Nuclear Theory·nucl-th

Tuesday·March 26, 2024

16 papers—7 primary·9 cross-listed

08
Scalar field with a time-independent classical source, not trivial after all: from vacuum decay to scattering
Leonardo Tinti🇵🇱 · Arthur Vereijken🇵🇱 · Shahriyar Jafarzade🇵🇱 · Francesco Giacosa🇵🇱
Historically it has been believed that a time-independent classical source has no effect on the scattering of relativistic uncharged field, in contrast with single particle quantum mechanics. In this work we show that the dynamics is not trivial. We solve exactly for the scattering amplitudes and find that a key ingredient is the production of particles from the unstable vacuum, conceptually similar to the Schwinger mechanism. We compute exactly the probabilities for the vacuum to decay in $n$ particles. The time dependence of such probabilities displays interesting properties such as the quantum Zeno effect and in particular has no regime where the exponential decay law is a good approximation. We show that the trivial scattering found in the past is the byproduct of the adiabatic switching of the interaction. In fact, it is not possible to switch off the interaction (adiabatically or otherwise) at distant times and recover the exact results. Finally, this non trivial vacuum behavior is a source of particle production. We argue that such non-perturbative calculations can be phenomenologically relevant for the production processes that are suppressed at the lower orders in perturbation theory, for instance dilaton production in a medium.
↳ hep-thhep-phnucl-thquant-phPRD(2024)·1 citation
09
From pole parameters to line shapes and branching ratios
L. A. Heuser🇩🇪 · G. Chanturia🇩🇪 · F.-K. Guo🇨🇳 · C. Hanhart🇩🇪 · M. Hoferichter🇨🇭 · B. Kubis🇩🇪
Resonances are uniquely characterized by their complex pole locations and the corresponding residues. In practice, however, resonances are typically identified experimentally as structures in invariant mass distributions, with branching fractions of resonances determined as ratios of count rates. To make contact between these quantities it is necessary to connect line shapes and resonance parameters. In this work we propose such a connection and illustrate the formalism with detailed studies of the $ρ (770)$ and $f_{0} (500)$ resonances. Based on the line shapes inferred from the resonance parameters along these lines, expressions for partial widths and branching ratios are derived and compared to other approaches in the literature.
↳ hep-phhep-exnucl-thEPJC(2024)·31 citations
10
Bottomonium suppression from the three-loop QCD potential
Nora Brambilla🇩🇪 · Tom Magorsch🇩🇪 · Michael Strickland🇺🇸 · Antonio Vairo🇩🇪 · Peter Vander Griend🇺🇸
We compute the suppression of bottomonium in the quark-gluon plasma using the three-loop QCD static potential. The potential describes the spin-averaged bottomonium spectrum below threshold with a less than 1% error. Within potential nonrelativistic quantum chromodynamics and an open quantum systems framework, we compute the evolution of the bottomonium density matrix. The values of the quarkonium transport coefficients are obtained from lattice QCD measurements of the bottomonium in-medium width and thermal mass shift; we additionally include for the first time a vacuum contribution to the dispersive coefficient $γ$ . Using the three-loop potential and the values of the heavy quarkonium transport coefficients, we find that the resulting bottomonium nuclear modification factor is consistent with experimental observations, while at the same time reproducing the lattice measurements of the in-medium width.
↳ hep-phhep-exnucl-exnucl-thPRD(2024)·21 citations
11
Exotic tetraquarks at the HL-LHC with JETHAD: A high-energy viewpoint
Francesco Giovanni Celiberto🇪🇸
We review the semi-inclusive hadroproduction of a neutral hidden-flavor tetraquark with light and heavy quark flavor at the HL-LHC, accompanied by another heavy hadron or a light-flavored jet. We make use of the novel TQHL1.0 determinations of leading-twist fragmentation functions to describe the formation mechanism of a tetraquark state within the next-to-leading order perturbative QCD. This framework builds on the basis of a spin-physics inspired model, taken as a proxy for the lowest-scale input of the constituent heavy-quark fragmentation channel. Then, all parton-to-tetraquark fragmentation functions are consistently obtained via the above-threshold DGLAP evolution in a variable-flavor number scheme. We provide predictions for a series of differential distributions calculated by the hands of the JETHAD method well-adapted to NLL/NLO+ hybrid-factorization studies, where the resummation of next-to-leading energy logarithms and beyond is included in the collinear picture. We provide corroborating evidence that high-energy observables sensitive to semi-inclusive tetraquark emissions at the HL-LHC exhibit a fair stability under radiative corrections as well as MHOU studies. Our analysis constitutes a prime contact point between QCD resummations and the exotic matter.
↳ hep-phhep-exhep-thnucl-ex+1Symmetry(2024)·29 citations
12
Generalized nonlinear Langevin equation from quantum nonlinear projection operator
Jin Hu🇨🇳
We systematically derive the quantum generalized nonlinear Langevin equation using Morozov's projection operator method. This approach extends the linear Mori-Zwanzig projection operator technique, allowing for the inclusion of nonlinear interactions among macroscopic modes. Additionally, we obtain the quantum generalized Fokker-Planck equation within the Heisenberg picture, which is consistent with Morozov's original formulation. These equations are fundamentally significant in non-equilibrium statistical physics, particularly in scenarios characterized by enhanced fluctuations, such as anomalous transport phenomena near critical points. The quantum nature of the derived generalized Langevin and Fokker-Planck equations is anticipated to provide a more detailed description than their classical equivalents. Specifically, the noise kernel in the quantum generalized Langevin equation is multiplicative, which broadens the applicability beyond Gaussian approximations. Given specific interactions, these equations are expected to be instrumental in investigating critical transport phenomena.
↳ cond-mat.stat-mechhep-phnucl-thquant-phPRD(2024)·3 citations
13
Nonstandard interactions of neutrinos with dense matter
Parada T. P. Hutauruk🇰🇷
Nonstandard interaction is expected to be a crucial hint in explaining the experimental data on neutrino scattering off electrons. In this context, the nonstandard interaction vector and axial-vector couplings are needed to be extracted from recent experiments and a few of them are now available in the literature. With these coupling bounds, in this paper, I explore their impacts on the neutrinos interacting with the free electron gas in dense matter. To this end, I compute and predict the neutrino differential cross section and mean free path in dense matter for those existing experimental bounds. Interesting behavior in the neutrino cross sections and mean free path is found for the different nonstandard interaction couplings from different experiment constraints. I also found that the neutrino cross-section and mean free path in the dense matter are very sensitive to values and signs of the nonstandard interaction couplings, leading to different prediction results to the Standard Model cross-section and mean free path as well as their totals, which is given by a sum of the Standard Model and nonstandard interaction.
↳ hep-phastro-ph.HEastro-ph.SRhep-ex+10 citations
14
Effect of Coriolis Force on Electrical Conductivity Tensor for Rotating Hadron Resonance Gas
Nandita Padhan🇮🇳 · Ashutosh Dwibedi🇮🇳 · Arghya Chatterjee🇮🇳 · Sabyasachi Ghosh🇮🇳
We have investigated the influence of the Coriolis force on the electrical conductivity of hadronic matter formed in relativistic nuclear collisions, employing the Hadron Resonance Gas (HRG) model. A rotating matter in the peripheral heavy ion collisions can be expected from the initial stage of quark matter to late-stage hadronic matter. Present work is focused on rotating hadronic matter, whose medium constituents - hadron resonances can face a non-zero Coriolis force, which can influence the hadronic flow or conductivity. We estimate this conductivity tensor by using the relativistic Boltzmann transport equation. In the absence of Coriolis force, an isotropic conductivity tensor for hadronic matter is expected. However, our study finds that the presence of Coriolis force can generate an anisotropic conductivity tensor with three main conductivity components - parallel, perpendicular, and Hall, similar to the effect of Lorentz force at a finite magnetic field. Our study has indicated that a noticeable anisotropy of conductivity tensor can be found within the phenomenological range of angular velocity $Ω = 0.001 - 0.02$ GeV and hadronic scattering radius $a = 0.2 - 2$ fm.
↳ hep-phnucl-thPRC(2024)·15 citations
15
A novel quark pairing in sQGP induced by the non-Abelian feature of the interaction
Fei Gao · Yi Lu · Yu-Xin Liu
We solve the coupled Dyson-Schwinger equations for quark propagator and quark gluon vertex in the Nambu-Gorkov basis which is widely applied to study the color superconductivity. After considering the non-Abelian feature in the off-diagonal part of quark gluon vertex, we acquire a quark pairing gap in chiral limit above the chiral phase transition temperature $T_{c}$ . The gap persists up to $2 - 3 T_{c}$ and vanishes at higher temperature. Such a quark pairing characterizes the strongly coupled quark gluon plasma phase as a new phase and distinct from the phase with quasi quarks and gluons. Its new features can be disclosed in the heavy ion collision experiments.
↳ hep-phhep-thnucl-th2 citations
16
Hydrodynamic fluctuations and topological susceptibility in chiral magnetohydrodynamics
Arpit Das🇬🇧 · Nabil Iqbal🇬🇧 · Napat Poovuttikul🇹🇭
Chiral magnetohydrodynamics is devoted to understanding the late-time and long-distance behavior of a system with an Adler-Bell-Jackiw anomaly at finite temperatures. The non-conservation of the axial charge is determined by the topological density $E \cdot B$ ; in a classical hydrodynamic description this decay rate can be suppressed by tuning the background magnetic field to zero. However it is in principle possible for thermal fluctuations of $E \cdot B$ to result in a non-conservation of the charge even at vanishing $B$ -field; this would invalidate the classical hydrodynamic effective theory. We investigate this by computing the real-time susceptibility of the topological density at one-loop level in magnetohydrodynamic fluctuations, relating its low-frequency limit to the decay rate of the axial charge. We find that the frequency-dependence of this susceptibility is sufficiently soft as to leave the axial decay rate unaffected, validating the classical hydrodynamic description. We show that the susceptibility contains non-analytic frequency-dependence which is universally determined by hydrodynamic data. We comment briefly on possible connections to the recent formulation of the ABJ anomaly in terms of non-invertible symmetry.
↳ hep-thastro-ph.HEhep-phnucl-thSciPost Phys.(2024)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE