Ponente
Descripción
High-precision measurements from recent cosmic-ray experiments have provided crucial insights into Galactic cosmic-ray spectra across a wide energy range, revealing spectral hardening in the GeV--TeV region that challenges conventional models of acceleration and propagation. Re-acceleration of cosmic rays by weak shocks from old supernova remnants offers a promising explanation, accounting for observed features in both primary and secondary nuclei, including the boron-to-carbon (B/C) ratio. In this scenario, cosmic rays are initially accelerated by strong supernova shocks and then diffuse through the Galaxy. During propagation, they may undergo additional acceleration upon encountering expanding supernova remnant shocks. Since older remnants, due to their larger sizes, are more likely to be encountered than younger ones, reacceleration is predominantly driven by weaker shocks. This process leads to a softened spectrum below $\sim 100$ GeV, while at higher energies the spectrum is dominated by cosmic rays from young supernova remnants. We perform a global Bayesian parameter estimation using observational data for the B/C ratio and proton spectrum from AMS-02, CALET, CREAM, DAMPE, and Voyager. This joint analysis constrains a single set of transport parameters that simultaneously reproduces both the B/C ratio and proton spectrum within a unified framework, using Markov Chain Monte Carlo (MCMC) methods. We further evaluate the model’s ability to reproduce the observed spectra of heavier nuclei.
