Chiral Effective Field Theory Description of Neutrino Nucleon–Nucleon Bremsstrahlung in Supernova Matter

Abstract

We revisit the rates of neutrino pair emission and absorption from nucleon-nucleon Bremsstrahlung in supernova matter using the T -matrix formalism in the long wavelength limit. Based on chiral effective field theory (χEFT) two-body potentials, we solve the Bethe-Goldstone equation accounting for the in-medium T -matrix including non-diagonal contributions. Our calculations consider nucleons with arbitrary degree of degeneracy and hence account for final state Pauli blocking. We compare our results with one pion exchange (OPE) rates, commonly used in supernova simulations, and calculations using an effective on-shell diagonal T -matrix from measured phase shifts. We also estimate that multiscattering processes and RPA correlations introduce small corrections on top of the in-medium T -matrix results at subsaturation densities.

Improved axion emissivity from a supernova via nucleon-nucleon bremsstrahlung

“…As already mentioned, we have not included the effects of the NN correlations. Moreover, in the case of neutrinos, the nucleon-nucleon bremsstrahlung calculations beyond OPE have been performed in the framework of modern nuclear interactions based on chiral effective field theory [56,58,59,63]. Such an approach has been proposed also for the case of axions [56].…”

Progress in nuclear astrophysics of east and southeast Asia

“…With such development, the dependence of the black-hole forming supernovae on different nuclear EoS and the stellar rotation rates was examined and the expected GW signals were computed [114,115]. Guo, Wu, and their collaborators then improved the treatment and consistency of the neutrino interactions in dense matter, including the inverse neutron-decay, muonic charged-current interactions, and nucleon-nucleon Bremsstrahlung [116][117][118][119], which allows to quantify the impact of these interactions on supernova simulations. Meanwhile, in a series of work [120,121], potential explosions of massive stars of ∼ 35 − 50 M triggered by the hadron-quark phase transition were suggested.…”

Impact of neutrino pair-production rates in Core-Collapse Supernovae

“…The second nucleon-nucleon bremsstrahlung interaction we consider is the recent formalism from Guo and Martinez-Pinedo [38]. They calculate the structure function (S σ (ω)) used in Eq.…”

“…A followup in [47] where the T-matrix formalism was shown to give modestly different results in supernova simulations from the OPE prescription above. The T-matrix formalism used in [38] is an improvement over [46] with the inclusion of off-shell T-matrix elements in addition to on-shell elements. In NuLib, we utilize the table of S σ (ω) values provided by the authors.…”

“…First we consider the commonly used one pion exchange (OPE) formalism by Hannestad and Raffelt [37]. We also consider a recent T-matrix formalism formulated by Guo et al [38] based on chiral effective field theory fitted to experimental phase shifts. We test these two different formalisms as well as a simplified version for the nucleon-nucleon bremsstrahlung based on [39].…”