Fri·Jul 17, 2015Friday·July 17, 2015

1. 01*

   Direct mass measurements of Cd isotopes show strong shell gap at N=82

   R. Knöbel🇩🇪 · M. Diwisch🇩🇪 · F. Bosch🇩🇪 · D. Boutin🇩🇪 · L. Chen🇩🇪 · C. Dimopoulou🇩🇪 · A. Dolinskii🇩🇪 · B. Franczak🇩🇪 · B. Franzke🇩🇪 · H. Geissel🇩🇪 · M. Hausmann🇺🇸 · C. Kozhuharov🇩🇪 and 23 other authors

   A ${}^{238}$U projectile beam was used to create cadmium isotopes via abrasion-fission at 410 MeV/u in a beryllium target at the entrance of the in-flight separator FRS at GSI. The fission fragments were separated with the FRS and injected into the isochronous storage ring ESR for mass measurements. The Isochronous Mass Spectrometry (IMS) was performed under two different experimental conditions, with and without B$\rho$-tagging at the dispersive central focal plane of the FRS. In the experiment with B$\rho$-tagging the magnetic rigidity of the injected fragments was determined by an accuracy of $2\times 10^{-4}$. A new method of data analysis, using a correlation matrix for the combined data set from both experiments, has provided mass values for 25 different isotopes for the first time. The high selectivity and sensitivity of the experiment and analysis has given access even to rare isotopes detected with a few atoms per week. In this letter we present for the ${}^{129,130,131}$Cd isotopes mass values directly measured for the first time. The Cd results clearly show a very pronounced shell effect at $N=82$ which is in agreement with the conclusion from $\gamma$-ray spectroscopy of ${}^{130}$Cd and confirms the assumptions of modern shell-model calculations.

   nucl-exastro-ph.HEnucl-th0 citations
2. 02*

   Search for 2K(2\nu)-capture of Xe-124

   Yu.M. Gavrilyuk🇷🇺 · A.M. Gangapshev🇷🇺 · V.V. Kazalov🇷🇺 · V.V. Kuzminov🇷🇺 · S.I. Panasenko🇺🇦 · S.S. Ratkevich🇺🇦 · D.A. Tekueva🇷🇺 · S.P. Yakimenko🇷🇺

   The results of a search for two neutrino mode of double K-capture of Xe-124 using a large copper low-background proportional counter are presented. Data collected during 3220 hours of measurements with 58.6 g of ${}^{124}$Xe provides us to a new limit on the half-life of Xe-124 regarding 2K-capture at the level: T_{1/2} >= 2.0*10^{21} years at a 90\% confidence level.

   nucl-exphysics.ins-detPhys.Part.Nucl.(2017)·7 citations
3. 03*

   Polarized Lepton-Nucleon Elastic Scattering and a Search for a Light Scalar Boson

   Yu-Sheng Liu🇺🇸 · Gerald A. Miller🇺🇸

   Lepton-nucleon elastic scattering, using the one-photon and one-scalar-boson exchange mechanisms considering all possible polarizations, is used to study searches for a new scalar boson and suggest new measurements of the nucleon form factors. A new light scalar boson, which feebly couples to leptons and nucleons, may account for the proton radius and muon $g-2$ puzzles. We show that the scalar boson produces relatively large effects in certain kinematic region when using sufficient control of lepton and nucleon spin polarization. We generalize current techniques to measure the ratio $G_E/G_M$ and present a new method to separately measure $G_M^2$ and $G_E^2$ using polarized incoming and outgoing muons.

   ↳ nucl-thhep-phnucl-exPRC(2015)·12 citations
4. 04*

   A crosstalk and non-uniformity correction method for the Compact Space-borne Compton Polarimeter POLAR

   Hualin Xiao · Wojtek Hajdas · Bobing Wu · Nicolas Produit · Tianwei Bao · Tadeusz Batsch · Ilia Britvich · Franck Cadoux · Junying Chai · Yongwei Dong · Neal Gauvin · Minnan Kong and 24 other authors

   In spite of extensive observations and numerous theoretical studies in the past decades several key questions related with Gamma-Ray Bursts (GRB) emission mechanisms are still to be answered. Precise detection of the GRB polarization carried out by dedicated instruments can provide new data and be an ultimate tool to unveil their real nature. A novel space-borne Compton polarimeter POLAR onboard the Chinese space station TG2 is designed to measure linear polarization of gamma-rays arriving from GRB prompt emissions. POLAR uses plastics scintillator bars (PS) as gamma-ray detectors and multi-anode photomultipliers (MAPMTs) for readout of the scintillation light. Inherent properties of such detection systems are crosstalk and non-uniformity. The crosstalk smears recorded energy over multiple channels making both non-uniformity corrections and energy calibration more difficult. Rigorous extraction of polarization observable requires to take such effects properly into account. We studied influence of the crosstalk on energy depositions during laboratory measurements with X-ray beams. A relation between genuine and recorded energy was deduced using an introduced model of data analysis. It postulates that both the crosstalk and non-uniformities can be described with a single matrix obtained in calibrations with mono-energetic X- and gamma-rays. Necessary corrections are introduced using matrix based equations allowing for proper evaluation of the measured GRB spectra. Validity of the method was established during dedicated experimental tests. The same approach can be also applied in space utilizing POLAR internal calibration sources. The introduced model is general and with some adjustments well suitable for data analysis from other MAPMT-based instruments.

