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Nuclear Theory·nucl-th

Tuesday·November 6, 2018

19 papers—13 primary·6 cross-listed

All19Primary13Cross-lists6
  1. 14

    The Entropy of a Jet

    Duff Neill🇺🇸 · Wouter J. Waalewijn🇳🇱

    Scattering processes often inevitably include the production of infrared states, which are highly correlated with the hard scattering event, and decohere the hard states. This can be described using the entropy of the hard reduced density matrix, which is obtained from tracing over infrared states. We determine this entropy for an asymptotically-free gauge theory by separating the Hilbert space into hard and infrared states, and calculate it in a leading-logarithmic approximation for jets. We find that the entropy increases when the resolution scales defining the hard radiation are lowered, that this entropy is related to the subjet multiplicity, and explore connections to using jet images for machine learning, and the forward-scattering density matrix of partons in a nucleon probed in deep-inelastic scattering.

    ↳ hep-phhep-thnucl-thPRL(2019)·47 citations
  2. 15

    Determining from hadronic decay: the pitfalls of truncating the OPE

    D. Boito🇧🇷 · M. Golterman🇺🇸 · K. Maltman🇨🇦 · S. Peris🇪🇸

    We discuss sum-rule determinations of from non-strange hadronic -decay data. We investigate, in particular, the reliability of the assumptions underlying the "truncated OPE strategy," which specifies a certain treatment of non-perturbative contributions, and which was employed in Refs. [1-3]. Here, we test this strategy by applying the strategy to the -ratio obtained from data, which extend beyond the mass, and, based on the outcome of these tests, we demonstrate the failure of this strategy.We then present a brief overview of new results on the form of duality-violating non-perturbative contributions, which are conspicuously present in the experimentally determined spectral functions. As we show, with the current precision claimed for the extraction of , including a representation of duality violations is unavoidable if one wishes to avoid uncontrolled theoretical errors.

    ↳ hep-phhep-latnucl-thSciPost Phys.Proc.(2019)·6 citations
  3. 16

    Temporal Correlators in the Continuous Time Formulation of Strong Coupling Lattice QCD

    Marc Klegrewe🇩🇪 · Wolfgang Unger🇩🇪

    We present results for lattice QCD in the limit of infinite gauge coupling on a discrete spatial but continuous Euclidean time lattice. A worm type Monte Carlo algorithm is applied in order to sample two-point functions which gives access to the measurement of mesonic temporal correlators. The continuous time limit, based on sending and the bare anistotropy to infinity while fixing the temperature in a non-perturbative setup, has various advantages: the algorithm is sign problem free, fast, and accumulates high statistics for correlation functions. Even though the measurement of temporal correlators requires the introduction of a binning in time direction, this discretization can be chosen to be by orders finer compared to discrete computations. For different spatial volumes, temporal correlators are measured at zero spatial momentum for a variety of mesonic operators. They are fitted to extract the pole masses and corresponding particles as a function of the temperature. We conclude discussing the possibility to extract transport coefficients from these correlators.

    ↳ hep-latnucl-thPoS(2018)·5 citations
  4. 17

    Temperature dependence of : uncertainties from the equation of state

    Jussi Auvinen🇷🇸 · Kari J. Eskola🇫🇮 · Pasi Huovinen🇵🇱 · Harri Niemi🇫🇮 · Risto Paatelainen🇨🇭 · Peter Petreczky🇺🇸

    We perform a global model-to-data comparison on Au+Au collisions at GeV and Pb+Pb collisions at TeV and TeV, using a 2+1D hydrodynamics model with the EKRT initial state and a shear viscosity over entropy density ratio with a linear dependence. To quantify the amount of uncertainty due to the choice of the equation of state (EoS), we compare analysis results based on four different EoSs: the well known parametrisation, an updated parametrisation based on the same list of particles in hadron resonance gas, but using recent lattice results for the partonic part of the EoS, and two new parametrisations based on the Particle Data Group 2016 particle list and the recent lattice results. We find that the choice of the EoS does affect the favoured minimum value of , although within the confidence limits of the analysis. On the other hand, our analysis hardly constrains the temperature dependence of , no matter the EoS.

    ↳ hep-phnucl-thPoS(2018)·4 citations
  5. 18

    Measurement of Nuclear Transparency Ratios for Protons and Neutrons

    M. Duer · O. Hen · E. Piasetzky · L.B. Weinstein · A. Schmidt · I. Korover · E. O. Cohen · H. Hakobyan · the CLAS Collaboration

    This paper presents, for the first time, measurements of neutron transparency ratios for nuclei relative to C measured using the (e,e'n) reaction, spanning measured neutron momenta of 1.4 to 2.4 GeV/c. The transparency ratios were extracted in two kinematical regions, corresponding to knockout of mean-field nucleons and to the breakup of Short-Range Correlated nucleon pairs. The extracted neutron transparency ratios are consistent with each other for the two measured kinematical regions and agree with the proton transparencies extracted from new and previous (e,e'p) measurements, including those from neutron-rich nuclei such as lead. The data also agree with and confirm the Glauber approximation that is commonly used to interpret experimental data. The nuclear-mass-dependence of the extracted transparencies scales as A^{\alpha} with {\alpha} = -0.289 {\pm} 0.007, which is consistent with nuclear-surface dominance of the reactions.

    ↳ nucl-exnucl-thPLB(2019)·27 citations
  6. 19

    Anisotropic hydrodynamics for Au-Au collisions at 200 GeV

    Mubarak Alqahtani🇸🇦 · Dekrayat Almaalol🇺🇸 · Michael Strickland🇺🇸

    In this proceedings, we review the basics of quasiparticle anisotropic hydrodynamics (aHydroQP). Thenwe present phenomenological comparisons between 3+1d quasiparticle anisotropic hydrodynamics and experimental data from RHIC experiments at 200 GeV Au-Au collisions. We show that 3+1d aHydroQP model is able to describe the experimental results quite well for the spectra, multiplicity, and elliptic flow for charged particles in different centrality classes.

    ↳ hep-phnucl-thMDPI Proc.(2019)·2 citations

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first authorsco-authorsvia INSPIRE