Tue·Jul 20, 2021Tuesday·July 20, 2021

1. 01*

   Measurement of the Bjorken Sum at very low $Q^2$

   A. Deur🇺🇸 · J. P. Chen🇺🇸 · S. E. Kuhn🇺🇸 · C. Peng🇺🇸 · M. Ripani🇮🇹 · V. Sulkosky🇺🇸 · K. Adhikari🇩🇪 · M. Battaglieri🇺🇸 · V. D. Burkert🇺🇸 · G. D. Cates🇺🇸 · R. De Vita🇮🇹 · G. E. Dodge🇺🇸 and 8 other authors

   We present new data on the Bjorken sum ${\overline{\Gamma }}_1^{p-n}(Q^2)$ at 4-momentum transfer $0.021\le Q^2\le 0.496$ GeV${}^2$. The data were obtained in two experiments performed at Jefferson Lab: EG4 on polarized protons and deuterons, and E97110 on polarized ${}^3$He from which neutron data were extracted. The data cover the domain where chiral effective field theory ($\chi$EFT), the leading effective theory of the Strong Force at large distances, is expected to be applicable. We find that our data and the predictions from $\chi$EFT are only in marginal agreement. This is somewhat surprising as the contribution from the $\Delta (1232)$ resonance is suppressed in this observable, which should make it more reliably predicted by $\chi$EFT than quantities in which the $\Delta$ contribution is important. The data are also compared to a number of phenomenological models with various degrees of agreement.

   nucl-exPLB(2022)·38 citations
2. 02*

   Production of $D_s^{\pm }$ mesons in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 200 GeV by STAR

   Chuan Fu🇨🇳

   Charm quarks are an excellent probe to study properties of the Quark-Gluon Plasma (QGP) created in ultra-relativistic heavy-ion collisions. In particular, measurements of the $D_s^{\pm }$ meson production can provide valuable information on the charm quark hadronization mechanism in the QGP. We report the measurements from the STAR experiment on the invariant yields of $D_s^{\pm }$ mesons as a function of transverse momentum for different centrality classes of Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 200 GeV. These measurements utilize the data with the Heavy Flavor Tracker detector from 2014 and 2016. The ratio between strange ($D_s^{\pm }$) and non-strange ($D^0$) open charm mesons will also be shown, and compared to PYTHIA and different model calculations. A clear enhancement relative to the PYTHIA calculation is seen in the ratio, while different model calculations incorporating strangeness enhancement and charm quark coalescence hadronization can describe the observed enhancement qualitatively. These results suggest that recombination of charm quarks with strange quarks in the QGP plays an important role in charm quark hadronization.

   nucl-exPoS(2021)·0 citations
3. 03*

   Heavy Flavor and Jet Studies for the Future Electron-Ion Collider to Explore the Hadronization Process

   Xuan Li🇺🇸

   Heavy flavor production at the future Electron-Ion Collider (EIC) will allow us to precisely determine the quark/gluon fragmentation processes in vacuum and the nuclear medium especially within the poorly constrained kinematic region. Heavy flavor hadron and jet reconstruction with the recent EIC detector design have been studies in simulation. Results of corresponding physics projections such as the flavor dependent hadron nuclear modification factor $R_{eA}$ in electron+nucleus collisions will be shown. The statistical precision obtained by these proposed heavy flavor measurements for the future EIC provides a strong discriminating power in separating different theoretical predictions.

   nucl-exhep-exhep-phnucl-thSciPost Phys.Proc.(2022)·6 citations
4. 04*

   ERLC (Twin LC) and LHC/FCC Based eA Colliders

   A. N. Akay🇹🇷 · B. Dagli🇹🇷 · B. Ketenoglu🇹🇷 · S. Sultansoy🇹🇷

   Construction of the ERLC (twin LC) collider tangential to LHC or FCC will give opportunity to realize eA collisions at multi-TeV center-of-mass energies. Luminosity estimations show that values comparable with that of ERL60 based eA colliders are achievable while center of mass energies are essentially higher. Certainly, proposed eA colliders have great potential for clarifying QCD basics and nuclear structure.

   ↳ physics.acc-phhep-exhep-phnucl-ex+11 citation
5. 05*

   Microscopic self-consistent description of induced fission: dynamical pairing degree of freedom

   Jie Zhao · Tamara Nikšić🇭🇷 · Dario Vretenar🇭🇷

   The role of dynamical pairing in induced fission dynamics is investigated using the time-dependent generator coordinate method in the Gaussian overlap approximation, based on the microscopic framework of nuclear energy density functionals. A calculation of fragment charge yields for induced fission of ${}^{228}$Th is performed in a three-dimensional space of collective coordinates that, in addition to the axial quadrupole and octupole intrinsic deformations of the nuclear density, also includes an isoscalar pairing degree of freedom. It is shown that the inclusion of dynamical pairing has a pronounced effect on the collective inertia, the collective flux through the scission hyper-surface, and the resulting fission yields, reducing the asymmetric peaks and enhancing the contribution of symmetric fission, in better agreement with the empirical trend.

   ↳ nucl-thnucl-exPRC(2021)·22 citations
6. 06*

   Hydrodynamic description of the baryon-charged quark-gluon plasma

   Lipei Du (Ohio State U.)🇺🇸

   One of the primary goals of nuclear physics is studying the phase diagram of Quantum Chromodynamics, where a hypothetical critical point serves as a landmark. A systematic model-data comparison of heavy-ion collisions at center-of-mass energies between 1 and 100 GeV per nucleon is essential for locating the critical point and the phase boundary between the deconfined quark-gluon plasma and the confined hadron resonance gas. At these energies the net baryon density of the system can be high and critical fluctuations can become essential in the presence of the critical point. Simulating their dynamical evolution thus becomes an indispensable part of theoretical modeling. In this thesis we first present the (3+1)-dimensional relativistic hydrodynamic code BEShydro, which solves the equations of motion of second-order Denicol-Niemi-Molnar-Rischke theory, including bulk and shear viscous components as well as baryon diffusion current. We then study the effects caused by the baryon diffusion on the longitudinal dynamics and on the phase diagram trajectories of fluid cells at different space-time rapidities of the system, and how they are affected by critical dynamics near the critical point. We finally explore the evolution of non-hydrodynamic slow processes describing long wavelength critical fluctuations near the critical point, by extending the conventional hydrodynamic description by coupling it to additional explicitly evolving slow modes, and their back-reaction to the bulk matter properties.

   ↳ nucl-thhep-phnucl-ex5 citations
7. 07*

   The Future of Solar Neutrinos

   G. D. Orebi Gann🇺🇸 · K. Zuber🇩🇪 · D. Bemmerer🇩🇪 · A. Serenelli🇪🇸

   In this article we review the current state of the field of solar neutrinos, including flavour oscillations, non-standard effects, solar models, cross section measurements, and the broad experimental program thus motivated and enabled. We discuss the historical discoveries that contributed to current knowledge, and define critical open questions to be addressed in the next decade. We discuss the state of the art of standard solar models, including uncertainties and problems related to the solar composition, and review experimental and model solar neutrino fluxes, including future prospects. We review the state of the art of the nuclear reaction data relevant for solar fusion in the proton-proton chain and carbon-nitrogen-oxygen cycle. Finally, we review the current and future experimental program that can address outstanding questions in this field.

   ↳ hep-phastro-ph.SRhep-exnucl-exAnn.Rev.Nucl.Part.Sci.(2021)·69 citations
8. 08*

   Two-neutrino double-beta decay matrix elements based on relativistic nuclear energy density functional

   N. Popara🇭🇷 · A. Ravlić🇭🇷 · N. Paar🇭🇷

   Nuclear matrix elements (NMEs) for two-neutrino double-beta decay ($2\nu \beta \beta$) are studied in the framework of relativistic nuclear energy density functional (REDF). The properties of nuclei involved in the decay are obtained using the relativistic Hartree-Bardeen-Cooper-Schrieffer theory and relevant nuclear transitions are described using the relativistic proton-neutron quasiparticle random phase approximation based on relativistic energy density functional (REDF-QRPA). Three effective interactions have been employed, including density-dependent meson-exchange (DD-ME2) and point coupling interactions (DD-PC1 and DD-PCX), and pairing correlations are described consistently both in $T=1$ and $T=0$ channels using a separable pairing interaction. The optimal values of $T=0$ pairing strength parameter $V_{0pp}$ are constrained by the experimental data on $\beta$-decay half lives. The $2\nu \beta \beta$ matrix elements and half-lives are calculated for several nuclides experimentally known to undergo this kind of decay: ${}^{48}$Ca, ${}^{76}$Ge, ${}^{82}$Se, ${}^{96}$Zr, ${}^{100}$Mo, ${}^{116}$Cd, ${}^{124}$Xe, ${}^{128}$Te, ${}^{130}$Te, ${}^{136}$Xe and ${}^{150}$Nd. The model dependence of the NMEs and their sensitivity on $V_{0pp}$ is investigated, and the NMEs obtained using optimal values of $V_{0pp}$ are discussed in comparison to previous studies. The results of the present work represent an important benchmark for the future applications of the relativistic framework in studies of neutrinoless double-beta decay.

   ↳ nucl-thnucl-exPRC(2022)·13 citations
9. 09*

   Unpolarized gluon distribution in the nucleon from lattice quantum chromodynamics

   Tanjib Khan🇺🇸 · Raza Sabbir Sufian🇺🇸 · Joseph Karpie🇺🇸 · Christopher J. Monahan🇺🇸 · Colin Egerer🇺🇸 · Bálint Joó🇺🇸 · Wayne Morris🇺🇸 · Kostas Orginos🇺🇸 · Anatoly Radyushkin🇺🇸 · David G. Richards🇺🇸 · Eloy Romero🇺🇸 · Savvas Zafeiropoulos🇫🇷

   In this study, we present a determination of the unpolarized gluon Ioffe-time distribution in the nucleon from a first principles lattice quantum chromodynamics calculation. We carry out the lattice calculation on a $32^3\times 64$ ensemble with a pion mass of $358$ MeV and lattice spacing of $0.094$ fm. We construct the nucleon interpolating fields using the distillation technique, flow the gauge fields using the gradient flow, and solve the summed generalized eigenvalue problem to determine the glounic matrix elements. Combining these techniques allows us to provide a statistically well-controlled Ioffe-time distribution and unpolarized gluon PDF. We obtain the flow time independent reduced Ioffe-time pseudo-distribution, and calculate the light-cone Ioffe-time distribution and unpolarized gluon distribution function in the $\overline{\mathrm{MS}}$ scheme at $\mu =2$ GeV, neglecting the mixing of the gluon operator with the quark singlet sector. Finally, we compare our results to phenomenological determinations.

   ↳ hep-lathep-exhep-phnucl-ex+1PRD(2021)·80 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.