The physics of heavy flavours at SuperB

Abstract

This is a review of the SuperB project, covering the accelerator, detector, and highlights of the broad physics programme. SuperB is a flavour factory capable of performing precision measurements and searches for rare and forbidden decays of B u,d,s , D, τ and Υ (nS) particles. These results can be used to test fundamental symmetries and expectations of the Standard Model, and to constrain many different hypothesised types of new physics. In some cases these measurements can be used to place constraints on the existence of light dark matter and light Higgs particles with masses below 10 GeV/c 2 . The potential impact of the measurements that will be made by SuperB on the field of high energy physics is also discussed in the context of data taken at both high energy in the region around the Υ (4S), and near charm threshold.

Lepton-number-violating four-body tau lepton decays

“…l AE l 0AE X Ç decays. With the large data sample of lepton pairs that are expected at superflavor factories [58,59], we may expect that sensitivities at or below the 10 À7 level may be easily reached for the branching ratios of these decay channels. Just to illustrate the potential of lepton decays to constrain the parameter space of the heavy neutrino, in Fig.…”

New Physics constraints from rareb→s+ (γ,ℓ+ℓ−) decays

“…Furthermore, the 2012 data set of LHCb with ≳ 2 fb −1 will hopefully allow first measurements of angular observables in B → K * + − and the precision will improve further with data of about 5 fb −1 in the years 2015 -2018 [5], before a shutdown for the planned upgrade. With the start of data taking in 2015, also the super-flavor factory Belle II will collect a substantial data set with (1.0 − 1.5) ⋅ 10 4 events [6] in the next decade. Very recently, LHCb found first evidence for the very rare decay B s → µ + µ − [7], known as an ideal probe of scalar and pseudo-scalar nonstandard interactions combining 2 fb −1 data from 2011 and 2012.…”

“…CP-violating effects in b → s transitions are predicted to be very small in the SM, being proportional to the doubly Cabibbo-suppressed combination Im(V ub V * us ). Here several CP asymmetries of the angular observables J 5,6,8,9 can be extracted from untagged B meson samples and moreover, CP asymmetries of J 7,8,9 are not suppressed by small QCD phases [19]. The first measurements of the CP asymmetry A im of J 9 [2] and the rate CP asymmetry of B → K * + − became available [4], where the latter equals to the one of B → K + − in the SM operator basis [20].…”

Theory status of b\rightarrow s l^+ l^- decays and their combined analysis

“…By now LHCb dominates statistically, adding about 2 fb −1 of data this year 2012 and possibly another 4 fb −1 until the year 2018 before a long shut-down. The Super-Flavour factories Belle II [5] and SuperB [6] will be able to collect data sets with about 10000 -15000 events [7].…”