Wed·Apr 22, 2015Wednesday·April 22, 2015

1. 01*

   Systematic study of charged-pion and kaon femtoscopy in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$=200 GeV

   A. Adare · S. Afanasiev · C. Aidala · N.N. Ajitanand · Y. Akiba · H. Al-Bataineh · J. Alexander · M. Alfred · K. Aoki · N. Apadula · Y. Aramaki · H. Asano and 488 other authors

   We present a systematic study of charged pion and kaon interferometry in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$=200 GeV. The kaon mean source radii are found to be larger than pion radii in the outward and longitudinal directions for the same transverse mass; this difference increases for more central collisions. The azimuthal-angle dependence of the radii was measured with respect to the second-order event plane and similar oscillations of the source radii were found for pions and kaons. Hydrodynamic models qualitatively describe the similar oscillations of the mean source radii for pions and kaons, but they do not fully describe the transverse-mass dependence of the oscillations.

   nucl-exPRC(2015)·43 citations
2. 02*

   The E00-110 experiment in Jefferson Lab's Hall A: Deeply Virtual Compton Scattering off the Proton at 6 GeV

   M. Defurne🇫🇷 · M. Amaryan🇺🇸 · K. A. Aniol🇺🇸 · M. Beaumel🇫🇷 · H. Benaoum🇺🇸 · P. Bertin🇫🇷 · M. Brossard🇫🇷 · A. Camsonne🇺🇸 · J.-P. Chen🇺🇸 · E. Chudakov🇺🇸 · B. Craver🇺🇸 · F. Cusanno🇮🇹 and 69 other authors

   We present final results on the photon electroproduction ($\vec{e}p\to ep\gamma$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Results of the $Q^2$- and $x_B$-dependences of both the helicity-dependent and helicity-independent cross sections are discussed. The $Q^2$-dependence illustrates the dominance of the twist-2 handbag amplitude in the kinematics of the experiment, as previously noted. Thanks to the excellent accuracy of this high luminosity experiment, it becomes clear that the unpolarized cross section shows a significant deviation from the Bethe-Heitler process in our kinematics, compatible with a large contribution from the leading twist-2 DVCS${}^2$ term to the photon electroproduction cross section. The necessity to include higher-twist corrections in order to fully reproduce the shape of the data is also discussed. The DVCS cross sections in this paper represent the final set of experimental results from E00-110, superseding the previous publication.

   nucl-exhep-exPRC(2015)·135 citations
3. 03*

   Spin Physics at J-PARC

   S. Kumano🇯🇵

   Spin-physics projects at J-PARC are explained by including future possibilities. J-PARC is the most-intense hadron-beam facility in the high-energy region above multi-GeV, and spin physics will be investigated by using secondary beams of kaons, pions, neutrinos, muons, and antiproton as well as the primary-beam proton. In particle physics, spin topics are on muon $g-2$, muon and neutron electric dipole moments, and time-reversal violation experiment in a kaon decay. Here, we focus more on hadron-spin physics as for future projects. For example, generalized parton distributions (GPDs) could be investigated by using pion and proton beams, whereas they are studied by the virtual Compton scattering at lepton facilities. The GPDs are key quantities for determining the three-dimensional picture of hadrons and for finding the origin of the nucleon spin including partonic orbital-angular-momentum contributions. In addition, polarized parton distributions and various hadron spin topics should be possible by using the high-momentum beamline. The strangeness contribution to the nucleon spin could be also investigated in principle with the neutrino beam with a near detector facility.

   ↳ hep-phhep-exnucl-exnucl-thInt.J.Mod.Phys.Conf.Ser.(2016)·24 citations
4. 04*

   Thermodynamics of strong-interaction matter from Lattice QCD

   Heng-Tong Ding🇨🇳 · Frithjof Karsch🇩🇪 · Swagato Mukherjee🇺🇸

   We review results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments. This review is organized as follows: 1) Introduction, 2) QCD thermodynamics on the lattice, 3) QCD phase diagram at high temperature, 4) Bulk thermodynamics, 5) Fluctuations of conserved charges, 6) Transport properties, 7) Open heavy flavors and heavy quarkonia, 8) QCD in external magnetic fields, 9) Summary.

   ↳ hep-lathep-phnucl-exnucl-thIJMPE(2015)·459 citations
5. 05*

   Quantitative Analysis and Efficiency Study of PSD Methods for a LaBr3:Ce Detector

   Ming Zeng · Jirong Cang · Zhi Zeng · Xiaoguang Yue · Jianping Cheng · Yinong Liu · Junli Li

   The LaBr3:Ce scintillator has been widely studied for nuclear spectroscopy because of its optimal energy resolution (<3%@ 662 keV) and time resolution (~300 ps). Despite these promising properties, the intrinsic radiation background of LaBr3:Ce is a critical issue, and pulse shape discrimination (PSD) has been shown to be an efficient potential method to suppress the alpha background from the 227Ac. In this paper, the charge comparison method (CCM) for alpha and gamma discrimination in LaBr3:Ce is quantitatively analysed and compared with two other typical PSD methods using digital pulse processing. The algorithm parameters and discrimination efficiency are calculated for each method. Moreover, for the CCM, the correlation between the CCM feature value distribution and the total charge (energy) is studied, and a fitting equation for the correlation is inferred and experimentally verified. Using the equations, an energy-dependent threshold can be chosen to optimize the discrimination efficiency. Additionally, the experimental results show a potential application in low-activity high-energy {\gamma} measurement by suppressing the alpha background.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2016)·7 citations
6. 06*

   Radiation Background Studies for 0$\nu \beta \beta$ decay in ${}^{124}$Sn

   Neha Dokania🇮🇳 · V. Singh🇮🇳 · C. Ghosh🇮🇳 · S. Mathimalar🇮🇳 · A. Garai🇮🇳 · S. Pal🇮🇳 · V. Nanal🇮🇳 · R.G. Pillay🇮🇳 · A. Shrivastava🇮🇳 · K.G. Bhushan🇮🇳

   Radiation background studies pertaining to $0\nu \beta \beta$ decay in ${}^{124}$Sn have been carried out. A TiLES setup has been installed at TIFR for this purpose. Neutron-induced background is studied in the TIN.TIN detector materials using fast neutron activation technique. The neutron flux ($E_n\le 15$ MeV) resulting from SF and ($\alpha ,n$) interactions for the rock in the INO cavern is estimated using MC simulations. A two layer composite shield of borated paraffin (20 cm) + Pb (5 cm) is proposed for the reduction of neutron flux.

   ↳ physics.ins-detnucl-ex2 citations
7. 07*

   Temperature dependence of scintillation properties of SrMoO4

   V. B. Mikhailik🇬🇧 · Yu. Elyashevskyi🇬🇧 · H. Kraus🇬🇧 · H. J. Kim🇰🇷 · V. Kapustianyk🇺🇦 · M. Panasyuk🇺🇦

   Studies of the X-ray luminescence and scintillation properties of a SrMoO4 crystal as function of temperature down to T=10 K have been carried out. The luminescence in SrMoO4 is quenched at room temperature, but below T<200 K the crystal exhibits a broad emission band with a maximum at a wavelength of 520 nm. The emission is attributed to the radiative decay of self-trapped excitons and defects acting as traps for the exactions at low temperatures. Such complex character of radiative decay is reflected in the kinetics which contains several components plus a contribution from delayed recombination at low temperatures. The temperature dependence of scintillation light output of SrMoO4 was studied. Comparing with a reference ZnWO4 crystal measured under the same experimental conditions it was found that the light output of SrMoO4 is 15+-5%. It is suggested, therefore, that there is scope for optimisation of strontium molybdate for application as scintillator in cryogenic rare event searches

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2015)·4 citations
8. 08*

   Observation of Hyperfine Transitions in Trapped Ground-State Antihydrogen

   Arthur Olin (for the ALPHA Collaboration)🇨🇦

   This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4~parts~in~$10^3$. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.

   ↳ hep-exnucl-exphysics.atom-phphysics.plasm-phHyperfine Interact.(2015)·1 citation

* 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.