新山　雅之
   所属   京都産業大学  理学部 物理科学科
   職種   教授
発行・発表の年月 2018/09
形態種別 その他
標題 Measurement of the CKM Matrix Element $|V_{cb}|$ from $B^{0} \to D^{*-} \ell^+ ν_\ell$ at Belle
執筆形態 その他
著者・共著者 E. Waheed,P. Urquijo,I. Adachi,K. Adamczyk,H. Aihara,S. Al Said,D. M. Asner,H. Atmacan,T. Aushev,R. Ayad,V. Babu,I. Badhrees,V. Bansal,P. Behera,C. Beleno,F. Bernlochner,B. Bhuyan,T. Bilka,J. Biswal,A. Bobrov,G. Bonvicini,A. Bozek,M. Bracko,T. E. Browder,M. Campajola,D. Cervenkov,P. Chang,V. Chekelian,A. Chen,B. G. Cheon,K. Chilikin,H. E. Cho,K. Cho,S. -K. Choi,Y. Choi,S. Choudhury,D. Cinabro,S. Cunliffe,S. Di Carlo,Z. Dolezal,T. V. Dong,D. Dossett,S. Eidelman,D. Epifanov,J. E. Fast,B. G. Fulsom
概要 We present a new measurement of the CKM matrix element $|V_{cb}|$ from $B^{0}
\to D^{*-} \ell^+ \nu_\ell$ decays, reconstructed with the full Belle data set
of $711 \, \rm fb^{-1}$ integrated luminosity. Two form factor
parameterizations, originally conceived by the Caprini-Lellouch-Neubert (CLN)
and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product
$\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|$ and the decay form factors, where
$\mathcal{F}(1)$ is the normalization factor and $\eta_{\rm EW}$ is a small
electroweak correction. In the CLN parameterization we find
$\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| = (35.06 \pm 0.15 \pm 0.56) \times
10^{-3}$, $\rho^{2}=1.106 \pm 0.031 \pm 0.007$, $R_{1}(1)=1.229 \pm 0.028 \pm
0.009$, $R_{2}(1)=0.852 \pm 0.021 \pm 0.006$. For the BGL parameterization we
obtain $\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|= (34.93 \pm 0.23 \pm 0.59)\times
10^{-3}$, which is consistent with the World Average when correcting for
$\mathcal{F}(1)\eta_{\rm EW}$. The branching fraction of $B^{0} \to D^{*-}
\ell^+ \nu_\ell$ is measured to be $\mathcal{B}(B^{0}\rightarrow
D^{*-}\ell^{+}\nu_{\ell}) = (4.90 \pm 0.02 \pm 0.16)\%$. We also present a new
test of lepton flavor universality violation in semileptonic $B$ decays,
$\frac{ { \cal B }(B^0 \to D^{*-} e^+ \nu)}{ { \cal B }(B^0 \to D^{*-} \mu^+ \nu)}
= 1.01 \pm 0.01 \pm 0.03~$. The errors correspond to the statistical and
systematic uncertainties respectively. This is the most precise measurement of
$\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|$ and form factors to date and the first
experimental study of the BGL form factor parameterization in an experimental
measurement.
DOI 10.1103/PhysRevD.100.052007
PermalinkURL http://arxiv.org/abs/1809.03290v3
researchmap用URL http://arxiv.org/pdf/1809.03290v3