Abstract
The well-known baryon and lepton numbers of the standard model of quarks and leptons are extended to include new fermions and bosons in a simple structure with several essential features. The usual heavy right-handed neutrino singlets (for neutrino mass and leptogenesis) are related to the axion which solves the strong CP problem. At the same time, baryon number is broken softly, allowing the proton to decay. Associated with this breaking, a long-lived dark-matter candidate (called the pseudo-sakharon) emerges. This new insight connects proton decay to a new component of dark matter.
Highlights
The standard model (SM) of quarks and leptons is known to have the built-in global Uð1Þ symmetries of baryon number B and lepton number L
It will be shown how a simple extension of the SM, which connects [2,3,4] the seesaw neutrino mass with the axion decay constant, may allow a new understanding of the longevity [5] of weak-scale dark matter (DM), i.e., that it is related to proton decay
A simple connection was proposed thirty years ago [3], where the neutrino mass seesaw anchor scale is identified with the vacuum expectation value of a singlet scalar field which couples anomalously to new very heavy quark singlet fields ðΨL;RÞ as well as the three very heavy right-handed neutrinos ðNRÞ
Summary
The standard model (SM) of quarks and leptons is known to have the built-in global Uð1Þ symmetries of baryon number B and lepton number L. If new particles are added, their B and L assignments may be chosen judiciously [1] to address a number of outstanding theoretical issues In the following, it will be shown how a simple extension of the SM, which connects [2,3,4] the seesaw neutrino mass with the axion decay constant, may allow a new understanding of the longevity [5] of weak-scale dark matter (DM), i.e., that it is related to proton decay. The axionneutrino connection implies the basic assumption [11,12] Uð1ÞPQ 1⁄4 Uð1ÞL, and that Ψ transforms under both B and L Another theoretical issue is whether or not DM is truly stable, in which case it should be protected by a symmetry, or just a very long-lived particle such as the invisible axion.
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