@article{7010e819bff24e9c92d1e6b5cd9f80e0,
title = "Measurement of the τ Michel parameters η and ξκ in the radiative leptonic decay τ - → l - ν τ ν l γ",
abstract = " We present a measurement of the Michel parameters of the τ lepton, η and ξκ, in the radiative leptonic decay τ - → l - ν τ ν l γ using 711 fb -1 of collision data collected with the Belle detector at the KEKB e + e - collider. The Michel parameters are measured in an unbinned maximum likelihood fit to the kinematic distribution of e + e - → τ + τ - → (π + π 0 ν τ )(l - ν τ ν l γ)(l = e or μ The measured values of the Michel parameters are η = -1.3 ± 1.5 ± 0.8 and ξκ = 0.5 ± 0.4 ± 0.2, where the first error is statistical and the second is systematic. This is the first measurement of these parameters. These results are consistent with the Standard Model predictions within their uncertainties, and constrain the coupling constants of the generalized weak interaction. ",
keywords = "MU-MESON DECAY, IDENTIFICATION, ANNIHILATION, LIBRARY, TRIGGER",
author = "{The BELLE collaboration} and N. Shimizu and H. Aihara and D. Epifanov and I. Adachi and Said, {S. Al} and Asner, {D. M.} and V. Aulchenko and T. Aushev and R. Ayad and V. Babu and I. Badhrees and Bakich, {A. M.} and V. Bansa and E. Barberio and V. Bhardwaj and B. Bhuyan and J. Biswal and A. Bobrov and A. Bozek and M. Bra{\v c}ko and Browder, {T. E.} and D. {\v C}ervenkov and Chang, {M. C.} and P. Chang and V. Chekelian and A. Chen and Cheon, {B. G.} and K. Chilikin and K. Cho and Choi, {S. K.} and Y. Choi and D. Cinabro and T. Czank and N. Dash and {Di Carlo}, S. and Z. Dole{\v z}al and D. Dutta and S. Eidelman and Fast, {J. E.} and T. Ferber and N. Gabyshev and A. Garmash and P. Krokovny and A. Kuzmin and V. Shebalin and B. Shwartz and Y. Usov and V. Vorobyev and V. Zhilich and V. Zhulanov",
year = "2018",
month = feb,
day = "1",
doi = "10.1093/ptep/pty003",
language = "English",
volume = "2018",
journal = "Progress of Theoretical and Experimental Physics",
issn = "2050-3911",
publisher = "Oxford University Press",
number = "2",
}