Kavli Affiliate: Hsiao-Mei (Sherry) Cho
| First 5 Authors: [#item_custom_name[1, [#item_custom_name[2, [#item_custom_name[3, [#item_custom_name[4, [#item_custom_name[5| Summary:We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_cb|$ from the decay $Bto Dellν_ell$ using a $365~mathrmfb^-1$ $e^+e^-toΥ(4S)to Bbar B$ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one $B$ meson is reconstructed in the modes $B^0to D^-(to K^+π^-π^-)ell^+ν_ell$ and $B^+to bar D^0(to K^+π^-)ell^+ν_ell$, where $ell$ denotes either an electron or a muon. Charge conjugation is implied. The second $B$ meson in the $Υ(4S)$ event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable $w=v_Bcdot v_D$, where $v_B$ and $v_D$ are the 4-velocities of the $B$ and $D$ mesons. We measure the total decay branching fractions to be $mathcalB(B^0to D^-ell^+ν_ell)=(2.06 pm 0.05,(mathrmstat.) pm 0.10,(mathrmsys.))%$ and $mathcalB(B^+tobar D^0ell^+ν_ell)=(2.31 pm 0.04,(mathrmstat.) pm 0.09,(mathrmsys.))%$. We probe lepton flavor universality by measuring $mathcalB(Bto Deν_e)/mathcalB(Bto Dμν_μ)=1.020 pm 0.020,(mathrmstat.)pm 0.022,(mathrmsys.)$. Fitting the partial decay branching fraction as a function of $w$ and using the average of lattice QCD calculations of the $Bto D$ form factor, we obtain $ |V_cb|=(39.2pm 0.4,(mathrmstat.) pm 0.6,(mathrmsys.) pm 0.5,(mathrmth.)) times 10^-3$.| Search Query: arXiv Query: search_query=au:Cho OR all:Hsiao-Mei&id_list=&start=0&max_results=3Read More