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

TL;DR

This paper investigates how quantum electrodynamics (QED) medium effects, enhanced by nuclear size and low-energy modes, influence lepton-nucleus scattering, revealing effects at the permille to percent level crucial for precise neutrino and electron experiments.

Contribution

It introduces a method to account for QED-medium effects in lepton-nucleus scattering, providing approximate formulas and evaluating their significance with realistic screening scales.

Findings

QED-medium effects can reach up to a percent in scattering cross sections.

Low-energy modes and nuclear size significantly enhance QED-medium contributions.

New permille- to percent-level effects are identified in elastic scattering processes.

Abstract

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 $\alpha$ 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.