Nuclear Theory·nucl-th

Friday·January 19, 2024

12 papers—5 primary·7 cross-listed

01
Hadronisation in event generators from small to large systems
Yuuka Kanakubo🇫🇮 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵
The results of the dynamical core-corona initialisation framework in p+p and Pb+Pb collisions at the LHC energies are presented. We extract the fractions of final hadron yields originating from equilibrated and non-equilibrated matter as functions of multiplicity. We show that the contribution from non-equilibrated matter is non-negligible even in intermediate and central Pb+Pb collisions. The particle production from non-equilibrated matter behaves as a correction on $c_{2} {4}$ that is purely obtained from the equilibrated matter. The result poses a warning on Bayesian parameter estimation with conventional hydrodynamic models. The observed flow coefficients might need a reinterpretation with new dynamical models which incorporate the particle production from non-equilibrated matter.
nucl-thhep-phnucl-exPoS(2024)·0 citations
02
Impact of Limited Statistics on the Measured Hyper-Order Cumulants of Net-Proton Distributions in Heavy-Ion Collisions
Lizhu Chen🇨🇳 · Ye-Yin Zhao🇨🇳 · Yunshan Cheng🇺🇸 · Gang Wang🇺🇸 · Zhiming Li🇨🇳 · Yuanfang Wu🇨🇳
Hyper-order cumulants $C_{5} / C_{1}$ and $C_{6} / C_{2}$ of net-baryon distributions are anticipated to offer crucial insights into the phase transition from quark-gluon plasma to hadronic matter in heavy-ion collisions. However, the accuracy of $C_{5}$ and $C_{6}$ is highly contingent on the fine shape of the distribution's tail, the detectable range of which could be essentially truncated by low statistics. In this paper, we use the fast Skellam-based simulations, as well as the Ultrarelativistic Quantum Molecular Dynamics model, to assess the impact of limited statistics on the measurements of $C_{5} / C_{1}$ and $C_{6} / C_{2}$ of net-proton distributions at lower RHIC energies. Both ratios decrease from the unity baseline as we reduce statistics, and could even turn negative without a pertinent physics mechanism. By incorporating statistics akin to experimental data, we can replicate the net-proton $C_{5} / C_{1}$ and $C_{6} / C_{2}$ values comparable to the corresponding measurements for Au+Au collisions at $s_{N N} =$ 7.7, 11.5 and 14.5 GeV. Our findings underscore a caveat to the interpretation of the observed beam energy dependence of hyper-order cumulants.
nucl-thnucl-exPRC(2024)·6 citations
03
Dense Hadronic Matter in Neutron Stars
Laura Tolos🇪🇸
In this lecture we discuss the properties of dense hadronic matter inside neutron stars. In particular, we pay attention to the role of strangeness in the core of neutron stars, by analysing the presence of baryons and mesons with strangeness. We consider two interesting possible scenarios in their interior, that is, the existence of hyperons leading to the so-called hyperon puzzle and the presence of a kaon condensed phase inside neutron stars.
nucl-thastro-ph.HEhep-phActa Phys.Polon.B(2024)·4 citations
04
Method of moments for a relativistic single-component gas
Caio V. P. de Brito🇧🇷 · Gabriel S. Denicol🇧🇷
We derive the equations of motion for all the irreducible moments of the single-particle distribution function. We find that these moment equations of motion are highly coupled, with the dynamics of lower-rank moments always being coupled to those of a higher-rank, leading to an endless tower of equations. Considering a massless gas in Bjorken flow, we investigate how this hierarchy of differential equations can be properly truncated and solved.
nucl-thPRD(2024)·10 citations
05
Chiral confining Hartree-Fock Lagrangians based on Nambu-Jona--Lasino model
M. Chamseddine🇫🇷 · J. Margueron🇫🇷 · H. Hansen🇫🇷 · G. Chanfray🇫🇷
We study a relativistic Hartree-Fock Lagrangian model which considers confinement, chiral symmetry breaking, nucleon form factor and short range correlations. The chiral potential originally based on the linear sigma-model is compared to an improved potential generated by the Nambu-Jona--Lasino (NJL) model for quark interaction. Our model is also anchored in fundamental hadronic properties predicted by Lattice-QCD calculations and a few nuclear empirical properties. We explore in a Bayesian approach the role of the saturation density, the energy per particle and the incompressibility modulus for the model selection. We find that most of our models could not reproduce these empirical quantities, unless a phenomenological "missing" energy is added. The properties of this "missing" energy are therefore inferred from our Bayesian analysis and we obtain that it shall be attractive. Finally we analyse the origin of the break down density in relativistic approaches and we relate it to the properties of the scalar potential.
nucl-thEPJA(2024)·4 citations
06
Proton and neutron electromagnetic radii and magnetic moments from lattice QCD
Miguel Salg🇩🇪 · Dalibor Djukanovic🇩🇪 · Georg von Hippel🇩🇪 · Harvey B. Meyer🇩🇪 · Konstantin Ottnad🇩🇪 · Hartmut Wittig🇩🇪
We present results for the electromagnetic form factors of the proton and neutron computed on the $(2 + 1)$ -flavor Coordinated Lattice Simulations (CLS) ensembles including both quark-connected and -disconnected contributions. The $Q^{2}$ -, pion-mass, lattice-spacing, and finite-volume dependence of our form factor data is fitted simultaneously to the expressions resulting from covariant chiral perturbation theory including vector mesons amended by models for lattice artefacts. From these fits, we determine the electric and magnetic radii and the magnetic moments of the proton and neutron, as well as the Zemach radius of the proton. To assess the influence of systematic effects, we average over various cuts in the pion mass and the momentum transfer, as well as over different models for the lattice-spacing and finite-volume dependence, using weights derived from the Akaike Information Criterion (AIC).
↳ hep-lathep-phnucl-thEPJ Web Conf.(2024)·1 citation
07
A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes
Ewan D. Barr🇩🇪 · Arunima Dutta🇩🇪 · Paulo C. C. Freire🇩🇪 · Mario Cadelano🇮🇹 · Tasha Gautam🇩🇪 · Michael Kramer🇩🇪 · Cristina Pallanca🇮🇹 · Scott M. Ransom🇺🇸 · Alessandro Ridolfi🇩🇪 · Benjamin W. Stappers🇬🇧 · Thomas M. Tauris🇩🇪 · Vivek Venkatraman Krishnan🇩🇪 and 13 other authors
Among the compact objects observed in gravitational wave merger events a few have masses in the gap between the most massive neutron stars (NSs) and least massive black holes (BHs) known. Their nature and the formation of their merging binaries are not well understood. We report on pulsar timing observations using the Karoo Array Telescope (MeerKAT) of PSR J0514-4002E, an eccentric binary millisecond pulsar in the globular cluster NGC 1851 with a total binary mass of $3.887 \pm 0.004$ solar masses. The companion to the pulsar is a compact object and its mass (between $2.09$ and $2.71$ solar masses, 95% confidence interval) is in the mass gap, so it either is a very massive NS or a low-mass BH. We propose the companion was formed by a merger between two earlier NSs.
↳ astro-ph.HEgr-qcnucl-thScience(2024)·113 citations
08
The proton-neutron resonance states by solving Schrodinger equation
Bao-Xi Sun🇨🇳 · Qin-Qin Cao🇨🇳 · Ying-Tai Sun🇨🇳
The proton-neutron interaction is investigated by solving the Schrodinger equation, where a Yukawa type of potential with one pion exchanging between the proton and the neutron is assumed. Since the deutron is the unique bound state of the proton-neutron system, the coupling constant is fixed according to the binding energy of the deutron. The scattering process of the proton and the neutron is studied when the outgoing wave condition is taken into account, and two proton-neutron resonance states are obtained by solving the Schrodinger equation, which lie at $1905 - i 13$ MeV and $2150 - i 342$ MeV on the complex energy plane, respectively. It is no doubt that the calculation results would give some hints on the experimental research on the proton-neutron interaction in future.
↳ hep-phnucl-thquant-ph1 citation
09
The possible $K K ˉ^{*}$ and $D D ˉ^{*}$ bound and resonance states by solving Schrodinger equation
Bao-Xi Sun🇨🇳 · Qin-Qin Cao🇨🇳 · Ying-Tai Sun🇨🇳
The Schrodinger equation with a Yukawa type of potential is solved analytically. When different boundary conditions are taken into account, a series of solutions are indicated as Bessel function, the first kind of Hankel function and the second kind of Hankel function, respectively. Subsequently, the scattering processes of $K K ˉ^{*}$ and $D D ˉ^{*}$ are investigated. In the $K K ˉ^{*}$ sector, the $f_{1} (1285)$ particle is treated as a $K K ˉ^{*}$ bound state, therefore, the coupling constant in the $K K ˉ^{*}$ Yukawa potential can be fixed according to the binding energy of the $f_{1} (1285)$ particle. Consequently, a $K K ˉ^{*}$ resonance state is generated by solving the Schrodinger equation with the outgoing wave condition, which lie at $1417 - i 18$ MeV on the complex energy plane. It is reasonable to assume that the $K K ˉ^{*}$ resonance state at $1417 - i 18$ MeV might correspond to the $f_{1} (1420)$ particle in the review of Particle Data Group(PDG).In the $D D ˉ^{*}$ sector, since the $X (3872)$ particle is almost located at the $D D ˉ^{*}$ threshold, the binding energy of it equals to zero approximately. Therefore, the coupling constant in the $D D ˉ^{*}$ Yukawa potential is determined, which is related to the first zero point of the zero order Bessel function. Similarly to the $K K ˉ^{*}$ case, four resonance states are produced as solutions of the Schrodinger equation with the outgoing wave condition. It is assumed that the resonance states at $3885 - i 1$ MeV, $4029 - i 108$ MeV, $4328 - i 191$ MeV and $4772 - i 267$ MeV might be associated with the $Z c (3900)$ , the $X (3940)$ , the $χ_{c 1} (4274)$ and $χ_{c 1} (4685)$ particles, respectively. It is noted that all solutions are isospin degenerate.
↳ hep-phnucl-thquant-phCommun.Theor.Phys.(2024)·3 citations
10
Jet Quenching: From Theory to Simulation
Shanshan Cao🇨🇳 · Abhijit Majumder🇺🇸 · Rouzbeh Modarresi-Yazdi🇨🇦 · Ismail Soudi🇺🇸 · Yasuki Tachibana🇯🇵
With the explosion of data on jet based observables in relativistic heavy-ion collisions at the Large Hadron Collider and the Relativistic Heavy-Ion Collider, perturbative QCD based simulations of these processes, often interacting with an expanding viscous fluid dynamical background, have taken center stage. This review is meant to bridge the gap between theory, simulation and phenomenology of jet modification in a dense medium. We will demonstrate how the existence of such end-to-end event generators with semi-realistic or even fully realistic final states allows for the most rigorous comparisons between pQCD based jet modification theory and experiment. State-of-the-art calculations of several jet based observables are presented. Extensions of this theory to jets in the small systems of $p$ - $A$ and $e$ - $A$ collisions is discussed.
↳ hep-phnucl-exnucl-thIJMPE(2024)·42 citations
11
A potential approach to the $X (3872)$ thermal behavior
Néstor Armesto🇪🇸 · Miguel Ángel Escobedo🇪🇸 · Elena G. Ferreiro🇪🇸 · Víctor López-Pardo🇪🇸
We study the potential of $X (3872)$ at finite temperature in the Born-Oppenheimer approximation under the assumption that it is a tetraquark. We argue that, at large number of colors, it is a good approximation to assume that the potential consists in a real part plus a constant imaginary term. The real part is then computed adapting an approach by Rothkopf and Lafferty and using as input lattice QCD determinations of the potential for hybrids. This model allows us to qualitatively estimate at which temperature range the formation of a heavy tetraquark is possible, and to propose a qualitative picture for the dissociation of the state in a medium. Our approach can be applied to other suggested internal structures for the $X (3872)$ and to other exotic states.
↳ hep-phnucl-thPLB(2024)·11 citations
12
Heavy Quarks in Polarised Deep-Inelastic Scattering at the Electron-Ion Collider
Felix Hekhorn🇮🇹 · Giacomo Magni🇳🇱 · Emanuele R. Nocera🇮🇹 · Tanjona R. Rabemananjara🇳🇱 · Juan Rojo🇳🇱 · Adrianne Schaus🇳🇱 · Roy Stegeman🇬🇧
We extend the FONLL general-mass variable-flavour-number scheme to the case of longitudinally polarised DIS structure functions, accounting for perturbative corrections up to $O (α_{s}^{2})$ . We quantify the impact of charm quark mass and higher-order perturbative corrections on projected measurements of inclusive and charm-tagged longitudinal asymmetries at the Electron-Ion Collider (EIC) and at the Electron-ion collider in China (EicC). We demonstrate how the inclusion of these corrections is essential to compute predictions with an accuracy that matches the projected precision of the measurements. The computation is made publicly available through the open-source EKO and YADISM programs
↳ hep-phhep-exnucl-exnucl-thEPJC(2024)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE