# Newly-Discovered Anomalies in Galactic Cosmic Rays: Time for Exotic Scenarios?

## TL;DR

Recent cosmic ray observations show significant anomalies challenging standard models, suggesting the need for new physics or sources like dark matter or pulsars to explain excess positrons and other deviations.

## Contribution

The paper critically assesses existing models and explores potential new physics or sources to explain recent anomalies in galactic cosmic rays.

## Key findings

- Anomalies challenge traditional CR production mechanisms in SNRs.
- A 20-30% excess in positron ratio remains unexplained.
- Standard models are insufficient to account for all observed deviations.

## Abstract

Recent observations of galactic cosmic rays (CR) in the 1-500 GeV energy range have revealed striking deviations from what deemed "standard." The anomalies cut across hadronic and leptonic CRs. I discuss findings that challenge physical mechanisms long held responsible for the CR production in galactic supernova remnants (SNR). I also consider some new physics of particle acceleration in SNR shocks that is not part of conventional models but may explain the anomalies. However, a possible 20-30\% excess remains unaccounted for in the $e^{+}/e^{+}$ ratio over the range of a few 100 GeV. If not explained by future models, it suggests an additional source of positrons such as a dark matter decay/annihilation or pulsar contribution. Earlier efforts to explain both the $e^{+}/e^{-}$ and $p$/He anomalies with the "standard" models by adjusting the SNR environmental parameters and multiple sources are critically assessed.