Prospects for direct cosmic ray mass measurements through the Gerasimova-Zatsepin effect

TL;DR

This paper explores the potential of detecting the Gerasimova-Zatsepin effect to directly identify cosmic ray primaries, analyzing event rates, detector requirements, and the feasibility of such measurements with current and future instruments.

Contribution

It provides detailed models and estimates for detecting the Gerasimova-Zatsepin effect, assessing its viability for cosmic ray composition studies.

Findings

Gerasimova-Zatsepin events are about 10^-5 of cosmic rays.

Estimated intrinsic event rate is approximately 0.07 km^-2 sr^-1 yr^-1.

Realistic detection rates are likely below 10^-2 yr^-1.

Abstract

The Solar radiation field may break apart ultra high energy cosmic nuclei, after which both remnants will be deflected in the interplanetary magnetic field in different ways. This process is known as the Gerasimova-Zatsepin effect after its discoverers. We investigate the possibility of using the detection of the separated air showers produced by a pair of remnant particles as a way to identify the species of the original cosmic ray primary directly. Event rates for current and proposed detectors are estimated, and requirements are defined for ideal detectors of this phenomenon. Detailed computational models of the disintegration and deflection processes for a wide range of cosmic ray primaries in the energy range of 10^16 to 10^20 eV are combined with sophisticated detector models to calculate realistic detection rates. The fraction of Gerasimova-Zatsepin events is found to be of the order of 10^-5 of the cosmic ray flux, implying an intrinsic event rate of around 0.07 km^-2 sr^-1 yr^-1 in the energy range defined. Event rates in any real experiment, however, existing or under construction, will probably not exceed 10^-2 yr^-1.