Dequantization of electric charge: Probing scenarios of cosmological multi-component dark matter

Abstract

Since the electric charge in the standard model is theoretically not quantized, we may have a variant of it, called dark charge. Similar to the electric charge, the dark charge neither commutes nor closes algebraically with SU (2)L. The condition of algebraic closure leads to a novel gauge extension, SU (2)L ⊗ U (1)Y ⊗ U (1)N , where Y and N determine the electric and dark charges, respectively, apart from the color group. We argue that the existence of the dark charge, thus N , leads to the novel scenarios of multi-component dark matter, in general. The dark matter stability is determined by a residual (or dark charge) gauge symmetry isomorphic to an even Z k discrete group, where k is specified dependent on the value of the neutrino dark charge. This residual symmetry divides the standard model particles into distinct classes, which possibly accommodate dark matter, but the dark matter candidate cannot decay due to the color and electric charge conservation. We analyze in detail three specific models according to k = 2, 4, 6 and determine the simplest dark matter candidates. For small U (1)N coupling, the twocomponent dark matter scenarios implied by the dark charge successfully explain the dark matter relic density and the recent XENON1T excess, as well as the beam dump, neutrino scattering, and astrophysical bounds. Otherwise, for large U (1)N coupling, we have multi-WIMPs coexisted beyond the weak scale.

Gauge Origin of Double Dark Parity and Implication for Dark Matter

“…where l aL ≡ (ν aL e aL ) T and q aL ≡ (u aL d aL ) T . The generic hypercharge depends on δ , called the parameter of charge dequantization [21][22][23].…”

“…where k 1,2,3,4 and n are generically integer (that determine m, with a given δ ) [23]. The first equation demands that m must be a positive even integer, i.e.…”

“…The above two cases may be simultaneously presented in the latter model relevant to the two U(1) factors, if introduced, recognizing a novel double dark parity, Z 2 ⊗ Z 2 , corresponding to δ 1 = 1/(3n 1 − 1) for n 1 odd and δ 2 = 1/(3n 2 − 1) for n 2 even. It is stressed that within a U(1) N factor, a residual symmetry Z 4 according to m = 4 may be hinted; but, this Z 4 is not isomorphic to a Z 2 ⊗ Z 2 [23]. The Klein symmetry Z 2 ⊗ Z 2 that is extensively used for recognizing two distinct kinds of odd fields of dark matter, might only arise from the two U(1)'s symmetry.…”

“…It is important to note that Ψ 2 can have an arbitrary mass. The symmetries SU(3) C , U(1) Q , and Z 2 jointly suppress the decay of the Ψ 2 dark matter, if Ψ 2 has a mass that is larger than the ordinary odd particles (e, d, φ + ,W + ) [22,23]. This is because the dark matter is electrically and color neutral, while the rest of odd fields is not.…”

“…The dark charge breaking not only produces the neutrino masses and makes the electric charge quantized, but also determines a dark parity as residual gauge symmetry, which is different from the studied Z 2 /matter parity and not commuted with the weak isospin, similar to the electric charge. This approach provides a possibility to unify both dark matter and normal matter in weak isospin multiplets, besides revealing a novel stability mechanism for dark matter with the aid of electric and color charge conservations, since the dark matter is electrically and color neutral [22,23].…”