Regular Article – Theoretical Physics
A puzzle in decays and extraction of the fragmentation fraction
Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Straße 3, 57068, Siegen, Germany
2 Technische Universität München, James-Franck-Straße 1, 85748, Garching, Germany
3 Dipartimento di Fisica, Università di Torino and INFN, Sezione di Torino, 10125, Turin, Italy
Accepted: 2 October 2020
Published online: 15 October 2020
We provide updated predictions for the hadronic decays and . They are based on results for the QCD factorization amplitudes at leading power and on recent results for the form factors up to order in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.
© The Author(s) 2020
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