First observations of the rare decays B + → K + π + π − μ + μ − and B +→ ϕK + μ + μ −

Abstract

First observations of the rare decays B + → K + π + π − µ + µ − and B + → φK + µ + µ − are presented using data corresponding to an integrated luminosity of 3.0 fb −1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The branching fractions of the decays are B(B + → K + π + π − µ + µ −) = 4.36 +0.29 −0.27 (stat) ± 0.21 (syst) ± 0.18 (norm) × 10 −7 , B(B + → φK + µ + µ −) = 0.82 +0.19 −0.17 (stat) +0.10 −0.04 (syst) ± 0.27 (norm) × 10 −7 , where the uncertainties are statistical, systematic, and due to the uncertainty on the branching fractions of the normalisation modes. A measurement of the differential branching fraction in bins of the invariant mass squared of the dimuon system is also presented for the decay B + → K + π + π − µ + µ − .

A general effective field theory description of $b \to s l^+ l^-$ lepton universality ratios

“…[32]. Similar inspection can be performed for the non-exclusive channels and are found to be at the order of 2.0 and 2.6 for the Kπ and Kππ hadronic systems, respectively [33,34]. As a result, this confirms the conclusion of Sec II that the limits obtained for the η i X parameters involving the K * (892) 0 resonance can be used as a proxy for these channels.…”

“…As the decays B + → K + π − π + e + e − and B 0 → K + π − e + e − have yet to be observed, their yields are extrapolated from the corresponding muonic decay modes from Refs. [33,34], by scaling with luminosity and the centre-of-mass energy. These muon yields are compared to the corresponding yield in the R K * measurement [35] to scale the resulting precision of the LFU ratio.…”

Parity doubling as a tool for right-handed current searches

“…Belle has reported a time-dependent measurement of B 0 → ρ 0 K s γ [56] and the rate B(B + → K + 1 (1270)γ) 4.3(9)(9) · 10 −5 [57]. At the LHCb experiment, the K 1 states were seen in B → K + π + π − at the LHCb [58], and the first observation of B (B s,d → f 1 (1285)J/Ψ) 7 · 10 −5 , 8 · 10 −6 was reported in [59].…”

Implications of new physics in B → K 1 μ + μ − decay processes

“…In this context, we would like to investigate these decay processes in a model independent framework, where the possible NP effects are quantified by introducing additional new operators to the SM effective Hamiltonian. It should be further emphasized that the differential branching ratio of the B + → K + π + π − μ + μ − process has been reported in the LHCb paper using the 7 TeV and 8 TeV data set corresponding to an integrated luminosity of 3.0 fb −1 [40] as…”