Tue·Sep 3, 2024Tuesday·September 3, 2024

1. 01*

   Status report on long-time decay measurements of 137Cs radioisotope

   Franciska Sprok · Edit Fenyvesi · Gábor Gyula Kiss🇭🇺 · Dénes Molnár · Péter Lévai · Gergely Gábor Barnaföldi🇭🇺

   The constancy of nuclear decay rates can be investigated via long-duration precision measurements. It is still an open question whether any (annual) modulation can be observed. Long-lasting nuclear decay rate measurements have been the subject of considerable research effort. A decay rate measurement with a 137Cs source is currently being conducted 30 meters below the ground at the Jánossy Underground Research Laboratory (JURLab, Csillebérc, Hungary) utilizing a High-purity Germanium (HPGe) detector. The laboratory is the low-radiation-background part of the Vesztergombi High Energy Laboratory (VLAB) on the KFKI campus, Csillebérc, Hungary. From October 2022 to April 2024, data of 18 months' worth have been collected, providing a new opportunity to look for variations in decay rates. The experimental setup, data processing method, and the first results of this measurement are presented here.

   nucl-ex0 citations
2. 02*

   Mini-Proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024)"

   P.Achenbach🇺🇸 · K.Aoki🇯🇵 · S.Aoki · C.Curceanu🇮🇹 · S.Diehl🇩🇪 · T.Doi🇯🇵 · M.Endo · M.Fujita🇯🇵 · T.Fukuda🇯🇵 · H.Garcia-Tecocoatzi🇮🇹 · L.S.Geng🇨🇳 · T.Gunji🇯🇵 and 49 other authors

   The mini proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024) [https://kds.kek.jp/event/46965]" held at J-PARC, February 19-21, 2024, are presented. The workshop was devoted to discussing the physics case that connects both the present and the future Hadron Experimental Facility at J-PARC, covering a wide range of topics in flavor, hadron, and nuclear physics related to both experimental and theoretical activities being conducted at the facility.

   nucl-exhep-exhep-phnucl-th5 citations
3. 03*

   Strength measurement of the $E_{\alpha }^{lab}$ = 830 keV resonance in ${}^{22}\mathrm{Ne}(\alpha ,\mathrm{n}{)}^{25}\mathrm{Mg}$ reaction using a stilbene detector

   Shahina🇺🇸 · R.J. deBoer🇺🇸 · J. Gorres · R. Fang🇺🇸 · M. Febbraro🇺🇸 · R. Kelmar · M. Matney🇺🇸 · K. Manukyan🇺🇸 · J.T. Nattress🇺🇸 · E. Robles · T.J. Ruland🇺🇸 · T.T. King🇺🇸 and 4 other authors

   The interplay between the ${}^{22}$Ne$(\alpha ,\gamma {)}^{26}$Mg and the competing ${}^{22}$Ne$(\alpha ,n{)}^{25}$Mg reactions determines the efficiency of the latter as a neutron source at the temperatures of stellar helium burning. In both cases, the rates are dominated by the $\alpha$-cluster resonance at 830 keV. This resonance plays a particularly important role in determining the strength of the neutron flux for both the weak and main $s$-process as well as the $n$-process. Recent experimental studies based on transfer reactions suggest that the neutron and $\gamma$-ray strengths for this resonance are approximately equal. In this study, the ${}^{22}$Ne$(\alpha ,n{)}^{25}$Mg resonance strength has been remeasured and found to be similar to the previous direct studies. This reinforces an 830 keV resonance strength that is approximately a factor of three larger for the ${}^{22}$Ne$(\alpha ,n{)}^{25}$Mg reaction than for the ${}^{22}$Ne$(\alpha ,\gamma {)}^{26}$Mg reaction.

   nucl-exPRC(2024)·5 citations
4. 04*

   Charm Sivers function at EicC

   Senjie Zhu🇨🇳 · Duxin Zheng🇨🇳 · Lei Xia🇨🇳 · Yifei Zhang🇨🇳

   The Electron-Ion Collider in China (EicC) is pivotal in enhancing our knowledge of the internal structure of nucleons and nuclei, particularly through the study of transverse momentum-dependent parton distributions (TMDs). Among the leading-twist TMDs, the Sivers function is of particular interest, as it provides crucial insights into the spin and momentum structure of hadrons and plays a significant role in describing transverse single spin asymmetries (SSAs) in high-energy scatterings. In this study, we focus on the theoretical framework and phenomenological implications of the Sivers function in the context of small-x physics, where it is intricately connected to the spin-dependent QCD odderon, demonstrating that the SSA can be expressed in terms of transverse momentum-dependent factorization within the Color Glass Condensate effective theory. Furthermore, we present simulation results using PythiaeRHIC to assess the feasibility of measuring the charm quark Sivers function at EicC. The simulation outcomes suggest that EicC, with its unique kinematic coverage, offers distinct advantages for probing the Sivers function, which would provide compelling evidence for the existence of the elusive spin-dependent odderon.

   ↳ hep-phnucl-exPRD(2025)·6 citations
5. 05*

   Pseudorapidity distributions of charged hadrons in lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV

   CMS Collaboration

   The pseudorapidity ($\eta$) distributions of charged hadrons are measured using data collected at the highest ever nucleon-nucleon center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV for collisions of lead-lead ions. The data were recorded by the CMS experiment at the LHC in 2022 and correspond to an integrated luminosity of 0.30 $\pm$ 0.03 $\mu$b${}^{-1}$. Using the CMS silicon pixel detector, the yields of primary charged hadrons produced in the range $|\eta |$ $<$ 2.6 are reported. The evolution of the midrapidity particle density as a function of collision centrality is also reported. In the 5% most central collisions, the charged-hadron $\eta$ density in the range $|\eta |$ $<$ 0.5 is found to be 2032 $\pm$ 91 (syst), with negligible statistical uncertainty. This result is consistent with an extrapolation from nucleus-nucleus collision data at lower center-of-mass energies. Comparisons are made to various Monte Carlo event generators and to previous measurements of lead-lead and xenon-xenon collisions at similar collision energies. These new data detail the dependence of particle production on the collision energy, initial collision geometry, and the size of the colliding nuclei.

   ↳ hep-exnucl-exPLB(2025)·19 citations
6. 06*

   Density correlations under global and local charge conservation

   Volodymyr Vovchenko🇺🇸

   This work presents a formalism to compute spatial $n$-point correlations of a conserved charge density in a large thermal system in the canonical ensemble, with explicit results presented up to 4th order. The resulting correlators contain local and balancing terms expressed through the grand-canonical susceptibilities for any equation of state. The new formalism is used to introduce a Gaussian local baryon number conservation in (spatial) rapidity in heavy-ion collisions at LHC conditions through a modulation of the balancing term. Connection to the conservation volume $V_c$ approach is established, indicating that the latter is appropriate for observables within a limited range around midrapidity. Quantitative analysis of the experimental data of the ALICE Collaboration on net proton cumulants in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV shows significant evidence for local baryon conservation.

   ↳ hep-phnucl-exnucl-thPRC(2024)·13 citations
7. 07*

   Origins and impacts of dynamical diquark correlations -- A continuum Schwinger functional approach --

   Jorge Segovia🇪🇸

   This conference proceedings contribution emphasizes the emergent hadron mass paradigm, which accounts for the majority of the visible mass in the universe, beyond the Higgs boson mechanism. The study delves into the Landau gauge gluon propagator and the dynamical generation of gluon mass, as well as the dressed-quark propagator and dynamical chiral symmetry breaking. It also tackles the baryon bound state problem through the Poincaré-covariant Faddeev equation, analyzing the composition and masses of octet and decuplet baryons. The document concludes with a discussion on the electromagnetic form factors of the nucleon and its first radial excitation, providing insights into the quark-diquark structure within baryons.

   ↳ hep-phhep-exhep-latnucl-ex+1PoS(2025)·0 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.