Search for Double Charged Particles as Direct Test for Dark Atom Constituents

The nonbaryonic dark matter of the Universe is assumed to consist of new stableparticles. Stable particle candidates for cosmological dark matter are usuallyconsidered as neutral and weakly interacting. However stable charged leptons andquarks can also exist hidden in elusive dark atoms and can play a role of darkmatter. Such possibility is strongly restricted by the constraints on anomalousisotopes of light elements that form positively charged heavy species withordinary electrons. This problem might be avoided, if stable particles withcharge-2 exist and there are no stable particles with charges +1 and-1. Theseconditions cannot be realized in supersymmetric models, but can be satisfied inseveral alternative scenarios, which are discussed in this paper. Theexcessive-2 charged particles are bound with primordial helium in O-heliumatoms, maintaining specific nuclear-interacting form of the dark matter.O-helium dark matter can provide solution for the puzzles of dark mattersearches. The successful development of composite dark matter scenarios appealsto experimental search for doubly charged constituents of dark atoms. Estimatesof production cross section of such particles at LHC are presented anddiscussed. Signatures of double charged particles in the ATLAS experiment areoutlined. Povzetek. Avtorji predpostavijo, da temno snov, ki ni iz barionovpoznanih treh družin, sestavljajo novi stabilni delci. Običajno za njihpredlagajo nevtralne delce s ˇ sibko interakcijo, pa tudi stabilne nabiteleptone in kvarke, vezane v " temne atome ". To zadnjo možnost so poskusi močnoomejili.Tem omejitvam se lahko izognemo, ˇ ce privzamemo, da obstajajo stabilni(temni) delci z nabojem −2, ni pa stabilnih (temnih) delcev z naboji +1 in −1.Tega privzetka ne moremo narediti v modelih s supersimetrijo, lahko pa ganaredimo v alternativnih modelih, ki jih avtorji obravnavajo. Višek delcev znabojem −2 se veže s prvotnim helijem v " atome " O-helija, katerega interakcijaje posledično običajna jedrska. Taka temna snov pojasni rezultate tistihposkusov iskanja temne snovi, ki jě se niso zaznali. Obravnavajo preseke za tedelce pri poskusih na LHC in predvidijo rezultate meritev na ATLASu. Presentedfirst part of talk at Bled Presented second part of talk by VIA teleconference