Wed·Jan 27, 2021Wednesday·January 27, 2021

1. 01*

   Nuclear matter distributions in the neutron-rich carbon isotopes ${}^{14-17}$C from intermediate-energy proton elastic scattering in inverse kinematics

   A.V. Dobrovolsky (a)🇷🇺 · G.A. Korolev (a)🇷🇺 · S. Tang (b,1)🇩🇪 · G.D. Alkhazov (a)🇷🇺 · G. Coló (c)🇮🇹 · I. Dillmann (b,2)🇩🇪 · P. Egelhof (b)🇩🇪 · A. Estradé (b,3)🇩🇪 · F. Farinon (b)🇩🇪 · H. Geissel (b)🇩🇪 · S. Ilieva (b)🇩🇪 · A.G. Inglessi (a)🇷🇺 and 16 other authors

   The absolute differential cross sections for small-angle proton elastic scattering off the nuclei ${}^{12,14-17}$C have been measured in inverse kinematics at energies near 700 MeV/u at GSI Darmstadt. The hydrogen-filled ionization chamber IKAR served simultaneously as a gas target and a detector for the recoil protons. The projectile scattering angles were measured with multi-wire tracking detectors. The radial nuclear matter density distributions and the root-mean-square nuclear matter radii were deduced from the measured cross sections using the Glauber multiple-scattering theory. A possible neutron halo structure in ${}^{15}$C, ${}^{16}$C and ${}^{17}$C is discussed. The obtained data show evidence for a halo structure in the ${}^{15}$C nucleus.

   nucl-exnucl-thNPA(2021)·21 citations
2. 02*

   Search for Double-Beta Decay of ${}^{130}\mathrm{Te}$ to the $0^{+}$ States of ${}^{130}\mathrm{Xe}$ with CUORE

   CUORE Collaboration: D. Q. Adams · C. Alduino · K. Alfonso · F. T. Avignone III · O. Azzolini · G. Bari · F. Bellini · G. Benato · M. Biassoni A. Branca · C. Brofferio · C. Bucci · J. Camilleri and 95 other authors

   The CUORE experiment is a large bolometric array searching for the lepton number violating neutrino-less double beta decay ($0\nu \beta \beta$) in the isotope ${}^{130}\mathrm{Te}$. In this work we present the latest results on two searches for the double beta decay (DBD) of ${}^{130}\mathrm{Te}$ to the first $0_2^{+}$ excited state of ${}^{130}\mathrm{Xe}$: the $0\nu \beta \beta$ decay and the Standard Model-allowed two-neutrinos double beta decay ($2\nu \beta \beta$). Both searches are based on a 372.5 kg$\times$yr TeO${}_2$ exposure. The de-excitation gamma rays emitted by the excited Xe nucleus in the final state yield a unique signature, which can be searched for with low background by studying coincident events in two or more bolometers. The closely packed arrangement of the CUORE crystals constitutes a significant advantage in this regard. The median limit setting sensitivities at 90\% Credible Interval (C.I.) of the given searches were estimated as ${\mathrm{S}}_{1/2}^{0\nu }=5.6\times 10^{24}\mathrm{yr}$ for the $0\nu \beta \beta$ decay and ${\mathrm{S}}_{1/2}^{2\nu }=2.1\times 10^{24}\mathrm{yr}$ for the $2\nu \beta \beta$ decay. No significant evidence for either of the decay modes was observed and a Bayesian lower bound at $90\%$ C.I. on the decay half lives is obtained as: $({\mathrm{T}}_{1/2}{)}_{0_2^{+}}^{0\nu }>5.9\times 10^{24}\mathrm{yr}$ for the $0\nu \beta \beta$ mode and $({\mathrm{T}}_{1/2}{)}_{0_2^{+}}^{2\nu }>1.3\times 10^{24}\mathrm{yr}$ for the $2\nu \beta \beta$ mode. These represent the most stringent limits on the DBD of ${}^{130}$Te to excited states and improve by a factor $\sim 5$ the previous results on this process.

