SM*A*S*H

TL;DR

SM*A*S*H is a minimal extension of the Standard Model that simultaneously addresses neutrino oscillations, baryogenesis, dark matter, inflation, and the strong CP problem through new particles and a high-scale PQ symmetry breaking.

Contribution

It introduces a unified model incorporating neutrino masses, axion dark matter, and inflation, connecting these phenomena via a common framework with testable predictions.

Findings

Solves five fundamental problems in particle physics and cosmology.

Predicts axion dark matter detectable by upcoming experiments.

Provides a high-scale PQ symmetry breaking at around 10^{11} GeV.

Abstract

We present a minimal model for particle physics and cosmology. The Standard Model (SM) particle content is extended by three right-handed SM-singlet neutrinos N_i and a vector-like quark Q, all of them being charged under a global lepton number and Peccei-Quinn (PQ) U(1) symmetry which is spontaneously broken by the vacuum expectation value v_sigma around 10^{11} GeV of a SM-singlet complex scalar field sigma. Five fundamental problems -- neutrino oscillations, baryogenesis, dark matter, inflation, strong CP problem -- are solved at one stroke in this model, dubbed "SM*A*S*H" (Standard Model*Axion*Seesaw*Higgs portal inflation). It can be probed decisively by upcoming cosmic microwave background and axion dark matter experiments.