The cross section for a Majorana Dark Matter particle annihilating into light fermions is helicity suppressed. We show that, if the Dark Matter is the neutral Majorana component of a multiplet which is charged under the electroweak interactions of the Standard Model, the emission of gauge bosons from the initial state lifts the suppression and allows an s-wave annihilation. The resulting energy spectra of stable Standard Model particles are importantly affected. This has an impact on indirect searches for Dark Matter. © 2011 IOP Publishing Ltd and SISSA.
Initial state radiation in Majorana Dark Matter annihilations / Ciafaloni, P.; Cirelli, M.; Comelli, D.; De Simone, A.; Riotto, A.; Urbano, A.. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 2011:10(2011). [10.1088/1475-7516/2011/10/034]
Initial state radiation in Majorana Dark Matter annihilations
Urbano A.
2011
Abstract
The cross section for a Majorana Dark Matter particle annihilating into light fermions is helicity suppressed. We show that, if the Dark Matter is the neutral Majorana component of a multiplet which is charged under the electroweak interactions of the Standard Model, the emission of gauge bosons from the initial state lifts the suppression and allows an s-wave annihilation. The resulting energy spectra of stable Standard Model particles are importantly affected. This has an impact on indirect searches for Dark Matter. © 2011 IOP Publishing Ltd and SISSA.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
