Search for the Radiative Leptonic Decay B^{+} to Gamma \ell^{+}\nu_{\ell}
Author :
Publisher :
Page : 7 pages
File Size : 20,81 MB
Release : 2007
Category :
ISBN :
Measurement of the D_s Leptonic Decay Constant F_{D_s} and Observation of New Resonances Decaying to D^(*)pi
Author : Jose Feliciano Benitez
Publisher : Stanford University
Page : 320 pages
File Size : 38,63 MB
Release : 2011
Category :
ISBN :
Book Description
The absolute branching fractions for the decays $D^-_s\rightarrow\ell^-\bar{\nu}_{\ell}$ ($\ell=e$, $\mu$, or $\tau$) are measured using a data sample corresponding to an integrated luminosity of 521 fb$^{-1}$ collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II $e^+e^-$ collider at SLAC. The number of $D_s^-$ mesons is determined by reconstructing the recoiling system $DKX\gamma$ in events of the type $e^+e^-{\rightarrow}DKXD^{*-}_s$, where $D^{*-}_s\rightarrow D^-_s\gamma$ and $X$ represents additional pions from fragmentation. The $D^-_s\rightarrow\ell^-\nu_{\ell}$ events are detected by full or partial reconstruction of the recoiling system $DKX\gamma\ell$. The following results are obtained: $B(D^-_s \to \mu^- \nu) = (6.02 \pm 0.38 \pm 0.34) \times 10^{-3}$, $B(D^-_s \to \tau^- \nu) = (5.00 \pm 0.35 \pm 0.49) \times 10^{-2}$, and $B(D^-_s \to e^- \nu)
Radiative and Leptonic B-meson Decays from the B-factories
Author :
Publisher :
Page : 7 pages
File Size : 28,59 MB
Release : 2011
Category :
ISBN :
Book Description
Radiative and leptonic decays of B-mesons represent an excellent laboratory for the search for New Physics. I present here recent results on radiative and leptonic decays from the Belle and BABAR collaborations. Radiative penguin and leptonic B-meson decays are excellent probes for investigating the effects of New Physics. Although current measurements are in agreement with the Standard Model expectations, they are still quite useful for setting bounds on possible NP models. The B → X{sub s}[gamma] and B → [tau][nu] measurements, for example, put strong constraints on the mass of charged Higgs bosons in Type II two-Higgs double models. The B → X{sub s}[gamma] branching fraction measurements also constrain models with universal extra dimensions.
Radiative Leptonic B Decays
Author :
Publisher :
Page : 312 pages
File Size : 35,93 MB
Release : 2007
Category :
ISBN :
Book Description
We present the results of a search for B+ meson decays into [gamma]l+vl, where l = e, [mu]. We use a sample of 232 million B$\bar{B}$ meson pairs recorded at the [Upsilon](4S) resonance with the BABAR detector at the PEP-II B factory. We measure a partial branching fraction [Delta][beta] in a restricted region of phase space that reduces the effect of theoretical uncertainties, requiring the lepton energy to be in the range 1.875 and 2.850 GeV, the photon energy to be in the range 0.45 and 2.35 GeV, and the cosine of the angle between the lepton and photon momenta to be less than -0.36, with all quantities computed in the [Upsilon](4S) center-of-mass frame. We find [Delta][beta](B+ 2![gamma]l+vl) = ( -0.31.5+1.3(statistical) -0.6+0.6(systematic) ± 0.1(theoretical)) x 10-6, under the assumption of lepton universality. Interpreted as a 90% confidence-level Bayesian upper limit, the result corresponds to 1.7 x 10-6 for a prior at in amplitude, and 2.3 x 10-6 for a prior at in branching fraction.
Model-Independent Results for the Decay B \to L Nu(L) Gamma at BaBar
Author :
Publisher :
Page : 6 pages
File Size : 37,50 MB
Release : 2012
Category :
ISBN :
Book Description
We present a search for the radiative leptonic decays B+ → e?{sub e}? and B+ →?+?{sub?}? using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in?(4S) → B+B− and then search for evidence of the signal decay within the rest of the event. This method provides clean kinematic information on the signal's missing energy and high momentum photon and lepton, and allows for a model-independent analysis of this decay. Using a data sample of 465 million B-meson pairs, we obtain sensitivity to branching fractions of the same order as predicted by the Standard Model. We report a model-independent branching fraction upper limit of?(B+ → l+?{sub l}?)
Measurement of the D_s Leptonic Decay Constant F_{D_s} and Observation of New Resonances Decaying to D^(*)pi
Author : Jose Feliciano Benitez
Publisher :
Page : pages
File Size : 11,21 MB
Release : 2011
Category :
ISBN :
Book Description
The absolute branching fractions for the decays $D^-_s\rightarrow\ell^-\bar{\nu}_{\ell}$ ($\ell=e$, $\mu$, or $\tau$) are measured using a data sample corresponding to an integrated luminosity of 521 fb$^{-1}$ collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II $e^+e^-$ collider at SLAC. The number of $D_s^-$ mesons is determined by reconstructing the recoiling system $DKX\gamma$ in events of the type $e^+e^-{\rightarrow}DKXD^{*-}_s$, where $D^{*-}_s\rightarrow D^-_s\gamma$ and $X$ represents additional pions from fragmentation. The $D^-_s\rightarrow\ell^-\nu_{\ell}$ events are detected by full or partial reconstruction of the recoiling system $DKX\gamma\ell$. The following results are obtained: $B(D^-_s \to \mu^- \nu) = (6.02 \pm 0.38 \pm 0.34) \times 10^{-3}$, $B(D^-_s \to \tau^- \nu) = (5.00 \pm 0.35 \pm 0.49) \times 10^{-2}$, and $B(D^-_s \to e^- \nu)
Search for the Rare Leptonic Decays B+̂ \to L+̂ \nu_l (l
Author :
Publisher :
Page : 8 pages
File Size : 47,25 MB
Release : 2009
Category :
ISBN :
Book Description
We have performed a search for the rare leptonic decays B → l+?{sub l}({ell} = e,?), using data collected at the?(4S) resonance by the BABAR detector at the PEP-II storage ring. In a sample of 468 x 106 B{bar B} pairs we find no evidence for a signal and set an upper limit on the branching fractions B(B+ → e+?{sub e})
Radiative Corrections to the Decays K[sub L][sup 0][r-arrow] E[sup+]e[sup[minus] and K[sub L][sup 0][r-arrow][mu][sup+][mu][sup[minus].
Author :
Publisher :
Page : pages
File Size : 38,85 MB
Release : 2001
Category :
ISBN :
Book Description
The authors calculate the rates and lepton ([ell]) invariant mass distributions for decays of the form 0[sup[minus]+][r-arrow][ell][sup+][ell][sup[minus]][gamma], which are important radiative corrections to the purely leptonic decays 0[sup[minus]+][r-arrow][ell][sup+][ell][sup[minus]]. The approach uses the loop diagrams which arise by including the two photon intermediate state and they retain the imaginary parts of the loops--a radiative extension of the unitarity bound for the process. These results are compared with those obtained using a model in which the meson couples directly to the leptons.
Radiative Leptonic B Decays
Author : Edward Tann Chen
Publisher :
Page : 562 pages
File Size : 35,38 MB
Release : 2007
Category : Electronic dissertations
ISBN :
Book Description
Measurement of Inclusive Radiative B -Meson Decay B -] X_s Gamma
Author :
Publisher :
Page : 206 pages
File Size : 20,86 MB
Release : 2006
Category :
ISBN :
Book Description
Radiative decays of the B meson, B 2!X{sub s}[gamma], proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B 2!X{sub s}[gamma] decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as ee− annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 ± 0.16) GeV/c2; [mu]{sub {pi}}2 = (0.65 ± 0.29) GeV2. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter.
