Neutrino absorption in hot and dense nuclear matter from renormalization-group evolved nucleon-nucleon potentials.

The behavior of neutrinos in core-collapse supernovae is a key yet poorly understood aspect of modeling these explosive stellar events. Neutrinos carry away approximately ninety-nine percent of the explosion’s energy, but modeling their effects requires accurate predictions of neutrino-nucleus cross sections under extreme conditions of temperature, density, and pressure. These interactions are governed by the nuclear matter response function, which determines the absorption cross section as a function of energy and momentum transfer. Our research investigates how this response function evolves across a range of core conditions using chiral effective field theory interactions and the Random Phase Approximation. We developed a modular pipeline combining Fortran-based many-body solvers with Python-based post-processing tools to compute and analyze differential and total cross sections. Our calculations spanned a wide range of momentum transfers at fixed density and temperature, and included detailed spin-isospin decomposition across angular momentum and isospin-coupling channels (J, icoup).

A central focus on this work is understanding how cross section predictions vary with the resolution scale at which the nuclear force is defined. As the nuclear force is not fundamental, but rather a residual interaction emerging from the underlying quark-gluon structure, many-body calculations carry inherent uncertainty from this choice of scale. We address this with our modular code design and comparing our results against known physical limits. Preliminary results show strong q-dependence in the response function with suppression from Pauli blocking at low momentum and enhancement from collective excitations, which significantly influence the neutrino opacity. Our work bridges nuclear theory with astrophysical modeling, and may improve predictions for neutrino signals in detectors like DUNE and Super-Kamiokande, with implications for neutrino physics and dark matter.