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Nuclear Theory·nucl-th

Monday·September 9, 2024

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 04

    Relaxation times for disoriented isospin condensates in high energy heavy ion collisions

    Olivia Chabowski🇺🇸 · Joseph I. Kapusta🇺🇸 · Mayank Singh🇺🇸

    Fluctuations between charged and neutral kaons measured by the ALICE Collaboration in Pb-Pb collisions at the LHC exceed conventional explanations. Previously it was shown that if the scalar condensate is accompanied by an electrically neutral isospin--1 field then the combination can produce large equilibrium fluctuations where . Hadronizing strange and anti-strange quarks might then strongly fluctuate between charged ( or ) and neutral ( or ) kaons. Here we estimate the times for the condensates to achieve their equilibrium probability distributions within causal volumes in high energy heavy ion collisions. This is achieved by modeling the temperature dependence of the condensates, mesonic collective excitations, decay rates of the associated fields, and employing the Langevin and Fokker-Planck equations. Within this model, we find that the equilibration times are short compared with the expansion time, making disoriented isospin condensates a viable explanation for the anomalous fluctuations observed at the LHC.

    ↳ hep-phnucl-thPRC(2025)·3 citations
  2. 05

    Direct quarkonium production in DIS from a joint CGC and NRQCD framework

    Vincent Cheung🇺🇸 · Zhong-Bo Kang🇺🇸 · Farid Salazar🇺🇸 · Ramona Vogt🇺🇸

    We compute the differential cross section for direct quarkonium production in high-energy electron-nucleus collisions at small . Our computation is performed within the nonrelativistic QCD factorization formalism that separates the calculation into short distance coefficients and long distance matrix elements that depend on the color and spin of the state. We obtain the short distance coefficients of the production of the heavy quark pair within the framework of the Color Glass Condensate effective field theory, which resums coherent multiple interactions of the heavy quark pair with the nucleus to all orders. Our results are expressed as the convolution of perturbatively calculable perturbative functions with multi-point light-like Wilson line correlators. In the correlation limit, we establish the correspondence between our CGC formulation with calculations employing the transverse momentum dependent (TMD) framework. We extend this correspondence by resumming kinematic power corrections within the improved TMD framework, which interpolates between the TMD formalism and factorization formalism. We present a detailed numerical analysis, focusing on production in the kinematics accessible at the future Electron-Ion Collider, highlighting the importance of genuine higher-order saturation contributions when the electron collides with a large nucleus.

    ↳ hep-phnucl-thPRD(2024)·13 citations
  3. 06

    Sensitivity of jet quenching to the initial state in heavy-ion collisions

    Souvik Priyam Adhya · Konrad Tywoniuk

    In heavy-ion collisions, nuclear matter is subjected to extreme conditions in a highly dynamical, rapidly evolving environment. This poses a tremendous challenge for calculating jet quenching observables. Current approaches rely on analytical results for static cases, introducing theoretical uncertainties and biases in our understanding of the pre-equilibrated medium. To address this issue, we employ resummation schemes to derive analytical rates for radiative energy loss in generic, evolving backgrounds. We investigate regimes where rare scattering and multiple scattering with the dynamical medium occurs, and extract relevant scales governing the in-medium emission rate of soft gluons. Our analysis indicates that strong jet quenching is only possible when the equilibration time of the medium is longer than its mean free path, highlighting the importance of medium modifications of jets in the earliest stages of heavy-ion collisions. We also demonstrate analytically that a medium evolution, which initially has a small coupling to jets, typically leads to a stronger jet azimuthal asymmetry at the same jet suppression factor.

    ↳ hep-phnucl-th14 citations
  4. 07

    Suppressing Gauge Drift in Quantum Simulations with Gauge Transformations

    Carter Ball🇺🇸

    The simulation of quantum lattice gauge theories faces the major challenge of maintaining gauge invariance, as various errors in the simulation push the state of the system out of the physical subspace of the system's exponentially larger Hilbert space. This paper outlines a method, based off of previous work, that uses gauge transformations in two ways. Firstly, the method exploits the Zeno effect by conducting frequent projections to suppress gauge drift. These projections utilize local gauge transformations to destructively interfere unphysical amplitudes via coupling to an ancillary qubit while the physical amplitudes are left untouched, up to a less than unity normalization factor. Secondly, gauge transformations are conducted throughout the time evolution of the system to hamper the speed of gauge drift. This paper demonstrates this method on a pure 1D SU toy model.

    ↳ hep-latnucl-thquant-phPRA(2025)·0 citations

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first authorsco-authorsvia INSPIRE