Mon·Sep 6, 2021Monday·September 6, 2021

1. 01*

   System size and energy dependence of resonance production in ALICE

   Vikash Sumberia (for the ALICE Collaboration)🇮🇳

   Hadronic resonances, thanks to their relatively short lifetimes, can be used to probe the properties of the hadronic phase in ultrarelativistic heavy-ion collisions. In particular their lifetimes are exploited to investigate the interplay between particle rescattering and regeneration after hadronization. In this contribution we present recent results on $\rho (770{)}^0$, $K^{\ast }$(892), $\varphi$(1020), $\Sigma$(1385)${}^{\pm }$, $\Xi (1530{)}^0$ and $\Lambda (1520)$ production in pp, p$-$Pb, Pb$-$Pb and Xe$-$Xe collisions at LHC energies.

   nucl-exhep-exEPJ Web Conf.(2022)·0 citations
2. 02*

   Search for Majoron-emitting modes of ${}^{136}$Xe double beta decay with the complete EXO-200 dataset

   S. Al Kharusi🇨🇦 · G. Anton🇩🇪 · I. Badhrees🇨🇦 · P.S. Barbeau🇺🇸 · D. Beck🇺🇸 · V. Belov🇷🇺 · T. Bhatta🇺🇸 · M. Breidenbach🇺🇸 · T. Brunner🇨🇦 · G.F. Cao🇨🇳 · W.R. Cen🇨🇳 · C. Chambers🇨🇦 and 94 other authors

   A search for Majoron-emitting modes of the neutrinoless double-beta decay of ${}^{136}$Xe is performed with the full EXO-200 dataset. This dataset consists of a total ${}^{136}$Xe exposure of 234.1 kg$\cdot$yr, and includes data with detector upgrades that have improved the energy threshold relative to previous searches. A lower limit of T${}_{1/2}^{{}^{136}\mathrm{Xe}}>$4.3$\cdot$10${}^{24}$ yr at 90\% C.L. on the half-life of the spectral index $n=1$ Majoron decay was obtained, a factor of 3.6 more stringent than the previous limit from EXO-200, corresponding to a constraint on the Majoron-neutrino coupling constant of $|⟨g_{ee}^M⟩|$$<(0.4$-$0.9)\cdot 10^{-5}$. The lower threshold and the additional data taken resulted in a factor 8.4 improvement for the $n=7$ mode compared to the previous EXO search. This search provides the most stringent limits to-date on the Majoron-emitting decays of ${}^{136}$Xe with spectral indices $n=1,2,3,$ and 7.

   ↳ hep-exnucl-exPRD(2021)·38 citations
3. 03*

   Bayesian evaluation of residual production cross sections in proton induced spallation reactions

   Peng Dan · Hui-Ling Wei🇨🇳 · Xi-Xi Chen · Xiao-Bao Wei · Yu-Ting Wang🇨🇳 · Jie Pu🇨🇳 · Kai-Xuan Cheng · Chun-Wang Ma🇨🇳

   The Bayesian neural network (BNN) method is used to construct a predictive model for fragment prediction of proton induced spallation reactions with the guidance of a simplified EPAX formula. Compared to the experimental data, it is found that the BNN + sEPAX model can reasonably extrapolate with less information compared with BNN method. The BNN + sEPAX method provides a new approach to predict the energy-dependent residual cross sections produced in proton-induced spallation reactions from tens of MeV/u up to several GeV/u.

   ↳ nucl-thnucl-exJ.Phys.G(2022)·19 citations
4. 04*

   Evidence of quadrupole and octupole deformations in ${}^{96}$Zr+${}^{96}$Zr and ${}^{96}$Ru+${}^{96}$Ru collisions at ultra-relativistic energies

   Chunjian Zhang🇺🇸 · Jiangyong Jia🇺🇸

   In the hydrodynamic model description of heavy ion collisions, the elliptic flow $v_2$ and triangular flow $v_3$ are sensitive to the quadrupole deformation ${\beta }_2$ and octupole deformation ${\beta }_3$ of the colliding nuclei. The relations between $v_n$ and ${\beta }_n$ have recently been clarified and were found to follow a simple parametric form. The STAR Collaboration have just published precision $v_n$ data from isobaric ${}^{96}$Ru+${}^{96}$Ru and ${}^{96}$Zr+${}^{96}$Zr collisions, where they observe large differences in central collisions $v_{2,\mathrm{Ru}}>v_{2,\mathrm{Zr}}$ and $v_{3,\mathrm{Ru}}<v_{3,\mathrm{Zr}}$. Using a transport model simulation, we show that these orderings are a natural consequence of ${\beta }_{2,\mathrm{Ru}}\gg {\beta }_{2,\mathrm{Zr}}$ and ${\beta }_{3,\mathrm{Ru}}\ll {\beta }_{3,\mathrm{Zr}}$. We reproduce the centrality dependence of the $v_2$ ratio qualitatively and $v_3$ ratio quantitatively, and extract values of ${\beta }_2$ and ${\beta }_3$ that are consistent with those measured at low energy nuclear structure experiments. STAR data provide the first direct evidence of strong octupole correlations in the ground state of ${}^{96}$Zr in heavy ion collisions. Our analysis demonstrates that flow measurements in high-energy heavy ion collisions, especially using isobaric systems, are a new precision tool to study nuclear structure physics.

   ↳ nucl-thhep-phnucl-exPRL(2022)·160 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.