Angular analysis of the B 0 → K *0 μ + μ − decay using 3 fb−1 of integrated luminosity

Abstract

An angular analysis of the B 0 → K *0(→ K + π −)μ + μ − decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb−1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K + π − system in an S-wave configuration. The angular observables and their correlations are reported in bins of q 2, the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q 2-dependent decay amplitudes in the region 1.1 < q 2 < 6.0 GeV2/c 4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions

Model independent new physics analysis in $$\Lambda _b\rightarrow \Lambda \mu ^+\mu ^-$$ Λ b → Λ μ + μ - decay

“…For example, LHCb measurements [1,2] of the ratio of branching ratios ofB → K (K * ) + − decays into di-muons over dielectrons deviate from the SM predictions ∼ 1 by about 3σ . Other notable deviations in the b → sμ + μ − mediated transitions include the so called P 5 anomaly between theory [3] and experiments [4][5][6][7] in theB → K * μ + μ − , and the systematic deficit in the branching ratio ofB s → φμ + μ − [8,9]. In the b → c ν mediated transitions, ratio of B → D ( * ) ν a e-mail: diganta99@gmail.com decay involving τ leptons over light leptons has been measured by BaBar [10,11], Belle [12][13][14] and LHCb [15,16] which deviate from the SM predictions [17,18] by about 2-3σ with a combined deviation of ≈ 4σ .…”

Probing new physics in $$B \rightarrow D \ell ^+ \ell ^-$$ B → D ℓ + ℓ -

“…On the other hand, with little direct experimental validation, there exists a vast possibility of physics beyond the SM. In addition to the direct collider searches, experimenters and theorists alike have tried to look for physics beyond the SM in various meson decays, most notably in the B → K * + − decays [1][2][3][4][5][6][7][8][9], where = e, μ. In such exciting times for new physics (NP), we a e-mail: cskim@yonsei.ac.kr b e-mail: sahoodibya@yonsei.ac.kr present the most general, model-independent study of a few hitherto unseen [10], very rare, semileptonic decays of the B meson, namely B 0 → D 0 + − , B + → D + + − and B 0 → D 0 + − , which are promising candidates to probe new physics.…”

“…However, for large Wilson coefficients such decays (especially B 0 → D 0 + − ) can have sizable branching ratios in the SM, O 10 −5 [15], such that they can be observed and studied experimentally. The decays B 0 → D 0 + − and B + → D + + − being CKM suppressed 1 have smaller branching ratios in the SM, O 10 −9 − 10 −11 , which has been estimated without considering the photon pole contribution [11,14]. However, assuming that these rare decays can be observed experimentally in near future, we provide angular observables which are easy to study in experiments and show how they can be utilized to unearth any underlying new physics in these decay modes.…”

A new generation of Lepton Flavour Universality observables from $B\rightarrow$$K^∗$$\mu^+$$\mu^−$

“…Further deviations were observed by LHCb in two of the large-recoil bins of the branching ratio of B s → φ µ + µ − [6] but also in the lowrecoil bins of B + → K * + µ µ and B s → φ µ µ with a 2.5σ and 2.2σ deviation respectively. Indeed a systematic trend of experimental data preferring values below SM expectations in semileptonic b → s decays is observed 1 . And finally, last year, the Belle experiment performed an independent measurement of P 5 [7] confirming the deviation w.r.t.…”

“…In particular, processes driven by the flavour-changing neutral current (FCNC) transition b → s + − have been providing hints of several deviations from the Standard Model (SM) in various observables. In 2015, the LHCb analysis [1] of the 3 fb −1 data on B → K * µ + µ − confirmed a ∼ 3σ anomaly in two large K * -recoil bins of the angular observable P 5 [2,3] that was already present in the 2013 results with 1 fb −1 [4]. The same experiment measured the observable R K = B(B → Kµ + µ − )/B(B → Ke + e − ) [5] in the dilepton mass range from 1 to 6 GeV 2 and found a 2.6σ tension with its SM value, predicted to be equal one (to a one per cent accuracy).…”