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Nuclear Theory·nucl-th

Monday·February 15, 2021

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 05

    Chiral magnetic effect reveals the topology of gauge fields in heavy-ion collisions

    Dmitri E. Kharzeev🇺🇸 · Jinfeng Liao🇺🇸

    The topological structure of vacuum is the cornerstone of non-Abelian gauge theories describing strong and electroweak interactions within the standard model of particle physics. However, transitions between different topological sectors of the vacuum (believed to be at the origin of the baryon asymmetry of the Universe) have never been observed directly. An experimental observation of such transitions in Quantum Chromodynamics (QCD) has become possible in heavy-ion collisions, where the chiral magnetic effect converts the chiral asymmetry (generated by topological transitions in hot QCD matter) into an electric current, under the presence of the magnetic field produced by the colliding ions. The Relativistic Heavy Ion Collider program on heavy-ion collisions such as the Zr-Zr and Ru-Ru isobars, thus has the potential to uncover the topological structure of vacuum in a laboratory experiment. This discovery would have far-reaching implications for the understanding of QCD, the origin of the baryon asymmetry in the present-day Universe, and for other areas, including condensed matter physics.

    ↳ hep-phcond-mat.str-elhep-thnucl-ex+1Nature Rev.Phys.(2021)·109 citations
  2. 06

    Corrections to the hadron resonance gas from lattice QCD and their effect on fluctuation-ratios at finite density

    Rene Bellwied🇺🇸 · Szabolcs Borsanyi🇩🇪 · Zoltan Fodor🇩🇪 · Jana N. Guenther🇫🇷 · Sandor D. Katz🇭🇺 · Paolo Parotto🇩🇪 · Attila Pasztor🇭🇺 · David Pesznyak🇭🇺 · Claudia Ratti🇺🇸 · Kalman K. Szabo🇩🇪

    The hadron resonance gas (HRG) model is often believed to correctly describe the confined phase of QCD. This assumption is the basis of many phenomenological works on QCD thermodynamics and of the analysis of hadron yields in relativistic heavy ion collisions. We use first-principle lattice simulations to calculate corrections to the ideal HRG. Namely, we determine the sub-leading fugacity expansion coefficients of the grand canonical free energy, receiving contributions from processes like kaon-kaon or baryon-baryon scattering. We achieve this goal by performing a two dimensional scan on the imaginary baryon number chemical potential () - strangeness chemical potential () plane, where the fugacity expansion coefficients become Fourier coefficients. We carry out a continuum limit estimation of these coefficients by performing lattice simulations with temporal extents of using the 4stout-improved staggered action. We then use the truncated fugacity expansion to extrapolate ratios of baryon number and strangeness fluctuations and correlations to finite chemical potentials. Evaluating the fugacity expansion along the crossover line, we reproduce the trend seen in the experimental data on net-proton fluctuations by the STAR collaboration.

    ↳ hep-lathep-phnucl-thPRD(2021)·25 citations
  3. 07

    Lattice QCD equation of state at finite chemical potential from an alternative expansion scheme

    S. Borsanyi🇩🇪 · Z. Fodor🇩🇪 · J. N. Guenther🇫🇷 · R. Kara🇩🇪 · S. D. Katz🇭🇺 · P. Parotto🇩🇪 · A. Pasztor🇭🇺 · C. Ratti🇺🇸 · K. K. Szabo🇩🇪

    Taylor expansion of the equation of state of QCD suffers from shortcomings at chemical potentials . First, one faces difficulties inherent in performing such an expansion with a limited number of coefficients; second, higher order coefficients determined from lattice calculations suffer from a poor signal-to-noise ratio. In this work, we present a novel scheme for extrapolating the equation of state of QCD to finite, real chemical potential that can extend its reach further than previous methods. We present continuum extrapolated lattice results for the new expansion coefficients and show the thermodynamic observables up to .

    ↳ hep-latnucl-thPRL(2021)·201 citations

Affiliations

first authorsco-authorsvia INSPIRE