Hadron Collider (LHC). The very first data collected with a minimal interaction trigger should allow the space alignment of the detector to be performed. Then, when energy and momentum scales have been calibrated, the particle identification will be commissioned. The trigger will also be commissioned ready for data-taking in 2010, when LHCb's nominal luminosity should be reached and the full physics programme deployed. First measurements comprise inclusive particle production, where final states containing a pair of oppositely charged muons (e.g. J/ψ production) will be isolated. We will report on the commissioning of the different subsystems performed with cosmic data and the few particle beams delivered by the accelerator last year and the progress made toward the first physics measurements.

The 10¹² B hadrons produced yearly at the LHCb interaction region will provide a unique opportunity for studying very rare B decays. Such processes occur via loops in the SM, and hence offer a high sensitivity to new physics through the effect of new particles in additional loops. At LHCb, many rare decay observables will allow either discovering new physics or constraining extensions of the SM. This article describes the LHCb potential on three of them. The first observable is the photon polarization in B_s→ϕ(→K⁺K^-)γ, which has not been measured yet. The second case considered are the angular distributions in B⁰→K*(→K⁺π⁻ μ⁺μ^- for which some studies have already been performed at the B factories. The third observable is the branching ratio of B_s→μ⁺μ^-. This extremely rare process is subject to large enhancements in many SUSY models, and it is potentially one of the first observables to be sensitive to new physics at the LHC.

We show that it is possible to accommodate the observed size of the phase in B_s⁰−_s⁰ mixing in the framework of a model with violation of 3 × 3 unitarity. This violation is associated to the presence of a new Q = 2/3 isosinglet quark T, which mixes both with t and c and has a mass not exceeding 500 GeV. The crucial point is the fact that this framework allows for χ ≡ arg(−V_tsV_cbV*_tbV*_cs) of order λ, to be contrasted with the situation in the Standard Model, where χ is constrained to be of order λ². We point out that this scenario implies rare top decays t→cZ at a rate observable at the LHC and |V_tb| significantly different from unity. In this framework, one may also account for the observed size of D⁰−⁰ mixing without having to invoke long distance contributions. It is also shown that in the present scenario, the observed size of D⁰−⁰ mixing constrains χ' ≡ arg(−V_cdV_usV_cs*V*_ud) to be of order λ⁴, which is significantly smaller than what is allowed in generic models with violations of 3 × 3 unitarity.

Hierarchical soft terms describe a class of supersymmetric theories in which the first two generations of squarks and sleptons are heavier than the rest of the supersymmetric spectrum. They make well-defined, interesting predictions as there are fewer free parameters than in the ordinary case of degenerate squarks and provide a characteristic correlation between ΔF = 1 and ΔF = 2 transitions. We study the constraints on the flavor-violating parameters and point out that values of the phase of B_s mixing larger than in the case of degenerate soft terms can be obtained.

The connection between B_s mixing phase and lepton flavor violation is studied in a supersymmetric SU(5) theory, in the light of the latest measurements thereof. The (1) phase, preferring a non-vanishing squark mixing, generically implies r→ (e + μ) γ and μ → eγ. In addition to the facts already well-known, stresses are put on the role of gaugino to scalar mass ratio at the GUT scale and the possible modifications due to Planck-suppressed non-renormalizable operators.

After a brief theoretical introduction of the warped extra-dimensional model with custodial protection the results of [1] are presented. In this work we analyze the impact of Kaluza-Klein (KK) gauge boson modes on ΔF = 2 observables, for the first time considering the full operator basis and including NLO renormalization group running. It is pointed out that the dominant contribution in the B-system does not come from the KK gluon, but that contributions from KK excitations of the weak gauge bosons are competitive. In a numerical analysis we assess the amount of fine-tuning necessary for obtaining realistic values for quark masses and mixings and at the same time realistic values for k, the measure for CP violation in K meson mixing. We are able to show that a mass of the lightest KK gauge boson of 2-3 TeV, and hence in the reach of the LHC, is still possible for moderate fine-tuning. These results enable us to make predictions for not yet measured ΔF = 2 observables, such as Sψπ and A₈^SL, which can differ significantly from their SM values.

