Current Location:home > Browse

1. chinaXiv:201711.02302 [pdf]

A systematic study on the cosmic ray antiproton ?ux

Su-Jie Lin; Xiao-Jun Bi; Jie Feng; Peng-Fei Yin; Zhao-Huan Yu
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Recently the AMS-02 collaboration has published the measurement of the cosmic antiproton to proton ratio p?/p and the p? ?ux with a high precision up to ? 450 GeV. In this work, we perform a systematic analysis of the secondary antiproton ?ux generated by the cosmic ray interaction with the interstellar gas. The uncertainty of the prediction originates from the cosmic ray propagation process and the hadronic interaction models. Although the cosmic ray propagation parameters have been well controlled by the AMS-02 B/C ratio data for a speci?ed model, di?erent propagation models can not be discriminated by the B/C data. The p? ?ux is also calculated for several hadronic interaction models, which are generally adopted by the cosmic ray community. However, the results for di?erent hadronic models do not converge. We ?nd the EPOS LHC model, which seems to ?t the collider data very well, predicts a slightly lower p?/p ratio than the AMS-02 data at the high energy end. Finally we derive the constraints on the dark matter annihilation cross section from the AMS-02 p?/p ratio for di?erent propagation and hadronic interaction models.

submitted time 2017-11-10 Hits1655Downloads925 Comment 0

2. chinaXiv:201711.02308 [pdf]

Excesses of Cosmic Ray Spectra from A Single Nearby Source

Wei Liu; Xiao-Jun Bi; Su-Jie Lin; Bing-Bing Wang; Peng-Fei Yin
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Growing evidence reveals universal hardening on various cosmic ray spectra, e.g. proton, positron, as well as antiproton fraction. Such universality may indicate they have a common origin. In this paper, we argue that these widespread excesses can be accounted for by a nearby supernova remnant surrounded by a giant molecular cloud. Secondary cosmic rays (p, e+) are produced through the collisions between the primary cosmic ray nuclei from this supernova remnant and the molecular gas. Different from the background, which is produced by the ensemble of large amount of sources in the Milky Way, the local injected spectrum can be harder. The time-dependent transport of particles would make the propagated spectrum even harder. Under this scenario, the anomalies of both primary (p, e?) and secondary (e+, ?p/p) cosmic rays can be properly interpreted. We further show that the TeV to sub-PeV anisotropy of proton is consistent with the observations if the local source is relatively young and lying at the anti-Galactic center direction.

submitted time 2017-11-10 Hits1439Downloads775 Comment 0

3. chinaXiv:201609.00074 [pdf]

Searching for Singlino-Higgsino Dark Matter in the NMSSM

Qian-Fei Xiang; Xiao-Jun Bi; Peng-Fei Yin; Zhao-Huan Yu
Subjects: Physics >> Nuclear Physics

We study a simplified scenario in the next-to-minimal supersymmetric standard model with a split electroweak spectrum, in which only the singlino and higgsinos are light and other superpartners are decoupled. Serving as a dark matter candidate, a singlino-dominated neutralino?χ~01?should have either resonant annihilation effects or sizable higgsino components to satisfy the observed relic abundance. The sensitivities of LHC searches and dark matter detection experiments are investigated. With an integrated luminosity of?30(300)fb?1,?$3l + \missET$?and?$2l + \missET$?searches at the 13 (14) TeV LHC are expected to reach up to?$m_{\chia}\sim 150 (270) \mathrm{GeV}$?and?mχ~02,χ~±1?320(500)GeV. Near future dark matter direct and indirect detection experiments can cover some parameter regions where collider searches lose their sensitivities.

submitted time 2016-09-06 Hits1149Downloads684 Comment 0

  [1 Pages/ 3 Totals]