Differential branching fraction and angular moments analysis of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^*_{0,2}(1430)^0$ region

TL;DR

This paper presents the first angular analysis of the rare decay $B^0 o K^+ o ext{pi}^- o ext{mu}^+ o ext{mu}^-$, measuring differential branching fractions and angular moments in specific mass and $q^2$ ranges using LHCb data.

Contribution

It introduces the first angular moments analysis of this decay, providing new insights into S-, P-, and D-wave contributions in the specified mass region.

Findings

Measured differential branching fractions in five $q^2$ bins.

Presented 40 normalized angular moments for $q^2$ range 1.1--6.0 GeV$^2$/c$^4$.

Performed the first angular analysis sensitive to multiple wave contributions.

Abstract

Measurements of the differential branching fraction and angular moments of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^+\pi^-$ invariant mass range $1330<m(K^+ \pi^-)<1530~MeV/c^2$ are presented. Proton-proton collision data are used, corresponding to an integrated luminosity of 3 $fb^{-1}$ collected by the LHCb experiment. Differential branching fraction measurements are reported in five bins of the invariant mass squared of the dimuon system, $q^2$, between 0.1 and 8.0 $GeV^2/c^4$. For the first time, an angular analysis sensitive to the S-, P- and D-wave contributions of this rare decay is performed. The set of 40 normalised angular moments describing the decay is presented for the $q^2$ range 1.1--6.0 $GeV^2/c^4$.