Secondary cosmic-ray nucleus spectra disfavor particle transport in the Galaxy without reacceleration. (arXiv:1810.03141v2 [astro-ph.HE] UPDATED)

Secondary cosmic-ray nucleus spectra disfavor particle transport in the Galaxy without reacceleration. (arXiv:1810.03141v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_Q/0/1/0/all/0/1">Qiang Yuan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_C/0/1/0/all/0/1">Cheng-Rui Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bi_X/0/1/0/all/0/1">Xiao-Jun Bi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wei_D/0/1/0/all/0/1">Da-Ming Wei</a>

The precise observations of Galactic cosmic ray fluxes of the secondary
family, such as Li, Be, B, are expected to have significant implications on our
understanding of the cosmic ray origin and propagation. Here we employ the
recent very precise measurements of those species by the Alpha Magnetic
Spectrometer on the International Space Station, together with their parent
species (C and O), as well as the data collected by the Voyager-1 spacecraft
outside the heliosphere and the Advanced Composition Explorer, to investigate
the propagation of cosmic rays in the Milky Way. We consider the diffusion of
cosmic rays plus reacceleration or convection effect during the propagation,
and find that the reacceleration model can fit the data significantly better
than the convection model. We further find that for the reacceleration model,
the spectral hardenings of both the primary and secondary particles can be well
described by the injection hardening without including additional propagation
hardening. This is due to that the reacceleration effect results in a steeper
secondary-to-primary ratio at low energies, and can thus naturally reproduce
the fact that the secondary spectra harden more than the primary spectra found
by AMS-02.

The precise observations of Galactic cosmic ray fluxes of the secondary
family, such as Li, Be, B, are expected to have significant implications on our
understanding of the cosmic ray origin and propagation. Here we employ the
recent very precise measurements of those species by the Alpha Magnetic
Spectrometer on the International Space Station, together with their parent
species (C and O), as well as the data collected by the Voyager-1 spacecraft
outside the heliosphere and the Advanced Composition Explorer, to investigate
the propagation of cosmic rays in the Milky Way. We consider the diffusion of
cosmic rays plus reacceleration or convection effect during the propagation,
and find that the reacceleration model can fit the data significantly better
than the convection model. We further find that for the reacceleration model,
the spectral hardenings of both the primary and secondary particles can be well
described by the injection hardening without including additional propagation
hardening. This is due to that the reacceleration effect results in a steeper
secondary-to-primary ratio at low energies, and can thus naturally reproduce
the fact that the secondary spectra harden more than the primary spectra found
by AMS-02.

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