arXiv subjects

R. A. Briere

Publications and source records attributed to R. A. Briere.

995 records · Page 56Linked to original sources

arXiv2002

Measurement of the lepton energy in the decay B-bar -> X l nu-bar and determination of the Heavy Quark Expansion Parameters

We measured two moments of the lepton momentum spectrum in B -> X l nu, where l= e or mu, for p_l > 1.5 GeV/c. From these we derive the Heavy Quark Expansion (HQE) parameters Lambda-bar(MS-bar) = 0.39 +- 0.03(stat) +- 0.06(sys) +- 0.12(th) GeV and lambda_1 = -0.25 +- 0.02(stat) +- 0.05(sys) +- 0.14(th) GeV^2, through order 1/M_B^3 in the non-perturbative expansion and beta_0 alpha_s^2 in the perturbative expansion. The theoretical expression needed to extract |V_cb| from the measured semileptonic width is evaluated using these HQE parameters. Combined with the world average of the semileptonic width, we find |V_cb|=(40.8 +- 0.5(Gamma_sl) +- 0.4(lambda_1,Lambda-bar) +- 0.9(th)) 10^{-3}. Finally, the short range b-quark mass m_b(1S) is evaluated and found to be 4.82 +- 0.07(exp) +- 0.11(th) GeV/c^2.

hep-ex↗

arXiv2002

Improved Measurement of |Vcb| using B --> D* l nu Decays

We determine the weak coupling |Vcb| between the b and c quarks using a sample of 3 million BB-bar events in the CLEO detector at the Cornell Electron Storage Ring. We determine the yield of reconstructed B --> D* l nu decays as a function of w, the boost of the D* in the B rest frame, and from this we obtain the differential decay rate dGamma/dw. By extrapolating dGamma/dw to w=1, the kinematic end-point at which the D* is at rest relative to the B, we extract the product |Vcb|F(1), where F(1) is the form factor at w=1. We find |Vcb|F(1) = 0.0431 +- 0.0013 (stat.) +- 0.0018 (syst.).

hep-ex↗

arXiv2001

Observation of $B\to ϕK$ and $B\to ϕK^{*}$

We have studied two-body charmless hadronic decays of $B$ mesons into the final states phi K and phi K^*. Using 9.7 million $B\bar{B}$ pairs collected with the CLEO II detector, we observe the decays B- -> phi K- and B0 -> phi K*0 with the following branching fractions: BR(B- -> phi K-)=(5.5 +2.1-1.8 +- 0.6) x 10^{-6} and BR(B0 -> phi K*0)=(11.5 +4.5-3.7 +1.8-1.7) x 10^{-6}. We also see evidence for the decays B0 -> phi K0 and B- -> phi K*-. However, since the statistical significance is not overwhelming for these modes we determine upper limits of <12.3 x 10^{-6} and <22.5 x 10^{-6} (90% C.L.) respectively.

hep-ex↗

arXiv2000

Measurements of Charm Fragmentation into $D_s^{*+}$ and $D_s^+$ in $e^+e^-$ Annihilations at $\sqrt{s}$=10.5 GeV

A study of charm fragmentation into $D_s^{*+}$ and $D_s^+$ in $e^+e^-$ annihilations at $\sqrt{s}$=10.5 GeV is presented. This study using $4.72 \pm 0.05$ fb$^{-1}$ of CLEO II data reports measurements of the cross-sections $σ(D_s^{*+})$ and $σ(D_s^+)$ in momentum regions above $x=0.44$, where $x$ is the $D_s$ momentum divided by the maximum kinematically allowed $D_s$ momentum. The $D_s$ vector to vector plus pseudoscalar production ratio is measured to be $P_V(x(D_s^+)>0.44)=0.44\pm0.04$

hep-ex↗

arXiv1999

Rare Decays of the $η^{'}$

We have searched for the rare decays of the eta prime meson to e+ e- eta, e+ e- pizero, e+ e- gamma, and e mu in hadronic events at the CLEO II detector. The search is conducted on 4.80 fb^-1 of e+ e- collisions at the Cornell Electron Storage Ring. We find no signal in any of these modes, and set 90% confidence level upper limits on their branching fractions of 2.4 X 10^-3, 1.4 X 10^-3, 0.9 X 10^-3, and 4.7 X 10^-4, respectively. We also investigate the Dalitz plot of the common decay of the eta prime to pi+ pi- eta. We fit the matrix element with the Particle Data Group parameterization and find Re(alpha) = -0.021 +- 0.025, where alpha is a linear function of the kinetic energy of the eta.

hep-ex↗