## Mirror-extended standard model with spontaneously broken left-right symmetry

#### by Alexander Kaganovich

*Ben-Gurion University*

##### at Particles and Fields Seminar

Mon, 20 Dec 2021, 14:00

Sacta-Rashi Building for Physics (54), room 207

#### Abstract

A left-right symmetric extension of the standard electroweak model (SM) with a doubled particle content is proposed. Mirror copy have the same $SU(2)\times U(1)$ gauge structure and parameters as SM; the mirror fermion counter-partners have opposite chiralities. The model contains neither additional dynamical degrees of freedom, nor additional interactions. A Two Measures Theory is used that allows one to obtain MESM in Minkowski space only if we start with an accurate account of gravity and only at the end go to the limit of Minkowski space. Spontaneous breaking of left-right symmetry and the "wrong" sign in the mass terms of the Higgs fields potentials arise due to the initial conditions imposed on the inflaton in the $\alpha$-attractor inflationary model. MESM allows choosing the universal Yukawa coupling constant $y$ in the underlying Lagrangian for all generations of charged leptons and up-quarks. As an example, with $y\approx10^{-3}$, it is shown that a set of additional dimensionless parameters in width range less than 0.5 is sufficient to obtain the masses of all known charged leptons and up-quarks. In this sense, MESM bypasses the problem of the fermion mass hierarchy. With this choice of parameters, MESM predicts that vacuum expectation value for the mirror Higgs field is $10^{14} GeV$ and masses of mirror particles are in the range $10^{8}GeV - 10^{14}GeV$. There is only gravitational interaction between particles of the SM and mirror sectors. Hence, mirror particles can constitute dark matter.

Created on 13-12-2021 by Palti, Eran (palti)

Updaded on 13-12-2021 by Palti, Eran (palti)