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Angular analysis of B0→D-Ds+ with Ds+→Ds+γ decays

Published version
Peer-reviewed

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Authors

Aaij, R 
Beteta, C Abellan 
Ackernley, T 
Adeva, B 
Adinolfi, M 

Abstract

The first full angular analysis of the B0→D∗−Ds∗+ decay is performed using 6 fb−1 of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The Ds∗+Ds+γ and D∗−D¯0π vector meson decays are used with the subsequent Ds+→K+Kπ+ and D¯0→K+π decays. All helicity amplitudes and phases are measured, and the longitudinal polarisation fraction is determined to be fL=0.578±0.010±0.011 with world-best precision, where the first uncertainty is statistical and the second is systematic. The pattern of helicity amplitude magnitudes is found to align with expectations from quark-helicity conservation in B decays. The ratio of branching fractions [B(B0→D∗−Ds∗+B(Ds∗+Ds+γ)]/B(B0→D∗−Ds+) is measured to be 2.045±0.022±0.071 with world-best precision. In addition, the first observation of the Cabibbo-suppressed Bs0→D∗−Ds+ decay is made with a significance of seven standard deviations. The branching fraction ratio B(Bs0→D∗−Ds+)/B(B0→D∗−Ds+) is measured to be 0.049±0.006±0.003±0.002, where the third uncertainty is due to limited knowledge of the ratio of fragmentation fractions.

Description

Keywords

B physics, Branching fraction, Hadron-Hadron scattering (experiments), Polarization

Journal Title

JOURNAL OF HIGH ENERGY PHYSICS

Conference Name

Journal ISSN

1029-8479
1029-8479

Volume Title

2021

Publisher

Springer Nature