Speaker
Description
Many extensions of the SM have been proposed to explain the discrepancies between b→sℓ+ℓ- data and the corresponding Standard Model predictions. In this talk, I will focus on important phenomenological implications of a prime solution to the anomalies: a neutral bosons (Z’). In particular, concerning a heavy neutral gauge boson, I will discuss the effect of the mixing of the Z′ with the SM Z, which cannot be avoided by any symmetry. I will show that that a mixing of the order of (mZ/mZ′)^2 as expected in generic models, leads to lepton flavour universal contributions, providing a good fit to b → sl+l− data and is also welcome by the global electroweak fit where the tension in the W mass prefers a non-zero value of it with intriguing consequences for model building.
On the other hand, a light Z’ boson is the only viable single particle solution to the anomalies predicting R(K(*))>0 in high q2 bins, providing an essential consistency test of data which will be available in the near future. I will discuss this solution together with the impact on B->K+invisible, Drell-Yan searches for muon pairs at LHC and e+e- -> μ+μ- + invisible. I will point out that the forthcoming improved limits on these processes, including the experimental sensitivities required for a proper treatment of the necessarily sizable Z’ width, can rule out a Z’ explanation of b→sℓ+ℓ- data with a mass below ~4 GeV.
