Nuclear Theory·nucl-th

Tuesday·August 29, 2023

21 papers—12 primary·9 cross-listed

01
[Submitted on 25 Aug 2023]
Core destruction in knockout reactions
C.A. Bertulani
A model is presented to calculate projectile core destruction in knockout reactions. It incorporates physics arguments similar to the formulation of the state of the art theory to calculate stripping and diffraction dissociation cross sections in heavy ion collisions with bombarding energies around 100 MeV/nucleon and larger. It is shown that secondary collisions between the incoming and struck nucleons and the projectile core decrease the core survival probability by as much as 9.5\%. However, no clear evidence is found for reduction of the cross section with increasing binding energy of the removed nucleon.
Comments:
6 pages, 4 figures, Phys. Lett. B, accepted
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2308.13675 [pdf]
PLB(2023)·11 citations
02
[Submitted on 26 Aug 2023]
Ab initio investigation of the $^{7}$ Li( $p, e^{+} e^{-}$ ) $^{8}$ Be process and the X17 boson
P. Gysbers🇨🇦 · P. Navratil🇨🇦 · K. Kravvaris🇺🇸 · G. Hupin🇫🇷 · S. Quaglioni🇺🇸
Observations of anomalies in the electron-positron angular correlations in high-energy decays in $^{4}$ He, $^{8}$ Be, and $^{12}$ C have been reported recently by the ATOMKI collaboration. These could be explained by the creation and subsequent decay of a new boson with a mass of $\sim 17$ MeV. Theoretical understanding of pair creation in the proton capture reactions used in these experiments is important for the interpretation of the anomalies. We apply the ab initio No-Core Shell Model with Continuum (NCSMC) to the proton capture on $^{7}$ Li. The NCSMC describes both bound and unbound states in light nuclei in a unified way with chiral two- and three-nucleon interactions as the only input. We investigate the structure of $^{8}$ Be, the $p +^{7}$ Li elastic scattering, the $^{7}$ Li( $p, γ$ ) $^{8}$ Be cross section and the internal pair creation $^{7}$ Li( $p, e^{+} e^{-}$ ) $^{8}$ Be. We discuss the impact of a proper treatment of the initial scattering state on the electron-positron angular correlation spectrum and compare our results to available ATOMKI data sets. Finally, we calculate $^{7}$ Li( $p, X$ ) $^{8}$ Be cross sections for several proposed models of the hypothetical X17 particle.
Comments:
32 pages, 13 figures. Matches more closely the published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2308.13751 [pdf]
PRC(2024)·11 citations
03
[Submitted on 26 Aug 2023]
Charged-current quasielastic neutrino scattering from $^{12}$ C in an extended superscaling model with two-nucleon emission
V. L. Martinez-Consentino🇪🇸 · J.E. Amaro🇪🇸
The quasielastic cross-section of charged-current neutrino and antineutrino scattering on $^{12}$ C is calculated using an improved superscaling model with relativistic effective mass. Our model encompasses two-particle emission induced by neutrinos, which we distinguish into two contributions. The first contribution arises from meson-exchange currents, and its calculation is performed at a microscopic level. The second contribution is phenomenological and extracted from the high-energy tail of the scaling function, assumed to be produced by 2p2h mechanisms where the one-body current plays a role, such as short-range correlations and interferences with MEC, final-state interaction, etc. The model explicitly includes the modification of the relativistic effective mass of the nucleon within the relativistic mean field model of nuclear matter. The meson exchange currents are also consistently calculated within the same model. With this model, we present predictions for the neutrino and antineutrino cross sections of $^{12}$ C that have been measured in accelerator experiments.
Comments:
15 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.13847 [pdf]
PRD(2023)·13 citations
04
[Submitted on 26 Aug 2023]
Establishing connection between neutron star properties and nuclear matter parameters through a comprehensive multivariate analysis
N. K. Patra🇦🇲 · Prafulla Saxena🇮🇳 · B. K. Agrawal🇦🇲 · T. K. Jha🇦🇲
We have attempted to mitigate the challenge of connecting the neutron star (NS) properties with the nuclear matter parameters that describe equations of state (EoSs). The efforts to correlate various neutron star properties with individual nuclear matter parameters have been inconclusive. A Principal Component Analysis is employed as a tool to uncover the connection between multiple nuclear matter parameters and the tidal deformability as well as the radius of neutron stars within the mass range of $1.2 - 1.8 M_{⊙}$ . The essential EOSs for neutron star matter at low densities have been derived using both uncorrelated uniform distributions and minimally constrained joint posterior distributions of nuclear matter parameters. For higher densities ( $ρ > 0.32$ fm $^{- 3}$ ), the EOSs have been established through a suitable parameterization of the speed of sound, which consistently maintains causality and gradually approaches the conformal limit. Our analysis reveals that in order to account for over 90\% of the variability in NS properties, it is crucial to consider two or more principal components, emphasizing the significance of employing multivariate analysis. To explain the variability in tidal deformability needs a greater number of principal components compared to those for the radius at a given NS mass. The contributions from iso-vector nuclear matter parameters to the tidal deformability and radius of NS decrease by $\sim$ 25\% with the increase in mass of NS from 1.2 $M_{⊙}$ to 1.8 $M_{⊙}$ .
Comments:
12 Pages, 7 Figures and 2 Tables (Accepted in Physical Review D)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.13896 [pdf]
PRD(2023)·14 citations
05
[Submitted on 26 Aug 2023]
Quark-hadron pasta phase in neutron stars: the role of medium-dependent surface and curvature tensions
Mauro Mariani🇦🇷 · Germán Lugones🇧🇷
We investigate the properties of the hadron-quark mixed phase, often termed the \textit{pasta} phase, expected to exist in the cores of massive neutron stars. To construct the equations of state (EoS), we combine an analytical representation based on the APR EoS for hadronic matter with the MIT bag model featuring vector interactions for quark matter. For modeling the mixed phase, we utilize the compressible liquid drop model that consistently accounts for finite-size and Coulomb effects. Unlike most previous analyses that treated surface tension as a constant free parameter and neglected curvature tension, we employ microphysical calculations using the multiple reflection expansion formalism to determine these parameters, while also ensuring their self-consistency with the EoS. We construct an extensive set of mixed hybrid EoSs by varying model parameters, solve the stellar structure equations to obtain neutron star mass-radius relationships, and select the models that satisfy current astrophysical constraints. Our findings closely align with calculations using a constant surface tension in terms of EoS stiffness and resulting stellar structure. However, they reveal significant differences in the types of geometric structures and their prevalence ranges within the mixed phase. Specifically, curvature effects enhance the emergence of tubes and bubbles at high densities despite the large value of surface tension, while suppressing the existence of drops and rods at low densities.
Comments:
18 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.13973 [pdf]
PRD(2024)·16 citations
06
[Submitted on 27 Aug 2023]
Momentum dependence of $ϕ$ meson's spin alignment
Xin-Li Sheng🇮🇹 · Shi Pu🇨🇳 · Qun Wang🇨🇳
We study the rapidity and azimuthal angle dependences of the global spin alignment $ρ_{00}$ for $ϕ$ mesons with respect to the reaction plane in Au+Au collisions at RHIC by the relativistic coalescence model in the spin transport theory. The global spin alignment of $ϕ$ mesons arises from local fluctuations of strong force fields whose values are extracted from the STAR's data. The calculated results show that $ρ_{00} < 1/3$ at the rapidity $Y = 0$ , and then it increases with rapidity and becomes $ρ_{00} > 1/3$ at $Y = 1$ . Such a rapidity dependence is dominated by the relative motion of the $ϕ$ meson in the bulk matter. We also give prediction for the azimuthal angle dependence of $ρ_{00}$ at different rapidities.
Comments:
RevTex 4, 5 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.14038 [pdf]
PRC(2023)·47 citations
07
[Submitted on 27 Aug 2023]
Production of various elements in ultraperipheral $^{208}$ Pb- $^{208}$ Pb collisions at the LHC
U.A. Dmitrieva🇷🇺 · I.A. Pshenichnov🇷🇺
As predicted by theory and confirmed by measurements, one, two or three neutrons are emitted frequently in ultraperipheral collisions (UPCs) of heavy relativistic nuclei, in particular, $^{208}$ Pb. The exchange of low-energy Weizsäcker--Williams photons dominates in such interactions. This leads to the excitation and decay of Giant Dipole Resonances (GDR) in colliding nuclei below the proton emission threshold. Less is known about the electromagnetic dissociation of $^{208}$ Pb induced by energetic photons leading to violent fragmentation of $^{208}$ Pb. The UPCs of lead nuclei at the LHC were modelled with Relativistic ELectromagnetic Dissociation (RELDIS) model to evaluate the contribution of photonuclear reactions in the domain of quasideuteron absorption and at higher photon energies. It was demonstrated that due to the presence of a single heavy residue in the final state mostly accompanied by free protons and neutrons, the cross sections of the production of specific elements can be well approximated by the proton emission cross sections, which can be measured in the ALICE experiment at the LHC.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2308.14094 [pdf]
Phys.Part.Nucl.Lett.(2023)·3 citations
08
[Submitted on 28 Aug 2023]
Bayesian analysis of a relativistic hadronic model constrained by recent astrophysical observations
B. A. de Moura S.🇧🇷 · C. H. Lenzi🇧🇷 · O. Lourenço🇧🇷 · M. Dutra🇧🇷
We use Bayesian analysis in order to constrain the equation of state for nuclear matter from astrophysical data related to the recent measurements from the NICER mission, LIGO/Virgo collaboration, and probability distributions of mass and radius from other 12 sources, including thermonuclear busters, and quiescent low-mass X-ray binaries. For this purpose, we base our study on a relativistic hadronic mean field model including an $ω - ρ$ interaction. Our results indicate optimal ranges for some bulk parameters at the saturation density, namely, effective mass, incompressibility, and symmetry energy slope ( $L_{0}$ ). For instance, we find $L_{0} = 50.7 9_{- 9.24}^{+ 15.16}$ MeV (Case 1) and $L_{0} = 75.0 6_{- 4.43}^{+ 8.43}$ MeV (Case 2) in a $68%$ confidence interval for the 2 cases analyzed (different input ranges for $L_{0}$ related to the PREX-II data). The respective parametrizations are in agreement with important nuclear matter constraints, as well as observational neutron star data, such as the dimensionless tidal deformability of the GW170817 event. From the mass-radius curves obtained from these best parametrizations, we also find the ranges of $11.97 \mbox k m ⩽ R_{1.4} ⩽ 12.73 \mbox k m$ (Case 1) and $12.34 \mbox k m ⩽ R_{1.4} ⩽ 13.06 \mbox k m$ (Case 2) for the radius of the $1.4 M_{⊙}$ neutron star.
Comments:
12 pages, 11 figures, 7 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2308.14417 [pdf]
MNRAS(2023)·6 citations
09
[Submitted on 28 Aug 2023]
Charm balance function in relativistic heavy-ion collisions
Tribhuban Parida🇮🇳 · Piotr Bozek🇵🇱 · Sandeep Chatterjee🇮🇳
We calculate the balance function for charm in relativistic heavy-ion collisions. The distribution of pairs of charm-anticharm quarks produced in hard processes in the early stages of the nucleus-nucleus collision evolves in the dense fireball formed in the collision. The evolution of the dense matter is described using a relativistic viscous hydrodynamic model and the quark diffusion with a Langevin equation. The evolution of the charm quark balance function from the formation of the charm-anticharm pair up to the freeze-out traces the partial thermalization of the heavy quarks in the dense matter. For the balance function in azimuthal angle we reproduce the collimation effect due to the transverse flow. The evolution in rapidity shows the thermalization of the longitudinal velocity of the quark in the fluid. We provide predictions for the one and two-dimensional balance functions for $D^{0}$ - $D^{0} ˉ$ mesons produced in ultarelativistic Pb+Pb collisions at $s_{N N} = 5.02$ TeV. The shape of the charm balance function in relative rapidity is sensitive to the rescattering of heavy quarks in the early stages of the collision, while the shape of the balance function in azimuthal angle is sensitive to the rescattering in the latter stages.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2308.14446 [pdf]
PRC(2024)·7 citations
10
[Submitted on 28 Aug 2023]
New covariant density functionals of nuclear matter for compact star simulations
Jia Jie Li (SWU, Chongqing)🇨🇳 · Armen Sedrakian (FIAS, Frankfurt and U. Wroclaw)🇩🇪
We generate three families of extended covariant density functionals of nuclear matter that have varying slope of symmetry energy and skewness at nuclear saturation density, but otherwise share the same basic parameters (symmetry energy, compressibility, saturation parameters, etc.) with the standard DDME2, DD2, and MPE functionals. Tables of the parameters of these new density functionals are given, which can be straightforwardly used in DDME2, DD2, and MPE parameterization-based codes. Furthermore, we provide tables of a large number of equations of state (81 for each family) that can be used in astrophysical simulations to assess the impact of variations of not-well-known slope of symmetry energy and skewness of nuclear systems on the astrophysics of compact objects. We also provide tables of computed integral parameters (mass, radius, and tidal deformability) that can be used, e.g., for modeling gravitational waveforms. Finally, for the extended DDME2-based parameterization, we implement a first-order phase transition to quark matter to obtain a family of equations of state that accommodates a phase transition to quark matter. Analogous tables of the equations of state and integral parameters are provided for this case as well.
