Angular analysis of the decay B0→ K⁎0μ+μ− from pp collisions at s=8 TeV

Abstract

The angular distributions and the differential branching fraction of the decay B 0 → K * (892) 0 µ + µ − are studied using data corresponding to an integrated luminosity of 20.5 fb −1 collected with the CMS detector at the LHC in pp collisions at √ s = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the K * (892) 0 longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.

Status of the $$B\rightarrow K^*\mu ^+\mu ^-$$ B → K ∗ μ +

“…• Angular observables in B 0 → K * 0 μ + μ − measured by CDF [45], LHCb [31], ATLAS* [37], and CMS* [38,46,47], • B 0,± → K * 0,± μ + μ − branching ratios by LHCb* [15,48], CMS [46,47], and CDF [45], Items marked with an asterisk have been updated since our previous global fit [32]. Concerning B 0 → K * 0 μ + μ − , both LHCb and ATLAS have performed measurements of CPaveraged angular observables S i as well as of the closely related "optimized" observables P i .…”

Round table: Flavour anomalies inb→sl+l−processes

“…The large dataset has also enabled the LHCb and CMS experiments to make the most precise measurements of the differential branching fraction of B → K ( * ) µ + µ − and B 0 s → φµ + µ − to date [5][6][7]. Above the open charm threshold, broad resonances are seen in the LHCb dataset [8].…”

“…The largest sources of systematic uncertainty arise from modelling of the experiments angular acceptance and the background angular distribution. Observables F L and A FB measured by the BaBar [15], Belle [16], CDF [17], CMS [7] and LHCb [18] experiments for the B → K * µ + µ − decay as a function of the dimuon invariant mass squared, q 2 . The shaded region indicates a theoretical prediction for the observables based on Refs.…”

“…The initial idea was to to include charm contributions in an α s -expansion, relying on cancellations when averaged over large enough bins. 7 As an estimate of these quark-hadron duality violations NF was taken as a guidance [37] yielding a 2% effect. One is then faced with the fact that the actual data [8] show much larger effects in the 10%-region [38].…”

“…Apart from the best-fit point together with the 1σ region, the tables feature the SM-pull of the respective new-physics scenarios. This number quantifies by how many sigmas the best fit point is preferred over the SM point {C NP i } = 0 and 7 The gateway to quark-hadron duality are dispersion relations valid at the level of amplitudes. Averaging at the decay rate level is only valid if the rate can be written as an amplitude which is the case for inclusive modes such as e + e − → hadrons and not the case for B → K ( * ) ��.…”