Markov chain Monte Carlo study on dark matter property related to the cosmic e{sup {+-}}excesses

Journal Article · Fri Jan 15 04:00:00 EST 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.023516· OSTI ID:21409049

Jie, Liu ^[1]; Qiang, Yuan; Xiaojun, Bi ^[2]; Hong, Li; Xinmin, Zhang ^[1]

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1. Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Science, P.O.Box 918-4, Beijing 100049 (China)
2. Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Science, P.O.Box 918-3, Beijing 100049 (China)

In this paper we develop a Markov chain Monte Carlo code to study the dark matter properties in frameworks to interpret the recent observations of cosmic ray electron/positron excesses. We assume that the dark matter particles couple dominantly to leptons and consider two cases, annihilating or decaying into lepton pairs, respectively. The constraint on the central density profile from the H.E.S.S. observation of diffuse {gamma} rays around the Galactic center is also included in the Markov chain Monte Carlo code self-consistently. In the numerical study, we have considered two cases of the background: fixed e{sup +}e{sup -} background and the relaxed one. Two data sets of electrons/positrons, i.e. PAMELA+ATIC (Data set I) and PAMELA+Fermi-LAT+H.E.S.S. (Data set II), are fitted independently, considering the current inconsistence between the observational data. We find that for Data set I, dark matter with m{sub {chi}{approx_equal}0}.70 TeV for annihilation (or 1.4 TeV for decay) and a non-negligible branching ratio to e{sup +}e{sup -} channel is favored; while for Data set II, m{sub {chi}{approx_equal}2}.2 TeV for annihilation (or 4.5 TeV for decay) and the combination of {mu}{sup +{mu}-} and {tau}{sup +{tau}-} final states can best fit the data. We also show that the background of electrons and positrons actually will significantly affect the branching ratios. The H.E.S.S. observation of {gamma} rays in the Galactic center ridge puts a strong constraint on the central density profile of the dark matter halo for the annihilation dark matter scenario. In this case the Navarro-Frenk-White profile, which is regarded as the typical predication from the cold dark matter scenario, is excluded with a high significance (>3{sigma}). For the decaying dark matter scenario, the constraint is much weaker.

• OSTI ID: 21409049
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 2 Vol. 81; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BRANCHING RATIO
CALCULATION METHODS
COSMIC RADIATION
DECAY
DENSITY
DIMENSIONLESS NUMBERS
ELECTROMAGNETIC RADIATION
ELECTRON-POSITRON INTERACTIONS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GAMMA RADIATION
INTERACTIONS
IONIZING RADIATIONS
LEPTON-LEPTON INTERACTIONS
LEPTONS
MARKOV PROCESS
MATHEMATICS
MATTER
MONTE CARLO METHOD
MUONS
MUONS MINUS
MUONS PLUS
NONLUMINOUS MATTER
NUMERICAL ANALYSIS
PARTICLE DECAY
PARTICLE INTERACTIONS
PHYSICAL PROPERTIES
POSITRONS
RADIATIONS
SIMULATION
STOCHASTIC PROCESSES
TEV RANGE
TEV RANGE 01-10