Nuclear Theory·nucl-th

Wednesday·October 23, 2024

13 papers—3 primary·10 cross-listed

04
Wiedemann-Franz law violation domain for graphene and nonrelativistic systems
Thandar Zaw Win · Cho Win Aung · Gaurav Khandal · Sabyasachi Ghosh
A systematic non-fluid to fluid transition framework and comparative research on Lorenz ratios for graphene and nonrelativistic systems have been studied to identify their Wiedemann-Franz law violation domain. Here, Lorenz ratio is defined as thermal conductivity divided by electrical conductivity times temperature times Lorenz number. In non-fluid framework, Lorenz ratio become exactly one, which means that the Wiedemann-Franz is obeyed within a Fermi Liquid domain. When one enters from Fermi Liquid to Dirac Fluid domain, Lorenz ratio becomes less than one in non-fluid framework but in fluid framework, it always remain greater than one for both domain. By compiling our outcomes and connecting with experimental data, a non-fluid to fluid transition framework is expected during the transition from Fermi Liquid to Dirac Fluid domain.
↳ cond-mat.mes-hallcond-mat.stat-mechnucl-thInt.J.Mod.Phys.B(2025)·4 citations
05
New Angles on Energy Correlators
Samuel Alipour-fard🇺🇸 · Ankita Budhraja🇳🇱 · Jesse Thaler🇺🇸 · Wouter J. Waalewijn🇳🇱
Energy correlators have recently come to the forefront of jet substructure studies at colliders due to their remarkable properties: they naturally separate physics at different scales, are robust to contamination from soft radiation, and offer a direct connection with quantum field theory. The current parametrization used for energy correlators, however, is based on redundant pairwise angles with complex phase space restrictions. In this Letter, we introduce a new parametrization of energy correlators that features a simpler phase space structure and preserves information about the orientation of jet constituents. Further, our parametrization drastically reduces the computational cost to compute energy correlators on experimental data; whereas the time to compute a traditional projected $N$ -point energy correlator scales as $M^{N} / N!$ on a jet with $M$ particles, our new parametrization achieves a scaling of $M^{2} lo g M$ , remarkably independently of N. Even for N=3, this improved scaling is particularly important for studies of heavy ion collisions, and higher values of $N$ will enable new qualitative understanding of gauge theories. Theoretical calculations for our new energy correlators differ from those of traditional parametrizations only at next-to-next-to-leading logarithmic accuracy and beyond, and we expect that our simpler phase space structure will simplify those calculations. We also discuss how to extend our parametrization to resolved $N$ -point energy correlators that encode angular distances between greater numbers of particles, yielding intuitive visualizations of jet substructure that are qualitatively different for different jet samples. We propose two possible generalizations for probing multi-prong jets and testing jet scaling behavior.
↳ hep-phhep-exnucl-exnucl-thPRL(2025)·21 citations
06
Universality in the Near-Side Energy-Energy Correlator
Xiaohui Liu🇨🇳 · Werner Vogelsang🇩🇪 · Feng Yuan🇩🇪 · Hua Xing Zhu🇨🇳
We investigate the energy-energy correlator (EEC) of hadrons produced on the same side in $e^{+} e^{-}$ annihilation or in leading jets in $pp$ collisions. We observe a remarkable universality of the correlator. Using a non-perturbative transverse momentum dependent (TMD) fragmentation function to model the transition from the ``free-hadron" region to the perturbative collinear region, we are able to describe the near-side shapes and peaks over a wide range of energy for both the $e^{+} e^{-}$ annihilation and the $pp$ jet substructure measurements in terms of just two parameters. We present further predictions for the ratio of the projected three-point energy correlator to the EEC. The excellent agreement between our calculations and the experimental data may provide new insights into the role of non-perturbative physics for EECs, and suggests the possibility of exploring non-perturbative TMDs using theoretical tools developed for the energy correlators.
↳ hep-phhep-exnucl-exnucl-thPRL(2025)·32 citations
07
Meson spin alignment and baryon polarization from coalescence with spin-vorticity non-equilibrium
Kayman J. Gonçalves🇵🇱 · Giorgio Torrieri🇵🇱 · Radoslaw Ryblewski🇵🇱
We estimate both the polarization of spin $1/2$ baryons and the spin density matrix coefficients of spin $1$ mesons using a thermal model that incorporates vorticity and polarization to describe quarks, along with a coalescence formalism where spin and vorticity are not in equilibrium. We find that while our model is not predictive due to its considerable number of free parameters, it has the potential to explain several seemingly puzzling features of experimental spin measurements, such as the absence of baryon polarization alongside significant vector meson spin alignment. We suggest the measuring meson spin off-diagonal matrix elements, and examining the dependence of polarization observables on azimuthal angles, as methods to falsify this model and gain insights into the freezeout details of baryon and meson spin structure.
↳ hep-phnucl-thPRC(2025)·8 citations
08
Double $ϕ$ Production in $p ˉ p$ Reactions Near Threshold
Dayoung Lee🇰🇷 · Jung Keun Ann🇰🇷 · Seung-il Nam🇰🇷
We employ an effective Lagrangian approach to investigate double $ϕ$ production in the $p ˉ p$ reaction near the threshold and describe a notable violation of the Okubo-Zweig-Iizuka (OZI) rule in this reaction process through hadronic degrees of freedom, using the currently available theoretical and experimental information. The ground-state nucleon and its $s$ -wave resonances, i.e., $N^{*} (1535, 1650, 1895)$ , are taken into account in the $t$ - and $u$ -channel tree-level diagrams. The pentaquark-like nucleon resonance $P_{s} (2071, 3/ 2^{-})$ is also considered. In the $s$ -channel diagrams, scalar and tensor mesons are incorporated, specifically $f_{0} (2020, 2100, 2200)$ and $f_{2} (1950, 2010, 2150)$ , respectively, along with the pseudoscalar meson $η (2225)$ . Our calculations suggest that contributions from the $N$ and $N^{*}$ resonances significantly enhance the cross-section near the threshold. At the same time, those from the $f_{0}$ and $f_{2}$ mesons produce distinctive peak structures around $W = 2.2$ GeV, qualitatively reproducing the JETSET experimental data. The openings of the $Λ ˉ Λ$ and $Σ ˉ Σ$ channels lead to the cusp structures, which can explain the nontrivial structures in the cross-section at $W \approx 2 M_{Λ}$ and $2 M_{Σ}$ observed in the data. It turns out that contributions from the $η$ and $P_{s}$ resonances are almost negligible. Additionally, polarization observables such as the spin density matrix element (SDME) provide crucial insights into the individual hadronic processes involved in this reaction.
↳ hep-phhep-exnucl-exnucl-thPLB(2025)·1 citation
09
Astrophysical constraints on neutron star $f$ -modes with a nonparametric equation of state representation
Sailesh Ranjan Mohanty · Utkarsh Mali · H.C. Das · Bharat Kumar · Philippe Landry
We constrain the fundamental-mode ( $f$ -mode) oscillation frequencies of nonrotating neutron stars using a phenomenological Gaussian process model for the unknown dense-matter equation of state conditioned on a suite of gravitational-wave, radio and X-ray observations. We infer the quadrupolar $f$ -mode frequency preferred by the astronomical data as a function of neutron star mass, with error estimates that quantify the impact of equation of state uncertainty, and compare it to the contact frequency for inspiralling neutron-star binaries, finding that resonance with the orbital frequency can be achieved for the coalescences with the most unequal mass ratio. For an optimally configured binary neutron star merger, we estimate the gravitational waveform's tidal phasing due to $f$ -mode dynamical tides as $7_{- 3}^{+ 2}$ rad at merger. We assess prospects for distinguishing $f$ -mode dynamical tides with current and future-generation gravitational-wave observatories.
↳ astro-ph.HEgr-qcnucl-thPRD(2025)·8 citations
10
Accelerated Quantum Circuit Monte-Carlo Simulation for Heavy Quark Thermalization
Wenyang Qian🇪🇸
Heavy quark thermalization in the quark-gluon plasma (QGP) is one of the most promising phenomena for understanding the strong interaction, where their energy loss and momentum broadening at low momentum can be well described by a stochastic process with drag and diffusion terms. We propose an accelerated quantum circuit Monte-Carlo (aQCMC) framework that ultilizes the quantum amplitude estimation (QAE) algorithm to simulate heavy quark thermalization with quadratically less resources. Specifically, we simulate the thermalization of a heavy quark in both 1D and 2D and in isotropic and anisotropic mediums using an ideal quantum simulator and compare that to analytical thermal expectations.
↳ hep-phnucl-thquant-phPoS(2025)·0 citations
11
Coupled-channel analysis of the near-threshold $e^{+} e^{-} \to N N ˉ$ cross sections
Zhao-Sai Jia🇨🇳 · Zhen-Hua Zhang🇨🇳 · Feng-Kun Guo🇨🇳 · Gang Li🇨🇳
The possible existence of nucleon-antinucleon bound states has been studied for decades. We investigate the $e^{+} e^{-} \to p p ˉ$ and $e^{+} e^{-} \to n n ˉ$ cross sections in the nonrelativistic effective field theory framework. The proton-antiproton and neutron-antineutron coupled-channel final state interactions are considered and found responsible for near-threshold enhancements. Both the proton-neutron mass difference and the Coulomb interaction between $p$ and $p ˉ$ are considered, and the $N N ˉ$ strong interactions are taken into account through a short-distance optical potential. By fitting the low energy constants in the amplitudes to the data for the near-threshold $e^{+} e^{-} \to N N ˉ$ cross sections from the BESIII and SND Collaborations, a $N N ˉ$ quasi-bound state is found just above the $p p ˉ$ threshold, and another $N N ˉ$ pole is found on the unphysical Riemann sheet, farther away from the threshold. The constructed coupled-channel amplitude with Coulomb effects also offers a framework that can be used directly in experimental analyses on fine structures near the $N N ˉ$ thresholds.
↳ hep-phhep-exnucl-exnucl-thPRD(2025)·7 citations
12
Vortex Avalanches and Collective Motion in Neutron Stars
I-Kang Liu · Andrew W. Baggaley · Carlo F. Barenghi · Toby S. Wood
We simulate the dynamics of about 600 quantum vortices in a spinning-down cylindrical container using a Gross--Pitaevskii model. For the first time, we find convincing spatial-temporal evidence of avalanching behaviour resulting from vortex depinning and collective motion. During a typical avalanche, about 10 to 20 vortices exit the container in a short period, producing a glitch in the superfluid angular momentum and a localised void in the vorticity. After the glitch, vortices continue to depin and circulate around the vorticity void in a similar manner to that seen in previous point-vortex simulations. We present evidence of collective vortex motion throughout this avalanche process. We also show that the effective Magnus force can be used to predict when and where avalanches will occur. Lastly, we comment on the challenge of extrapolating these results to conditions in real neutron stars, which contain many orders of magnitude more vortices.
↳ astro-ph.HEastro-ph.SRcond-mat.quant-gasnucl-thApJ(2025)·7 citations
13
Resolved photoproduction in {\tt MadGraph5\_aMC@NLO}
Laboni Manna🇵🇱 · Anton Safronov🇵🇱 · Carlo Flore🇮🇹 · Daniel Kikola🇵🇱 · Jean-Philippe Lansberg🇫🇷 · Olivier Mattelaer🇧🇪
The upcoming Electron-Ion Collider (EIC), with its high luminosity, will offer an unprecedented opportunity to explore the internal structure of atomic nucleus over an extended energy range from $s_{e p} =$ 45 GeV to $s_{e p} =$ 140 GeV. A particularly promising aspect of this collider is the study of the partonic structure with quasi-real photons which can also be studied in inclusive ultra-peripheral collisions at the Large Hadron Collider (LHC). In this work, we present our validation of resolved photoproduction at fixed order for (next-to-)leading order using \texttt{MadGraph5\_aMC@NLO}, a widely adopted framework at the LHC.
↳ hep-phhep-exnucl-thPoS(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE