Measurement of form-factor independent observables in the decay $B^{0} \to K^{*0} \mu^+ \mu^-$

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We present a measurement of form-factor independent angular observables in the decay $B^0\to K^{*}(892)^{0}\mu^+ \mu^-$. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0fb$^{-1}$, collected by the LHCb experiment in $pp$ collisions at a center-of-mass energy of 7TeV. Four observables are measured in six bins of the dimuon invariant mass squared, $q^2$, in the range $0.1<q^2<19.0$GeV$^{2}$/c$^{4}$. Agreement with Standard Model predictions is found for 23 of the 24 measurements. A local discrepancy, corresponding to $3.7$ Gaussian standard deviations, is observed in one $q^2$ bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is $0.5\%$.

Figures and captions

Measured values of $P_{4}^{\prime}$ and $P_5^{\prime}$ (black points) compared with SM predictions from Ref. \cite{Descotes-Genon:2013vna} (blue bands).

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P5prime.pdf [14 KiB]
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Tables and captions

Measurement of the observables $P_{4,5,6,8}^{\prime}$ and $S_{4,5,7,8}$ in the six $q^2$ bins of the analysis. For the observables $P_i^{\prime}$ the measurement in the $q^2$-bin $1.0<q^2<6.0$ $ {\mathrm{ Ge V^2 /}c^4}$ , which is the theoretically preferred region at large recoil, is also reported. The first uncertainty is statistical and the second is systematic.

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Created on 20 February 2021.