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Register a new userMeasurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States
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Using the data accumulated in 2002-2004 with the DO detector in proton-antiproton collisions at the Fermilab Tevatron collider with centre-of-mass energy 1.96 TeV, the branching fractions of the decays B -> bar{D}_1^0(2420) mu^+ u_mu X and B -> bar{D}_2^{*0}(2460) mu^+ u_mu X and their ratio have been measured: BR(bar{b}->B) cdot BR(B-> bar{D}_1^0 mu^+ u_mu X) cdot BR(bar{D}_1^0 -> D*- pi+) = (0.087+-0.007(stat)+-0.014(syst))%; BR(bar{b}->B)cdot BR(B->D_2^{*0} mu^+ u_mu X) cdot BR(bar{D}_2^{*0} -> D*- pi^+) = (0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> bar{D}_2^{*0} mu^+ u_mu X)BR(D2*0->D*- pi+)) / (BR(B -> bar{D}_1^{0} mu^+ u_mu X)cdot BR(bar{D}_1^{0}->D*- pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge conjugated states are always implied.
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The ratio of charged and neutral B meson production at the Upsilon(4S), f_{+-}/f_{00}, is measured through the decays B bar -> D* l- nu_l bar, reconstructed using a partial reconstruction method where the D* is detected only through a pion daughter from the decay D* -> D pi. Using data collected by the CLEO II detector, the charged and neutral B decays are measured in such a way that their ratio is independent of decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This measurement yields the ratio of production fractions times the ratio of semileptonic branching fractions, f_{+-}b_{+}/f_{00}b_0. Assuming that b_+/b_0 is equal to the lifetime ratio tau_+/tau_0 and using the world average value of tau_+/tau_0 as input, we obtain f_{+-}/f_{00}=1.058+- 0.084+- 0.136.
The decay of the narrow resonance $overline{B}{}_{s2}^{*0}!rightarrow B^- K^+$ can be used to determine the $B^-$ momentum in partially reconstructed decays without any assumptions on the decay products of the $B^-$ meson. This technique is employed for the first time to distinguish contributions from $D^0$, $D^{*0}$, and higher-mass charmed states ($D^{**0}$) in semileptonic $B^-$ decays by using the missing-mass distribution. The measurement is performed using a data sample corresponding to an integrated luminosity of 3.0 fb${}^{-1}$ collected with the LHCb detector in $pp$ collisions at center-of-mass energies of 7 and 8 TeV. The resulting branching fractions relative to the inclusive $B^- !rightarrow D^0 X mu^- overline{ u}_mu$ are $f_{D^0} = mathcal{B}( B^- rightarrow D^0mu^-overline{ u}_mu )/mathcal{B}( B^- rightarrow D^0 X mu^- overline{ u}_mu ) = 0.25 pm 0.06$, $f_{D^{**0}} = mathcal{B}( B^- rightarrow ( D^{**0} rightarrow D^0 X)mu^-overline{ u}_mu )/mathcal{B}( B^- rightarrow D^0 X mu^- overline{ u}_mu ) = 0.21 pm 0.07$, with $f_{D^{*0}} = 1 - f_{D^0} - f_{D^{**0}}$ making up the remainder.
Using a data sample of $e^+e^-$ collision data with an integrated luminosity of 2.93 fb$^{-1}$ taken at the center-of-mass energy $sqrt s= 3.773$~GeV with the BESIII detector operating at the BEPCII storage rings, we measure the absolute branching fractions of the two-body hadronic decays $D^+to pi^+pi^0$, $K^+ pi^0$, $pi^+ eta$, $K^+eta$, $pi^+eta^prime$, $K^+eta^prime$, $K_S^0 pi^+$, $K_S^0 K^+$, and $D^0to pi^+ pi^-$, $K^+ K^-$, $K^mp pi^pm$, $K_S^0 pi^0$, $K_S^0 eta$, $K_S^0 eta^prime$. Our results are consistent with previous measurements within uncertainties. Among them, the branching fractions for $D^+topi^+pi^0$, $K^+pi^0$, $pi^+eta$, $pi^+eta^prime$, $K_S^0 pi^+$, $K_S^0 K^+$ and $D^0 to K_S^0 pi^0$, $K_S^0 eta$, $K_S^0 eta^prime$ are determined with improved precision compared to the world average values.
Using 482 pb$^{-1}$ of data taken at $sqrt{s}=4.009$ GeV, we measure the branching fractions of the decays of $D^{*0}$ into $D^0pi^0$ and $D^0gamma$ to be $BR(D^{*0} to D^0pi^0)=(65.5pm 0.8pm 0.5)%$ and $BR(D^{*0} to D^0gamma)=(34.5pm 0.8pm 0.5)%$ respectively, by assuming that the $D^{*0}$ decays only into these two modes. The ratio of the two branching fractions is $BR(D^{*0} to D^0pi^0)/BR(D^{*0} to D^0gamma) =1.90pm 0.07pm 0.05$, which is independent of the assumption made above. The first uncertainties are statistical and the second ones systematic. The precision is improved by a factor of three compared to the present world average values.
The decays Upsilon(4S) -> BB, followed by B -> D* pi and D* -> D pi, permit reconstruction of all kinematic quantities that describe the sequence without reconstruction of the D, with reasonably low backgrounds. Using an integrated e+e- luminosity of 3.1 fb^{-1} accumulated at the Upsilon(4S) by the CLEO-II detector, we report measurements of BR(B0 -> D*+ pi-) = (2.81 +/- 0.11 +/- 0.21 +/- 0.05) x 10^{-3} and BR(B- -> D*0 pi-) = (4.34 +/- 0.33 +/- 0.34 +/- 0.18) x 10^{-3}.
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