Comments:
v2: matches published version. v1: 8 pages, 4 figures, 5 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.14457 [pdf]
ApJ(2023)·21 citations
11
[Submitted on 28 Aug 2023]
Renormalization of many-body effective field theory
Bing-Nan Lu🇨🇳 · Bao-Ge Deng🇨🇳
The renormalization of the effective field theories (EFTs) in many-body systems is the most pressing and challenging problem in modern nuclear ab initio calculation. For general non-relativistic EFTs, we prove that the renormalization group (RG) invariance can be achieved if and only if all single-particle momenta are regulated with a universal cutoff \Lambda. For a numerical demonstration, we construct a series of N^{2}LO chiral forces with \Lambda varying from 250 MeV to 400 MeV. With all low energy constants fixed in two- and three-nucleon systems, we reproduce the experimental binding energies of ^{4}He and ^{16}O nearly independently of \Lambda. In contrast, all recent nuclear EFT constructions regulate the relative momenta for Galilean invariance, thus inherently break the RG invariance. This explains the unpleasantly strong cutoff-dependences observed in recent ab initio calculations. Our method can also be used to build RG-invariant EFTs with non-perturbative interactions.
Comments:
11 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Lattice (hep-lat)
arXiv:
2308.14559 [pdf]
4 citations
12
[Submitted on 28 Aug 2023]
Circumventing the odd particle-number sign problem in the shell model Monte Carlo
Y. Alhassid · P. Fanto · C. Özen
The shell model Monte Carlo (SMMC) method is a powerful method for calculating exactly (up to statistical errors) thermal observables and statistical properties of atomic nuclei. However, its application has been limited by a sign problem at low temperatures that arises from the projection onto odd particle number even for good-sign interactions. Here, we develop a technique - the partition function extrapolation method (PFEM) - to extract the ground-state energy of an odd-mass nucleus from the excitation partition function calculated at temperatures at which this sign problem is moderate. We validate the PFEM in heavy even-mass nuclei and systematically calculate ground-state energies for isotopic chains of heavy odd-mass nuclei. The PFEM can be extended to other finite-size quantum many-body systems.
Comments:
5 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.14698 [pdf]
PRC(2024)·2 citations
13
[Submitted on 23 Aug 2023] (cross-list from math-ph)
Solving the matrix exponential function for special orthogonal groups SO(n) and the exceptional G $_{2}$
Norbert Kaiser
In this work the matrix exponential function is solved analytically for the special orthogonal groups $S O (n)$ up to $n = 9$ . The number of occurring $k$ -th matrix powers gets limited to $0 \leq k \leq n - 1$ by exploiting the Cayley-Hamilton relation. The corresponding expansion coefficients can be expressed as cosine and sine functions of a vector-norm $V$ and the roots of a polynomial equation that depends on a few specific invariants. Besides the well known case of $S O (3)$ , a quadratic equation needs to be solved for $n = 4, 5$ , a cubic equation for $n = 6, 7$ , and a quartic equation for $n = 8, 9$ . As an interesting subgroup of $S O (7)$ , the exceptional Lie group $G_{2}$ of dimension $14$ is constructed via the matrix exponential function through a remarkably simple constraint on an invariant, $ξ = 1$ . The calculation of the trace of the $S O (n)$ -matrices arising from the exponential function, results in a sum of cosines of several angles, which specify the associated conjugation class as a point on a maximal torus.
Comments:
14 pages, 3 figures
Subjects:
Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2308.12123 [pdf]
0 citations
14
[Submitted on 25 Aug 2023] (cross-list from hep-ph)
Realtime dynamics of hyperon spin correlations from string fragmentation in a deformed four-flavor Schwinger model
João Barata🇺🇸 · Wenjie Gong🇺🇸 · Raju Venugopalan🇺🇸
Self-polarizing weak decays of $Λ$ -hyperons provide unique insight into the role of entanglement in the fragmentation of QCD strings through measurements of the spin correlations of $Λ Λ ˉ$ -pairs produced in collider experiments. The simplest quantum field theory representing the underlying parton dynamics is the four-flavor massive Schwinger model plus an effective spin-flip term, where the flavors are mapped to light (up/down) and heavy (strange) quarks and their spins. This construction provides a novel way to explore hyperon spin-correlations in 1+1-dimensions. We investigate the evolution of these correlations for different string configurations that are sensitive to the rich structure of the model Hamiltonian.
Comments:
9 pages, 5 figures, v2: Additional results on real time evolution. Expanded discussion of model
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2308.13596 [pdf]
PRD(2024)·53 citations
15
[Submitted on 25 Aug 2023] (cross-list from hep-ph)
Constraining the pion distribution amplitude using Drell-Yan reactions on a proton
H.-Y. Xing🇨🇳 · M. Ding🇩🇪 · Z.-F. Cui🇨🇳 · A. V. Pimikov🇨🇳 · C. D. Roberts🇨🇳 · S. M. Schmidt🇩🇪
Using a reaction model that incorporates pion bound state effects and continuum results for proton parton distributions and the pion distribution amplitude, $φ_{π}$ , we deliver parameter-free predictions for the $μ^{+}$ angular distributions in $π N \to μ^{+} μ^{-} X$ reactions on both unpolarised and polarised targets. The analysis indicates that such angular distributions are sensitive to the pointwise form of $φ_{π}$ and suggests that unpolarised targets are practically more favourable. The precision of extant data is insufficient for use in charting $φ_{π}$ ; hence, practical tests of this approach to charting $φ_{π}$ must await data with improved precision from new-generation experiments. The reaction model yields a nonzero single-spin azimuthal asymmetry, without reference to $T$ -odd parton distribution functions (DFs). This may necessitate additional care when attempting to extract such $T$ -odd DFs from data.
Comments:
8 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2308.13695 [pdf]
PLB(2024)·7 citations
16
[Submitted on 26 Aug 2023] (cross-list from hep-th)
The Schrödinger Representation and 3d Gauge Theories
V.P. Nair🇺🇸
In this review we consider the Hamiltonian analysis of Yang-Mills theory and some variants of it in three spacetime dimensions using the Schrödinger representation. This representation, although technically more involved than the usual covariant formulation, may be better suited for some nonperturbative issues. Specifically for the Yang-Mills theory, we explain how to set up the Hamiltonian formulation in terms of manifestly gauge-invariant variables and set up an expansion scheme for solving the Schrödinger equation. We review the calculation of the string tension, the Casimir energy and the propagator mass and compare with the results from lattice simulations. The computation of the first set of corrections to the string tension, string breaking effects, extensions to the Yang-Mills-Chern-Simons theory and to the supersymmetric cases are also discussed. We also comment on how entanglement for the vacuum state can be formulated in terms of the BFK gluing formula. The review concludes with a discussion of the status and prospects of this approach.
