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Advances in High Energy Physics
Volume 2014, Article ID 406458, 7 pages
Research Article

Probes for 4th Generation Constituents of Dark Atoms in Higgs Boson Studies at the LHC

1National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409, Russia
2Centre for Cosmoparticle Physics “Cosmion” Moscow 115409, Russia
3APC laboratory 10, rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France

Received 20 October 2013; Revised 18 December 2013; Accepted 18 December 2013; Published 18 February 2014

Academic Editor: Konstantin Belotsky

Copyright © 2014 M. Yu. Khlopov and R. M. Shibaev. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3.


The nonbaryonic dark matter of the Universe can consist of new stable charged species, bound in heavy neutral “atoms” by ordinary Coulomb interaction. Stable (anti-)quarks of 4th generation, bound in stable colorless clusters, are captured by the primordial helium, produced in Big Bang Nucleosynthesis, thus forming neutral “atoms” of O-helium (OHe), a specific nuclear interacting dark matter that can provide solution for the puzzles of direct dark matter searches. However, the existence of the 4th generation quarks and leptons should influence the production and decay rates of Higgs boson and is ruled out by the experimental results of the Higgs boson searches at the LHC, if the Higgs boson coupling to 4th generation fermions is not suppressed. Here, we argue that the difference between the three known quark-lepton families and the 4th family can naturally lead to suppression of this coupling, relating the accelerator test for such a composite dark matter scenario to the detailed study of the production and modes of decay of the 125.5 GeV boson, discovered at the LHC.