Nuclear Theory·nucl-th

Thursday·July 30, 2020

9 papers—3 primary·6 cross-listed

01
Strange hadron production in a quark combination model in Au+Au collisions at RHIC energies
Jun Song🇨🇳 · Xiao-feng Wang🇨🇳 · Hai-hong Li🇨🇳 · Rui-qin Wang🇨🇳 · Feng-lan Shao🇨🇳
We apply a quark combination model to study yield densities and transverse momentum ( $p_{T}$ ) spectra of strange (anti-)hadrons at mid-rapidity in central Au+Au collisions at $s_{N N} =$ 7.7, 11.5, 19.6, 27, 39 and 200 GeV. We show that experimental data for $p_{T}$ spectra of (anti-)hadrons in these collisions can be systematically described by the equal velocity combination of constituent quarks and antiquarks at hadronization. We obtain $p_{T}$ spectra of quarks and antiquarks at hadronization and study their collision energy dependence. We also reproduce the yield densities of hadrons and anti-hadrons. In particular, we demonstrate that yield ratios of anti-hadrons to hadrons $K^{-} / K^{+}$ , $p ˉ / p$ , $Λ ˉ /Λ$ , $Ξ ˉ^{+} / Ξ^{-}$ and $Ω ˉ^{+} / Ω^{-}$ simply correlate with each other and their experimental data except $Ω ˉ^{+} / Ω^{-}$ at $s_{N N} =$ 7.7 GeV are systematically described by the model. These results suggest that the equal velocity combination mechanism for quarks and antiquarks at hadronization plays an important role in Au+Au collisions at low RHIC energies ( $s_{N N} \geq$ 11.5 GeV).
nucl-thhep-phPRC(2021)·13 citations
02
Applications of the chiral potential with the semi-local regularization in momentum space to the disintegration processes
V.Urbanevych🇵🇱 · R.Skibiński🇵🇱 · H.Witała🇵🇱 · J.Golak🇵🇱 · K.Topolnicki🇵🇱 · A.Grassi🇵🇱 · E.Epelbaum🇩🇪 · H.Krebs🇩🇪
We apply the chiral potential with the momentum space semi-local regularization to the $^{2}$ H and $^{3}$ He photodisintegration processes and to the (anti)neutrino induced deuteron breakup reactions. Specifically, the differential cross section, the photon analyzing power and the final proton polarization have been calculated for the deuteron photodisintegration at the photon energies 30 MeV and 100 MeV. For the $^{3}$ He photodisintegration predictions for the semi-inclusive and exclusive differential cross sections are presented for the photon energies up to 120 MeV. The total cross section is calculated for the (anti)neutrino disintegrations of the deuteron for the (anti)neutrino energies below 200 MeV. The predictions based on the Argonne V18 potential or on the older chiral force with regularization applied in coordinate space are used for comparison. Using the fifth order chiral nucleon-nucleon potential supplemented with dominant contributions from the sixth order allows us to obtain converged predictions for the regarded reactions and observables. Our results based on the newest semi-local chiral potentials show even smaller cutoff dependence for the considered electroweak observables than the previously reported ones with a coordinate-space regulator. However, some of the studied polarization observables in the deuteron photodisintegration process reveal more sensitivity to the regulator value than the unpolarized cross section. The chiral potential regularized semi-locally in momentum space yields also fast convergence of results with the chiral order. These features make the used potential a high quality tool to study electroweak processes.
nucl-thPRC(2021)·5 citations
03
Simple relativistic quark models
Sirajudheen Kuthini Kunhammed🇺🇸 · W. N. Polyzou🇺🇸
A class of phenomenological relativistic models of hadronic systems motivated by QCD that have dual representations as models of mesons and nucleons or quarks and gluons is investigated. These models are designed to provided qualitative insight into the role of sea quarks in hadronic structure and reactions. The model assumption is that the Hamiltonian can be divided into two parts; one that involves degrees of freedom in the same connected local and global color singlet and the remaining interactions that allow the connected local and global color singlets to interact. The first class of interactions results in infinite towers of bare "particles" with hadronic quantum numbers. All but a finite number of these remain stable when the second class of interactions is included. The model interactions are expressed in terms of sub-hadronic degrees of freedom, which determine the bare hadronic spectrum and the interactions involving the bare hadrons in terms of a small number of sub-hadronic model parameters. As a first test, this paper considers the simplest case of mesons that interact via a string-breaking interaction. One virtue of this model is that all of the bare meson masses and eigenfunctions can be computed analytically. In addition, the string breaking interaction leads to production vertices that can also be computed analytically. The relativistic wave functions have a light-front kinematic symmetry. The goal is to find a simple relativistic quantum mechanical model based on sub-hadronic degrees of freedom that can provide an efficient, qualitatively consistent description of hadronic masses, lifetimes, cross sections, sea quark effects, and electromagnetic properties. The simplicity of the model makes it a potentially useful tool to study the impact of sea quarks on hadronic structure and reactions.
nucl-thhep-phPRC(2020)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Strange hadron production in a quark combination model in Au+Au collisions at RHIC energies

Applications of the chiral potential with the semi-local regularization in momentum space to the disintegration processes

Simple relativistic quark models

Affiliations