We present a particular warped extra dimensional model, where the flavour diagonal and flavour non-diagonal Z boson couplings to left-handed down quarks are protected by the custodial symmetry P_lr. After a brief introduction of the model and of its main theoretical motivations, we present a complete study of rare K and B meson decays, including K⁺ → π⁺v, K_L → π⁰v, B_s,d → μ⁺μ^- and B_s,d → X_s,dv. In particular we restrict the parameter space of the model to the subspace which fits all quark masses, CKM mixing parameters and all the measured ΔF = 2 observables, keeping the Kaluza-Klein scale in the reach of LHC (∼ (2 — 3)TeV). There we show that, in addition to the one loop contribution of the Standard Model (SM), the dominating new physics contribution to the rare decays of K and B_s,d mesons is the tree level exchange of the Z boson of the SM governed by right-handed couplings to down-type quarks. In order to reduce the parameter dependence, we study correlations between various branching ratios of B and K mesons and between ΔF = 1 and ΔF = 2 observables. The patterns that we find allow to distinguish this new physics scenario from the SM and can offer an opportunity to future experiments to confirm or rule out the model.

Recent measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. This empirical data suggests the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I that gives mass to the Majorana neutrinos. We asssume that the similar mass hierarchies of charged lepton masses and quark masses allows one to represent all the mass matrices of Dirac fermions in terms of a four zeros Fritzsch texture.

The radiative correction as a commonly used methods of a comparison of the effects with different scales is known, for example, as Schwinger QED correction α/2π =1.15910^-3. It was found that the ratio between known Standard Model parameters m_μ/M_Z=1.159 10^-3 coincides with QED correction, while the lepton ratio m_μ/m_e=206.77 becomes integer 207.01 after small QED correction for the electron rest mass. We follow Nambu suggestion that empirical relations in particle masses could be useful for the SM-development and consider empirical relations in well-known particle masses, including top-quark and tau-lepton. Indirect confirmation of the tuning effects in particle masses was found in the analysis of nuclear data.

We have studied in a heavy ion storage ring at GSI Darmstadt, Germany, the time dependence of the orbital electron capture decays of H-like ¹⁴⁰Pr, ¹⁴²Pm, and ¹²²I ions and found that the electron capture rate is not purely exponential but in addition time modulated with periods of T= 7.o6(8) s, 7.10(22) s and 6.11(3) s for ¹⁴⁰Pr, ¹⁴²Pm and ¹²²I, respectively, measured in the laboratory system of the ions moving with 71% of speed of light (Lorentz factor γ= 1.43). The modulation amplitude is a= 0.20(3) in average for all three ions. Such modulation periods correspond to a small energy difference of 8.6x10^-16 eV, and 7.5x10^-16 eV, respectively, for a quantum beat type phenomenon. We attribute it to the mixing of massive electron neutrinos emitted in the decays with squared mass difference Δm² = 2.20(3) x10^-4 eV². It is about 2.9 times larger than latest value reported by the KamLAND antineutrino oscillation experiment.

The hypothesis of neutrino flavour changing in weak interaction representation via oscillations is confirmed by several experiments, all based on the observation of the disappearance of a given neutrino flavour. The direct appearance of a flavour different from the initial one, was never observed so far. OPERA is the first long baseline neutrino oscillation experiment employing nuclear emulsions for the direct observation of tau neutrinos in the CERN to Gran Sasso muon neutrino beam. At present the experiment is in the data taking phase. The number of detected neutrino interactions have exceeded one thousand. Experiment status and a summary of results from 2007 and 2008 runs is presented in this paper.

