On the Contribution of "Fresh" Cosmic Rays to the Excesses of Secondary Particles

TL;DR

This paper proposes that fresh cosmic rays from young accelerators contribute to observed excesses in secondary particles, explaining discrepancies in gamma-ray, neutrino, and positron data, and predicts observable signatures in upcoming experiments.

Contribution

It introduces a novel model where local, young cosmic rays explain multiple secondary particle excesses and aligns well with recent high-precision observations.

Findings

Two-component gamma-ray spectrum matches observations.

Neutrino contribution could explain ~60% of IceCube data.

Positron excesses can be accounted for by the model.

Abstract

The standard model of cosmic ray propagation has been very successful in explaining all kinds of the Galactic cosmic ray spectra. However, high precision measurement recently revealed the appreciable discrepancy between data and model expectation, from spectrum observations of $\gamma$-rays, $e^+/e^-$ and probably the $B/C$ ratio starting from $\sim$10 GeV energy. In this work, we propose that the fresh cosmic rays, which are supplied by the young accelerators and detained by local magnetic field, can contribute additional secondary particles interacting with local materials. As this early cosmic ray has a hard spectrum, the model calculation results in a two-component $\gamma$-ray spectrum, which agree very well with the observation. Simultaneously, the expected neutrino number from the galactic plane could contribute $\sim60\%$ of IceCube observation neutrino number below a few hundreds of TeV. The same pp-collision process can account for a significant amount of the positron excesses. Under this model, it is expected that the excesses in $\overline p/p$ and $B/C$ ratio will show up when energy is above $\sim$10 GeV. We look forward that the model will be tested in the near future by new observations from AMS02, IceCube, AS$\gamma$, HAWC and future experiments such as LHASSO, HiSCORE and CTA.