Standard Model

We perform a combined study of the two hadronic decays D+ → K−π+π+ and D+s → K+K+π− using a detailed analysis of the semileptonic decays D+ → K−π+l+νl (l=e, μ) thanks to the high-statistics dataset provided by the BESIII Collaboration. We propose simple and suitable amplitude parametrizations of the studied reactions that shall be of interest to experimentalists for upcoming analyses. These new parametrizations are based on the naïve-factorization hypothesis and the description of the resulting matrix elements in terms of well-known hadronic form factors, with special emphasis on the Kπ scalar and vector cases. Such form factors account for two-body final-state interactions which fulfill analyticity, unitarity, and chiral symmetry constraints. As a result of our study, we find that the P-wave contribution fits nicely within the naïve-factorization approach, whereas the S-wave contribution requires complex Wilson coefficients that hint for possibly genuine three-body nonfactorizable effects. Our hypothesis is further supported by the examination of D+s → K+K+π− decays, where we achieve a description in overall good agreement with data.

We present the first data-driven result for aμwin,lqc, the isospin-limit light-quark connected component of the intermediate-window Hadronic-vacuum-polarization contribution to the muon anomalous magnetic moment. Our result, (198.8±1.1)×10-10, is in significant tension with eight recent mutually compatible high-precision lattice-QCD determinations, and provides enhanced evidence for a puzzling discrepancy between lattice and data-driven determinations of the intermediate-window quantity, one driven largely by a difference in the light-quark connected component.