Fri·Nov 16, 2018Friday·November 16, 2018

1. 01*

   Identical pion intensity interferometry in central Au+Au collisions at 1.23A GeV

   J. Adamczewski-Musch · O. Arnold · C. Behnke · A. Belounnas · A. Belyaev · J.C. Berger-Chen · J. Biernat · A. Blanco · C. Blume · M. Böhmer · P. Bordalo · S. Chernenko and 105 other authors

   We investigate identical pion HBT intensity interferometry for central Au+Au collisions at 1.23A GeV. High-statistics ${\pi }^{-}{\pi }^{-}$ and ${\pi }^{+}{\pi }^{+}$ data are measured with HADES at SIS18/GSI. The radius parameters, derived from the correlation function depending on relative momenta in the longitudinal-comoving system and parametrized as three-dimensional Gaussian distribution, are studied as function of transverse momentum. A substantial charge-sign difference of the source radii is found, particularly pronounced at low transverse momentum. The extracted Coulomb-corrected source parameters agree well with a smooth extrapolation of the center-of-mass energy dependence established at higher energies, extending the corresponding excitation functions down towards a very low energy. Our data would thus rather disfavour any strong energy dependence of the radius parameters in the low energy region.

   nucl-exPLB(2019)·26 citations
2. 02*

   Astrophysical $S_{E2}$ factor of the ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ reaction through the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^7\mathrm{Li}){}^{16}\mathrm{O}$ transfer reaction

   Y. P. Shen · B. Guo · Z. H. Li · Y. J. Li · D. Y. Pang · S. Adhikari · Z. D. An · J. Su · S. Q. Yan · X. C. Du · Q. W. Fan · L. Gan and 11 other authors

   The ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ reaction plays a key role in the evolution of stars with masses of $M>$ 0.55 $M_{\odot }$. The cross-section of the ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ reaction within the Gamow window ($E_{\text{c.m.}}$ = 300 keV, $T_{\text{9}}$ = 0.2) is extremely small (about $10^{-17}$ barn), which makes the direct measurement in a ground-based laboratory with existing techniques unfeasible. Up until now, the cross-sections at lower energies can only be extrapolated from the data at higher energies. However, two subthreshold resonances, located at $E_x$ = 7.117 MeV and $E_x$ = 6.917 MeV, make this extrapolation more complicated. In this work, the 6.917 MeV subthreshold resonance in the ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ reaction was investigated via the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^7\mathrm{Li}){}^{16}\mathrm{O}$ reaction. The experiment was performed using the Q3D magnetic spectrograph at the HI-13 tandem accelerator. We measured the angular distribution of the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^7\mathrm{Li}){}^{16}\mathrm{O}$ transfer reaction leading to the 6.917 MeV state. Based on the FRDWBA analysis, we derived the asymptotic normalization coefficient (ANC) of the 6.917 MeV level in ${}^{16}$O to be (1.10 $\pm$ 0.29) $\times 10^{10}$ fm${}^{-1}$, with which the reduced $\alpha$ width was computed to be $18.0\pm 4.7$ keV at the channel radius of 6.5 fm. Finally, we calculated the astrophysical $S_{E2}(300)$ factor of the ground-state transitions to be 46.2 $\pm$ 7.7 keV b. The result for the astrophysical $S_{E2}(300)$ factor confirms the values obtained in various direct and indirect measurements and presents an independent examination of the most important data in nuclear astrophysics.

   nucl-exPRC(2019)·16 citations
3. 03*

   Hadronic resonance production with ALICE at the LHC

   Sergey Kiselev (for the ALICE collaboration)🇷🇺

   We present recent results on short-lived hadronic resonances obtained by the ALICE experiment at LHC energies, including results from the Xe--Xe run. The ALICE results on transverse momentum spectra, yields, their ratio to long-lived particles, and nuclear modification factors will be discussed. The results will be compared with model predictions and measurements at lower energies.

   nucl-exEPJ Web Conf.(2019)·0 citations
4. 04*

   Final results of the Aurora experiment to study 2$\beta$ decay of ${}^{116}$Cd with enriched ${}^{116}$CdWO${}_4$ crystal scintillators

   A.S. Barabash🇷🇺 · P. Belli🇮🇹 · R. Bernabei🇮🇹 · F. Cappella🇮🇹 · V. Caracciolo🇮🇹 · R. Cerulli🇮🇹 · D.M. Chernyak🇺🇦 · F.A. Danevich🇺🇦 · S. d'Angelo🇮🇹 · A. Incicchitti🇮🇹 · D.V. Kasperovych🇺🇦 · V.V. Kobychev🇺🇦 and 8 other authors

   The double-beta decay of ${}^{116}$Cd has been investigated with the help of radiopure enriched ${}^{116}$CdWO${}_4$ crystal scintillators (mass of 1.162 kg) at the Gran Sasso underground laboratory. The half-life of ${}^{116}$Cd relatively to the $2\nu 2\beta$ decay to the ground state of ${}^{116}$Sn was measured with the highest up-to-date accuracy as $T_{1/2}=(2.63_{-0.12}^{+0.11})\times 10^{19}$ yr. A new improved limit on the 0$\nu$2$\beta$ decay of ${}^{116}$Cd to the ground state of ${}^{116}$Sn was set as $T_{1/2}\ge 2.2\times 10^{23}$ yr at 90\% C.L., which is the most stringent known restriction for this isotope. It corresponds to the effective Majorana neutrino mass limit in the range $⟨m_{\nu }⟩\le (1.0-1.7)$ eV, depending on the nuclear matrix elements used in the estimations. New improved half-life limits for the 0$\nu$2$\beta$ decay with majoron(s) emission, Lorentz-violating $2\nu 2\beta$ decay and $2\beta$ transitions to excited states of ${}^{116}$Sn were set at the level of $T_{1/2}\ge 10^{20}-10^{22}$ yr. New limits for the hypothetical lepton-number violating parameters (right-handed currents admixtures in weak interaction, the effective majoron-neutrino coupling constants, R-parity violating parameter, Lorentz-violating parameter, heavy neutrino mass) were set.

   nucl-exPRD(2018)·88 citations
5. 05*

   Understanding the energy resolution of liquid argon neutrino detectors

   Alexander Friedland🇺🇸 · Shirley Weishi Li🇺🇸

   Available estimates for the energy resolution of DUNE vary by as much as a factor of four. To address this controversy, and to connect the resolution to the underlying physical processes, we build an independent simulation pipeline for neutrino events in liquid argon, combining the public tools GENIE and FLUKA. Using this pipeline, we first characterize the channels of non-hermeticity of DUNE, including subthreshold particles, charge recombination, and nuclear breakup. Particular attention is paid to the role of neutrons, which are responsible for a large fraction of missing energy in all channels. Next, we determine energy resolution, by quantifying event-to-event stochastic fluctuations in missing energy. This is done for several sets of assumptions about the reconstruction performance, including those available in the literature. The resulting migration matrices, connecting true and reconstructed neutrino energies, are presented. Finally, we quantify the impact of different improvements on the experimental performance. For example, we show that dropping particle identification information degrades the resolution by a factor of two, while omitting charge deposits from de-excitation gammas worsens it by about 25%. In the future, this framework can be used to assess the impact of cross section uncertainties on the oscillation sensitivity.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2019)·87 citations
6. 06*

   Small-$x$ physics at the LHeC

   Heikki Mäntysaari🇫🇮

   The Large Hadron-electron Collider LHeC is a proposed upgrade of the LHC. It would add an electron beam to the LHC, and make it possible to study electron-proton and electron-nucleus collisions at very high energies. We present some of the highlights of the LHeC physics program related to the studies of partonic structure of protons and nuclei, and to the non-linear QCD phenomena visible at small $x$.

   ↳ hep-phnucl-exnucl-thPoS(2018)·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.