The Double Chooz reactor neutrino experiment will be the next detector to search for a non vanishing θ₁₃ mixing angle with unprecedented sensitivity, which might open the way to unveiling CP violation in the leptonic sector. The measurement of this angle will be based in a precise comparison of the antineutrino spectrum at two identical detectors located at different distances from the Chooz nuclear reactor cores in France. Double Chooz is particularly attractive because of its capability to measure sin² (2θ₁₃) to 3σ if sin² (2θ₁₃) > 0.05 or to exclude sin² (2θ₁₃) down to 0.03 at 90% C.L. for Δm² = 2.5 x 10^-3 eV² in three years of data taking with both detectors. The installation of the far detector started in May 2008 and the first neutrino interactions are expected in 2009. The advantages of reactor neutrino experiments to measure the θ₁₃ mixing angle are described in this article and in particular, the design, current status and expected performance of the Double Chooz detector.

Neutrinos, unlike the other fermions, could be Majorana particles, that is, truly neutral particles identical to their antiparticles. This would have deep consequences in particle physics and cosmology. A unique signature of Majorana neutrinos is the observation of neutrinoless double beta decays (ββ^0ν). The discovery of neutrino oscillations — which has shown that neutrinos have masses — and the possible evidence of a ββ^0ν signal in the Heildelberg-Moscow experiment have revolutionized the double beta decay comunity. A new generation of experiments with improved sensitivity is currently under design and construction. This paper reviews some of these proposals, with special emphasis in NEXT, that aims at building a 100-kg, high-pressure gas xenon TPC to be hosted in the new Canfranc Underground Laboratory (LSC), in Spain.

We model tri-bimaximal lepton mixing from first principles in a way that avoids the problem of the vacuum alignment characteristic of such models. This is achieved by using a softly broken A₄ symmetry realized with an isotriplet fermion, also triplet under A₄. No scalar A₄-triplet is introduced. This represents one possible realization of general schemes characterized by the minimal set of either three or five physical parameters. In the three parameter versions m_ee vanishes, while in the five parameter schemes the absolute scale of neutrino mass, although not predicted, is related to the two Majorana phases. The model realization we discuss is potentially testable at the LHC through the peculiar leptonic decay patterns of the fermionic and scalar triplets.

Assuming high-energy tri-bi-maximal mixing we study the radiative running of leptonic mixing angles and obtain limits on the high-energy scale from requiring consistency with the observed mixing. We construct a model in which a non-Abelian discrete family symmetry leads both to a quasi-degenerate neutrino mass spectrum and to near tri-bi-maximal mixing.

We present a formalism that provides a precise description of 2v oscillations in a medium with a symmetric but otherwise arbitrary density profile. The analytical expressions, derived in terms of the first and second order Magnus approximations of the evolution operator, prove to be remarkably simple and can be used in a wide interval of the neutrino energies. They incorporate in accurate way the matter effects on the flavor amplitudes for neutrinos crossing trough the Earth. When applied to calculations in the GeV regime characteristic of atmospheric and accelerator neutrinos, this accuracy is complemented by a good reproduction of the position of the maxima in the corresponding transition probabilities.

We present some recent results on the connection between leptogenesis and low energy observables in the framework of specific flavour structures for the fundamental leptonic mass matrices with zero textures.

We study the phenomenology of supersymmetric models that explain neutrino masses through the spontaneous breaking of R-parity, finding strong correlations between the decays of the lightest neutralino and the neutrino mixing angles. In addition, the existence of a Goldstone boson, usually called Majoron (J), completely modifies the phenomenology with respect to the standard picture, inducing large invisible branching ratios and charged lepton decays, like μ → eJ, interesting signals that can be used to constrain the model.

In minimal supergravity (mSugra), the neutrino sector is related to the slepton sector by means of the renormalization group equations. This opens a door to indirectly test the neutrino sector via measurements at the LHC. Concretely, for the simplest seesaw type-I, we present the correlations between seesaw parameters and ratio of stau lepton flavour violating (LFV) branching ratios. We find some simple, extreme scenarios for the unknown right-handed parameters, where ratios of LFV rates correlate with neutrino oscillation parameters. On the other hand, we scan the mSugra parameter space, for both seesaw type-I and II, to find regions where LFV stau decays can be maximized, while respecting low-energy experimental bounds. We estimate the expected number of events at the LHC for a sample luminosity of L = 100fb^-1.

The possible interplay in 'flavoured' leptogenesis between the 'low energy' CP violation originating from the PMNS neutrino mixing matrix U, and the 'high energy' CP-violation which can be present in the matrix of neutrino Yukawa couplings, λ, and can manifest itself only in 'high' energy scale processes, is discussed. The results reported are obtained for type I see-saw model with three heavy right-handed Majorana neutrinos having hierarchical spectrum. It is shown that in the case of inverted hierarchical light neutrino mass spectrum, there exist regions in the corresponding leptogenesis parameter space where the relevant 'high energy' phases have large CP-violating values, but the purely 'high energy' contribution in Y_b plays a sub-dominant role in the production of baryon asymmetry compatible with the observations.

We prove that taking correctly into account the lepton flavour dependence of the CP asymmetries and washout processes, it is possible to obtain successful thermal leptogenesis from the decays of the second right-handed neutrino. The asymmetries in the muon and tau-flavour channels are then not erased by the inverse decays of the lightest right-handed neutrino, N₁. In this way, we reopen the possibility of 'thermal leptogenesis' in models with a strong hierarchy in the right-handed Majorana masses that is typically the case in models with up-quark–neutrino Yukawa unification.

Effects of the lightest neutrino mass in 'flavoured' leptogenesis when the CP-violation necessary for the generation of the baryon asymmetry of the Universe is due exclusively to the Dirac and/or Majorana phases in the neutrino mixing matrix U are discussed. The type I see-saw scenario with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. The 'orthogonal' parametrisation of the matrix of neutrino Yukawa couplings, which involves a complex orthogonal matrix R, is employed. Results for light neutrino mass spectrum with normal and inverted ordering (hierarchy) are reviewed.

We consider variations of the standard leptogenesis picture arising from the presence of an additional scale related to the breaking of a U(1)_X abelian flavor symmetry. We show that quite generically the presence of an additional energy scale might introduce new qualitative and quantitative changes on leptogenesis. Especially interesting is the possibility of having succesful TeV leptogenesis with a vanishing total CP violating asymmetry. By solving the corresponding Boltzmann equations it is shown that these kind of scenarios encounters no difficulties in generating the Cosmic baryon asymmetry.

Lepton-flavor violating (LFV) decay in τ, B and γ(nS) is expected to be very small in the Standard Model, even taking into account the effect of neutrino mixing. Therefore, the observation of such decays would be a clear signal of new physics. The production rate of τ pairs at B factory is comparable to that of B meson pairs and hence B factories are also excellent τ factories. Many LFV decay modes have been searched for at the B factories. We present the current status of searches for tau LFV decays as well as B and γ(nS) LFV decays. Some of the upper limits are now reaching to a range predicted by some new physics models.

We present the experimental issues and discovery potentials for a fourth generation charge -1/3 quark decaying to a W and a top quark and for a right-handed W that decays to a lepton and a heavy neutrino, predicted by Left-Right-symmetric models. Both produce almost background-free final states containing multiple leptons and jets. The residual backgrounds and reach for each type of particle is presented for 100 pb^-1 of 14 TeV data.

A variety of lepton flavour violating effects related to neutrino oscillations and mixings will be systematically discussed in the framework of a minimal S₃-invariant extension of the Standard Model. After a brief review of some results on neutrino masses and mixings, we will give explicit analytical expressions for the matrices of the Yukawa couplings and the results of a computation of the branching ratios of some selected flavour-changing neutral current (FCNC) processes, as well as, the contribution of the exchange of neutral flavour-changing scalars to the anomaly of the magnetic moment of the muon, in terms of the masses of the charged leptons and the neutral Higgs bosons. It will also be shown that the S₃ × Z₂ flavour symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector and give a nearly tri-bimaximal neutrino mixing matrix. The contribution of the FCNCs to the anomaly of the magnetic moment of the muon is small but non-negligible.

