Thu·Jun 11, 2015Thursday·June 11, 2015

1. 01*

   Elliptic and Triangular Flow of Identified Particles from the AMPT Model at RHIC Energies

   Xu Sun🇨🇳 · Jianli Liu🇨🇳 · Alexander Schmah🇺🇸 · Shusu Shi🇨🇳 · Jingbo Zhang🇨🇳 · Lei Huo🇨🇳 · Hanzhi Jiang🇨🇳

   The elliptic flow ($v_2$) at $\sqrt{s_{\mathrm{NN}}}=$ 11.5, 39, and 200 GeV and triangular flow ($v_3$) at $\sqrt{s_{\mathrm{NN}}}=$ 200 GeV of identified particles (${\pi }^{\pm },K^{\pm },K_S^0,p,\bar{p},\varphi ,\Lambda$ and $\bar{\Lambda }$) from 0\%--80\% central Au+Au collisions are analyzed using a multiphase transport (AMPT) model. It is shown that the experimental results from the $\eta$-sub event plane method can be reproduced with a parton scattering cross section between 1.5 and 3 mb. We also studied the differential and integrated $v_2/v_3$ ratios and conclude that they are anti-corrected with the parton scattering cross section.

   nucl-exhep-exhep-phnucl-thJ.Phys.G(2015)·8 citations
2. 02*

   Enhanced time response of 1-in. LaBr3(Ce) crystals by leading edge and constant fraction techniques

   V. Vedia🇪🇸 · H. Mach🇪🇸 · L.M. Fraile🇪🇸 · J.M. Udias🇪🇸 · S. Lalkovski

   We have characterized in depth the time response of three detectors equipped with cylindrical LaBr${}_3$ (Ce) crystals with dimensions of 1-in. in height and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and 10%. Measurements were performed at ${}^{60}$Co and ${}^{22}$Na {\gamma}-ray energies against a fast BaF${}_2$ reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the parameters of the constant fraction discriminator, namely the zero-crossing and the external delay. We report here on the optimal time resolution of the three crystals. It is observed that timing properties are influenced by the amount of Ce doping and the crystal homogeneity. For the crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays in addition to the Hamamatsu R9779 PMT has made it possible to improve the LaBr${}_3$(Ce) time resolution from the best literature value at 60Co photon energies to below 100 ps.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2015)·14 citations
3. 03*

   $2\nu \beta \beta$ decay of ${}^{76}$Ge into excited states with GERDA Phase I

   M. Agostini🇩🇪 · M. Allardt🇩🇪 · A.M. Bakalyarov🇷🇺 · M. Balata🇮🇹 · I. Barabanov🇷🇺 · N. Barros🇩🇪 · L. Baudis🇨🇭 · C. Bauer🇩🇪 · N. Becerici-Schmidt🇩🇪 · E. Bellotti🇮🇹 · S. Belogurov🇷🇺 · S.T. Belyaev🇷🇺 and 104 other authors

   Two neutrino double beta decay of ${}^{76}$Ge to excited states of ${}^{76}$Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in ${}^{76}$Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation $\gamma$ ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: $0_{g.s.}^{+}-2_1^{+}$: $T_{1/2}^{2\nu }>$1.6$\cdot 10^{23}$ yr, $0_{g.s.}^{+}-0_1^{+}$: $T_{1/2}^{2\nu }>$3.7$\cdot 10^{23}$ yr and $0_{g.s.}^{+}-2_2^{+}$: $T_{1/2}^{2\nu }>$2.3$\cdot 10^{23}$ yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the $0_{g.s.}^{+}-0_1^{+}$ transition.

   ↳ hep-exnucl-exJ.Phys.G(2015)·36 citations
4. 04*

   Statistical features of the thermal neutron capture cross sections

   M. S. Hussein🇧🇷 · B. V. Carlson🇧🇷 · A. K. Kerman🇺🇸

   We discuss the existence of huge thermal neutron capture cross sections in several nuclei. The values of the cross sections are several orders of magnitude bigger than expected at these very low energies. We lend support to the idea that this phenomenon is random in nature and is similar to what we have learned from the study of parity violation in the actinide region. The idea of statistical doorways is advanced as a unified concept in the delineation of large numbers in the nuclear world. The average number of maxima per unit mass, $<n_A>$ in the capture cross section is calculated and related to the underlying cross section correlation function and found to be $<n_A>=3/(\pi \sqrt{2}{\gamma }_A)$, where ${\gamma }_A$ is a characteristic mass correlation width which designates the degree of remnant coherence in the system. We trace this coherence to nucleosynthesis which produced the nuclei whose neutron capture cross sections are considered here.

   ↳ nucl-thnucl-exActa Phys.Polon.B(2016)·4 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.