Explaining the Flavour Anomalies with the Pati-Salam Vector Leptoquark

Aug 8, 2018
7 pages
Published in:
  • PoS LHCP2018 (2018) 269
Contribution to:
  • Published: Aug 8, 2018 by SISSA

Citations per year

20202021202201
Abstract: (SISSA)
In recent years several experiments revealed intriguing hints for new physics (NP) in BB meson decays involving \bctaunu and bs+b\to s\ell^+\ell^- transitions at the 45σ4-5\,\sigma level. These signs for NP are supported by slight disagreements in the analogous observables with buτνb\to u \tau\nu and bdμ+μb\to d\mu^+\mu^- transitions. While not significant on their own, these processes point in the same direction. Since all these observables are semi-leptonic, leptoquarks are prime candidates for a solution to these puzzels since they give tree-level effects here while their contributions to other flavour observables, which agree with the SM predictions, are loop suppressed. In these proceedings we focus on the vector leptoquark SU(2)SU(2) singlet which provides a natural explanations for both the bc(u)τνb\to c(u) \tau\nu and the bs(d)μ+μb\to s(d)\mu^+\mu^- data. However, to account for the preferred NP effect in bc(u)τνb\to c(u) \tau\nu large couplings to τ\tau leptons are necessary and loop effects become important. Including them in the phenomenological analysis, the fit to data is even improved.Finally, we review two UV complete models which give rise to the desired vector leptoquark SU(2)SU(2) singlet. The first possibility is to add either three generations of vector-like fermions to the original Pati-Salam model and break the symmetry with a Higgs mechanism. Alternatively, it is possible to break the PS gauge group to the SM one on a compact extra dimension like in Randall Sundrum models.
  • meson: decay
  • B: decay
  • leptoquark: vector particle
  • singlet
  • Randall-Sundrum model
  • higher-dimensional
  • tree approximation
  • Pati-Salam model
  • symmetry breaking
  • Higgs mechanism