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Nuclear Theory·nucl-th

Thursday·July 18, 2024

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    Breakup dynamics of a neutron-halo projectile on heavy target at deep sub-barrier energies

    B. Mukeru · T. Sithole · Lauro Tomio

    By studying the total fusion and breakup cross-sections in the interaction of the neutron-halo projectile on the lead target Pb, it is shown that, even for the neutron-halo projectile, the breakup channel remains the most dominant reaction channel at sub-barrier energies, following a characteristic behavior that was also previously verified for the case of the proton-halo projectile . This feature is found to emanate from the enhancement of the breakup cross-section, due to the continuum-continuum couplings coming exclusively from its Coulomb component. We further speculate that the enhancement of the Coulomb breakup cross-section at sub-barrier incident energies by the continuum-continuum couplings could be associated with the projectile breaking up on the outgoing trajectory, provided these couplings can be proven to delay the breakup process.

    nucl-thnucl-exJ.Phys.G(2024)·0 citations
  2. 02

    On a possible H hypernucleus with HAL QCD interaction

    Igor Filikhin🇺🇸 · Roman Ya. Kezerashvili🇺🇸 · Branislav Vlahovic🇺🇸

    Within the framework of the Faddeev formalism in configuration space, we investigate bound states in the system with total isospin and . The recently proposed lattice HAL QCD potential in the channel does not support either or bound states. The HAL QCD potential in the channel suggests the bound states for and systems. However, the binding energies are highly sensitive to variations of the enhancement factor , and the system is extremely strongly bound in the state . Considering a spin-averaged potential % for the state yields a bound state for H hypernucleus with the binding energy (BE) 14.9 MeV when . The evaluation of the BE for the , three-body state results in 5.47 MeV. %Also, We evaluated the BE for the , three-body state as 5.47 MeV. Additionally, calculations using our approach confirm the bound states for the ( and ) system previously predicted with the Yukawa-type potential motivated by the QCD van der Waals attractive force, mediated by multi-gluon exchanges.

    nucl-thhep-phPRD(2024)·17 citations
  3. 03

    Bulk viscosity of two-color superconducting quark matter in neutron star mergers

    Mark Alford🇺🇸 · Arus Harutyunyan🇦🇲 · Armen Sedrakian🇵🇱 · Stefanos Tsiopelas🇵🇱

    We study the bulk viscosity of moderately hot and dense, neutrino-transparent color superconducting quark matter arising from weak-interaction-driven direct URCA processes. The quark matter is modeled using the Nambu--Jona-Lasinio model improved to account for vector and 't Hooft interactions as well as antisymmetric pairing among the red/green up and down quarks. The unpaired excitations are the strange quarks and the blue up or down quarks. We compute the relaxation rates associated with and -quark decay and electron capture processes on quark for blue color. The resulting bulk viscosity for density oscillations in the 1--10\,kHz range shows a resonant peak at , and the damping time may drop below 10 ms. This is short enough to affect the postmerger evolution and is very similar to the damping predicted in nuclear matter.

    nucl-thastro-ph.HEhep-phPRD(2024)·19 citations
  4. 04

    BCS-BEC crossover of the strongly interacting Li-K mixture

    Stefano Gandolfi · Ryan Curry · Alexandros Gezerlis

    We present Quantum Monte Carlo calculations of the properties of a two-component mass imbalanced Fermi gas, corresponding to the Li-K mixture. We compute the equation of state of the unpolarized system as a function of the scattering length with particular attention paid to the unitary limit, where the effect of the effective range of the interaction is explored. We have also computed the pair distribution function and the momentum distribution over a range of interaction strengths to provide information about the structure of the system. Finally, we have computed the heavy/light quasiparticle spectrum. Our theoretical predictions, based on Quantum Monte Carlo calculations, can be tested by future experiments with ultracold fermionic gases.

    ↳ cond-mat.quant-gasnucl-thPRA(2024)·4 citations
  5. 05

    Spin polarization of fermions at local equilibrium: Second-order gradient expansion

    Xin-Li Sheng🇮🇹 · Francesco Becattini🇮🇹 · Xu-Guang Huang🇨🇳 · Zhong-Hua Zhang🇨🇳

    We present a calculation of the spin polarization of spin-1/2 fermions in a relativistic fluid at local thermodynamic equilibrium at the second order in the gradient expansion, including second-order derivatives. The second-order derivative terms vanish if the local equilibrium hypersurface is the hyperplane in the collision center-of-mass frame. However, since the freeze-out hypersurface has a non-trivial space-time structure, these terms may result in a non-vanishing contribution to the spin polarization, whose magnitude needs to be assessed with numerical computations.

    ↳ hep-thhep-phnucl-thPRC(2024)·12 citations
  6. 06

    Review of nonflow estimation methods and uncertainties in relativistic heavy-ion collisions

    Yicheng Feng🇺🇸 · Fuqiang Wang🇺🇸

    Collective anisotropic flow, where particles are correlated over the entire event, is a prominent phenomenon in relativistic heavy-ion collisions and is sensitive to the properties of the matter created in those collisions. It is often measured by two- and multi-particle correlations and is therefore contaminated by nonflow, those genuine few-body correlations unrelated to the global event-wise correlations. Many methods have been devised to estimate nonflow contamination with various degrees of successes and difficulties. Here, we review those methods pedagogically, discussing the pros and cons of each method, and give examples of ballpark estimate of nonflow contamination and associated uncertainties in relativistic heavy-ion collisions. We hope such a review of the various nonflow estimation methods in a single place would prove helpful to future researches.

    ↳ nucl-exnucl-thJ.Phys.G(2025)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE