Search results for " Anni"
showing 10 items of 847 documents
Search for the decayB+→Ks0Ks0π+
2009
We search for charmless decays of charged B mesons to the three-body final state (KSKS0)-K-0 pi(+). Using a data sample of 423.7 fb(-1) collected at the Gamma(4S) resonance with the BABAR detector, corresponding to (465.1 +/- 5.1) x 10(6) (B) over bar B pairs, we find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10(-7).
Evidence ofB+→τ+νdecays with hadronicBtags
2013
We present a search for the decay B+→τ+ν using 467.8×10^6 BB pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the hadronic decay mode (B-→D(*)0X- and B-→J/ψX-). We examine the rest of the event to search for a B+→τ+ν decay. We identify the τ+ lepton in the following modes: τ+→e+νν , τ+→μ+νν , τ+→π+ν and τ+→ρ+ν . We find an excess of events with respect to the expected background, which excludes the null signal hypothesis at the level of 3.8σ (including systematic uncertainties) and corresponds to a branching fraction value of B(B+→τ+ν)=(1.83_(-0.49)^(+0.53)(stat)±0.24(syst))×10^(…
Measurement of the form factors in the decayD+→ωe+νeand search for the decayD+→ϕe+νe
2015
Using 2.92 fb(-1) of electron-positron annihilation data collected at a center-of-mass energy of root s = 3.773 GeV with the BESIII detector, we present an improved measurement of the branching fra ...
B-physics results from LEP
1996
Abstract The LEP collider continues to improve our knowledge and understanding of B-physics. Recent results are presented in the areas of B-hadron lifetimes, BB oscillations, B-spectroscopy and rare B-decays.
QED box amplitude in heavy fermion production
2002
We evaluate the two-photon box contribution to heavy fermion production in electron positron annihilation, that provides O(alpha^2) electromagnetic corrections to the Born cross section. The study of its non-relativistic expansion, relevant at energies close to the threshold of production, is also performed. We also verify that the threshold expansion of the one-loop integrals correctly reproduces our results, thus extending the applicability of this technique to heavy fermion production diagrams.
Measurement of the Inclusive Charmless Semileptonic Branching Ratio ofBMesons and Determination of|Vub|
2004
We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)…
Observation of a Charged Charmoniumlike Structure ine+e−→(D*D¯*)±π∓ats=4.26 GeV
2014
We study the process e(+)e(-) -> (D* (D) over bar*)(+/-)pi(-/+) at a center-of-mass energy of 4.26 GeV using a 827 pb(-1) data sample obtained with the BESIII detector at the Beijing Electron Positron Collider. Based on a partial reconstruction technique, the Born cross section is measured to be (137 +/- 9 +/- 15) pb. We observe a structure near the (D* (D) over bar*)(+/-) threshold in the pi(-/+) recoil mass spectrum, which we denote as the Z(c)(+/-) (4025). The measured mass and width of the structure are (4026.3 +/- 2.6 +/- 3.7) MeV/c(2) and (24.8 +/- 5.6 +/- 7.7) MeV, respectively. Its production ratio sigma(e(+)e(-) -> Z(c)(+/-)(4025)pi(-/+)-> (D* (D) over bar*)(+/-)pi(-/+)/sigma(e(+)e…
Right-handed neutrino magnetic moments
2009
PACS numbers: 14.60.St, 13.15.+g, 13.35.Hb, 13.66.Hk
The topology dependence of charged particle multiplicities in three-jet events
1997
A study of individual jet and whole-event charged particle multiplicities in three-jet events measured in e(+)e(-) annihilation at the Z reveals a significant topology dependence. Mean jet multiplicities are inadequately described by jet energies; interjet angles must also be specified. Quantitative tests suggest that it is necessary to use transverse-momentum-like scales to describe the data. RI ANTONELLI, ANTONELLA/C-6238-2011; Passalacqua, Luca/F-5127-2011; Murtas, Fabrizio/B-5729-2012; St.Denis, Richard/C-8997-2012; Sanchez, Federico/F-5809-2012; Forti, Francesco/H-3035-2011; Ferrante, Isidoro/F-1017-2012
Decoupling or nondecoupling: Is that theRbquestion?
1996
The top quark is well known for the nondecoupling effects it implies in ρ and Rb. The recent experimental Rb data exhibits a disagreement with the SM prediction at more than the 3σ level. It is tempting to explore whether this might be due to nondecoupling New Physics effects, opposite to those of the top. We investigate this issue in the context of models with an extra family of right or left handed, singlet or doublet quarks. It is shown that, contrary to what