Journal article
Measurement of the tau Lepton Polarization and R(D*) in the Decay (B)over-bar -> D* tau(-) (v)over-bar(tau)
S Hirose, T Iijima, I Adachi, K Adamczyk, H Aihara, S Al Said, DM Asner, H Atmacan, V Aulchenko, T Aushev, R Ayad, V Babu, I Badhrees, AM Bakich, V Bansal, E Barberio, P Behera, M Berger, B Bhuyan, J Biswal Show all
PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2017
Abstract
We report the first measurement of the τ lepton polarization Pτ(D∗) in the decay B→D∗τ-ντ as well as a new measurement of the ratio of the branching fractions R(D∗)=B(B→D∗τ-ντ)/B(B→D∗-ν), where - denotes an electron or a muon, and the τ is reconstructed in the modes τ-→π-ντ and τ-→ρ-ντ. We use the full data sample of 772×106 BB pairs recorded with the Belle detector at the KEKB electron-positron collider. Our results, Pτ(D∗)=-0.38±0.51(stat)-0.16+0.21(syst) and R(D∗)=0.270±0.035(stat)-0.025+0.028(syst), are consistent with the theoretical predictions of the standard model.
Grants
Awarded by Grants-in-Aid for Scientific Research
Funding Acknowledgements
We acknowledge Y. Sakaki, M. Tanaka, and R. Watanabe for their invaluable suggestions and help. We thank the KEKB group for excellent operation of the accelerator; the KEK cryogenics group for efficient solenoid operations; and the KEK computer group, the NII, and PNNL/EMSL for valuable computing and SINET5 network support. We acknowledge support from MEXT, JSPS and Nagoya's TLPRC (Japan); ARC (Australia); FWF (Austria); NSFC and CCEPP (China); MSMT (Czechia); CZF, DFG, EXC153, and VS (Germany); DST (India); INFN (Italy); MOE, MSIP, NRF, BK21Plus, WCU, RSRI, FLRFAS project and GSDC of KISTI (Korea); MNiSW and NCN (Poland); MES and RFAAE (Russia); ARRS (Slovenia); IKERBASQUE and UPV/EHU (Spain); SNSF (Switzerland); MOE and MOST (Taiwan); and DOE and NSF (USA). This work is supported by a Grant-in-Aid for Scientific Research (S) "Probing New Physics with TauLepton" (No. 26220706) and was partly supported by a Grant-in-Aid for JSPS Fellows (No. 25.3096).