English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

It is well known that the annihilation of Majorana dark matter into fermionsis helicity suppressed. Here, we point out that the underlying mechanism is asubtle combination of two distinct effects, and we present a comprehensiveanalysis of how the suppression can be partially or fully lifted by theinternal bremsstrahlung of an additional boson in the final state. As aconcrete illustration, we compute analytically the full amplitudes andannihilation rates of supersymmetric neutralinos to final states that containany combination of two standard model fermions, plus one electroweak gaugeboson or one of the five physical Higgs bosons that appear in the minimalsupersymmetric standard model. We classify the various ways in which thesethree-body rates can be large compared to the two-body rates, identifying casesthat have not been pointed out before. In our analysis, we put special emphasison how to avoid the double counting of identical kinematic situations thatappear for two-body and three-body final states, in particular on how tocorrectly treat differential rates and the spectrum of the resulting stableparticles that is relevant for indirect dark matter searches. We find that boththe total annihilation rates and the yields can be significantly enhanced whentaking into account the corrections computed here, in particular for modelswith somewhat small annihilation rates at tree-level which otherwise would notbe testable with indirect dark matter searches. Even more importantly, however,we find that the resulting annihilation spectra of positrons, neutrinos,gamma-rays and antiprotons differ in general substantially from themodel-independent spectra that are commonly adopted, for these final states,when constraining particle dark matter with indirect detection experiments.

the journal of high energy physics/the journal of high energy physics

Electroweak and Higgs Boson Internal Bremsstrahlung: General  considerations for Majorana dark matter annihilation and application to MSSM  neutralinos