Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anomalies in Cosmic Ray Composition: Explanation Based on Mass to Charge
  Ratio   High precision spectrometry of galactic cosmic rays (CR) has revealed the
lack of our understanding of how different CR elements are extracted from the
supernova environments to be further accelerated in their shocks. Comparing the
spectra of accelerated particles with different mass to charge ratios is a
powerful tool for studying the physics of particle injection into the diffusive
shock acceleration (DSA). Recent AMS-02 demonstration of the similarity of
He/$p$, C/$p$, and O/$p$ rigidity spectra has provided new evidence that
injection is a mass-to-charge dependent process. We performed hybrid
simulations of collisionless shocks and analyzed a joint injection of $p$ and
He$^{2+}$ in conjunction with upstream waves they generate. By implication, our
results equally apply to C and O fully ionized ions, since they have similar
mass to charge ratios. By convolving the time-dependent injection rates of $p$
and He, obtained from the simulations, with a decreasing shock strength over
the active life of SNRs, we generate the integrated SNR spectra for $p$ and He.
These spectra are consistent with the AMS-02 and Pamela data and earlier
theoretical predictions. Our interpretation of the elemental anomaly is
therefore intrinsic to collisionless shock mechanisms and does not require
additional assumptions, such as the contributions from several different SNRs,
their inhomogeneous environments or acceleration from grains.

11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
2
The categories of this paper are: math