   ↳ physics.ins-detnucl-exAstropart.Phys.(2016)·12 citations
5. 05*

   Beamed neutron emission driven by laser accelerated light ions

   S. Kar🇬🇧 · A. Green🇬🇧 · H. Ahmed🇬🇧 · A. Alejo🇬🇧 · A.P.L. Robinson🇬🇧 · M. Cerchez🇩🇪 · R. Clarke🇬🇧 · D. Doria🇬🇧 · S. Dorkings🇬🇧 · J. Fernandez🇪🇸 · S.R. Mirfyazi🇬🇧 · P. McKenna🇬🇧 and 9 other authors

   We report on the experimental observation of beam-like neutron emission with peak flux of the order of 10^9 n/sr, from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by high power laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of 70 degrees, with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)^1H and d(d,n)^3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons' spatial and spectral profiles are most likely related to the directionality and high energy of the projectile ions.

   ↳ physics.plasm-phnucl-exphysics.acc-phNew J.Phys.(2016)·21 citations
6. 06*

   Inverse-square law violation and reactor antineutrino anomaly

   D.V. Naumov🇷🇺 · V.A. Naumov🇷🇺 · D.S. Shkirmanov🇷🇺

   We discuss a possibility that the so-called reactor antineutrino anomaly can be, at least in part, explained by applying a quantum field-theoretical approach to neutrino oscillations, which in particular predicts a small deviation from the classical inverse-square law at short but macroscopic distances between the neutrino source and detector. An extensive statistical analysis of the reactor data is performed to examine this speculation.

   ↳ hep-phhep-exnucl-exphysics.data-anPhys.Part.Nucl.(2017)·11 citations
7. 07*

   Development of cryogenic low background detector based on enriched zinc molybdate crystal scintillators to search for neutrinoless double beta decay of ${}^{100}$Mo

   Dmitry Chernyak (Dmytro Cherniak)🇫🇷

   ZnMoO${}_4$ scintillators with a mass of $\sim$ 0.3 kg, as well as Zn${}^{100}$MoO${}_4$ crystals enriched in the isotope ${}^{100}$Mo were produced for the first time by using the low-thermal-gradient Czochralski technique. The optical and luminescent properties of the produced crystals were studied to estimate the progress in crystal growth quality. The low-temperature tests with a 313 g ZnMoO${}_4$ and two enriched Zn${}^{100}$MoO${}_4$ crystals were performed aboveground in the Centre de Sciences Nucléaires et de Sciences de la Matière. The low background measurements with a three ZnMoO${}_4$ and two enriched detectors installed in the EDELWEISS set-up at the Laboratoire Souterrain de Modane were carried out. To optimize the light collection in ZnMoO${}_4$ scintillating bolometers, we have simulated the collection of scintillation photons in a detector module for different geometries by Monte Carlo method using the GEANT4 package. Response to the 2$\nu$2$\beta$ decay of ${}^{100}$Mo was simulated for the enriched Zn${}^{100}$MoO${}_4$ detectors of different shape and mass to understand the dependence of 2$\nu$2$\beta$ decay spectra on crystal shape. We have simulated 48 Zn${}^{100}$MoO${}_4$ crystals with a size of Ø60 $\times$ 40 mm installed in the EDELWEISS cryostat. The contribution to background from the internal radioactive contamination of the crystals, cosmogenic activation and radioactive contamination of the set-up were simulated. Taking into account poor time resolution of the low temperature bolometers, we also studied contribution to background at the Q${}_{2\beta }$ energy of random coincidences of signals, in particular of 2$\nu$2$\beta$ decay, which is one of the main sources of background in cryogenic bolometers. Methods of the randomly coinciding events rejection were developed and compared. We have also analyzed dependence of the rejection efficiency on a cryogenic detector performance.

   ↳ physics.ins-detnucl-ex4 citations
8. 08*

   Femto-cyclones and hyperon polarization in Heavy-Ion Collisions

   M.I. Baznat🇷🇺 · K.K. Gudima🇲🇩 · A.S. Sorin🇷🇺 · O.V. Teryaev🇷🇺

   We study the structure of vorticity and hydrodynamic helicity fields in peripheral heavy-ion collisions using the kinetic Quark-Gluon String Model. The angular momentum conservation within this model holds with a good accuracy. We observe the formation of specific toroidal structures of vorticity field (vortex sheets). Their existence is mirrored in the polarization of hyperons of the percent order.

   ↳ nucl-thhep-phnucl-exPRC(2016)·67 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.