The SUSY flavour problem is deeply related to the origin of flavour and hence to the origin of the SM Yukawa couplings themselves. Since all CP-violation in the SM is restricted to the flavour sector, it is possible that the SUSY CP problem is related to the origin of flavour as well. In this work, we present three variations of an SU(3) flavour model with spontaneous CP violation. Such models explain the hierarchy in the fermion masses and mixings, and predict the structure of the flavoured soft SUSY breaking terms. In such a situation, both SUSY flavour and CP problems do not exist. We use electric dipole moments and lepton flavour violation processes to distinguish between these models, and place constraints on the SUSY parameter space.

It is presented an analysis on lepton flavour violating transitions, leptonic magnetic dipole moments and electric dipole moments in a class of models characterized by the flavour symmetry A₄ x Z₃ x U(1)fn, whose choice is motivated by the approximate Tri-Bimaximal mixing observed in neutrino oscillations. A low-energy effective Lagrangian is constructed, where these effects are dominated by dimension six operators, suppressed by the scale M of new physics. All the flavour breaking effects are universally described by the vacuum expectation values (Φ) of a set of spurions. Two separate cases, a supersymmetric and a general one, are described. An upper limit on θ₁₃ of a few percent is concluded.

We present recent results of searches for leptoquarks with the DØ and CDF detectors at Tevatron. Leptoquarks are exotic bosons which would mediate lepton-quark interactions as predicted in multiple extensions of the Standard Model, among which supersymmetry. The DØ and CDF detectors have recorded about 5 fb^-1 of proton-antiproton collisions delivered by the Fermilab Tevatron collider. Operating at 1.96 TeV, the Tevatron remains at the energy frontier and is one of the best device to test theories beyond the Standard Model. A summary of the latest searches for leptoquarks with the DØ and CDF experiments is presented in this talk, corresponding to an integrated luminosity from 1 to 2.5 fb^-1.

The LHC will be a top quark factory, producing large numbers of top quarks even at the initial low luminosities. This will enable a rich program of top quark physics to be explored, both within the Standard Model and using top quarks as probes of physics beyond the Standard Model. Recent studies from ATLAS are presented, including prospects for the measurements of the production of top pairs and single top production, angular correlations in the top decay, and the precision measurement of the top quark mass. The search for physics beyond the Standard Model will be illustrated with searches for rare top decays involving Flavour Changing Neutral Currents, and the reconstruction of t resonances resulting from new heavy particles in various models.

The study of the associated production of weak vector bosons at the LHC allows to search for New Physics through the measurement of possible deviations of the weak boson self-couplings from the expectation within the Standard Model. The sensitivity of the ATLAS experiment to Standard Model diboson (W⁺W^-, W^plusmn;Z⁰, Z⁰Z⁰, W^± γ, and Z⁰ γ) production in pp collisions at = 14 TeV, using final states containing electrons, muons and photons, is presented. These studies use Monte Carlo data sets with full detector simulation from the ATLAS Computer System Commissioning, which furthermore include detailed trigger information as well as effects of detector calibration and alignment corrections. The influence of backgrounds on diboson detection is assessed using large samples of fully simulated background events. The sensitivity of the ATLAS experiment to anomalous triple gauge boson couplings is determined. Even for small integrated luminosities (about 0.1 fb^-1) the sensitivity to anomalous triple gauge boson couplings can be significantly improved by ATLAS, when comparing to results from the Tevatron that use 1.0 fb^-1 of data.

The search for Supersymmetry (SUSY) among the possible scenarios of new physics is one of the most relevant goals of the ATLAS experiment running at CERN's Large Hadron Collider. In the present work the expected prospects for discovering SUSY with the ATLAS detector are reviewed, in particular for the first fb^-1 of collected integrated luminosity. All studies and results reported here are based on inclusive search analyses realized with Monte Carlo signal and background data simulated through the ATLAS apparatus.

In certain Supersymmetry (SUSY) breaking scenarios, characteristic signatures can be expected which would not necessarily be found in generic SUSY searches for events containing high-pT multi-jets and large missing transverse energy. In this document, the expected response of the ATLAS detector to signatures involving high-pT photons which may or may not appear to point back to the primary collision vertex and long-lived charged sleptons and R-hadrons is presented. Such processes often have the advantage of small Standard Model backgrounds and their observation could provide unique constraints on the different SUSY breaking scenarios. Using these signatures, discovery potentials are estimated for either Gauge-Mediated Supersymmetry Breaking or Split-Supersymmetry scenarios. These studies have been performed using Monte Carlo samples of SUSY and background processes corresponding to integrated luminosity of about 1 fb^-1 and = 14TeV.

Models with compactified extra space dimensions offer a new way to address outstanding problems in and beyond the Standard Model. In these models, the strength of gravity is strongly increased at small distances, which opens up the possibility of observing quantum gravity effects in the TeV energy range reachable by the LHC. One of the most spectacular phenomena would be the production of microscopic black holes. Searches for black holes are foreseen in the ATLAS experiment with the start-up of data taking in 2009. We present feasibility studies for the triggering, selection and reconstruction of the black hole event topologies, the black hole discovery potential and their identification.

A possible solution to the hierarchy problem is the presence of extra space dimensions beyond the three ones which are known from our everyday experience. The phenomenological ADD model of large extra-dimensions predicts a E_T^miss +jet signature. Randall-Sundrum-type extra-dimensions predict di-lepton and di-jet resonances. This contribution addresses an overview of experimental issues and discovery potential for these new particles at the LHC, focusing on perspectives with the CMS detector during early data taking.

With the next start of LHC, a huge production of top quarks is expected. There are several models that predict the existence of heavy colored resonances decaying to top quarks in the TeV energy range. A peak in the differential cross section could reveal the existence of such a resonance, but this is experimentally challenging, because it requires selecting data samples where top and antitop quarks are highly boosted. Nonetheless, the production of such resonances might generate a sizable charge asymmetry of top versus antitop quarks. We consider a toy model with general flavour independent couplings of the resonance to quarks, of both vector and axial-vector kind. The charge asymmetry turns out to be a more powerful observable to detect new physics than the differential cross section, because its highest statistical significance is achieved with data samples of top-antitop quark pairs of low invariant masses.

When the mass difference between the lightest slepton and the lightest neutralino is smaller than the tau mass, the lifetime of the lightest slepton in the constrained Minimal Supersymmetric Standard Model (MSSM) increases in many orders of magnitude with respect to typical lifetimes of other supersymmetric particles. In a general MSSM, the lifetime of the lightest slepton is inversely proportional to the square of the intergenerational mixing in the slepton mass matrices. Such a long-lived slepton would produce a distinctive signature at LHC and a measurement of its lifetime would be relatively simple. Therefore, the long-lived slepton scenario offers an excellent opportunity to study lepton flavour violation at ATLAS and CMS detectors in the LHC and an improvement of the leptonic mass insertion bounds by more than five orders of magnitude would be possible.

We study the supersymmetric type-II seesaw model assuming minimal supergravity boundary conditions. We calculate branching ratios for lepton flavour violating (LFV) scalar tau decays, potentially observable at the LHC, as well as LFV decays at low energy, such as l_i → l_j + γ and compare their sensitivity to the unknown seesaw parameters. In the minimal case of only one triplet coupling to the standard model lepton doublets, ratios of LFV branching ratios can be related unambigously to neutrino oscillation parameters. We also discuss how measurements of soft SUSY breaking parameters at the LHC can be used to indirectly extract information of the seesaw scale.

In the Minimal Supersymmetric Standard Model, physical phases of complex parameters lead to CP violation. We show how triple products of particle momenta or spins can be used to construct asymmetries, that allow us to probe these CP phases. To give specific examples, we discuss the production of neutralinos at the International Linear Collider (ILC). For the Large Hadron Collider (LHC), we discuss CP asymmetries in squark decays, and in the tri-lepton signal. We find that the CP asymmetries can be as large as 60%.

All-loop Finite Unified Theories (FUTs) are very interesting N=1 GUTs in which a complete reduction of couplings has been achieved. FUTs realize an old field theoretical dream and have remarkable predictive power. Reduction of dimensionless couplings in N=1 GUTs is achieved by searching for renormalization group invariant (RGI) relations among them holding beyond the unification scale. Finiteness results from the fact that there exists RGI relations among dimensionless couplings that guarantee the vanishing of the β-functions in certain N=1 supersymmetric GUTS even to all orders. Furthermore, developments in the soft supersymmetry breaking sector of N=1 GUTs and FUTs lead to exact RGI relations also in this dimensionful sector of the theories. Of particular interest for the construction of realistic theories is a RGI sum rule for the soft scalar masses holding to all orders.

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, leading to a large reduction in the number of free parameters. We confront the predictions of SU(5) FUTs with the top and bottom quark masses, which allows us to discriminate among different models. We include further low-energy phenomenology constraints, such as B physics observables, the bound on the SM Higgs mass and the cold dark matter density, and then are able to make predictions for the lightest Higgs boson mass and the sparticle spectrum.

Heavy flavor physics measurements, in particular B and τ physics results from the B Factories, currently provide strong constraints on models of physics beyond the Standard Model. SuperB, a next generation asymmetric collider with 50 to 100 times the luminosity of existing colliders, can, in a dialog with LHC and ILC, provide unique insights into New Physics phenomena seen at those machines.

We are preparing a major upgrade of the KEKB electron-positron collider, the Super KEK B factory (SuperKEKB) – a project that could detect new phenomena arising from physics beyond the Standard Model by using a large amount of data, corresponding to the integrated luminosity of 50 ab^-1. This data set will allow studies of rare processes in B meson decays, D meson decays and τ lepton decays with an unprecedented sensitivity. To achieve the goal of this ambitious project, the design luminosity of the SuperKEKB is 8 ∣ 10³⁵ cm^-2s^-1 – 50 times larger than that of the present KEKB collider. The current Belle detector will also be upgraded to take a full advantage of the high collider luminosity. The new detector, SuperBelle, is designed in such a way that it should perform at least as well as the present Belle spectrometer, despite the substantial increase in beam-induced backgrounds.

By the end of 2009 the KLOE-2 detector is expected to start data taking at the improved DAϕNE ψ-factory of the Laboratori Nazionali di Frascati of INFN. The KLOE-2 physics program is wide, spanning from studies on neutral kaon quantum interferometry, to precise tests of lepton flavour violation, to low energy QCD studies.

In this paper, the status of the project is described. Some more attention is given to the contribution of KLOE-2 to the study of discrete symmetries conservation/violation.

Looking towards first LHC collisions, the ATLAS detector is being commissioned using all types of physics data available: cosmic rays and events produced during a few days of LHC single beam operations. In addition to putting in place the trigger and data acquisition chains, commissioning of the full software chain is a main goal. This is interesting not only to ensure that the reconstruction, monitoring and simulation chains are ready to deal with LHC physics data, but also to understand the detector performance in view of achieving the physics requirements. The status of the integration of the complete software chain will be presented as well as the data analysis results.

This article gives an overview of the trigger system of the CMS experiment. The unprecedentedly high luminosity at the LHC and the expected complexity of the data produced in collisions represents a formidable challenge for the design of a trigger system. Here we outline the approach taken by the CMS experiment to meet the goals of high trigger efficiencies at reasonable processing time and cost. The challenges to detect physics beyond the standard model are highlighted as well as the strategies that have been developed to these challenges.

A model independent analysis approach in CMS is presented, systematically scanning the data for deviations from the Monte Carlo expectation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Furthermore, due to the minimal theoretical bias this approach is sensitive to a variety of models of new physics, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving Supersymmetry and new heavy gauge bosons are used as an input to the search algorithm.

To do precise CP violation measurements, the best possible determination of the flavour of the B-meson is necessary. This report summarizes the flavour tagging performances for the LHCb experiment. The flavour tagging is obtained through a combination of several methods, based on different signatures. The use of control channels, which are decays to flavour-specific final states, will allow to determine the wrong tag fraction ω (the probability of a tag to be wrong), which can be used as an input for the determination of CKM unitarity triangle angles.