Saving fourth generation and baryon number by living long

TL;DR

This paper proposes that a long-lived fourth generation of particles can evade current constraints, preserve baryon asymmetry, and produce distinctive signatures at the LHC, offering new avenues for beyond Standard Model physics.

Contribution

It introduces the idea that long-lived fourth generation particles can preserve baryon asymmetry and allow for exact B-L symmetry, expanding the parameter space for new physics.

Findings

Long-lived fourth generation can evade electroweak constraints.

Preserves baryon and lepton asymmetries against sphaleron erasure.

Predicts unique LHC signatures of long-lived particles.

Abstract

Recent studies of precision electroweak observables have led to the conclusion that a fourth generation is highly constrained. However, we point out that a long-lived fourth generation can reopen a large portion of the parameter space. In addition, it preserves baryon and lepton asymmetries against sphaleron erasure even if $B-L=0$. It opens up the possibility of exact $B-L$ symmetry and hence Dirac neutrinos. The fourth generation can be observed at the LHC with unique signatures of long-lived particles in the near future.