Comments:
134 pages, 13 figures, Expanded version of lectures at Understanding Confinement: Prospects in Theoretical Physics Summer School, Institute for Advanced Study, Princeton, July 2023
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Lattice (hep-lat); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2308.13926 [pdf]
Int.J.Mod.Phys.A(2023)·5 citations
17
[Submitted on 27 Aug 2023] (cross-list from hep-ph)
Production of the newly observed $T ˉ_{c s ˉ 0}$ by kaon-induced reactions on a proton/neutron target
Yin Huang🇨🇳 · Hao Hei🇨🇳 · Jing-wen Feng🇨🇳 · Xurong Chen🇨🇳 · Rong Wang🇨🇳
Recently, a new doubly charged tetraquark $T_{c s ˉ 0}^{a} (2900)^{++}$ and its neutral partner $T_{c s ˉ 0}^{a} (2900)^{0}$ at the invariant mass spectrum of $π D_{s}$ were observed by the LHCb Collaboration. According to its properties, such as the mass and decay width, the $T_{c s ˉ 0}^{a} (2900)^{++ /0}$ have been suggested to be a compact multi-quark state or a hadron molecule. In order to distinguish the various interpretations of the $T_{c s ˉ 0}^{a} (2900)^{++ /0}$ , we investigate the possibility to study the $T ˉ_{c s ˉ 0}^{a} (2900)$ [the antiparticle of $T_{c s ˉ 0}^{a} (2900)$ ] by kaon-induced reactions on a proton target in an effective Lagrangian approach. The production mechanism is characterized by the $t$ -channel $D$ meson exchange. Our theoretical approach is based on the assumption that $T ˉ_{c s ˉ 0}^{a} (2900)$ can be either a $K^{*} D^{*} - D_{s}^{*} ρ$ molecule or a compact tetraquark state. Using the coupling constants of the $T ˉ_{c s ˉ 0}^{a} (2900)$ to $K D$ channel obtained from molecule or compact tetraquark picture of the $T ˉ_{c s ˉ 0}^{a} (2900)$ , we compute the cross-sections for the process $K^{-} n \to T ˉ_{c s ˉ 0}^{a} (2900)^{--} Λ_{c}^{+}$ . The $K ˉ N$ initial state interaction mediated by Pomeron and Reggeon exchanges is also included, which reduces the production of the $T ˉ_{c s ˉ 0}^{a} (2900)$ . Our calculations show that whether $T ˉ_{c s ˉ 0}^{a} (2900)$ is a molecule or a compact tetraquark state, the cross-sections for the $K^{-} n \to T ˉ_{c s ˉ 0}^{a} (2900)^{--} Λ_{c}^{+}$ reaction are of similar magnitude, ranging from approximately 0.075 nb to 0.270 nb.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2308.14148 [pdf]
PRD(2023)·9 citations
18
[Submitted on 28 Aug 2023] (cross-list from hep-ph)
Heavy quark diffusion and radiation at intermediate momentum
Juhee Hong🇰🇷
We discuss heavy quark diffusion and radiation in an intermediate-momentum regime where finite mass effects can be significant. Diffusion processes are described in the Fokker-Planck approximation for soft momentum transfer, while radiative ones are taken into account by nearly collinear gluon emission from a single scattering in the Boltzmann equation. We also consider radiative corrections to the transverse momentum diffusion coefficient, which are $O (g^{2})$ suppressed than the leading-order diffusion coefficient but logarithmically enhanced. Numerical results show that the heavy quark distribution function depends on the energy loss mechanism so that the momentum dependence of suppression is distinguishable. Employing the heavy quark diffusion coefficient constrained by lattice QCD data, we estimate the nuclear modification factor which exhibits a transition from diffusion at low momentum to radiation at high momentum. The significance of radiative effects at intermediate momentum depends on the diffusion coefficient and running coupling constant.
Comments:
15 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2308.14530 [pdf]
PRC(2024)·8 citations
19
[Submitted on 28 Aug 2023] (cross-list from hep-ph)
Production of leptons from decay of heavy-flavor hadrons in high-energy nuclear collisions
Sa Wang🇨🇳 · Yao Li🇨🇳 · Shuwan Shen🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳
This paper presents a theoretical study on the production of the heavy-flavour decay lepton (HFL) in high-energy nuclear collisions at the LHC. The pp-baseline is calculated by the FONLL program, which matches the next-to-leading order pQCD calculation with the next-to-leading-log large- $p_{T}$ resummation. The in-medium propagation of heavy quarks is driven by the modified Langevin equations, which consider both the elastic and inelastic partonic interactions. We propose a method to separate the respective influence of the six factors, such as pp-spectra, the cold nuclear matter (CNM) effects, in-medium energy loss (E-loss), fragmentation functions (FFs), coalescence (Coal), and decay channels, which may contribute to the larger $R_{AA}$ of HFL $\leftarrow b$ compared to that of HFL $\leftarrow c$ in nucleus-nucleus collisions. Based on quantitative analysis, we demonstrate that both coalescence hadronization, decay channels and the mass-dependent E-loss play an essential role at $p_{T} < 5$ GeV, while the latter dominates the higher $p_{T}$ region. It is also found that the influences of the CNM effects and FFs are insignificant. At the same time, different initial pp-spectra of charm and bottom quarks have a considerable impact at $p_{T} > 5$ GeV. Furthermore, we explore the path-length dependence of jet quenching by comparing the HFL $R_{AA}$ in two different collision systems. Our investigations show smaller HFL $R_{AA}$ in Pb+Pb than in Xe+Xe within the same centrality bin, consistent with the ALICE data. The longer propagation time and more effective energy loss of heavy quarks in Pb+Pb collisions play critical roles in the stronger yield suppression of the HFL compared to that in Xe+Xe. In addition, we observe a scaling behavior of the HFL $R_{AA}$ in Xe+Xe and Pb+Pb collisions.
Comments:
13 pages, 9 figures. Version published in Phys. Rev. C
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2308.14538 [pdf]
PRC(2025)·5 citations
20
[Submitted on 28 Aug 2023] (cross-list from physics.chem-ph)
Seniority and Hierarchy Configuration Interaction for Radicals and Excited States
Fábris Kossoski · Pierre-François Loos
Hierarchy configuration interaction (hCI) has been recently introduced as an alternative configuration interaction (CI) route combining excitation degree and seniority number, which showed to efficiently recover both dynamic and static correlations for closed-shell molecular systems [\href{https://doi.org/10.1021/acs.jpclett.2c00730}{\textit{J.~Phys.~Chem.~Lett.}~\textbf{2022}, \textit{13}, 4342}]. Here, we generalize hCI for an arbitrary reference determinant, allowing calculations for radicals and for excited states in a state-specific way. We gauge this route against excitation-based CI (eCI) and seniority-based CI (sCI) by evaluating how different ground-state properties of radicals converge to the full CI limit. We find that hCI outperforms or matches eCI, whereas sCI is far less accurate, in line with previous observations for closed-shell molecules. Employing the second-order Epstein-Nesbet (EN2) perturbation theory as a correction significantly accelerates the convergence of hCI and eCI. We further explore various hCI and sCI models to calculate excitation energies of closed- and open-shell systems. Our results underline that both the choice of the reference determinant and the set of orbitals drive the fine balance between correlation of ground and excited states. State-specific hCI2 and higher order models perform similarly to their eCI counterparts, whereas lower orders of hCI deliver poor results, unless supplemented by the EN2 correction, which substantially improves their accuracy. In turn, sCI1 produces decent excitation energies for radicals, encouraging the development of related seniority-based coupled-cluster methods.
Comments:
18 pages, 5 figures
Subjects:
physics.chem-ph (physics.chem-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:
2308.14618 [pdf]
J.Chem.Theor.Comput.(2023)·3 citations
21
[Submitted on 28 Aug 2023] (cross-list from hep-ph)
Azimuthal Anisotropy at high transverse momentum in $p$ - $p$ and $p$ - $A$ collisions
Ismail Soudi🇺🇸 · Abhijit Majumder🇺🇸
We explore the possibility that the initial transverse momentum distribution of unpolarized and polarized partons within unpolarized nucleons, both with and without the anisotropy of unpolarized hadrons produced in the fragmentation of outgoing partons, could lead to the observed azimuthal anisotropy of high transverse momentum (high- $p_{T}$ ) hadrons produced in high energy proton-proton ( $p$ - $p$ ) or proton-ion ( $p$ - $A$ ) collisions. Including simple Gaussian forms for transverse momentum dependent parton distribution functions (PDF) and fragmentation functions, and assuming an $A^{1/3}$ enhancement of a PDF in $p$ - $P b$ collisions, we show that the observed anisotropy, with \emph{no modification} to the angle integrated spectra ( $R_{p A} = 1$ ) for 5~GeV~ $≲ p_{T} ≲ 50$ ~GeV, can be straightforwardly understood as arising from a few processes dominated by gluon-gluon to gluon-gluon scattering.
Comments:
11 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2308.14702 [pdf]
PLB(2024)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE