Nuclear Theory·nucl-th

Friday·April 2, 2021

6 papers—4 primary·2 cross-listed

01
Constraints on $Ξ^{-}$ nuclear interactions from capture events in emulsion
E. Friedman🇮🇱 · A. Gal🇮🇱
Five $Ξ^{-} p \to ΛΛ$ two-body capture events in $^{12}$ C and $^{14}$ N emulsion nuclei, in which a pair of single- $Λ$ hypernuclei is formed and identified by their weak decay, have been observed in $(K^{-}, K^{+})$ emulsion exposures at KEK and J-PARC. Applying a $Ξ^{-}$ -nucleus optical potential methodology to study atomic and nuclear transitions, we confirm that these capture events occur from Coulomb assisted $1 p_{Ξ^{-}}$ nuclear states. Long-range $Ξ N$ shell-model correlations are found essential to achieve consistency between the $^{12}$ C and $^{14}$ N events. The resulting $Ξ$ -nuclear interaction is strongly attractive, with $Ξ$ potential depth in nuclear matter $V_{Ξ} ≳ 20$ MeV. Implications to multi-strangeness features of dense matter are outlined.
nucl-thhep-phnucl-exPLB(2021)·49 citations
02
The effect of strong magnetic field on heavy Quarkonia in a hot medium using Nikiforov-Uvarov Method
M. Abu-shady🇪🇬 · H. M. Fath-Allah🇪🇬
Recent analyses show that it is possible to produce a strong magnetic field at a very early stage of ultrarelativistic heavy ion collisions (URHIC), therefore, the effect of homogeneity and constant strong magnetic field on the heavy meson spectrum quarkonium is studied which the states are described as charmonium and bottominum in a non-relativistic framework and by Debye screen potential. In particular, a model that takes into account potential isotopes emerging at the level of quark-static potential, as has been observed in recent studies. Investigation is performed with and without regard to the non-isotope of fixed potential, in order to better clarify its effects.
nucl-th1 citation
03
Statistical uncertainties of the $v_{n} {2 k}$ harmonics from Q-cumulants
L. Nadderd🇷🇸 · J. Milosevic🇷🇸 · F. Wang🇨🇳
Analytic formulas to calculate statistical uncertainties of $v_{n} {2 k}$ harmonics extracted from the Q-cumulants are presented. The Q-cumulants are multivariate polynomial functions of the weighted means of $2 m$ -particle azimuthal correlations, $\llangle 2 m \rrangle$ . Variances and covariances of the $\llangle 2 m \rrangle$ are included in the analytic formulas of the uncertainties that can be calculated simultaneously with the calculations of the $v_{n} {2 k}$ harmonics. The calculations are performed using a simple toy model which roughly simulates elliptic flow azimuthal anisotropy with magnitudes around 0.05. The results are compared with the results obtained by the many data sub-sets, and by the bootstrapping method. The first one is a common way of estimation of the statistical uncertainties of the $v_{n} {2 k}$ harmonics in a real experiment. In order to increase precision in the measurement of the $v_{n} {2 k}$ harmonics, a large number of 15000 sub-sets and the same number of the re-sampling in the bootstrap method is used. A very good agreement in the comparison with the proposed way of the analytic calculation of the $v_{n} {2 k}$ statistical uncertainties is found. Additionally, a recurrence equation for Q-cumulants calculation is also presented.
nucl-thPRC(2021)·9 citations
04
Charge Balance Functions for Heavy-Ion Collisions at LHC Energies
Scott Pratt🇺🇸 · Christopher Plumberg🇺🇸
Heavy-ion collisions at the LHC provide the conditions to investigate regions of quark-gluon plasma that reach higher temperatures and that persist for longer periods of time compared to collisions at the Relativistic Heavy Ion Collider. This extended duration allows correlations from charge conservation to better separate during the quark-gluon plasma phase, and thus be better distinguished from correlations that develop during the hadron phase or during hadronization. In this study charge balance functions binned by relative rapidity and azimuthal angle and indexed by species are considered. A detailed theoretical model that evolves charge correlations throughout the entirety of an event is compared to preliminary results from the ALICE Collaboration. The comparison with experiment provides insight into the evolution of the chemistry and diffusivity during the collision. A ratio of balance functions is proposed to better isolate the effects of diffusion and thus better constrain the diffusivity.
nucl-thPRC(2021)·30 citations
05
Spinning Gluons from the QCD Light-Ray OPE
Hao Chen🇨🇳 · Ian Moult🇺🇸 · Hua Xing Zhu🇨🇳
We study the transverse spin structure of the squeezed limit of the three-point energy correlator, $⟨ E (n_{1}) E (n_{2}) E (n_{3})⟩$ . To describe its all orders perturbative behavior, we develop the light-ray operator product expansion (OPE) in QCD. At leading twist the iterated OPE of $E (n_{i})$ operators closes onto light-ray operators $O^{[J]} (n)$ with spin $J$ , and transverse spin $j = 0, 2$ . We compute the $E (n_{1}) E (n_{2})$ , $E (n_{1}) O^{[J]} (n_{2})$ and $O^{[J_{1}]} (n_{1}) O^{[J_{2}]} (n_{2})$ OPEs as analytic functions of $J$ , which allows for the description of arbitrary squeezed limits of $N$ -point correlators in QCD. We use these results with $J = 3$ to reproduce the perturbative expansion in the squeezed limit of the three-point correlator, as well as to resum the leading twist singular structure for both quark and gluon jets, including transverse spin contributions, as required for phenomenological applications. Finally, we briefly comment on the transverse spin structure at higher twists, and show that to all orders in the twist expansion the highest transverse spin contributions are universal between quark and gluon jets, and are descendants of the leading twist transverse spin-2 operator, allowing their resummation into a simple two-dimensional Euclidean conformal block. Due to the general applicability of our results to arbitrary correlation functions of energy flow operators, we anticipate that they can be widely applied to improving our understanding of jet substructure at the LHC.
↳ hep-phhep-exhep-thnucl-ex+1JHEP(2022)·84 citations
06
Neutral and charged mesons in magnetic fields: A resonance gas in a non-relativistic quark model
Toru Kojo🇨🇳
We analyze mesons in constant magnetic fields ( $B$ ) within a non-relativistic constituent quark model. Our quark model contains a harmonic oscillator type confining potential, and we perturbatively treat short range correlations to account for the spin-flavor energy splittings. We study both neutral and charged mesons taking into account the internal quark dynamics. The neutral states are labelled by two-dimensional momenta for magnetic translations, while the charged states by two discrete indices related to angular momenta. For $B ≪ Λ_{QCD}^{2}$ ( $Λ_{QCD} \sim 200$ MeV: the QCD scale), the analyses proceed as in usual quark models, while special precautions are needed for strong fields, $B \sim Λ_{QC D}^{2}$ , especially when we treat short range correlations such as the Fermi-Breit-Pauli interactions. We compute the energy spectra of mesons up to energies of $\sim 2.5$ GeV and use them to construct the meson resonance gas. Within the assumption that the constituent quark masses are insensitive to magnetic fields, the phase space enhancement for mesons significantly increases the entropy, assisting a transition from a hadron gas to a quark gluon plasma. We confront our results with the lattice data, finding reasonable agreement for the low-lying spectra and the entropy density at low temperature less than $\sim 100$ MeV, but our results at higher energy scale suffer from artifacts of our confining potential and non-relativistic treatments.
↳ hep-phhep-latnucl-thEPJA(2021)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE

Constraints on Ξ− nuclear interactions from capture events in emulsion

The effect of strong magnetic field on heavy Quarkonia in a hot medium using Nikiforov-Uvarov Method

Statistical uncertainties of the vn​{2k} harmonics from Q-cumulants

Charge Balance Functions for Heavy-Ion Collisions at LHC Energies

Spinning Gluons from the QCD Light-Ray OPE

Neutral and charged mesons in magnetic fields: A resonance gas in a non-relativistic quark model

Affiliations

Constraints on $Ξ^{-}$ nuclear interactions from capture events in emulsion

Statistical uncertainties of the $v_{n} {2 k}$ harmonics from Q-cumulants