Wed·Jun 29, 2016Wednesday·June 29, 2016

1. 01*

   Charge-changing-cross-section measurements of ${}^{12-16}$C at around $45A$ MeV and development of a Glauber model for incident energies $10A-2100A$ MeV

   D.T. Tran · H.J. Ong🇯🇵 · T.T. Nguyen🇩🇪 · I. Tanihata · N. Aoi🇯🇵 · Y. Ayyad🇯🇵 · P.Y. Chan · M. Fukuda · T. Hashimoto · T.H. Hoang · E. Ideguchi🇯🇵 · A. Inoue and 17 other authors

   We have measured for the first time the charge-changing cross sections (${\sigma }_{\text{CC}}$) of ${}^{12-16}$C on a ${}^{12}$C target at energies below $100A$ MeV. To analyze these low-energy data, we have developed a finite-range Glauber model with a global parameter set within the optical-limit approximation which is applicable to reaction cross section (${\sigma }_{\text{R}}$) and ${\sigma }_{\text{CC}}$ measurements at incident energies from 10$A$ to $2100A$ MeV. Adopting the proton-density distribution of ${}^{12}$C known from the electron-scattering data, as well as the bare total nucleon-nucleon cross sections, and the real-to-imaginary-part ratios of the forward proton-proton elastic scattering amplitude available in the literatures, we determine the energy-dependent slope parameter ${\beta }_{\mathrm{pn}}$ of the proton-neutron elastic differential cross section so as to reproduce the existing ${\sigma }_{\text{R}}$ and interaction-cross-section data for ${}^{12}$C+${}^{12}$C over a wide range of incident energies. The Glauber model thus formulated is applied to calculate the ${\sigma }_{\text{R}}$'s of ${}^{12}$C on a ${}^9$Be and ${}^{27}$Al targets at various incident energies. Our calculations show excellent agreement with the experimental data. Applying our model to the ${\sigma }_{\text{R}}$ and ${\sigma }_{\text{CC}}$ for the "neutron-skin" ${}^{16}$C nucleus, we reconfirm the importance of measurements at incident energies below $100A$ MeV. The proton root-mean-square radii of ${}^{12-16}$C are extracted using the measured ${\sigma }_{\text{CC}}$'s and the existing ${\sigma }_{\text{R}}$ data. The results for ${}^{12-14}$C are consistent with the values from the electron scatterings, demonstrating the feasibility, usefulness of the ${\sigma }_{\text{CC}}$ measurement and the present Glauber model.

   nucl-exnucl-thPRC(2016)·31 citations
2. 02*

   Axial anomaly and energy dependence of hyperon polarization in Heavy-Ion Collisions

   A. Sorin🇷🇺 · O. Teryaev🇷🇺

   We address the issue of energy and charge dependence of global polarization of $\Lambda$ hyperons in peripheral $Au-Au$ collisions recently observed by the STAR collaboration at RHIC. We compare different contributions to the anomalous mechanism relating polarization to vorticity and hydrodynamic helicity in QCD matter. We stress that the suppression of the gravitational anomaly contribution in strongly correlated matter observed in lattice simulations confirms our earlier prediction of rapid decrease of polarization with increasing collision energy. Our mechanism leads to polarization of $\bar{\Lambda }$ of the same sign and larger magnitude than the polarization of $\Lambda$. The energy and charge dependence of polarization is suggested as a sensitive probe of fine details of QCD matter structure.

   ↳ nucl-thhep-lathep-phnucl-exPRC(2017)·54 citations
3. 03*

   Measurement of the 2$\nu \beta \beta$ decay half-life of ${}^{150}$Nd and a search for 0$\nu \beta \beta$ decay processes with the full exposure from the NEMO-3 detector

   NEMO-3 Collaboration: R. Arnold (1) · C. Augier (2) · J.D. Baker (3) · A.S. Barabash (4) · A. Basharina-Freshville (5) · S. Blondel (2) · S. Blot (6) · M. Bongrand (2) · V. Brudanin (7 and 8) · J. Busto (9) · A.J. Caffrey (3) · S. Calvez (2) and 82 other authors

   We present results from a search for neutrinoless double-$\beta$ ($0\nu \beta \beta$) decay using 36.6 g of the isotope ${}^{150}$Nd with data corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We construct a complete background model for this isotope, including a measurement of the two-neutrino double-$\beta$ decay half-life of $T_{1/2}^{2\nu }=$[9.34 $\pm$ 0.22 (stat.) ${}_{-0.60}^{+0.62}$ (syst.)]$\times 10^{18}$ y for the ground state transition, which represents the most precise result to date for this isotope. We perform a multivariate analysis to search for \zeronu decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for \zeronu decay is observed, we derive lower limits on half-lives for several mechanisms involving physics beyond the Standard Model. The observed lower limit, assuming light Majorana neutrino exchange mediates the decay, is $T_{1/2}^{0\nu }>$ 2.0 $\times 10^{22}$ y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of $⟨m_{\nu }⟩$ $<$ 1.6 - 5.3 eV..

   ↳ hep-exnucl-exphysics.ins-detPRD(2016)·136 citations
4. 04*

   Application of Origen2.1 in the decay photon spectrum calculation of spallation products

   Shuang Hong · Yong-Wei Yang · Hu-Shan Xu🇨🇳 · Hai-Yan Meng · Lu Zhang · Zhao-Qing Liu · Yu-Cui Gao · Kang Chen

   Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactor, to calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by a Monte Carlo code: FLUKA. All the data used to make the Origen2.1 libraries is obtained from Nuclear structure & decay Data (NuDat2.6). The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper.

   ↳ nucl-thnucl-exCPC(2016)·1 citation
5. 05*

   Procedure for measuring particle's circular polarization variation with respect to the reaction plane in relativistic heavy-ion collisions

   A.H. Tang🇺🇸 · G. Wang🇺🇸

   The EM field pattern created by spectators in relativistic heavy-ion collisions plants a seed of positive (negative) magnetic helicity in the hemisphere above (below) the reaction plane. Owing to the chiral anomaly, the magnetic helicity interacts with the fermionic helicity of the collision system, and causes photons emitted in upper- and lower-hemispheres to have different preferences in the circular polarization. In this paper, we lay down a procedure to measure the variation of the circular polarization w.r.t the reaction plane in relativistic heavy-ion collisions for massless photons, as well as similar polarization patterns for vector mesons decaying into two daughters. We propose to study the yield differentially and compare the yield between upper- and lower-hemispheres in order to identify and quantify such effects.

   ↳ nucl-thnucl-exPRC(2016)·2 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.