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Register a new user$Z^prime$ models with less-minimal flavour violation
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We study the phenomenology of simplified $Z^prime$ models with a global $U(2)^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation, protects $Delta F=2$ processes from dangerously large new physics (NP) effects, and at the same time provides a free complex phase in $bto s$ transitions, allowing for an explanation of the hints for additional direct CP violation in kaon decays ($epsilon^prime/epsilon$) and in hadronic $B$-decays ($Bto Kpi$ puzzle). Furthermore, once the couplings of the $Z^prime$ boson to the leptons are included, it is possible to address the intriguing hints for NP (above the 5$,sigma$ level) in $bto s ell^+ell^-$ transitions. Taking into account all flavour observables in a global fit, we find that $epsilon^prime/epsilon$, the $Bto Kpi$ puzzle and $bto s ell^+ell^-$ data can be explained simultaneously. Sizeable CP violation in $bto s ell^+ell^-$ observables, in particular $A_8$, is predicted, which can be tested in the near future, and an explanation of the $Bto Kpi$ and $epsilon^prime/epsilon$ puzzles leads to effects in di-jet tails at the LHC, that are not far below the current limits. Once $bto s ell^+ell^-$ is included, cancellations in di-muon tails, possibly by a second $Z^prime$, are required by LHC data.
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