Journal article
Evidence for B -→Ds K -ℓ -ν ̄ℓ and search for B -→Ds* K -ℓ -ν ̄ℓ
J Stypula, M Rozanska, I Adachi, K Adamczyk, H Aihara, DM Asner, T Aushev, AM Bakich, V Bhardwaj, B Bhuyan, M Bischofberger, A Bondar, G Bonvicini, A Bozek, M Bračko, TE Browder, MC Chang, P Chang, V Chekelian, A Chen Show all
Physical Review D Particles Fields Gravitation and Cosmology | Published : 2012
Abstract
We report measurements of the decays B -→Ds(*)+K -ℓ -ν ̄ℓ in a data sample containing 657×106BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e +e - collider. We observe a signal with a significance of 6σ for the combined D s and Ds* modes and find the first evidence of the B -→Ds+K -ℓ -ν ̄ℓ decay with a significance of 3.4σ. We measure the following branching fractions: B(B -→Ds+K -ℓ -ν ̄ℓ)=(0.30±0.09(stat)-0.08+0.11(syst)) ×10 -3 and B(B -→Ds(*)+K -ℓ -ν ̄ℓ)=(0.59±0.12(stat) ±0.15(syst))×10 -3 and set an upper limit B(B -→Ds*+K -ℓ -ν ̄ℓ)<0.56×10 -3 at the 90% confidence level. We also present the first measurement of the Ds+K - invariant mass distribution in these d..
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Funding Acknowledgements
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 SINET4 network support. We acknowledge support from MEXT, JSPS and Nagoya's TLPRC (Japan); ARC and DIISR (Australia); NSFC (China); MSMT (Czechia); DST (India); INFN (Italy); MEST, NRF, GSDC of KISTI, and WCU (Korea); MNiSW and NCN (Poland); MES and RFAAE (Russia); ARRS (Slovenia); SNSF (Switzerland); NSC and MOE (Taiwan); and DOE and NSF (U.S.A.).