Mon·Apr 20, 2015Monday·April 20, 2015

1. 01*

   Excitation functions of proton-induced reactions on natural Nd and production of radionuclides relevant for double beta decay: Completing measurement in 5-35 MeV energy range

   O. Lebeda (1)🇨🇿 · V. Lozza (2)🇩🇪 · J. Petzoldt (2)🇩🇪 · J. Stursa (1) · V. Zdychova (1) · K. Zuber (2) ((1) Nuclear Physics Institute AS CR (2) Institut fuer Kern und Teilchenphysik,Universitaet Dresden)🇩🇪

   Cross-sections for the proton-induced reactions on natural neodymium in energy regions 5-10 MeV and 30-35 MeV were measured using the cyclotron U-120M at the Nuclear Physics Institute at Rez near Prague. This measurement completes the investigation previously done in the 10-30 MeV energy range. Results revealed practical production thresholds and secondary maxima and minima in the excitation functions. It allowed for more appropriate calculation of thick target yields and production rates of many longer-lived radionuclides potentially disturbing the search for neutrinoless double beta decay. Measured cross-sections are consistent with our previously published data.

   nucl-exNPA(2014)·16 citations
2. 02*

   Direct Evidence of Washing out of Nuclear Shell Effects

   A. Chaudhuri🇮🇳 · T.K. Ghosh🇮🇳 · K. Banerjee🇮🇳 · S. Bhattacharya🇮🇳 · Jhilam Sadhukhan🇮🇳 · C. Bhattacharya🇮🇳 · S. Kundu🇮🇳 · J. K. Meena · G. Mukherjee🇮🇳 · R. Pandey🇮🇳 · T.K. Rana🇮🇳 · P. Roy🇮🇳 and 3 other authors

   Constraining excitation energy at which nuclear shell effect washes out has important implications on the production of super heavy elements and many other fields of nuclear physics research. We report the fission fragment mass distribution in alpha induced reaction on an actinide target for wide excitation range in close energy interval and show direct evidence that nuclear shell effect washes out at excitation energy ~40 MeV. Calculation shows that second peak of the fission barrier also vanishes around similar excitation energy.

   nucl-exnucl-thPRC(2015)·37 citations
3. 03*

   Ground-State Electromagnetic Moments of Calcium Isotopes

   R. F. Garcia Ruiz🇧🇪 · M. L. Bissell🇧🇪 · K. Blaum🇩🇪 · N. Frommgen🇩🇪 · M. Hammen🇩🇪 · J. D. Holt🇨🇦 · M. Kowalska🇨🇭 · K. Kreim🇩🇪 · J. Menendez🇯🇵 · R. Neugart🇩🇪 · G. Neyens🇧🇪 · W. Nortershauser🇩🇪 and 6 other authors

   High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the ${}^{43-51}$Ca isotopes. The ground state magnetic moments of ${}^{49,51}$Ca and quadrupole moments of ${}^{47,49,51}$Ca were measured for the first time, and the ${}^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the ${}^{40}$Ca core in their ground state.

   nucl-exnucl-thPRC(2015)·64 citations
4. 04*

   Characterization of relativistic heavy-ion collisions at the Large Hadron Collider through temperature fluctuations

   Sumit Basu🇮🇳 · Rupa Chatterjee🇮🇳 · Bastanta K. Nandi🇮🇳 · Tapan K. Nayak🇮🇳

   We propose to characterize heavy-ion collisions at ultra-relativistic energies by using fluctuations of energy density and temperature. Temperature fluctuations on an event-by-event basis have been studied both in terms of global temperature of the event, and locally by constructing fluctuation maps in small phase space bins in each event. Global temperature fluctuations provide an estimation of the specific heat of the system. Local temperature fluctuations of the event may be ascribed to the remnants of initial energy density fluctuations. Together these two observables give an insight into the system created in heavy-ion collisions and its evolution. Event-by-event hydrodynamic calculations indeed provide adequate theoretical basis for understanding the origin of the fluctuations. We demonstrate the feasibility of studying global and local temperature fluctuations at the Large Hadron Collider energy by the use of AMPT event generator.

   nucl-exnucl-thSpringer Proc.Phys. 174 (2016) 189-194·8 citations
5. 05*

   Measurement of charged-particle spectra in Pb+Pb collisions at $\sqrt{s_{\mathsf{NN}}}=2.76$ TeV with the ATLAS detector at the LHC

   ATLAS Collaboration

   Charged-particle spectra obtained in 0.15 nb${}^{-1}$ of Pb+Pb interactions at $\sqrt{s_{\mathsf{NN}}}=2.76$TeV and 4.2 pb${}^{-1}$ of pp interactions at $\sqrt{s}=2.76$ TeV with the ATLAS detector at the LHC are presented in a wide transverse momentum ($0.5<p_{\mathrm{T}}<150$ GeV) and pseudorapidity ($|\eta |<2$) range. For Pb+Pb collisions, the spectra are presented as a function of collision centrality, which is determined by the response of the forward calorimeter located on both sides of the interaction point. The nuclear modification factors $R_{\mathrm{AA}}$ and $R_{\mathrm{CP}}$ are presented in detail as function of centrality, $p_{\mathrm{T}}$ and $\eta$. They show a distinct $p_{\mathrm{T}}$-dependence with a pronounced minimum at about 7 GeV. Above 60 GeV, $R_{\mathrm{AA}}$ is consistent with a plateau at a centrality-dependent value, within the uncertainties. The value is $0.55\pm 0.01(stat.)\pm 0.04(syst.)$ in the most central collisions. The $R_{\mathrm{AA}}$ distribution is consistent with flat $|\eta |$ dependence over the whole transverse momentum range in all centrality classes.

   ↳ hep-exnucl-exJHEP(2015)·254 citations
6. 06*

   Completing the picture of the Roper resonance

   Jorge Segovia🇪🇸 · Bruno El-Bennich🇧🇷 · Eduardo Rojas🇨🇴 · Ian C. Cloet🇺🇸 · Craig D. Roberts🇺🇸 · Shu-Sheng Xu🇨🇳 · Hong-Shi Zong🇨🇳

   We employ a continuum approach to the three valence-quark bound-state problem in relativistic quantum field theory to predict a range of properties of the proton's radial excitation and thereby unify them with those of numerous other hadrons. Our analysis indicates that the nucleon's first radial excitation is the Roper resonance. It consists of a core of three dressed-quarks, which expresses its valence-quark content and whose charge radius is 80% larger than the proton analogue. That core is complemented by a meson cloud, which reduces the observed Roper mass by roughly 20%. The meson cloud materially affects long-wavelength characteristics of the Roper electroproduction amplitudes but the quark core is revealed to probes with $Q^2\gtrsim 3m_N^2$.

   ↳ nucl-thhep-lathep-phnucl-exPRL(2015)·144 citations
7. 07*

   Influence of statistics on the measured moments of conserved quantities in relativistic heavy ion collisions

   Lizhu Chen🇨🇳 · Zhiming Li🇨🇳 · Xia Zhong🇨🇳 · Yuncun He🇨🇳 · Yuanfang Wu🇨🇳

   We study statistics dependence of the probability distributions and the means of measured moments of conserved quantities, respectively. The required statistics of all interested moments and their products are estimated based on a simple simulation. We also explain why the measured moments are underestimated when the statistics are insufficient.With the statistics at RHIC/BES, the second and third order moments can be reliably obtained based on the method of Centrality bin width correction (CBWC), which can not be applied for the fourth order moments at low energy. With planning statistics at RHIC/BES II, and improved CBWC method, $\kappa {\sigma }^2$ in a finer centrality bin scale should be measurable. This will help us to understand the current observation of energy and centrality dependence of high-order moments.

   ↳ nucl-thnucl-exJ.Phys.G(2015)·6 citations
8. 08*

   Hyperon Semileptonic decay constants with flavor SU(3) symmetry breaking

   Ghil-Seok Yang🇰🇷 · Hyun-Chul Kim🇰🇷

   We investigate the hyperon semileptonic decay constants, $f_2/f_1$, and $g_1/f_1$, within a general framework of a chiral soliton model. All relevant parameters for the SU(3) baryon wave functions were unambiguously determined by using the experimental data for the masses of the baryon octet and the decuplet. Using then the existing experimental data for the magnetic moments of the baryon octet and the decay constants of hyperon semileptonic decays, we are able to determine all the hyperon semileptonic decay constants $f_2/f_1$ and $g_1/f_1$ of the baryon octet unequivocally. In addition, we also present the results of the axial-vector transition constants from the baryon decuplet to the octet.

   ↳ hep-phhep-exnucl-exPRC(2015)·53 citations
9. 09*

   A Prototype of LaBr3:Ce in situ Gamma-Ray Spectrometer for Marine Environmental Monitoring

   Ming Zeng · Zhi Zeng · Jirong Cang · Xingyu Pan · Tao Xue · Hao Ma · Hongchang Yi · Jianping Cheng

   A prototype of LaBr3:Ce in situ gamma-ray spectrometer for marine environmental monitoring is developed and applied for in situ measurement. A 3-inch LaBr3:Ce scintillator is used in the detector, and a digital pulse process electronics is chosen as the pulse height analyzer. For this prototype, the energy response of the spectrometer is linear and the energy resolution of 662keV is 2.6% (much better than NaI). With the measurement of the prototype in a water tank filled with 137Cs, the detect efficiency for 137Cs is (0.288 0.01)cps/(Bq/L), which is close to the result of Monte Carlo simulation, 0.283cps/(Bq/L). With this measurement, the MDAC for 137Cs in one hour has been calculated to 0.78Bq/L, better than that of NaI(Tl) in-situ gamma spectrometer, which is ~1.0Bq/L.

   ↳ physics.ins-detnucl-ex0 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.