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Recently, a large statistics sample of approximately 3 × 10⁷η decays was collected with the Wide Angle Shower Apparatus (WASA) detector at COoler SYnchrotron (COSY) using the pd → ³Heη reaction at the proton kinetic energy of 1 GeV. These data are being used to study the not so rare η decays involving charged pions, such as η → π⁺π⁻π⁰. This decay proceeds mainly via a strong isospin violating contribution, where the decay width is proportional to the light quark mass difference squared, (m_d − m_u)². The status of the analysis is presented, which preliminarily gives 1.8 × 10⁵η → π⁺π⁻π⁰ candidates in the Dalitz plot.

We have studied the three-particle decay of ¹²C, ⁹Be and ⁶Be resonances. These nuclei have been described as three-body systems by means of the complex scaled hyperspherical adiabatic expansion method. The short-distance part of the wave function is responsible for the energies, whereas the information related to the observable decay properties is contained at large distances, which must be computed accurately. As an illustration we show the results for the angular distribution of ⁹Be and ⁶Be resonances.

An experimental technique combining the well-established α/p–decay–recoil–tagging method with a differential plunger has recently been successful in producing results in the neutron-deficient region near ¹⁰⁰Sn. This experimental technique is briefly presented here and the result of a recent measurement for ¹⁰⁸Te is put in the context of the systematics of B(E2) values for the Te and Sn isotopic chains. New state-of-the-art shell-model calculations are presented for the Sn data, and possible explanations for the unusually large B(E2) values for the Sn isotopes near the N = 50 shell closure are given.

A micromegas detector with a segmented anode in two orthogonal directions, equipped with a neutron/charged particle converter, was developed by a joint effort at CEA and CERN. This 'XY-micromegas' allows the determination of a neutron beam image on an area of 6×6 cm² with a spatial resolution of 0.5 mm as a function of neutron time of flight (n_TOF). The experimental results collected in three years of operation at the n_TOF facility are summarized together with a comparison with simulations performed by means of the FLUKA code.

Neutron-induced fission cross section measurements of ²³³U, ²⁴³Am and ²⁴¹Am relative to ²³⁵U have been carried out at the neutron time-of-flight facility n_TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference ²³⁵U target are subject to the same neutron beam.

The PANDA detector will be installed at FAIR to enterprise a long-term, wide-spectrum physics program in the strong interaction framework. The detector will be installed at the HESR accumulation ring, which will provide an anti-proton beam of unprecedented luminosity and momentum definition. The beam will interact with an internal target. The detector has been designed to allow a 4π coverage around the interaction region. Due to the relatively high energy of the beam, up to 15 GeV, PANDA will feature two magnetic spectrometers: the target spectrometer (TS), with a superconducting solenoid and covering the interaction region, and a forward spectrometer (FS), with a normal-conducting dipole and covering the small angles region. Since the physics program is wide and the requirements on the various subsystems are different, the detector has been designed to be as flexible as possible. The complete detector will be described in detail, both from the viewpoint of the proposed techniques and from the viewpoint of the expected performances. An overview of the status of various components of the detector will be presented, too.

Atomic layer deposition coatings are under investigation to reduce the diffusion of radioxenon into plastic scintillators. This paper investigates the impact of such surface coating on the light collection efficiency in a cylindrical geometry. A high and uniform light collection efficiency is important to preserve detector resolution. Monte Carlo simulations and measurements have been carried out to study the influence of coating thickness, refractive index and surface quality. It was found that it is important to achieve a smooth coating and good optical match between the refractive indices of the coating and the plastic scintillator. Taking into account these considerations, the detector under study could be coated without a significant degradation of its resolution.

The level ordering in the unbound nucleus ¹³Be is firmly established by using a time-dependent projectile fragmentation model, comparing to experimental data and using structure inputs obtained from a semi-phenomenological core-vibration coupling model of two-neutron halo nuclei. Thus, from the shell ordering, the neutron–core interaction is determined, which is needed by any three-body model of Borromean nuclei. As a consistency test, we show that the energy spectra of some beryllium isotopes obtained using the particle–particle random phase approximation predict the same shell ordering as those extracted from the reaction model versus data analysis.

The ³He(α, γ)⁷Be reaction plays a crucial role both in primordial nucleosynthesis and in the pp-chains of hydrogen burning in main-sequence stars like our Sun. Existing experimental data for the ³He(α, γ)⁷Be cross section show a significant discrepancy at high energies, which results in a serious uncertainty in the cross-section extrapolations to low, astrophysical energies. Therefore, high-energy experimental data are clearly needed to resolve this discrepancy. A new experimental program has been started at ATOMKI to measure this reaction cross section with the activation technique. Some details of this ongoing experiment are presented here.

