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Nuclear Theory·nucl-th

Monday·October 12, 2020

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    Dilepton Signature of a First-Order Phase Transition

    Florian Seck🇩🇪 · Tetyana Galatyuk🇩🇪 · Ayon Mukherjee🇭🇺 · Ralf Rapp🇺🇸 · Jan Steinheimer🇩🇪 · Joachim Stroth🇩🇪 · Maximilian Wiest🇩🇪

    The search for a first-order phase transition in strongly interacting matter is one of the major objectives in the exploration of the phase diagram of Quantum Chromodynamics (QCD). In the present work we investigate dilepton radiation from the hot and dense fireballs created in Au-Au collisions at projectile energies of 1-2 GeV for potential signatures of a first-order transition. Toward this end, we employ a hydrodynamic simulation with two different equations of state, with and without a phase transition. The latter is constrained by susceptibilities at vanishing chemical potential from lattice-QCD as well as neutron star properties, while the former is implemented via modification of the mean-fields in the quark phase. We find that the latent heat involved in the first-order transition leads to a substantial increase in the low-mass thermal emission signal, by about a factor of two above the cross-over scenario.

    nucl-thPRC(2022)·35 citations
  2. 02

    BCS-BEC Crossover Effects and Pseudogap in Neutron Matter

    David Durel🇫🇷 · Michael Urban🇫🇷

    Due to the large neutron-neutron scattering length, dilute neutron matter resembles the unitary Fermi gas, which lies half-way in the crossover from the BCS phase of weakly coupled Cooper pairs to the Bose-Einstein condensate of dimers. We discuss crossover effects in analogy with the T-matrix theory used in the physics of ultracold atoms, which we generalize to the case of a non-separable finite-range interaction. A problem of the standard Nozieres-Schmitt-Rink approach and different ways to solve it are discussed. It is shown that in the strong-coupling regime, the spectral function exhibits a pseudo-gap at temperatures above the critical temperature T_c. The effect of the correlated density on the density dependence of T_c is found to be rather weak, but a possibly important effect due to the reduced quasiparticle weight is identified.

    nucl-thcond-mat.quant-gasUniverse(2020)·8 citations
  3. 03

    Modelling overlap functions for one-nucleon removal: role of the effective three-nucleon force

    N.K. Timofeyuk

    One-nucleon overlap functions, needed for nucleon-removal reaction calculations, are solutions of an inhomogeneous equation with the source term defined by the wave functions of the initial and final nuclear states and interaction between the removed nucleon with the rest. The source term approach (STA) allows the overlaps with correct asymptotic decrease to be modelled while using nuclear many-body functions calculated in minimal model spaces. By properly choosing the removed nucleon interaction the minimum-model-space STA can reproduce reduced values of spectroscopic factors extracted from nucleon-removal reactions and predicts isospin asymmetry in the spectroscopic factor reduction. It is well-known that model space truncation leads to the appearance of higher-order induced forces, with three-nucleon force being the most important. In this paper the role of such a force on the source term calculation is studied. Applications to one-nucleon removal from double-magic nuclei show that three-nucleon force improves the description of available phenomenological overlap functions and reduces isospin asymmetry in spectroscopic factors.

    nucl-thnucl-exJ.Phys.G(2020)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE