PaperPanorama

Nuclear Theory·nucl-th

Thursday·March 14, 2024

12 papers4 primary·8 cross-listed

  1. 05

    Collisional energy loss of a heavy quark in a semiquark-gluon plasma

    Qianqian Du🇨🇳 · Mudong Du🇨🇳 · Yun Guo🇨🇳

    By utilizing a background field effective theory, we compute the collisional energy loss of a heavy quark moving through a semiquark-gluon plasma characterized by nontrivial holonomy for Polyakov loops. We consider the elastic scatterings between the incident heavy quark and the thermal partons with both hard and soft momentum transfers. As compared to the energy loss obtained from the perturbation theory, the hard processes get modified through the thermal distribution functions that depend on the background field, while the proper treatment of the soft processes strongly relies on the use of the hard-thermal-loop resummed gluon propagator derived from the background field effective theory. Our results show that the heavy quark energy loss is significantly suppressed in the semiquark-gluon plasma due to a background field that is self-consistently generated in the effective theory. On the other hand, the suppression has a strong dependence on the temperature of the plasma which becomes negligible above times the critical temperature. For a realistic coupling constant, ignoring a relatively weak dependence on the heavy quark velocity, the suppression on the collisional energy loss can be approximated by an overall factor determined solely by the background field. This simple conclusion is expected to be useful for phenomenological applications in the heavy flavor physics.

    hep-phnucl-thPRD(2024)·11 citations
  2. 06

    Energy loss of a heavy fermion in a collisional QED plasma

    Yun Guo🇨🇳 · Luhua Qiu🇨🇳 · Ruizhe Zhao🇨🇳 · Michael Strickland🇺🇸

    We compute the energy loss of heavy fermions moving in a plasma, taking into account the modification of the photon collective modes induced by collisions using a Bhatnagar-Gross-Krook collisional kernel. We include contributions from both hard and soft scatterings of the heavy fermion using a collisionally modified hard-thermal-loop resummed propagator. Using this method, one does not need to introduce a separation scale between hard- and soft-momentum exchanges. To place our calculation in context, we review other theoretical approaches to computing the collisional energy loss of fermions and discuss the systematics and results obtained in each approach compared to using a resummed propagator for both hard and soft momentum exchanges. Our final results indicate that self-consistently including the effect of collisions in the self-energies of the resummed propagator results in an increased energy loss compared to using collisionless hard-thermal-loop propagators. The effect becomes larger as the magnitude of the coupling constant and the velocity of the fermion increase.

    hep-phnucl-thPRD(2024)·8 citations
  3. 07

    SPINAS: Spinor Amplitude Subroutines for Constructive Diagram Evaluations

    Neil Christensen🇺🇸

    SPINAS is a C++ package created for the implementation and numerical computation of phase-space points of constructive amplitudes in particle physics. This package contains a suite of classes and methods for handling particles, propagators, spinor products, and processes. SPINAS is structured to offer straightforward usability while ensuring maximum efficiency. This is achieved through a design that emphasizes the storage and reuse of intermediate results within amplitude calculations for each phase-space point. We include a user guide describing how to use the components, a complete example of how to use SPINAS for a scattering amplitude, a discussion of the design and implementation useful for those wishing to contribute, and a discussion of our validation of this package, including both a validation of individual components of the package and a comparison of a complete set of Standard Model processes with Feynman diagrams.

    hep-phnucl-thEPJC(2024)·5 citations
  4. 08

    Nucleon charge and magnetisation distributions: flavour separation and zeroes

    Zhao-Qian Yao🇨🇳 · Daniele Binosi🇮🇹 · Zhu-Fang Cu🇨🇳 · Craig D. Roberts🇨🇳

    A symmetry-preserving truncation of the quantum field equations describing hadron properties is used to deliver parameter-free predictions for all nucleon elastic electromagnetic form factors and their flavour separation to large values of momentum transfer, . The proton electric form factor, , possesses a zero, whereas that of the neutron, , does not. The difference owes to the behaviour of the Pauli form factor of the proton's singly-represented valence -quark. Consequently, on a material large- domain. These predictions can be tested in modern experiments.

    hep-phhep-exhep-latnucl-ex+1Fund.Res.(2026)·22 citations
  5. 09

    First identification of a doublet wobbling excitation mode in Pd

    A. Karmakar · P. Datta · N. Rather · S. Pal · R. Palit · A. Goswami · G.H. Bhat · J. A. Sheikh · S. Jehangir · S. Chattopadhyay · S. Frauendorf

    An experimental investigation of Pd has revealed, for the first time, the existence of two wobbling bands, both having one phonon configuration and originating from excitation which is the wobbling from the yrast band with the quasineutron fully aligned with the short axis, and from an excited band with the same quasineutron but with less alignment along the short axis. These observations have been drawn from the measured ratios of the inter-band and intra-band gamma transition rates. Model calculations based on the triaxial projected shell model (TPSM) approach have been performed and are found to be in good agreement with the experimental energies and relative transition probabilities. The analysis of the TPSM results provides an insight into the nature of the observed structures at a microscopic level.

    nucl-exnucl-thPRC(2025)·7 citations
  6. 10

    Variance Minimisation of the Lipkin-Meshkov-Glick Model on a Quantum Computer

    Isaac Hobday🇬🇧 · Paul Stevenson🇬🇧 · James Benstead🇬🇧

    Quantum computing can potentially provide advantages for specific computational tasks. The simulation of fermionic systems is one such task that lends itself well to quantum computation, with applications in nuclear physics and electronic systems. Here we present work in which we use a variance minimisation method to find the full spectrum of energy eigenvalues of the Lipkin-Meshkov-Glick model; an exactly-solvable nuclear shell model-type system. We perform these calculations using both quantum simulators and real quantum hardware accessed via IBM cloud-based quantum computers. Using these IBM quantum computers we are able to obtain all eigenvalues for the cases of three and seven fermions (nucleons) in the Lipkin-Meshkov-Glick model.

    quant-phnucl-th3 citations
  7. 11

    BHAC-QGP: three-dimensional MHD simulations of relativistic heavy-ion collisions, I. Methods and tests

    Markus Mayer🇩🇪 · Ashutosh Dash🇩🇪 · Gabriele Inghirami🇩🇪 · Hannah Elfner🇩🇪 · Luciano Rezzolla🇩🇪 · Dirk H. Rischke🇩🇪

    We present BHAC-QGP, a new numerical code to simulate the evolution of matter created in heavy-ion collisions in the presence of electromagnetic fields. It is derived from the Black Hole Accretion Code (BHAC), which has been designed to model astrophysical processes in a general-relativistic magnetohydrodynamical description. As the original Black Hole Accretion Code, BHAC-QGP benefits from the use of Adaptive Mesh Refinement (AMR), which allows us to dynamically adjust the resolution where necessary, and makes use of time-dependent Milne coordinates and the ultrarelativistic equation of state, . We demonstrate that BHAC-QGP accurately passes a number of systematic and rigorous tests.

    hep-phnucl-thPRC(2025)·10 citations
  8. 12

    BHAC-QGP: three-dimensional MHD simulations of relativistic heavy-ion collisions, II. Application to Au-Au collisions

    Markus Mayer🇩🇪 · Ashutosh Dash🇩🇪 · Gabriele Inghirami🇩🇪 · Hannah Elfner🇩🇪 · Luciano Rezzolla🇩🇪 · Dirk H. Rischke🇩🇪

    We present BHAC-QGP, a new numerical code to simulate the evolution of matter created in heavy-ion collisions. BHAC-QGP is based on the Black Hole Accretion Code (BHAC), which has been designed to model astrophysical processes through the solution of the equations of general-relativistic magnetohydrodynamics. Like the mother code, BHAC-QGP uses Adaptive Mesh Refinement (AMR), which allows for a dynamic adjustment of the resolution in regions of the computational domain where a particularly high accuracy is needed. We here discuss a number of applications of BHAC-QGP to Au-Au collisions at Relativistic Heavy-Ion Collider (RHIC) energies and show that the code is able to reproduce results of other simulations of these scenarios, but with much higher accuracy.

    hep-phnucl-thPRC(2025)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE