Tue·Nov 9, 2021Tuesday·November 9, 2021

1. 01*

   Perspectives in Small Systems : Heavy Quarks and HBT Radii

   Debasish Das🇮🇳

   Recent observations of QGP-like phenomena in small collision systems like p+p and p+A collisions have questioned our understanding of the basic paradigms of high energy heavy-ion physics. A brief discussion of these new aspects in small systems which in turn influence our understanding of hard probes like heavy quarks has been provided. Furthermore, a closer observation of the two-particle Hanbury-Brown Twiss (HBT) interferometry measurements provide new insights in our understanding of medium-like phenomena in small systems. An outlook of future goals and measurements is also made.

   nucl-exhep-exhep-phnucl-thNPA(2021)·4 citations
2. 02*

   New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering Over a Range of Spin-0 Nuclei

   PREX · CREX Collaborations: D. Adhikari (1) · H. Albataineh (2) · D. Androic (3) · K. Aniol (4) · D. S. Armstrong (5) · T. Averett (5) · C. Ayerbe Gayoso (5) · S. Barcus (6) · V. Bellini (7) · R. S. Beminiwattha (8) · J. F. Benesch (6) and 93 other authors

   We report precision determinations of the beam normal single spin asymmetries ($A_n$) in the elastic scattering of 0.95 and 2.18~GeV electrons off ${}^{12}$C, ${}^{40}$Ca, ${}^{48}$Ca, and ${}^{208}$Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of $A_n$ for ${}^{40}$Ca and ${}^{48}$Ca are found to be similar to that of ${}^{12}$C, consistent with expectations thus demonstrating the validity of theoretical calculations for nuclei with Z~$\le 20$. We also report $A_n$ for ${}^{208}$Pb at two new momentum transfers (Q${}^2$) extending the previous measurement. Our new data confirm the surprising result previously reported, with all three data points showing significant disagreement with the results from the $Z\le 20$ nuclei. These data confirm our basic understanding of the underlying dynamics that govern $A_n$ for nuclei containing $\lesssim 50$ nucleons, but point to the need for further investigation to understand the unusual $A_n$ behaviour discovered for scattering off ${}^{208}$Pb.

   nucl-exPRL(2022)·29 citations
3. 03*

   Invariant yield and azimuthal anisotropy measurements of strange and multi-strange hadrons in Au+Au collision at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV at STAR

   Prabhupada Dixit (for the STAR collaboration)🇮🇳

   In this proceedings, we have presented the invariant yield measurements of strange and multi strange hadrons such as $K_S^0$, $\Lambda$, $\bar{\Lambda }$, $\varphi$, ${\Xi }^{-}$, ${\bar{\Xi }}^{+}$, ${\Omega }^{-}$, ${\bar{\Omega }}^{+}$ in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV at midrapidity ($|y|<0.5$). The second and third-order azimuthal anisotropic flow of the above mentioned particles at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV are also discussed. Some of the important observables such as nuclear modification factor ($R_{CP}$), baryon to meson ratio ($\Omega /\varphi$), transverse momentum dependence of $v_2$ and $v_3$ are measured. The number of constituent quark (NCQ) scaling of $v_2$ and $v_3$ is studied for all these particles.

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

   Azimuthal anisotropy measurement of multi-strange hadrons in Au+Au collision at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV at STAR

   Prabhupada Dixit (for the STAR collaboration)🇮🇳

   In these proceedings, we present the second order ($v_2$) and the third order ($v_3$) azimuthal anisotropy measurements of strange and multi-strange hadrons such as $K_S^0$, $\Lambda$, $\bar{\Lambda }$, $\varphi$, ${\Xi }^{-}$, ${\bar{\Xi }}^{+}$, ${\Omega }^{-}$, ${\bar{\Omega }}^{+}$ in Au+Au collisions at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV at STAR. The centrality dependence of $v_2$ and $v_3$ as well as the number of constituent quark scaling (NCQ scaling) for all the particles mentioned above are discussed. The ratio of $v_2$ of $\varphi$ mesons to that of $\bar{p}$ is presented at $\sqrt{s_{NN}}$ = 54.4 GeV which gives a hint of mass ordering violation at low $p_T$.

   nucl-exhep-exEPJ Web Conf.(2022)·1 citation
5. 05*

   Transverse momentum dependent distributions in dijet and heavy hadron pair production at EIC

   Rafael F. del Castillo🇪🇸 · Miguel G. Echevarria🇪🇸 · Yiannis Makris🇮🇹 · Ignazio Scimemi🇪🇸

   We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in impact parameter space shows the appearance of a specific new soft factor matrix element on top of angular a complex valued anomalous dimensions. We show in detail how these features can be treated consistently and we discuss a scale prescription for the evolution kernel of the dijet soft function. As a result we obtain phenomenological predictions for unpolarized and angular modulated cross-sections for the electron-ion collider (EIC) using current available information on unpolarized TMD.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2022)·30 citations
6. 06*

   Probing charged lepton flavor violation with a positron beam at CEBAF (JLAB)

   Yulia Furletova🇺🇸 · Sonny Mantry🇺🇸

   The addition of a high intensity 11 GeV polarized positron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) at JLAB would allow for a search of Charged Lepton Flavor Violation (CLFV) via the process $e^{+}N\to {\mu }^{+}X$. The proposed Solenoidal Large Intensity Detector (SoLID) spectrometer, in the configuration with muon chambers, would be ideal for such CLFV searches. Various new physics scenarios, including the phenomenologically convenient Leptoquark (LQ) framework, predict CLFV rates that are within reach of current or planned experiments. A positron beam with instantaneous luminosity, $\mathcal{L}\sim 10^{38}$ cm${}^{-2}$s${}^{-1}$, could improve on existing HERA limits by two or three orders of magnitude. The availability of positron beam polarization would also allow for distentangling CLFV effects mediated by left-handed vs. right-handed LQs.

   ↳ hep-phhep-exnucl-exEPJA(2021)·5 citations
7. 07*

   Dineutron in the $2_1^{+}$ state of ${}^6$He

   Shoya Ogawa🇯🇵 · Takuma Matsumoto🇯🇵

   We investigate the dineutron in the $2_1^{+}$ state of ${}^6$He via analysis of its decay mode by using the complex scaling method. In this letter, we propose the cross section for the resonant state to distinguish the resonant contributions from the nonresonant ones. As the results, it is found that the shoulder peak appears in the cross section for the resonant state as a function of ${\epsilon }_{n\text{-}n}$. Furthermore, we show that the $S$ = 0 component of the cross section, where $S$ is the total spin of the valence two neutrons, has a peak around the shoulder peak, which comes from the dineutron configuration in the $2_1^{+}$ state. Thus we conclude that the shoulder peak is expected to indicate the existence of the dineutron in the $2_1^{+}$ state.

   ↳ nucl-thnucl-exPRC(2022)·2 citations
8. 08*

   Initial-state temperature of light meson emission source from squared momentum transfer spectra in high-energy collisions

   Qi Wang🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿

   The squared momentum transfer spectra of light mesons, ${\pi }^0$, ${\pi }^{+}$, $\eta$, and ${\rho }^0$, produced in high-energy virtual photon-proton (${\gamma }^{\ast }p$) $\to \mathrm{meson}+\mathrm{nucleon}$ process in electron-proton ($ep$) collisions measured by the CLAS Collaboration are analyzed by the Monte Carlo calculations, where the transfer undergoes from the incident ${\gamma }^{\ast }$ to emitted meson or equivalently from the target proton to emitted nucleon. In the calculations, the Erlang distribution from a multi-source thermal model is used to describe the transverse momentum spectra of emitted particles. Our results show that the average transverse momentum ($⟨p_T⟩$) and the initial-state temperature ($T_i$) increase from lower squared photon virtuality ($Q^2$) and Bjorken variable ($x_B$) to higher one. This renders that the excitation degree of emission source, which is described by $⟨p_T⟩$ and $T_i$, increases with increasing of $Q^2$ and $x_B$.

   ↳ hep-phhep-exnucl-exnucl-thFront.in Phys.(2021)·13 citations
9. 09*

   New hadron configuration: The double-gluon hybrid state

   Hua-Xing Chen🇨🇳 · Wei Chen🇨🇳 · Shi-Lin Zhu🇨🇳

   This is the first study on the double-gluon hybrid, which consists of one valence quark and one valence antiquark together with two valence gluons. We concentrate on the one with the exotic quantum number $J^{PC}=2^{+-}$ that conventional $\bar{q}q$ mesons can not reach. We apply QCD sum rule method to evaluate its mass to be $2.26_{-0.25}^{+0.20}$ GeV, and study its possible decay patterns. Especially, its three-meson decay patterns are generally not suppressed severely compared to two-meson decay patterns, so the $S$-wave three-meson decay channels $f_1\omega \pi /f_1\rho \pi$ can be useful in identifying its nature, which is of particular importance to the direct test of QCD in the low energy sector.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2022)·16 citations
10. 10*

    Can we decipher the composition of the core of a neutron star?

    Chiranjib Mondal🇫🇷 · Francesca Gulminelli🇫🇷

    General relativity guarantees a unique one-to-one correspondence between static observables of neutron stars (NSs) accessible by multi-messenger astronomy, such as mass-radius or tidal deformability, and the equation of state (EoS) of beta equilibrated matter. It is well known that these static properties are not enough to discern conventional NSs from hybrid stars. However, if one assumes that hadrons present in the neutron star core are only neutrons and protons, the lepton fraction is in principle determined unequivocally by the condition of chemical equilibrium. Using a simple analytical method based on a polynomial expansion of the EoS, we show that multiple solutions are possible to the beta-equilibrium equation, leading to a characteristic indetermination on the composition of the interiors of NSs, even in the purely nucleonic hypothesis. We further show that additional empirical information on symmetric matter at high densities are not very efficient to pin down the composition, if uncertainties on measurements are accounted for. We conclude that constraints on the symmetry energy at high densities only, can make meaningful impact to decipher the composition of neutron star core. Our results give a lower limit to the uncertainty on the NS core composition that can be obtained with astrophysical and terrestrial experiments.

    ↳ nucl-thastro-ph.HEnucl-exPRD(2022)·42 citations
11. 11*

    Systematic shell-model study on spectroscopic properties in the south region of ${}^{208}$Pb

    Cenxi Yuan🇨🇳 · Menglan Liu · Noritaka Shimizu🇯🇵 · Zs. Podolyak🇬🇧 · Toshio Suzuki🇯🇵 · Takaharu Otsuka🇯🇵 · Zhong Liu🇨🇳

    We aim to study the properties of nuclei in the south region of ${}^{208}$Pb systematically, including the binding and excitation energies and electromagnetic properties, in order to predict unknown properties of these nuclei, such as isomerism, utilizing a theoretical model which describes the experimentally known properties precisely. We also address whether the $N=126$ shell closure is robust or not when the proton number decreases from ${}^{208}$Pb. We performed large-scale shell-model calculations with a new Hamiltonian suggested in the present work. The model space is taken as the five proton orbits within $50<Z⩽82$ and the thirteen neutron orbits within $82<N⩽184$. And one-particle one-hole excitation is allowed across the $N=126$ gap. The Hamiltonian is constructed by combining the existing Hamiltonians, KHHE (with adjustment of its proton-proton part) and KHPE, and the monopole based universal interaction. The shell-model results well reproduce the experimentally observed binding energies and spectroscopic properties, such as isomerism, core excitation, and electromagnetic properties. Some possible isomeric states in neutron-rich Pb, Tl, and Hg isotopes are predicted with transition energies and half-lives. We also examine the effective charges and the quenching of the $g$ factors suitable for this region by systematic comparisons between observed and calculated electromagnetic properties. A new Hamiltonian is constructed for nuclei in the south region of ${}^{208}$Pb, mainly including Pb, Tl, Hg, Au, Pt, Ir, Os, Re, and W isotopes around $N=126$, and provides them reasonable descriptions on nuclear properties including binding energies, excitation energies and electromagnetic properties through comprehensive and systematic studies.

    ↳ nucl-thnucl-exPRC(2022)·24 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.