Resolving <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math> boson mass shift and CKM unitarity violation in left-right symmetric models with a universal seesaw mechanism
Ritu Dcruz, K. S. Babu
Abstract
We explore the possibility of resolving simultaneously the $W$-boson mass shift reported by the CDF Collaboration and the apparent deviation from unitarity in the first row of the CKM mixing matrix in a class of left-right symmetric models. The fermion masses are generated in these models through a universal seesaw mechanism, utilizing vectorlike partners of the usual fermions. We find a unique solution to the two anomalies where the mixing of the down quark with a vectorlike quark (VLQ) resolves the CKM unitarity puzzle, and the mixing of the top quark with a VLQ partner explains the $W$ boson mass shift. The validity of this setup is tested against the stability of the Higgs potential up to higher energies. We find upper bounds of (4, 4) TeV on the masses of the top-partner VLQ, and a neutral scalar associated with $SU(2{)}_{R}$ gauge symmetry breaking, respectively. This class of models can solve the strong $CP$ problem via parity symmetry without the need for an axion.