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Nuclear Theory·nucl-th

Thursday·June 23, 2022

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    QED medium effects in (anti)neutrino-nucleus and electron-nucleus scattering: elastic scattering on nucleons

    Oleksandr Tomalak🇺🇸 · Ivan Vitev🇺🇸

    Interpretation of current and future neutrino oscillation and electron scattering experiments requires knowledge of lepton-nucleon and lepton-nucleus interactions at the percent level. We study the exchange of photons between charged particles and the nuclear medium for (anti)neutrino-, electron-, and muon-induced reactions inside a large nucleus. While quantum electrodynamics (QED)-medium contributions are formally suppressed by two powers of the electromagnetic coupling constant when compared to the leading-order cross sections, low-energy modes and the nuclear size enhance the effect by orders of magnitude. They require a proper infrared regularization, which we implement as a screening of the electromagnetic interactions at atomic length scales or above. We provide approximate analytic expressions for the distortion of (anti)neutrino-nucleus and charged lepton-nucleus cross sections and evaluate the QED-medium effects for realistic values of the screening scale on the example of elastic scattering with nucleons inside the nucleus. We find new permille- to percent-level effects, which were not considered in either (anti)neutrino-nucleus or electron-nucleus scattering.

    nucl-thhep-exhep-phnucl-exPLB(2022)·9 citations
  2. 02

    The Entanglement Entropy between Short Range Correlations and the Fermi Sea in Nuclear Structure

    Ehoud Pazy

    We calculate the nuclear structure orbital entanglement entropy of short range correlations (SRC) based on the nuclear scale separation. Specifically, the entanglement between the SRC orbitals and the rest of the system. It should be stressed that this is a single nucleon not a pair entanglement entropy between the proton and neutron. The entanglement arises from the probability for a nucleon to occupy a momentum state above the Fermi momentum. We separate the momentum space of the nucleus into two parts such that nucleons can occupy the meanfield part of the wave function, i.e. Fermi sea (FS) and separately the high-momentum SRC part. The orbital entropy we obtain is between these two parts where we essentially define two momentum subspaces, one containing all the low momentum FS states and the other the high-momentum part as a SRC "orbital" state. For the calculation we employ the decoupling of low and high-momenta which was established by the similarity normalization group the SRC is viewed as a further "orbital" which can be multiply occupied. Since the probability of the occupation of a single SRC is given by the nuclear contact we are able to obtain a simple general expression of the orbital entanglement entropy for SRC by employing the generalized contact formalism. This general formula for the SRC orbital entanglement entropy of a nuclear structure in terms of the nuclear contact, allows us to obtain the scaling of the entropy in terms the mass number, . We find that, unlike the entanglement entropy of many quantum systems which scales with the surface area, the orbital entanglement entropy associated with the SRC in large nuclei is linearly dependent on , i.e., it is shown to be extensive.

    nucl-thPRC(2023)·37 citations
  3. 03

    Probing high-density nuclear symmetry energy with ratio in heavy-ion collisions at GeV

    Gao-Chan Yong🇨🇳 · Bao-An Li🇺🇸 · Zhi-Gang Xiao🇨🇳 · Zi-Wei Lin🇺🇸

    Recent beam energy scan (BES) experiments at RHIC by the STAR Collaboration (PLB {\bf 827},137003 (2022) and PRL {\bf 128}, 202303 (2022)) found that hadronic interactions dominate the collective flow and the proton cumulant ratios are driven by baryon number conservation in a region of high baryon density in = 3 GeV Au+Au reactions, indicating the dense medium formed in such collisions is likely hadronic matter. Within an updated ART (A Relativistic Transport) model with momentum dependent isoscalar and isovector single-nucleon mean-field potentials corresponding to different symmetry energies at suprasaturation densities, the , , , and ratios are studied for central Au+Au collisions at = 3 GeV where the maximum central density reaches about . The doubly strange ratio is found to have the strongest sensitivity to the variation of high-density nuclear symmetry energy. Thus, the ratio in relativistic heavy-ion reactions at GeV may help probe sensitively the poorly known symmetry energy of dense neutron-rich matter critically important for understanding various properties of neutron stars.

    nucl-thastro-ph.HEnucl-exPRC(2022)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE