Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-energy Cosmic-Ray Positrons from Hidden-Gauge-Boson Dark Matter   We provide a scenario in which a hidden U(1) gauge boson constitutes dark
matter of the Universe and decays into the standard-model particles through a
kinetic mixing with an $U(1)_{B-L}$ gauge boson. Interestingly, our model can
naturally account for the steep rise in the positron fraction recently reported
by PAMELA. Moreover, we find that due to the charge assignment of $U(1)_{B-L}$,
only a small amount of antiprotons are produced in the decay, which is also
consistent with the PAMELA and other observational data.

31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat