Amplitude analysis and branching fraction measurement of 𝐵�+→𝐷�∗−𝐷�+𝑠�𝜋�+ decays

Abstract

The decays of the B+ meson to the final state 𝐷∗−𝐷+𝑠𝜋+ are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb−1. The ratio of branching fractions of the 𝐵+→𝐷∗−𝐷+𝑠𝜋+ and 𝐵0→𝐷∗−𝐷+𝑠 decays is measured to be 0.173 ± 0.006 ± 0.010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed 𝐷∗+𝑠→𝐷+𝑠𝛾 and 𝐷+𝑠𝜋0 decays, the ratio of branching fractions between the 𝐵+→𝐷∗−𝐷∗+𝑠𝜋+ and 𝐵+→𝐷∗−𝐷+𝑠𝜋+ decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the 𝐵+→𝐷∗−𝐷+𝑠𝜋+ decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D*−π+ final state. No significant evidence of exotic contributions in the 𝐷+𝑠𝜋+ or 𝐷∗−𝐷+𝑠 channels is found. The fit fraction of the scalar state 𝑇∗𝑐𝑠⎯⎯⎯0(2900)++ observed in the 𝐵+→𝐷−𝐷+𝑠𝜋+ decay is determined to be less than 2.3% at a 90% confidence level.