Tue·Oct 18, 2016Tuesday·October 18, 2016

1. 01*

   A new method for measuring the neutron lifetime using an in situ neutron detector

   C. L. Morris🇺🇸 · E. R. Adamek🇺🇸 · L. J. Broussard🇺🇸 · N. B. Callahan🇺🇸 · S. M. Clayton🇺🇸 · C. Cude-Woods🇺🇸 · S. A. Currie🇺🇸 · X. Ding🇺🇸 · W. Fox🇺🇸 · K. P. Hickerson🇺🇸 · A. T. Holley🇺🇸 · A. Komives🇺🇸 and 19 other authors

   The neutron lifetime is important in understanding the production of light nuclei in the first minutes after the big bang and it provides basic information on the charged weak current of the standard model of particle physics. Two different methods have been used to measure the neutron lifetime: disappearance measurements using bottled ultracold neutrons and decay rate measurements using neutron beams. The best measurements using these two techniques give results that differ by nearly 4 standard deviations. In this paper we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold neutrons that provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. We present results obtained using our method.

   nucl-exphysics.ins-detRev.Sci.Instrum.(2017)·31 citations
2. 02*

   Thick-target transmission method for excitation functions of interaction cross sections

   M.Aikawa · S.Ebata · S.Imai🇯🇵

   We propose a method, called as thick-target transmission (T3) method, to obtain an excitation function of interaction cross sections. In an ordinal experiment to measure the excitation function of interaction cross sections by the transmission method, we need to change the beam energy for each cross section. In the T3 method, the excitation function is derived from the beam attenuations measured at the targets of different thicknesses without changing the beam energy. The advantage of the T3 method is the simplicity and availability for radioactive beams. To confirm the availability, we perform a simulation for the 12C+27Al system with the PHITS code instead of actual experiments. Our results have large uncertainties but well reproduce the tendency of the experimental data.

   nucl-exNucl.Instrum.Meth.B(2016)·0 citations
3. 03*

   Proton-proton correlations in distinguishing the two-proton emission mechanism of ${}^{23}$Al and ${}^{22}$Mg

   D. Q. Fang🇨🇳 · Y. G. Ma🇨🇳 · X. Y. Sun🇨🇳 · P. Zhou🇨🇳 · Y. Togano🇯🇵 · N. Aoi🇯🇵 · H. Baba🇯🇵 · X. Z. Cai🇨🇳 · X. G. Cao🇨🇳 · J. G. Chen🇨🇳 · Y. Fu🇨🇳 · W. Guo🇨🇳 and 34 other authors

   The proton-proton momentum correlation functions ($C_{pp}(q)$) for kinematically complete decay channels of ${}^{23}$Al $\to$ p + p + ${}^{21}$Na and ${}^{22}$Mg $\to$ p + p + ${}^{20}$Ne have been measured at the RIKEN RI Beam Factory. From the very different correlation strength of $C_{pp}(q)$ for ${}^{23}$Al and ${}^{22}$Mg, the source size and emission time information were extracted from the $C_{pp}(q)$ data by assuming a Gaussian source profile in the correlation function calculation code (CRAB). The results indicated that the mechanism of two-proton emission from ${}^{23}$Al was mainly sequential emission, while that of ${}^{22}$Mg was mainly three-body simultaneous emission. By combining our earlier results of the two-proton relative momentum and the opening angle, it is pointed out that the mechanism of two-proton emission could be distinguished clearly.

   nucl-exnucl-thPRC(2016)·29 citations
4. 04*

   PHENIX results on Lévy analysis of Bose-Einstein correlation functions

   Dániel Kincses (for the PHENIX Collaboration)🇭🇺

   The nature of the quark-hadron phase transition can be investigated through analyzing the space-time structure of the hadron emission source. For this, the Bose-Einstein or HBT correlations of identified charged particles are among the best observables. In this paper we present the latest results from the RHIC PHENIX experiment on such measurements.

   nucl-exActa Phys.Polon.Supp.(2017)·4 citations
5. 05*

   Initial partonic eccentricity fluctuations in a multi-phase transport model

   L. Ma🇨🇳 · G.L. Ma🇨🇳 · Y. G. Ma🇨🇳

   Initial partonic eccentricities in Au+Au collisions at center-of-mass energy $\sqrt{s_{NN}}$ = 200 GeV are investigated using a multi-phase transport model with string melting scenario. The initial eccentricities in different order of harmonics are studied using participant and cumulant definitions. Eccentricity in terms of second-, fourth- and sixth order cumulants as a function of number of participant nucleons are compared systematically with the traditional participant definition. The ratio of the cumulant eccentricities $\epsilon \left\{4\right\}/\epsilon \left\{2\right\}$ and $\epsilon \left\{6\right\}/\epsilon \left\{4\right\}$ are studied in comparison with the ratio of the corresponding flow harmonics. The conversion coefficients ($v_n/{\epsilon }_n$) are explored up to fourth order harmonic based on cumulant method. Furthermore, studies on transverse momentum ($p_T$) and pseudo-rapidity ($\eta$) dependencies of eccentricities and their fluctuations are presented. As in ideal hydrodynamics initial eccentricities are expected to be closely related to the final flow harmonics in relativistic heavy-ion collisions, studies of the fluctuating initial condition in the AMPT model will shed light on the tomography properties of the initial source geometry.

   ↳ nucl-thnucl-exPRC(2016)·30 citations
6. 06*

   Thermal and transport properties in central heavy-ion reactions around a few hundred MeV/nucleon

   X. G. Deng🇨🇳 · Y. G. Ma🇨🇳 · M. Veselsky🇸🇰

   Thermalization process of nuclear matter in central fireball region of heavy-ion collisions is investigated by employing an extension model of Boltzmann-Uehling-Uhlenbeck, namely the Van der Waals Boltzmann-Uehling-Uhlenbeck (VdWBUU) model. Temperature ($T$) is extracted by the quantum Fermion fluctuation approach and other thermodynamic quantities, such as density ($\rho$), entropy density ($s$), shear viscosity ($\eta$), isospin diffusivity ($D_I$) and heat conductivity ($\kappa$), are also deduced. The liquid-like and gas-like phase signs are discussed through the behavior of shear viscosity during heavy-ion collisions process with the VdWBUU model.

   ↳ nucl-thnucl-exPRC(2016)·20 citations
7. 07*

   Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment

   Daya Bay Collaboration: F. P. An · A. B. Balantekin · H. R. Band · M. Bishai · S. Blyth · D. Cao · G. F. Cao · J. Cao · W. R. Cen · Y. L. Chan · J. F. Chang · L. C. Chang and 210 other authors

   A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GW${}_{\mathrm{th}}$ nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of ${\overline{\nu }}_e$'s. Comparison of the ${\overline{\nu }}_e$ rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors ($\sim$1500-1950 m) relative to detectors near the reactors ($\sim$350-600 m) allowed a precise measurement of ${\overline{\nu }}_e$ disappearance. More than 2.5 million ${\overline{\nu }}_e$ inverse beta decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (Dec. 2011--Jul. 2012) with a subsequent 1013 days using the complete configuration of eight detectors (Oct. 2012--Jul. 2015). The ${\overline{\nu }}_e$ rate observed at the far detectors relative to the near detectors showed a significant deficit, $R=0.949\pm 0.002(stat.)\pm 0.002(syst.)$. The energy dependence of ${\overline{\nu }}_e$ disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle ${\sin }^{2}2{\theta }_{13}=0.0841\pm 0.0027(stat.)\pm 0.0019(syst.)$ and the effective neutrino mass-squared difference of $\left|\Delta m_{\mathrm{ee}}^2\right|=(2.50\pm 0.06(stat.)\pm 0.06(syst.))\times 10^{-3}{\mathrm{eV}}^2$. Analysis using the exact three-flavor probability found $\Delta m_{32}^2=(2.45\pm 0.06(stat.)\pm 0.06(syst.))\times 10^{-3}{\mathrm{eV}}^2$ assuming the normal neutrino mass hierarchy and $\Delta m_{32}^2=(-2.56\pm 0.06(stat.)\pm 0.06(syst.))\times 10^{-3}{\mathrm{eV}}^2$ for the inverted hierarchy.

   ↳ hep-exnucl-exphysics.ins-detPRD(2017)·335 citations
8. 08*

   Measurement of Fast Neutron Rate for NEOS Experiment

   Y.J. Ko🇰🇷 · J.Y. Kim · B.Y. Han🇰🇷 · C.H. Jang🇰🇷 · E.J. Jeon🇰🇷 · K.K. Joo🇰🇷 · B.R. Kim · H.J. Kim · H.S. Kim · Y.D. Kim · Jaison Lee · J.Y. Lee and 8 other authors

   The fast neutron rate is measured at the site of NEOS experiment, a short baseline neutrino experiment located in a tendon gallery of a commercial nuclear power plant, using a 0.78-liter liquid scintillator detector. A pulse shape discrimination technique is used to identify neutron signals. The measurements are performed during the nuclear reactor-on and off periods and found to be ~20 per day for both periods. The fast neutron rate is also measured at an overground site with a negligible overburden and is found to be ~100 times higher than that at the NEOS experiment site.

   ↳ physics.ins-detnucl-exJ.Korean Phys.Soc.(2016)·9 citations
9. 09*

   Single-Transverse-Spin-Asymmetry studies with a fixed-target experiment using the LHC beams (AFTER@LHC)

   J.P. Lansberg🇫🇷 · M. Anselmino🇮🇹 · R. Arnaldi🇮🇹 · S.J. Brodsky🇺🇸 · V. Chambert🇫🇷 · C. Da Silva🇺🇸 · J.P. Didelez🇫🇷 · M.G Echevarria🇪🇸 · E.G. Ferreiro🇪🇸 · F. Fleuret🇫🇷 · Y. Gao🇨🇳 · B. Genolini🇫🇷 and 25 other authors

   We discuss the potential of AFTER@LHC to measure single-transverse-spin asymmetries in open-charm and bottomonium production. With a HERMES-like hydrogen polarised target, such measurements over a year can reach precisions close to the per cent level. This is particularly remarkable since these analyses can probably not be carried out anywhere else

   ↳ hep-exhep-phnucl-exnucl-thPoS(2016)·6 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.