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Nuclear Theory·nucl-th

Tuesday·September 27, 2022

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 07

    [Submitted on 22 Sept 2022] (cross-list from hep-th)

    Stability of multi-component relativistic viscous hydrodynamics from Israel-Stewart and reproducing DNMR from maximizing the entropy

    Dekrayat Almaalol🇺🇸 · Travis Dore🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸

    The Quark Gluon Plasma produced in heavy-ion collisions has three relevant conserved charges: baryon number (B), strangeness (S), and electric charge (Q). Here we derive the Israel-Stewart framework for BSQ diffusion coupled to shear and bulk viscosity and the thermodynamic derivatives needed to couple this to a BSQ equation of state. We reproduce a subset of the terms in the DNMR approach and propose a technique to derive other terms from the maximum entropy principle. Finally, we preform a stability analysis that can be used to constraint transport coefficients in BSQ hydrodynamics.

    Comments:
    24 pages, 0 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2209.11210 [pdf]
    PRD(2025)·26 citations
  2. 08

    [Submitted on 24 Sept 2022] (cross-list from hep-lat)

    Determination of Lattice QCD Equation of state at a finite chemical potential

    Sabarnya Mitra🇮🇳

    Exponential resummation to all orders in is a promising scheme which can capture contributions to all orders in by considering only the first few Taylor coefficients in the Taylor expansion of thermodynamic observables in lattice QCD. This approach however, gets affected by biased estimates of -point correlation functions whose effects can significantly hinder probe of finite density QCD. We present an unbiased exponential resummation formalism, which can reproduce the Taylor series up to the desired order in , besides retaining the original form of the all-order resummation estimate of QCD partition function.

    Comments:
    6 pages, 2 figures, Contribution to 25th DAE BRNS Symposium 12-16 December 2022
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2209.11937 [pdf]
    Springer Proc.Phys.(2024)·5 citations
  3. 09

    [Submitted on 24 Sept 2022] (cross-list from nucl-ex)

    Higher-Order Cumulants and Correlation Functions of Proton Multiplicity Distributions in = 3 GeV Au+Au Collisions at the RHIC STAR Experiment

    STAR Collaboration: M. S. Abdallah · B. E. Aboona · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · D. M. Anderson · E. C. Aschenauer · J. Atchison and 361 other authors

    We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity () and transverse momentum () region and GeV/ in the center-of-mass frame. A systematic analysis of the proton cumulants and correlation functions up to sixth-order as well as the corresponding ratios as a function of the collision centrality, , and are presented. The effect of pileup and initial volume fluctuations on these observables and the respective corrections are discussed in detail. The results are compared to calculations from the hadronic transport UrQMD model as well as a hydrodynamic model. In the most central 5\% collisions, the value of proton cumulant ratio is negative, drastically different from the values observed in Au+Au collisions at higher energies. Compared to model calculations including Lattice QCD, a hadronic transport model, and a hydrodynamic model, the strong suppression in the ratio of at 3 GeV Au+Au collisions indicates an energy regime dominated by hadronic interactions.

    Comments:
    25 pages, 20 figures, 4 tables
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2209.11940 [pdf]
    PRC(2023)·69 citations
  4. 10

    [Submitted on 25 Sept 2022] (cross-list from nucl-ex)

    An Indirect Measurement of Li(n,) Cross Sections

    Midhun C.V · M.M Musthafa · S.V Suryanarayana · Gokuldas H · Shaima A · Hajara. K · Antony Joseph · T. Santhosh · A. Baishya · A Pal · P.C Rout · S Santra and 5 other authors

    The Li(n,)Li cross sections in the neutron energy range of 0.6 to 4 MeV have been measured by the experimental implementation of the direct capture formalism. This was done by measuring the transition probability experimentally and accounting for the spin factor by theoretical calculation. The electromagnetic transition probabilities from Li analogous to the initial neutron capture states of Li were measured by populating the J states of Li through Li()Li reaction. The impact of coupling of resonant states, above neutron separation threshold of Li, in the neutron capture, is observed from the capture spectrum. The measured cross sections were reproduced through {\sc fresco} and Talys-1.95 Direct Capture Calculations.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2209.12165 [pdf]
    3 citations
  5. 11

    [Submitted on 26 Sept 2022] (cross-list from hep-ph)

    Kaon spectrum revisited

    U. Taboada-Nieto🇪🇸 · P.G. Ortega🇪🇸 · D.R. Entem🇪🇸 · F. Fernández🇪🇸 · J. Segovia🇪🇸

    The European Organization for Nuclear Research (CERN) has recently approved a world-unique QCD facility in which an updated version of the external M2 beam line of the CERN SPS in conjunction with a universal spectrometer of the COMPASS experiment is used. One of its main goals is to use highly intense and energetic kaon beams to map out the complete spectrum of excited kaons with an unprecedented precision; having a broad impact not only on low-energy QCD phenomenology, but also on many high-energy particle processes where excited kaons appear, such as the study of CP violation in heavy-meson decays studied at LHCb and Belle~II. In support of the experimental effort, the kaon spectrum is computed herein using a constituent quark model which has been successfully applied to a wide range of hadronic observables, from light to heavy quark sectors, and thus the model parameters are completely constrained. The model's prediction can be used as a template against which to compare the already collected data and future experimental findings, in order to distinguish between conventional and exotic kaon states. We also compare our results with those available in the literature in order to provide some general statements, common to all calculations.

    Comments:
    11 pages, 1 figure, 13 tables
    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:
    2209.12555 [pdf]
    EPJA(2023)·13 citations
  6. 12

    [Submitted on 26 Sept 2022] (cross-list from hep-lat)

    Lattice regularizations of vacua: Anomalies and qubit models

    Mendel Nguyen🇺🇸 · Hersh Singh🇺🇸

    Anomalies are a powerful way to gain insight into possible lattice regularizations of a quantum field theory. In this work, we argue that the continuum anomaly for a given symmetry can be matched by a manifestly-symmetric, local, lattice regularization in the same spacetime dimensionality only if (i) the symmetry action is offsite, or (ii) if the continuum anomaly is reproduced exactly on the lattice. We consider lattice regularizations of a class of prototype models of QCD: the (1+1)-dimensional asymptotically-free Grassmannian nonlinear sigma models (NLSMs) with a term. Using the Grassmannian NLSMs as a case study, we provide examples of lattice regularizations in which both possibilities are realized. For possibility (i), we argue that Grassmannian NLSMs can be obtained from antiferromagnets with a well-defined continuum limit, reproducing both the infrared physics of vacua and the ultraviolet physics of asymptotic freedom. These results enable the application of new classical algorithms to lattice Monte Carlo studies of these quantum field theories, and provide a viable realization suited for their quantum simulation. On the other hand, we show that, perhaps surprisingly, the conventional lattice regularization of vacua due to Berg and Lüscher reproduces the anomaly exactly on the lattice, providing a realization of the second possibility.

    Comments:
    10 pages + appendices
    Subjects:
    High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2209.12630 [pdf]
    PRD(2023)·10 citations
  7. 13

    [Submitted on 26 Sept 2022] (cross-list from astro-ph.HE)

    The Radius of PSR J0740+6620 from NICER with NICER Background Estimates

    Tuomo Salmi🇳🇱 · Serena Vinciguerra🇳🇱 · Devarshi Choudhury🇳🇱 · Thomas E. Riley🇳🇱 · Anna L. Watts🇳🇱 · Ronald A. Remillard🇺🇸 · Paul S. Ray🇺🇸 · Slavko Bogdanov🇺🇸 · Sebastien Guillot🇫🇷 · Zaven Arzoumanian🇺🇸 · Cecilia Chirenti🇺🇸 · Alexander J. Dittmann🇺🇸 and 6 other authors

    We report a revised analysis for the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, studied previously with joint fits to NICER and XMM-Newton data by Riley et al. (2021) and Miller et al. (2021). We perform a similar Bayesian estimation for the pulse-profile model parameters, except that instead of fitting simultaneously the XMM-Newton data, we use the best available NICER background estimates to constrain the number of photons detected from the source. This approach eliminates any potential issues in the cross-calibration between these two instruments, providing thus an independent check of the robustness of the analysis. The obtained neutron star parameter constraints are compatible with the already published results, with a slight dependence on how conservative the imposed background limits are. A tighter lower limit causes the inferred radius to increase, and a tighter upper limit causes it to decrease. We also extend the study of the inferred emission geometry to examine the degree of deviation from antipodality of the hot regions. We show that there is a significant offset to an antipodal spot configuration, mainly due to the non-half-cycle azimuthal separation of the two emitting spots. The offset angle from the antipode is inferred to be above 25 degrees with 84% probability. This seems to exclude a centered-dipolar magnetic field in PSR J0740+6620.

    Comments:
    29 pages, 18 figures (10 of which are figure sets), 1 animation, 10 tables. Published in ApJ
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2209.12840 [pdf]
    ApJ(2022)·128 citations

Affiliations

first authorsco-authorsvia INSPIRE