Nuclear structure studies far from stability, which mainly rely on the availability of radioactive nuclear beams, can complementarily be addressed by means of high-intensity beams of stable ions. In such a context, deep-inelastic and multi-nucleon transfer reactions are a powerful tool to populate yrast and non-yrast states in neutron-rich nuclei. Particularly successful here is the combination of large acceptance spectrometers with highly segmented γ-detector arrays. Such devices can provide the necessary channel selectivity to identify very rare signals. Examples are the CLARA and AGATA γ-ray detector arrays coupled with the PRISMA spectrometer at the Legnaro National Laboratories (LNL) in Italy. Large data sets have been collected at LNL for nuclei close to the N=20, 28, 40, 50 and 82 shell closures as well as in new regions of deformation such as, for example, at A=60. Here I will shortly review some recent results.

The ²⁷Al(¹²C,¹¹B)²⁸Si reactions have been studied at 73, 81 and 85 MeV to extract spectroscopic factors for the ground (0⁺), first (2⁺) and second (4⁺) excited states of ²⁸Si using a transfer reaction. The elastic scattering angular distributions have been fitted using the computer code ECIS94, and finite range distorted-wave Born approximation calculations have been performed using DWUCK5. The extracted spectroscopic factors are compared with shell model calculations.

In this work, we present recent shell model calculations, based on a realistic nucleon–nucleon interaction, for the light ^{107, 109}Sn nuclei. By combining the calculations with the semi-classical Coulomb excitation code GOSIA, a set of γ-ray intensities has been generated. The calculated intensities are compared with the data from recent Coulomb excitation studies in inverse kinematics at the REX-ISOLDE facility with the nucleus ¹⁰⁷Sn. The results are discussed in the context of the ordering of the single-particle orbits relative to ¹⁰⁰Sn.

A detailed experimental study of the ⁶²Zn nucleus was conducted by combining the data sets from four fusion–evaporation reaction experiments. Apart from the previous published data, the present results include ten new rotational band structures and two new superdeformed bands. The GAMMASPHERE Ge-detector array in conjunction with the 4π charged-particle detector array Microball allowed for detection of γ-rays in coincidence with evaporated light particles. The deduced level scheme includes some 260 excited states, which are connected with 450 γ-ray transitions. The multipolarities have been assigned via directional correlations of γ-rays emitted from oriented states. The experimental characteristics of the rotational bands are analyzed and compared with the results from the cranked Nilsson–Strutinsky calculations.

Quantum chromodynamics (QCD) is the theory of the strong interaction, but the properties of hadrons cannot be directly calculated from the QCD Lagrangian. Alternative approaches are then used: lattice QCD, effective field theories, chiral dynamics and the constituent quark models. To test these different approaches, precise measurements of hadron properties are of extreme importance. This is the main motivation for the hadron spectroscopy experimental programme which has been carried out over many years with different probes and different detectors. A survey of the most recent results in the field is presented and commented on with some hints on the opportunities offered by forthcoming experimental programmes.

The collision of ¹³⁶Xe with a proton and with ¹²C at 1 GeV per nucleon has been studied in inverse kinematics with the SPALADIN setup at GSI. The detection in coincidence of the final state fragments (projectile residues, neutrons and Z ⩾ 2 charged fragments) with a large geometrical efficiency is provided by the inverse kinematics combined with a large-aperture dipole magnet and large detectors. Such a coincidence, measured on an event basis, allows us to select the excitation energy of the prefragment formed after the nuclear cascade and study its different de-excitation channels such as evaporation of light particles, asymmetric binary decay or multifragmentation. After a short summary of spallation reactions modeling, followed by the description of the setup, some preliminary results will be shown including the cross-sections of the reaction on the proton, compared in particular to other measurements as well as the cross-sections for the various fragment multiplicities. In the last section, we explain our method for the selection of the prefragment excitation energy and give a hint of the variables available in our experiment to study the excitation energy dependence of the prefragment de-excitation mechanism for both reactions.

Measuring the lifetimes of excited nuclear states provides direct information on electromagnetic transition rates and on the collectivity of nuclear excitations. The recoil distance Doppler-shift (RDDS) method is a well-established technique for measuring picosecond lifetimes of excited states, which has been extensively used in combination with fusion-evaporation reactions to measure lifetimes in neutron-deficient nuclei. Here we discuss novel ways of combining the RDDS technique with multi-nucleon transfer and fusion–fission reactions, which allow measurement of picosecond lifetimes in neutron-rich nuclei. Experiments were performed at both GANIL and Legnaro National Laboratories (LNL) with the goal to investigate the onset of collectivity around ⁶⁸Ni and the evolution of shapes and shape coexistence in medium-heavy fission fragments.

The NFS (Neutrons For Science) facility is part of the SPRIAL 2 project at GANIL, Caen, France. The facility is currently under construction and the first beam is expected in early 2013. NFS will have a white neutron source covering the 1–40 MeV energy range with a neutron flux higher than comparable facilities. A quasi-mono-energetic neutron beam will also be available. In these energy ranges, especially above 14 MeV, there is a large demand for neutron-induced data for a wide range of applications involving dosimetry, medical therapy, single-event upsets in electronics and nuclear energy. Today, there are a few or no cross section data on reactions such as (n, fission), (n, xn), (n, p), (n, d) and (n, α). We propose to install experimental equipment for measuring neutron-induced light-charged particle production and fission relative to the H(n, p) cross section. Both the H(n, p) cross section and the fission cross section for ²³⁸U are important reference cross sections used as standards for many other experiments. Nuclear data for certain key elements, such as closed shell nuclei, are also of relevance for the development of nuclear reaction models. Our primary intention is to measure charged particle production (protons, deuterons and alphas) from ¹²C, ¹⁶O, ²⁸Si and ⁵⁶Fe and neutron-induced fission cross sections from ²³⁸U and ²³²Th.

The role of superfluidity in incompressibility is studied in nuclear matter and finite nuclei. Pairing has a weak effect on nuclear matter incompressibility at saturation density, but the effects are strong at lower densities. The pairing effect on the centroid energy of the isoscalar Giant Monopole Resonance (GMR) is also evaluated by using a microscopic constrained-Hartree–Fock Bogoliubov approach. The measurement of the GMR in isotopic chains including unstable nuclei is useful for the determination of nuclear incompressibility.

The ⁸Li(α,n)¹¹B reaction at the center-of-mass E_cm=0.3–2 MeV is of key importance in nuclear astrophysics, as it is a possible channel to bypass the A=8 mass gap during the primordial nucleosynthesis and a viable path leading to the production of seed nuclei for the r-process in core-collapse supernovae. From a comparison of the total cross section, given by the ¹¹B- and n-inclusive measurements, with the threshold-affected n −¹¹B-exclusive data, the branching ratios for the ¹²B→¹¹B+n decay to different ¹¹B excited states were evaluated. This allowed us to draw interesting conclusions on the nuclear structure and clustering of ¹²B and to extrapolate the cross section down to the energy region of interest for the big-bang nucleosynthesis.

The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyväskylä, has been supplied with a new cyclotron which will provide proton or deuteron beams of the order of 100 μA with up to 30 MeV energy. This makes it an ideal place for measurements of neutron-induced fission fragments from various actinides, in view of proposed future nuclear fuel cycles. In the present paper, some considerations for the design of a neutron converter, based on simulations with the Monte Carlo codes MCNPX and FLUKA, are described.

We study hot and dense hadronic matter by means of an effective relativistic mean-field model with the inclusion of the full octet of baryons, the Δ-isobar degrees of freedom and the lightest pseudoscalar and vector mesons. These last particles are considered by taking into account an effective chemical potential and an effective mass depending on the self-consistent interaction between baryons. The analysis is performed by requiring the Gibbs conditions on the global conservation of baryon number, electric charge fraction and zero net strangeness.

Within the framework of the cluster-tunneling model, a folded α-core potential that is based on the Woods–Saxon potential is proposed to investigate α-decays in the superheavy mass region. The calculated α-decay half-lives of even–even superheavy nuclei from Z = 100 to Z = 116 are in reasonable agreement with the experimental data.

Effects related to the neutron to proton ratio (N/Z) degree of freedom in nuclear collisions ⁴⁰Ca + ⁴⁰Ca, ⁴⁰Ca + ⁴⁸Ca and ⁴⁸Ca + ⁴⁸Ca at 25 MeV per nucleon, analyzed by means of the Chimera multi-detector, have been investigated. Strong isotopic effects are found in mass distributions of light isotopes. Moreover, the competition between various reaction mechanisms at semi-central impact parameters seems to be influenced by the neutron richness of the total system formed.

We describe the neutron Cooper pair, the pair vibrational states and the associated two-neutron transfer strength by applying the Skyrme–Hartree–Fock–Bogoliubov mean-field model and the quasiparticle random phase approximation to neutron-rich Sn isotopes. The wave function of the Cooper pair exhibits a strong spatial correlation favoring short relative distances smaller than a few fm, in contrast to the case of the single-j Cooper pair. The model also predicts an anomalous pair vibration in neutron-rich isotopes beyond the N = 82 magic number, which originates from the weak binding of the last neutrons.

For the sustainable development of nuclear energy, the handling of used nuclear fuel is a key issue. Innovative fuel cycles are being developed for the transmutation of minor actinides and long-lived fission products. In view of these developments, accurate knowledge of the fuel inventory is necessary. The IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyväskylä, will be used to measure independent fission yield distributions from neutron-induced fission on different actinides. In this paper, an analysis tool is developed, using the CERN-based ROOT Data Analysis Framework, with the objective of performing full data analysis within the same code. The analysis tool is currently being tested on the data from measurements with 25 MeV protons on a ²³²Th target, and some preliminary results are presented.

We present a new model for describing the dynamics of an incomplete fusion reaction, concentrating on the basic ideas. Calculated α-particle spectra for the ¹²C + ¹¹⁸Sn reaction are compared to the experimental data.

Precision measurements in nuclear β decay provide a sensitive means of searching for new physics beyond the standard electroweak model. This paper reviews the status of selected precision measurements of correlation observables in nuclear and neutron β decay and discusses the prospects and future plans.

One of the major problems in nuclear astrophysics concerns the estimation of electron screening effects on nuclear reaction rates. We have proposed investigating the electron screening effects of nuclear systems which decay via α-particles, using fragmented beams at relativistic energies produced at the present GSI FRS-ESR facility. By looking at the modification of the half-lives and Q_α-value of highly charged emitters, we expect to estimate the electron screening energies.

We address the question of whether it is possible to interpret the low-lying scalar mesons f₀(600) and a₀(980) as states within a U(3)×U(3) linear sigma model containing vector and axial-vector degrees of freedom.

We describe the 'islands of inversion' that occur when approaching the neutron drip line around the magic numbers N=20, N=28 and N=40 in the framework of the interacting shell model in very large valence spaces. We explain these configuration inversions (and the associated shape transitions) as the result of the competition between the spherical mean field (monopole) that favors magicity and the correlations (multipole) that favor deformed intruder states. We also show that the N=20 and N=28 islands are in reality a single one, which for the magnesium isotopes is limited by N=18 and N=32.

The seniority scheme has been shown to be extremely useful for the classification of nuclear states in semi-magic nuclei. The neutron–proton (np) correlation breaks the seniority symmetry in a major way. As a result, the corresponding wave function is a mixture of many components with different seniority quantum numbers. In this paper, we show that the np interaction may favor a new kind of coupling in N=Z nuclei, i.e. the so-called isoscalar spin-aligned np pair mode. Shell model calculations reveal that the ground and low-lying yrast states of the N=Z nuclei ⁹²Pd and ⁹⁶Cd may be mainly built upon such spin-aligned np pairs, each carrying the maximum angular momentum J=9 allowed by the shell 0 g_9/2 which is dominant in this nuclear region.

Recently, we applied, for the first time, the angular momentum and isospin-projected nuclear density functional theory to calculate isospin-symmetry breaking (ISB) corrections to superallowed β-decay. With the calculated set of ISB corrections, we found that |V_ud|=0.97447(23) for the leading element of the Cabibbo–Kobayashi–Maskawa matrix. This is in good agreement with both the recent result of Towner and Hardy (2008 Phys. Rev. C 77 025501) and the central value deduced from the neutron decay. In this paper, we extend our calculations of the ISB corrections covering all superallowed transitions A, I^π=0⁺, T=1, T_z→A, I^π=0⁺, T=1 and T_z+1 where T_z=− 1, 0, and A ranges from 10 to 74.

A recently developed novel method for calculating fission-fragment mass distributions is discussed. It treats the nuclear shape evolution as Brownian motion and in its simplest form performs random walks on previously calculated five-dimensional potential-energy surfaces. Remarkably good reproduction of experimentally measured data is obtained without introduction of any new parameters.

Neutron-rich Co isotopes from N = 34 to 40 were studied through multinucleon transfer by bombarding a ²³⁸U target with a 460 MeV ⁷⁰Zn beam at the Legnaro National Laboratories. Gamma-recoil coincidences were recorded identifying the ions by using a high-acceptance magnetic spectrometer (PRISMA) and detecting the gamma radiation by using an array of HPGe clover detectors (CLARA). The results are discussed in comparison with the predictions of large-scale shell-model calculations.

For more than 20 years, relativistic energy density functionals have been used in nuclear physics. Technically more complicated, they have some essential advantages compared to the much older non-relativistic functionals.

The aim of the COMPASS hadron program is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the SPS at CERN and features a two-stage spectrometer with high momentum resolution, large acceptance, particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with J^PC=1⁻⁺ consistent with the debated π₁(1600). In addition, Coulomb production at low momentum transfer data provide a test of chiral perturbation theory. During 2008 and 2009, a world leading data set was collected with the hadron beam, which is currently being analysed. The large statistics allows for a thorough decomposition of the data into partial waves. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of quantum chromodynamics.

One of the missing keys in the present understanding of the spin structure of the nucleon is the contribution from the gluons: the so-called gluon polarization. This quantity can be determined in deep inelastic scattering (DIS) through the photon–gluon fusion process, in which two analysis methods may be used: (i) identifying open charm events or (ii) selecting events with high-transverse-momentum (high-p_T) hadrons. The data used in the present work were collected in the COMPASS experiment, where a 160 GeV/c naturally polarized muon beam, impinging on a polarized nucleon fixed target, is used. Preliminary results for the gluon polarization from high-p_T and open charm analyses are presented. The gluon polarization result for high-p_T hadrons is divided, for the first time, into three statistically independent measurements at leading order (LO) in quantum chromodynamic (QCD). The result from open charm analysis is obtained at LO and next-to-leading order in QCD. In both analyses a new weighted method based on a neural network approach is used.

In the abundance spectrum of r-process nuclei the most prominent features are the peaks that form when the r-process flow passes through the closed neutron shells. However, there are also other features in the abundance spectrum that cannot be explained by shell effects; for example, the peak in the region of the rare-earth nuclei around mass A=160. It has been argued that this peak is related to the deformation maximum of the neutron-rich isotopes. In recent years, both experimental and theoretical work has been carried out to study the deformation of neutron-rich rare-earth nuclei and to search for the point of maximum deformation. This work has focused on the nuclei around ¹⁷⁰Dy with the aim of understanding the evolution of collectivity in the neutron shell with 82<N<126. These investigations will be discussed in terms of the Harris parameters of the variable moment of inertia model. Finally, we will discuss the possibility of reaching further into the neutron-rich rare-earth region in the future at the new experimental facilities using radioactive beams.

Neutrinoless double-beta (0νββ) decay of nuclei is a process that requires the neutrino to be a massive Majorana particle and thus cannot proceed in the standard model of electro-weak interactions. The 0νββ decay takes place in atomic nuclei where it can be observed, at least in principle, by underground neutrino experiments. This work touches a special topic of the 0νββ decay, namely the emerging field of experimental and theoretical studies of the resonant neutrinoless double electron-capture decay of an atomic nucleus.

The progress within atomic and nuclear physics relies on refining and adding new observables. One of these is the polarization of the nuclear spin, where there is a manifest interest in accessing a wide variety of polarized beams, e.g. at energies suitable for Coulomb excitation and transfer experiments. In particular, exotic nuclei with half-lives considerably less than one second are difficult to produce, but the issues present in traditional methods could be overcome by using the tilted foils technique. Two setups for measuring the degree of polarization of an ion beam after the REX-ISOLDE linear accelerator at CERN are being evaluated. An approach based on Coulomb excitation has been utilized in an experiment and preliminary results will be presented. Furthermore, a β-NMR setup is currently under construction that will take radioactive beams soon.

In this paper, we describe a measurement of the ¹⁹Ne half-life with high precision (∼0.05%) and accuracy. We also obtain data from the same experiment to extract the 1/2⁺ → 1/2⁺ branch for this isospin T = 1/2 mirror transition. Together, these experimental results are important for precision tests of the Standard Model and an analysis of the parity mixing of the states in ¹⁹F.

It is argued that N ∼ Z nuclei with 90 ⩽ A ⩽ 100 can be interpreted in terms of aligned neutron–proton pairs with angular momentum J = 2j and isospin T = 0. Based on this observation, a version of the interacting boson model is formulated in terms of isoscalar high-spin bosons. To illustrate its possible uses, the model is applied to the 21⁺ isomer in ⁹⁴Ag.

Experiments with the WASA detector focus on studies of symmetries and symmetry breaking patterns in hadronic systems as well as hadron spectroscopy. The goal is to investigate the properties of quantum chromodynamics in the non-perturbative regime, where confinement and chiral symmetry breaking are distinctive phenomena. Here, we report latest results on decays of the pseudoscalar η meson and exclusive data on ππ production which might indicate the existence of a new resonance in the proton–neutron and ΔΔ systems.