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1. chinaXiv:202201.00019 [pdf]

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

Chen, Jun-Liang ; Yun, Su-Jun ; Dong, Tie-Kuang ; Ren, Zhong-Zhou ; Zhang, Xiao-Ping
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology

The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet. In this study, a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays (GCRs); the model was built and studied using the Geant4 toolkit. The simulation results were compared with the data reported by a radiation assessment detector (RAD).

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits899Downloads235 Comment 0

2. 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 Hits1907Downloads1084 Comment 0

3. chinaXiv:201711.02306 [pdf]

Perspective on the cosmic-ray electron spectrum above TeV

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

The AMS-02 has measured the cosmic ray electron (plus positron) spectrum up to ?TeV with an unprecedent precision. The spectrum can be well described by a power law without any obvious features above 10 GeV. The satellite instrument Dark Matter Particle Explorer (DAMPE), which was launched a year ago, will measure the electron spectrum up to 10 TeV with a high energy resolution. The cosmic electrons beyond TeV may be attributed to few local cosmic ray sources, such as supernova remnants. Therefore, spectral features, such as cuto? and bumps, can be expected at high energies. In this work we give a careful study on the perspective of the electron spectrum beyond TeV. We ?rst examine our astrophysical source models on the latest leptonic data of AMS-02 to give a self-consistent picture. Then we focus on the discussion about the candidate sources which could be electron contributors above TeV. Depending on the properties of the local sources (especially on the nature of Vela), DAMPE may detect interesting features in the electron spectrum above TeV in the future.

submitted time 2017-11-10 Hits1846Downloads1093 Comment 0

4. 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 Hits1694Downloads927 Comment 0

5. chinaXiv:201711.02326 [pdf]

Discriminating between Thermal and Nonthermal Cosmic Relic Neutrinos through Annual Modulation at PTOLEMY

Guo-yuan Huang; Shun Zhou
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

If massive neutrinos are Dirac particles, the proposed PTOLEMY experiment will hopefully be able to discover cosmic neutrino background via e+3H ! 3He+e? with a capture rate of ?D 4 yr?1. Recently, it has been pointed out that right-handed com-ponents of Dirac neutrinos could also be copiously produced in the early Universe and become an extra thermal or nonthermal ingredient of cosmic relic neutrinos, enhancing the capture rate to ?D 5:1 yr?1 or ?D 6:1 yr?1. In this work, we investigate the possibility to distinguish between thermal and nonthermal spectra of cosmic relic neu-trinos by measuring the annual modulation of the capture rate. For neutrino masses of 0:1 eV, we have found the amplitude of annual modulation in the standard case is M 0:05%, which will be increased to 0:1% and 0:15% in the presence of additional thermal and nonthermal right-handed neutrinos, respectively. The future detection of such a modulation will be helpful in understanding the Majorana or Dirac nature of massive neutrinos.

submitted time 2017-11-10 Hits2030Downloads1151 Comment 0

6. chinaXiv:201612.00470 [pdf]

Dark Matter in the Singlet Extension of MSSM: Explanation of Pamela and Implication on Higgs Phenomenology

Wang,W; Xiong,Z; Yang,JM; Yu,L
Subjects:

As discussed recently by Hooper and Tait, the singlino-like dark matter in the Minimal Supersymmetric Standard Model (MSSM) extended by a singlet Higgs superfield can give a perfect explanation for both the relic density and the Pamela result through the

submitted time 2016-12-28 Hits3259Downloads2012 Comment 0

7. chinaXiv:201612.00461 [pdf]

Dark matter in the MSSM and its singlet extension

Yang,J
Subjects:

We briefly review the supersymetric explanation for the cosmic dark matter. Although the neutralino in the minimal supersymmetric model (MSSM), the next-to-minimal supersymmetric model (NMSSM) and the nearly minimal supersymmetric model (nMSSM) can natura

submitted time 2016-12-28 Hits2072Downloads1231 Comment 0

8. chinaXiv:201612.00400 [pdf]

Interpreting the galactic center gamma-ray excess in the NMSSM

Cao,J; Shang,L; Wu,P; Yang,JM; Zhang,Y
Subjects:

In the Next-to-Minimal Supersymmetric Standard Model (NMSSM), all singlet-dominated particles including one neutralino, one CP-odd Higgs boson and one CP-even Higgs boson can be simultaneously lighter than about 100 GeV. Consequently, dark matter (DM) in the NMSSM can annihilate into multiple final states to explain the galactic center gamma-ray excess (GCE). In this work we take into account the foreground and background uncertainties for the GCE and investigate these explanations. We carry out a sophisticated scan over the NMSSM parameter space by considering various experi- mental constraints such as the Higgs data, B-physics observables, DM relic density, LUX experiment and the dSphs constraints. Then for each surviving parameter point we per- form a fit to the GCE spectrum by using the correlation matrix that incorporates both the statistical and systematic uncertainties of the measured excess. After examining the properties of the obtained GCE solutions, we conclude that the GCE can be well explained by the pure annihilations χ ?01χ ?01 → b ?b and χ ?01χ ?01 → A1Hi with A1 being the lighter singlet- dominated CP-odd Higgs boson and Hi denoting the singlet-dominated CP-even Higgs boson or SM-like Higgs boson, and it can also be explained by the mixed annihilation χ ?01χ ?01 → W+W?,A1H1. Among these annihilation channels, χ ?01χ ?01 → A1Hi can provide the best interpretation with the corresponding p-value reaching 0.55. We also discuss to what extent the future DM direct detection experiments can explore the GCE solutions and conclude that the XENON-1T experiment is very promising in testing nearly all the solutions.

submitted time 2016-12-28 Hits1918Downloads1107 Comment 0

9. chinaXiv:201612.00373 [pdf]

Prospect of a very long baseline neutrino oscillation experiment: HIPA to Beijing

H2B-1,VSG; Chen,H; Ding,L; He,J; Kuang,H; Lu,Y; Ma,Y; Shan,L; Shen,C; Wang,Y; Yang,C; Zhang,X; Zhu,Q; Qing,C; Xiong,Z; Yang,JM; Zhang,Z; Chen,J; Ye,Y; Lee,S
Subjects:

We discuss the prospects of a very long baseline neutrino oscillation experiment from HIPA to Beijing. The current understanding of neutrino oscillations, both theoretically and experimentally, are summarized. The figure of merits for interested physics m

submitted time 2016-12-28 Hits2198Downloads1202 Comment 0

10. chinaXiv:201612.00349 [pdf]

Dark Matter in the Singlet Extension of MSSM: Explanation of Pamela and Implication on Higgs Phenomenology

Wang,W; Xiong,Z; Yang,JM; Yu,L
Subjects:

As discussed recently by Hooper and Tait, the singlino-like dark matter in the Minimal Supersymmetric Standard Model (MSSM) extended by a singlet Higgs superfield can give a perfect explanation for both the relic density and the Pamela result through the

submitted time 2016-12-28 Hits1715Downloads954 Comment 0

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