Measurement of the Branching Fraction Ratios 𝑅(𝐷+) and 𝑅(𝐷*+) Using Muonic 𝜏 Decays

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Measurement of the Branching Fraction Ratios 𝑅(𝐷+) and 𝑅(𝐷*+) Using Muonic 𝜏 Decays

Physical Review Letters. 2025. Vol. 134. Article 061801.

Ratnikov F., Hushchyn M., Ryzhikov A., Boldyrev A., Bocharnikov V.

The branching fraction ratios of ¯𝐵0→𝐷+⁢𝜏−⁢¯𝜈𝜏 and ¯𝐵0→𝐷*+⁢𝜏−⁢¯𝜈𝜏 decays are measured with respect to their muonic counterparts, using a data sample corresponding to an integrated luminosity of 2.0 fb−1 collected by the LHCb experiment in proton-proton collisions at √𝑠 =13 TeV. The reconstructed final states are formed by combining 𝐷+ mesons with 𝜏−→𝜇−⁢¯𝜈𝜇⁢𝜈𝜏 candidates, where the 𝐷+ is reconstructed via the 𝐷+ →𝐾−⁢𝜋+⁢𝜋+ decay. The results are 𝑅⁡(𝐷+)=0.249±0.043±0.047, 𝑅⁡(𝐷*+)=0.402±0.081±0.085, where the first uncertainties are statistical and the second systematic. The two measurements have a correlation coefficient of −0.39 and are compatible with the standard model.

Research target: Physics

Publication based on the results of:

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