Decaying Dark Atom Constituents and Cosmic Positron Excess

K Belotsky,M Laletin,M Khlopov,C Kouvaris

doi:10.1155/2014/214258

K Belotsky, M Laletin + Show 2 more

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https://doi.org/10.1155/2014/214258

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Abstract

We present a scenario where dark matter is in the form of dark atoms that can accommodate the experimentally observed excess of positrons in PAMELA and AMS-02 while being compatible with the constraints imposed on the gamma-ray ux from Fermi/LAT. This scenario assumes that the dominant component of dark matter is in the form of a bound state between a helium nucleus and a-2particle and a small component is in the form of a WIMP-like dark atom compatible with direct searches in underground detectors. One of the constituents of this WIMP-like state is a+2metastable particle with a mass of 1 TeV or slightly below that by decaying toe+e+,μ+μ+andτ+τ+produces the observed positron excess. These decays can naturally take place via GUT interactions. If it exists, such a metastable particle can be found in the next run of LHC. The model predicts also the ratio of leptons over baryons in the universe to be close to-3.

Highlights

We present a scenario where dark matter is in the form of dark atoms that can accommodate the experimentally observed excess of positrons in PAMELA and AMS-02 while being compatible with the constraints imposed on the gamma-ray ux from Fermi/LAT
Dark matter can potentially be in the form of neutral OHe dark atoms made of stable heavy doubly charged particles and primordial He nuclei bound by ordinary Coulomb interactions
It can be realized in the framework of Minimal Walking Technicolor, in which an exact relation between the dark matter density and baryon asymmetry can be naturally obtained predicting the ratio of leptons over baryons in the universe

Summary

Introduction

The possibility of dark matter being in the form of “dark atoms” has been studied extensively [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21]. All these models predict corresponding +2 charge particles If these positively charged particles remain free in the early universe, they can recombine with ordinary electrons in anomalous helium, which is strongly constrained in terrestrial matter. (ii) Free positively charged particles are already suppressed in the early universe and the abundance of anomalous helium in the galaxy is negligible [29, 44] These two possibilities correspond to two different cosmological scenarios of dark atoms. The cosmological scenario of the OHe universe can explain many results of experimental searches for dark matter [29] Such a scenario is insensitive to the properties of O−−, since the main features of the OHe dark atoms are determined by their nuclear interacting helium shell.

Dark Atoms from Techniparticles

Techniparticle Excess

Decaying Dark Matter

Positron Excess and Fit to the PAMELA and AMS-02 Data

Findings

Conclusions