Progenitor model of Cosmic Ray knee

TL;DR

This paper proposes a new model suggesting that the steepening of the cosmic ray spectrum at the knee is due to the mass distribution of progenitors, offering a different primary composition scenario beyond the knee.

Contribution

It introduces a progenitor-based model explaining the cosmic ray knee without fine tuning, differing from existing models in composition predictions.

Findings

Model accounts for observed spectral features without fine tuning.

Predicts a distinct primary composition beyond the knee.

Can be tested with precise composition measurements.

Abstract

Primary energy spectrum of cosmic rays exhibits a knee at about $3$ PeV where a change in the spectral index occurs. Despite many efforts the origin of such a feature of the spectrum is not satisfactorily solved yet. Here it is proposed that the steepening of the spectrum beyond the knee may be a consequence of mass distribution of progenitor of cosmic ray source. The proposed speculative model can account all the major observed features about cosmic rays without invoking any fine tuning to match flux or spectra at any energy point. The prediction of the proposed model regarding primary composition scenario beyond the knee is quite different from most of the prevailing models of the knee and thereby can be discriminated from precise experimental measurement of the primary composition.