   nucl-exEPJC(2021)·16 citations
3. 03*

   Two-particle azimuthal correlations in photonuclear ultraperipheral Pb+Pb collisions at 5.02 TeV with ATLAS

   ATLAS Collaboration

   Two-particle long-range azimuthal correlations are measured in photonuclear collisions using 1.7 nb${}^{-1}$ of 5.02 TeV Pb+Pb collision data collected by the ATLAS experiment at the LHC. Candidate events are selected using a dedicated high-multiplicity photonuclear event trigger, a combination of information from the zero-degree calorimeters and forward calorimeters, and from pseudorapidity gaps constructed using calorimeter energy clusters and charged-particle tracks. Distributions of event properties are compared between data and Monte Carlo simulations of photonuclear processes. Two-particle correlation functions are formed using charged-particle tracks in the selected events, and a template-fitting method is employed to subtract the non-flow contribution to the correlation. Significant nonzero values of the second- and third-order flow coefficients are observed and presented as a function of charged-particle multiplicity and transverse momentum. The results are compared with flow coefficients obtained in proton-proton and proton-lead collisions in similar multiplicity ranges, and with theoretical expectations. The unique initial conditions present in this measurement provide a new way to probe the origin of the collective signatures previously observed only in hadronic collisions.

   nucl-exhep-exPRC(2021)·103 citations
4. 04*

   Determining the temperature in heavy-ion collisions with multiplicity distribution

   Y. D. Song🇨🇳 · R. Wang🇨🇳 · Y. G. Ma🇨🇳 · X. G. Deng🇨🇳 · H. L. Liu🇨🇳

   By relating the charge multiplicity distribution and the temperature of a de-exciting nucleus through a deep neural network, we propose that the charge multiplicity distribution can be used as a thermometer of heavy-ion collisions. Based on an isospin-dependent quantum molecular dynamics model, we study the caloric curve of reaction ${}^{103}$Pd + ${}^9$Be with the apparent temperature determined through the charge multiplicity distribution. The caloric curve shows a characteristic signature of nuclear liquid-gas phase transition around the apparent temperature $T_{\mathrm{ap}}$ $=$ $6.4\mathrm{MeV}$, which is consistent with that through a traditional heavy-ion collision thermometer, and indicates the viability of determining the temperature in heavy-ion collisions with multiplicity distribution.

   ↳ nucl-thhep-phnucl-exPLB(2021)·33 citations
5. 05*

   Weak Kaon Production off the nucleon and Watson's theorem

   E. Saul-Sala🇪🇸 · J. E. Sobczyk🇩🇪 · M. Rafi Alam🇮🇳 · L. Alvarez-Ruso🇪🇸 · J. Nieves🇪🇸

   We have improved the tree-level model of Ref arXiv:1004.5484 [hep-ph] for weak production of kaons off nucleons by partially restoring unitarity. This is achieved by imposing Watson's theorem to the dominant vector and axial-vector contributions in appropriate angular momentum and isospin quantum number sectors. The observable consequences of this procedure are investigated.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2021)·2 citations
6. 06*

   Photon pair distributions and event-mixing at low invariant mass

   Mike Sas🇳🇱 · Lizette Lamers🇳🇱 · Thomas Peitzmann🇳🇱

   Neutral meson cross-section and direct photon HBT measurements in high energy pp, pA, and AA collisions rely on either subtracting or dividing out the background underlying the $M_{\mathrm{inv}}$ or $Q_{\mathrm{inv}}$ distributions. In this paper we investigate the photon pair distributions for simulated proton-proton collisions at $\sqrt{s}=13$TeV, and study why the background in $M_{\mathrm{inv}}$ gets poorly described by the conventional event-mixing method implemented in experimental analyses. We show that it fails to describe the background as it gives a qualitatively different shape especially at invariant masses around the ${\pi }^0$ and $\eta$ meson mass, which is mainly caused by the correlations originating from parton fragmentation.

   ↳ hep-phnucl-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.