Semiclassical theory of charged pion radiation by nucleons in a strong homogeneous magnetic field

TL;DR

This paper develops a semiclassical model to analyze charged pion radiation from high-energy protons in strong magnetic fields, revealing a sharp energy cutoff and spectral similarities to neutral pion synchrotron radiation, relevant for cosmic neutrino sources.

Contribution

It introduces a semiclassical approach to calculate pion radiation spectra in strong magnetic fields, highlighting a distinct energy cutoff and spectral characteristics.

Findings

Charged pion radiation exhibits a sharp lower energy cutoff at 0.25 times the proton energy.

Spectral power matches neutral pion synchrotron radiation spectra in the cutoff region.

The model provides insights into cosmic neutrino production mechanisms.

Abstract

Charged pions produced in very high energy hadronic interactions might be the dominant source of cosmic neutrinos in the GeV--TeV range. Spectral energy power of \pi^+ radiation by high energy protons moving in strong magnetic fields typical for magnetars is determined with a semiclassical treatment of the effective pion-nucleon model. The main characteristics emerging from a saddle point approximation to the summation over the allowed range of Landau levels is a sharp lower cut: E_\pi>0.25 E_p. The magnitude of the spectral power agrees in this region with the synchrotron radiation spectra of neutral pions.