Thu·Dec 2, 2021Thursday·December 2, 2021

1. 01*

   Physics with CEBAF at 12 GeV and Future Opportunities

   J. Arrington🇺🇸 · M. Battaglieri🇺🇸 · A. Boehnlein🇺🇸 · S.A. Bogacz🇺🇸 · W.K. Brooks🇨🇱 · E. Chudakov🇺🇸 · I. Cloet🇺🇸 · R. Ent🇺🇸 · H. Gao🇺🇸 · J. Grames🇺🇸 · L. Harwood🇺🇸 · X.Ji🇺🇸 and 12 other authors

   We summarize the ongoing scientific program of the 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF) and give an outlook into future scientific opportunities. The program addresses important topics in nuclear, hadronic, and electroweak physics including nuclear femtography, meson and baryon spectroscopy, quarks and gluons in nuclei, precision tests of the standard model, and dark sector searches. Potential upgrades of CEBAF are considered, such as higher luminosity, polarized and unpolarized positron beams, and doubling the beam energy.

   nucl-exhep-exhep-phnucl-thPPNP(2022)·133 citations
2. 02*

   Measurements of Proton High Order Cumulants in 3 GeV Au+Au Collisions and Implications for the QCD Critical Point

   STAR Collaboration: M. S. Abdallah · B. E. Aboona · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D.M. Anderson and 390 other authors

   We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at 3.0 GeV, measured by the STAR experiment in the kinematic acceptance of rapidity ($y$) and transverse momentum ($p_{\mathrm{T}}$) within $-0.5<y<0$ and $0.4<p_{\mathrm{T}}<2.0$ GeV/$c$. In the most central 0--5\% collisions, a proton cumulant ratio is measured to be $C_4/C_2=-0.85\pm 0.09(stat.)\pm 0.82(syst.)$, which is less than unity, the Poisson baseline. The hadronic transport UrQMD model reproduces our $C_4/C_2$ in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in $C_4/C_2$ is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3\,GeV.

   nucl-exPRL(2022)·140 citations
3. 03*

   Measurements of lepton-jet azimuthal decorrelation and 1-jetttiness event shape at high $Q^2$ in deep inelastic scattering (DIS) with the H1 experiment at HERA

   Sookhyun Lee🇺🇸

   Recent progress towards realizing the Electron-Ion Collider (EIC) that was announced in 2020 to be built at Brookhaven National Laboratory (BNL) in the United States has revived interests in the deep-inelastic-scattering (DIS) data taken from $ep$ collisions at Hadron-Electron Ring Accelerator (HERA). The H1 detector equipped with tracking and fully instrumented calorimeter detectors in its hermetic and asymmetric design is well suited for jet and event shape measurements. Proposed measurements involving jets, global events shapes and correlations in DIS for HERA and EIC focus on the three-dimensional description of nucleon structure and hadronization and their their flavor dependence as well as precision measurements for QCD and BSM. This contribution presents recent results on the lepton-jet azimuthal decorrelation and the 1-jettiness event shape measurements performed using the DIS data at high $Q^2$ taken with the H1 detector at HERA.

   nucl-exhep-exPoS(2022)·0 citations
4. 04*

   Production of light (anti)nuclei in pp collisions at $\sqrt{s}=5.02$ TeV

   ALICE Collaboration

   The study of the production of nuclei and antinuclei in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper, the production of protons, deuterons and ${}^3$He and their charge conjugates at midrapidity is studied as a function of the charged-particle multiplicity in inelastic pp collisions at $\sqrt{s}=5.02$ TeV using the ALICE detector. Within the uncertainties, the yields of nuclei in pp collisions at $\sqrt{s}=5.02$ TeV are compatible with those in pp collisions at different energies and to those in p-Pb collisions when compared at similar multiplicities. The measurements are compared with the expectations of coalescence and Statistical Hadronisation Models. The results suggest a common formation mechanism behind the production of light nuclei in hadronic interactions and confirm that they do not depend on the collision energy but on the number of produced particles.

   nucl-exhep-exEPJC(2022)·39 citations
5. 05*

   Perturbative and non-perturbative effects in ultraperipheral production of lepton pairs

   I.M. Dremin🇷🇺

   Perturbative and non-perturbative terms of the cross sections of ultraperipheral production of lepton pairs in ion collisions are taken into account. It is shown that production of low-mass $e^{+}{e}^{-}$ pairs is strongly enhanced (compared to perturbative estimates) due to the non-perturbative Sommerfeld-Gamow-Sakharov (SGS) factor. Coulomb attraction of the non-relativistic components of those pairs leads to the finite value of their mass distribution at lowest masses. Their annihilation can result in the increased intensity of 511 keV photons. It can be recorded at the NICA collider and is especially crucial in astrophysical implications regarding the 511 keV line emitted from the Galactic center. The analogous effect can be observed in lepton pairs production at LHC. Energy spectra of lepton pairs created in ultraperipheral nuclear collisions and their transverse momenta are calculated.

   ↳ hep-phastro-ph.HEhep-exnucl-ex+10 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.