The ratio of branching fractions , where is an electron or muon, is measured using a Belle II data sample with an integrated luminosity of at the SuperKEKB asymmetric-energy collider. Data is collected at the resonance, and one meson in the decay is fully reconstructed in hadronic decay modes. The accompanying signal meson is reconstructed as using leptonic decays. The normalization decay, , produces the same observable final-state particles. The ratio of branching fractions is extracted in a simultaneous fit to two signal-discriminating variables in both channels and yields . This result is consistent with the current world average and with Standard Model predictions.
Adachi, I., et al. "Test of lepton flavor universality with a measurement of <math display='inline'> <mi>R</mi> <mo stretchy='false'>(</mo> <msup> <mi>D</mi> <mo>*</mo> </msup> <mo stretchy='false'>)</mo> </math> using hadronic <math display='inline'> <mi>B</mi> </math> tagging at the Belle II experiment." Physical Review. D., vol. 110, no. 7, Oct. 2024. https://doi.org/10.1103/PhysRevD.110.072020
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Anh Ky, N., Asner, D. M., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Ayad, R., Babu, V., Bae, H., Bahinipati, S., Bambade, P., ... Žlebčík, R. (2024). Test of lepton flavor universality with a measurement of <math display='inline'> <mi>R</mi> <mo stretchy='false'>(</mo> <msup> <mi>D</mi> <mo>*</mo> </msup> <mo stretchy='false'>)</mo> </math> using hadronic <math display='inline'> <mi>B</mi> </math> tagging at the Belle II experiment. Physical Review. D., 110(7). https://doi.org/10.1103/PhysRevD.110.072020
Adachi, I., Adamczyk, K., Aggarwal, L., et al., "Test of lepton flavor universality with a measurement of <math display='inline'> <mi>R</mi> <mo stretchy='false'>(</mo> <msup> <mi>D</mi> <mo>*</mo> </msup> <mo stretchy='false'>)</mo> </math> using hadronic <math display='inline'> <mi>B</mi> </math> tagging at the Belle II experiment," Physical Review. D. 110, no. 7 (2024), https://doi.org/10.1103/PhysRevD.110.072020
@article{osti_2475426,
author = {Adachi, I. and Adamczyk, K. and Aggarwal, L. and Ahmed, H. and Aihara, H. and Akopov, N. and Aloisio, A. and Anh Ky, N. and Asner, D. M. and Atmacan, H. and others},
title = {Test of lepton flavor universality with a measurement of <math display='inline'> <mi>R</mi> <mo stretchy='false'>(</mo> <msup> <mi>D</mi> <mo>*</mo> </msup> <mo stretchy='false'>)</mo> </math> using hadronic <math display='inline'> <mi>B</mi> </math> tagging at the Belle II experiment},
annote = { The ratio of branching fractions R ( D * ) = B ( B ¯ → D * τ − ν ¯ τ ) / B ( B ¯ → D * ℓ − ν ¯ ℓ ) , where ℓ is an electron or muon, is measured using a Belle II data sample with an integrated luminosity of 189 fb − 1 at the SuperKEKB asymmetric-energy e + e − collider. Data is collected at the ϒ ( 4 S ) resonance, and one B meson in the ϒ ( 4 S ) → B B ¯ decay is fully reconstructed in hadronic decay modes. The accompanying signal B meson is reconstructed as B ¯ → D * τ − ν ¯ τ using leptonic τ decays. The normalization decay, B ¯ → D * ℓ − ν ¯ ℓ , produces the same observable final-state particles. The ratio of branching fractions is extracted in a simultaneous fit to two signal-discriminating variables in both channels and yields R ( D * ) = 0.262 − 0.039 + 0.041 ( stat ) − 0.032 + 0.035 ( syst ) . This result is consistent with the current world average and with Standard Model predictions. Published by the American Physical Society 2024 },
doi = {10.1103/PhysRevD.110.072020},
url = {https://www.osti.gov/biblio/2475426},
journal = {Physical Review. D.},
issn = {ISSN 2470-0010},
number = {7},
volume = {110},
place = {United States},
publisher = {American Physical Society},
year = {2024},
month = {10}}
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