arXiv subjects

Peng-fei Yin

Publications and source records attributed to Peng-fei Yin.

12 recordsLinked to original sources

arXiv2018

Discriminating Local Sources of High-Energy Cosmic Electrons and Positrons by Current and Future Anisotropy Measurements

The Fermi-LAT detects no significant anisotropy of the cosmic-ray (CR) electrons and positrons ($e^-+e^+$) with seven years of data, which provides the strongest restriction to the $e^-+e^+$ anisotropy up to now. As next generation CR observatory, HERD is expected to have a better capability of anisotropy detection than Fermi-LAT. In this paper, we discuss several models aimed to explain the AMS-02 data by the present and future anisotropy measurements. We find that the upper limits of Fermi-LAT disfavor Vela SNR as the dominant source in sub-TeV, while other cases that remain safe under the constraint of Fermi-LAT are expected to be distinguished from each other by HERD. We then discuss the possibilities of remarkable TeV spectral features, and test the corresponding anisotropies. We find the conditions under which the TeV model can have a prominent spectral feature and avoid the constraint of Fermi-LAT at the same time. Furthermore, the expected performance of HERD is sensitive enough to detect the anisotropies of all these TeV models, and even for the case of a featureless TeV spectrum. Thus HERD may play a crucial part in the study of the origin of cosmic electrons and positrons.

astro-ph.HE↗

arXiv2017

Explanations of the DAMPE high energy electron/positron spectrum in the dark matter annihilation and pulsar scenarios

Many studies have shown that either the nearby astrophysical source or dark matter (DM) annihilation/decay is required to explain the origin of high energy cosmic ray (CR) $e^\pm$, which are measured by many experiments, such as PAMELA and AMS-02. Recently, the Dark Matter Particle Explorer (DAMPE) collaboration has reported its first result of the total CR $e^\pm$ spectrum from $25 \,\mathrm{GeV}$ to $4.6 \,\mathrm{TeV}$ with high precision. In this work, we study the DM annihilation and pulsar interpretations of the DAMPE high energy $e^\pm$ spectrum. In the DM scenario, the leptonic annihilation channels to $τ^+τ^-$, $4μ$, $4τ$, and mixed charged lepton final states can well fit the DAMPE result, while the $μ^+μ^-$ channel has been excluded. In addition, we find that the mixed charged leptons channel would lead to a sharp drop at $\sim$ $\mathrm{TeV}$. However, these DM explanations are almost excluded by the observations of gamma-ray and CMB, unless some complicated DM models are introduced. In the pulsar scenario, we analyze 21 nearby known pulsars and assume that one of them is the primary source of high energy CR $e^\pm$.Considering the constraint from the Fermi-LAT observation of the $e^\pm$ anisotropy, we find that two pulsars are possible to explain the DAMPE data. Our results show that it is difficult to distinguish between the DM annihilation and single pulsar explanations of high energy $e^\pm$ with the current DAMPE result.

astro-ph.HE↗

arXiv2010

Detecting light long-lived particle produced by cosmic ray

We investigate the possibility of detecting light long-lived particle (LLP) produced by high energy cosmic ray colliding with atmosphere. The LLP may penetrate the atmosphere and decay into a pair of muons near/in the neutrino telescope. Such muons can be treated as the detectable signal for neutrino telescope. This study is motivated by recent cosmic electron/positron observations which suggest the existence of $O(TeV)$ dark matter and new light $O(GeV)$ particle. It indicates that dark sector may be complicated, and there may exist more than one light particles, for example the dark gauge boson $A'$ and associated dark Higgs boson $h'$. In this work, we discuss the scenario with $A'$ heavier than $h'$ and $h'$ is treated as LLP. Based on our numerical estimation, we find that the large volume neutrino telescope IceCube has the capacity to observe several tens of di-muon events for favorable parameters if the decay length of LLP can be comparable with the depth of atmosphere. The challenge here is how to suppress the muon backgrounds induced by cosmic rays and atmospheric neutrinos.

hep-ph↗

arXiv2010

Neutrino Constraints on Inelastic Dark Matter after CDMS II

We discuss the neutrino constraints from solar and terrestrial dark matter (DM) annihilations in the inelastic dark matter (iDM) scenario after the recent CDMS II results. To reconcile the DAMA/LIBRA data with constraints from all other direct experiments, the iDM needs to be light ($m_χ< 100$ GeV) and have a large DM-nucleon cross section ($σ_n \sim$ 10$^{-4}$ pb in the spin-independent (SI) scattering and $σ_n \sim$ 10 pb in the spin-dependent (SD) scattering). The dominant contribution to the iDM capture in the Sun is from scattering off Fe/Al in the SI/SD case. Current bounds from Super-Kamiokande exclude the hard DM annihilation channels, such as $W^+W^-$, $ZZ$, $t\bar{t}$ and $τ^+ τ^-$. For soft channels such as $b\bar{b}$ and $c \bar{c}$, the limits are loose, but could be tested or further constrained by future IceCube plus DeepCore. For neutrino constraints from the DM annihilation in the Earth, due to the weaker gravitational effect of the Earth and inelastic capture condition, the constraint exists only for small mass splitting $δ<$ 40 keV and $m_χ\sim (10, 50)$ GeV even in the $τ^+ τ^-$ channel.

hep-ph↗

arXiv2009

Discriminating different scenarios to account for the cosmic $e^\pm$ excess by synchrotron and inverse Compton radiation

The excesses of the cosmic positron fraction recently measured by PAMELA and the electron spectra by ATIC, PPB-BETS, Fermi and H.E.S.S. indicate the existence of primary electron and positron sources. The possible explanations include dark matter annihilation, decay, and astrophysical origin, like pulsars. In this work we show that these three scenarios can all explain the experimental results of the cosmic $e^\pm$ excess. However, it may be difficult to discriminate these different scenarios by the local measurements of electrons and positrons. We propose possible discriminations among these scenarios through the synchrotron and inverse Compton radiation of the primary electrons/positrons from the region close to the Galactic center. Taking typical configurations, we find the three scenarios predict quite different spectra and skymaps of the synchrotron and inverse Compton radiation, though there are relatively large uncertainties. The most prominent differences come from the energy band $10^4\sim 10^9$ MHz for synchrotron emission and $\gtrsim 10$ GeV for inverse Compton emission. It might be able to discriminate at least the annihilating dark matter scenario from the other two given the high precision synchrotron and diffuse $γ$-ray skymaps in the future.

astro-ph↗

arXiv2009

Detecting light leptophilic gauge boson at BESIII detector

The $ O(GeV)$ extra $ U(1)$ gauge boson named U-boson, has been proposed to mediate the interaction among leptons and dark matter (DM), in order to account for the observations by PAMELA and ATIC. In such kind of models, the extra U(1) gauge group can be chosen as $U(1)_{L_i-L_j}$ with $L_i$ the $i-$th generation lepton number. This anomaly-free model provides appropriate dark matter relic density and boost factor required by experiments. In this work the observability of such kind of U-boson at BESIII detector is investigated through the processes $ e^ + e^ - \to Uγ$, followed by $U\to e^+e^-$, $U\to μ^+μ^-$ and $U\to ν\overlineν$. In the invisible channel where U-boson decays into neutrinos, BESIII can measure the coupling of the extra $ U(1)$ down to $ O(10^{- 4}) \sim O(10^{- 5})$ because of the low Standard Model backgrounds. In the visible channel where U-boson decays into charged lepton pair, BESIII can only measure the coupling down to $ O(10^{- 3}) \sim O(10^{- 4})$ due to the large irreducible QED backgrounds.

hep-ph↗

arXiv2009

Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark Matter to Account for the PAMELA and ATIC results

Recent PAMELA data show that positron fraction has an excess above several GeV while anti-proton one is not. Moreover ATIC data indicates that electron/positron flux have a bump from 300 GeV to 800 GeV. Both annihilating dark matter (DM) with large boost factor and decaying DM with the life around $ 10^{26} s$ can account for the PAMELA and ATIC observations if their main final products are charged leptons ($e$, $μ$ and $τ$). In this work, we calculated the neutrino flux arising from $μ$ and $τ$ which originate from annihilating/decaying DM, and estimated the final muon rate in the neutrino telescopes, namely Antares and IceCube. Given the excellent angular resolution, Antares and IceCube are promising to discover the neutrino signals from Galactic center and/or large DM subhalo in annihilating DM scenario, but very challenging in decaying DM scenario.

astro-ph↗

arXiv2008

PAMELA data and leptonically decaying dark matter

Recently PAMELA released their first results on the positron and antiproton ratios. Stimulated by the new data, we studied the cosmic ray propagation models and calculated the secondary positron and antiproton spectra. The low energy positron ratio can be consistent with data in the convection propagation model. Above $\sim 10$ GeV PAMELA data shows a clear excess on the positron ratio. However, the secondary antiproton is roughly consistent with data. The positron excess may be a direct evidence of dark matter annihilation or decay. We compare the positron and anti-proton spectra with data by assuming dark matter annihilates or decays into different final states. The PAMELA data actually excludes quark pairs being the main final states, disfavors gauge boson final states. Only in the case of leptonic final states the positron and anti-proton spectra can be explained simultaneously. We also compare the decaying and annihilating dark matter scenarios to account for the PAMELA results and prefer to the decaying dark matter. Finally we consider a decaying neutralino dark matter model in the frame of supersymmetry with R-parity violation. The PAMELA data is well fitted with neutralino mass $600\sim 2000$ GeV and life time $\sim 10^{26}$ seconds. We also demonstrate that neutralino with mass around 2TeV can fit PAMELA and ATIC data simultaneously.

hep-ph↗

arXiv2008

Constraints on the Dark Matter Annihilations by Neutrinos with Substructure Effects Included

Dark matter (DM) annihilations in the Galaxy may produce high energy neutrinos, which can be detected by the neutrino telescopes, for example IceCube, ANTARES and Super-Kamiokande. The neutrinos can also arise from hadronic interaction between cosmic ray and atmosphere around the Earth, known as atmospheric neutrino. Current measurements on neutrino flux is consistent with theoretical prediction of atmospheric neutrino within the uncertainties. In this paper, by requiring that the DM annihilation neutrino flux is less than the current measurements, we obtain an upper bound on the cross section of dark matter annihilation $ < {σv} >$. Compared with previous investigations, we improve the bound by including DM substructure contributions. In our paper, two kinds of substructure effects are scrutinized. One is the substructure average contribution over all directions. The other is point source effect by single massive sub-halo. We found that the former can improve the bound by several times, while the latter can improve the bound by $ 10^1 \sim 10^4$ utilizing the excellent angular resolution of neutrino telescope IceCube. The exact improvement depends on the DM profile and the sub-halo concentration model. In some model, IceCube can achieve the sensitivity of $ < {σv} > \sim 10^{- 26} cm^3 s^{- 1} $.

astro-ph↗

arXiv2008

Neutrino Signals from Solar Neutralino Annihilations in Anomaly Mediated Supersymmetry Breaking Model

The lightest neutralino, as the dark matter candidate, can be gravitationally captured by the Sun. In this paper, we studied the high energy neutrino signals from solar neutralino annihilations in the core of the Sun in the anomaly mediated supersymmetry (SUSY) breaking (AMSB) model. Based on the event-by-event monte carlo simulation code WimpSim, we studied the detailed energy and angular spectrum of the final muons at large neutrino telescope IceCube. More precisely we simulated the processes since the production of neutrino via neutralino annihilation in the core of the Sun, neutrino propagation from the Sun to the Earth, as well as the converting processes from neutrino to muon. Our results showed that in the AMSB model it is possible to observe the energetic muons at IceCube, provided that the lightest neutralio has relatively large higgsino component, as a rule of thumb $ N_{13}^2 + N_{14}^2 > 4%$ or equivalently $ σ_{SD} > 10^{- 5} pb$. Especially, for our favorable parameters the signal annual events can reach 102 and the statistical significance can reach more than 20. We pointed out that the energy spectrum of muons may be used to distinguish among the AMSB model and other SUSY breaking scenarios.

hep-ph↗

arXiv2007

H\to hh in the Mirror Model at the CERN Large Hadron Collider

The Higgs sector may play an important role in detecting the mirror particles, which can be the candidates of the dark matter and appear as missing energy in the detectors at the LHC. In this paper we worked out the Higgs boson spectrum and the Higgs couplings for the symmetric vacuum, namely $v_1=v_2=v$, in the mirror model, and investigated the constraints from electro-weak precision observable (EWPO). Our study showed that the EWPO has already constrained the Higgs boson sector severely. We then explored the Higgs boson phenomenology, and focused on the scenario that the heavier Higgs boson $H$ can decay into a pair of lighter Higgs boson $h$. We proposed to study the invisible decay of the Higgs boson via the pair production of them, in which one Higgs boson decays into bottom quarks and the other decays invisibly. Our detail simulation for signals and backgrounds showed that the observation of signal can reach $5σ$ significance for $m_H=260$ GeV and $m_h=115$ GeV with $10 fb^{-1}$integrated luminosity at the LHC. Moreover the possible method to further suppress dominant $Zb\bar{b}$ background was discussed. We also simulated the signals and backgrounds for $H \to h h \to 4b$. Our results showed that it is very difficult to isolate the signals from huge QCD continuum backgrounds.

hep-ph↗

arXiv2007

Unique Higgs boson signature at colliders

The HyperCP collaboration has observed three events for the decay $Σ^+ \to p μ^+ μ^-$. The three events may be interpreted as a new narrow-width CP-odd scalar $a$ with the mass $214.3 \pm 0.5$ MeV. Here $a$ decays dominantly into di-muon ($μ^+μ^-$). As the consequence of tiny mass difference between $m_a$ and 2$m_μ$ ($2 m_μ \approx$ 211.3 MeV), di-muon will be boosted to almost the same direction at colliders. Such kind of di-muon events have been overlooked in the past experiments. Provided that the precision data preferred light SM-like Higgs boson $h$ decays dominantly into $a a$ other than into $b\bar b$, in order to be consistent with null Higgs boson search at LEP, the $h\to aa \to 4μ$ ($2μ^+ 2μ^-$) will be the unique Higgs boson signature which has not been noticed before. The SM-like Higgs boson may hide itself from the usual analysis of LEP and Tevatron experiments, which should be reanalyzed in the light of new theoretical and experimental developments. In this paper, we also investigate this unique Higgs boson signature at colliders and conclude that the SM-like Higgs boson could be discovered with rather low integrated luminosity, provided that the $h\to 4μ$ reconstruction efficiency is not extremely low. It is not impossible that such kind of unique Higgs boson $4μ$ events are now lurking in the existing LEP and/or Tevatron data.

hep-ph↗