Emergent dark matter, baryon, and lepton numbers

Abstract

We present a new mechanism for transferring a pre-existing lepton or baryon asymmetry to a dark matter asymmetry that relies on mass mixing which is dynamically induced in the early universe. Such mixing can succeed with only generic scales and operators and can give rise to distinctive relationships between the asymmetries in the two sectors. The mixing eliminates the need for the type of additional higherdimensional operators that are inherent to many current asymmetric dark matter models. We consider several implementations of this idea. In one model, mass mixing is temporarily induced during a two-stage electroweak phase transition in a two Higgs doublet model. In the other class of models, mass mixing is induced by large field vacuum expectation values at high temperatures -either moduli fields or even more generic kinetic terms. Mass mixing models of this type can readily accommodate asymmetric dark matter masses ranging from 1 GeV to 100 TeV and expand the scope of possible relationships between the dark and visible sectors in such models.

Dark Matter Decay between Phase Transitions at the Weak Scale

“…We focus on models in which fermionic DM particles couple to a new scalar species and argue that the resulting scalar potential may undergo multiple phase transitions, "flip-flopping" between phases in which the symmetry stabilising the DM is intact and a phase where it is broken. Similar behaviour is found in models of electroweak baryogenesis [8][9][10][11][12][13][14], see also [15] for related work. During the broken phase, the initially overabundant DM particles are depleted until their relic density reaches the value observed today.…”

The phenomenology of lepton flavored dark matter

“…Accordingly, we refer to this scenario as 'lepton flavored dark matter'. Sneutrino dark matter and Kaluza-Klein neutrino dark matter are special cases that fall into this category, as does the model of [12]. Similarly, we label the corresponding case where χ couples to a quark as 'quark flavored dark matter'.…”

“…Other realizations of flavored dark matter that have received recent study include theories where dark matter couples primarily to quarks, potentially giving rise to interesting flavor violating signals [10,11]. It has also been shown that flavored dark matter may play a role in explaining the baryon asymmetry [12], and that extending the SM flavor structure to the dark sector can explain the stability of dark matter [13].…”

Spontaneous baryogenesis from extremely light asymmetric dark matter

“…In the context of the Standard Model, the lowest dimensional operator that breaks B − L is the familiar lepton number violating dimension five interaction that can generate neutrino masses: 10 GeV. When T > T EW we can set both the electromagnetic charge and the weak isospin charge, 13) to zero since SU (2) L is a good symmetry of the theory and inflation diluted away initial charges. Since at T > T EW , the Higgs field has not obtained a vev, µ 0 can be non-zero.…”

“…On the other hand, asymmetric dark matter models can naturally relate the two quantities by either generating an asymmetry in one sector and then transferring it to the other sector, or by generating both at the same time. Cases in which the asymmetry is transferred via electroweak sphalerons [2][3][4][5][6][7][8][9][10][11] or other baryon number violating interactions [12][13][14][15][16][17][18][19][20][21][22][23][24] have been explored extensively in the literature. These models typically predict Ω DM /Ω B ≈ m DM /m B , once the symmetric component of dark matter is annihilated away.…”