Search results for "Branch"
showing 10 items of 1278 documents
Study ofCPviolation in Dalitz-plot analyses ofB0→K+K−KS0,B+→K+K−K+, andB+→KS0KS0K+
2012
We perform amplitude analyses of the decays B0→K +K -KS0, B +→K +K -K +, and B +→KS0KS0K +, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106 BB decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B +→K +K -K +, we find a direct CP asymmetry in B +→(1020)K + of A CP=(12.8±4.4±1.3)%, which differs from zero by 2.8σ. For B0→K +K -KS0, we measure the CP-violating phase β eff((1020)KS0)=(21±6±2)°. For B +→KS0KS0K +, we measure an overall direct CP asymmetry of A CP=(4-5+4±2)%. We also perform an angular-moment analysis of the three c…
Observation ofB+→ρ+K0and measurement of its branching fraction and charge asymmetry
2007
We present the first observation of the decay B+→ρ+K0, using a data sample of 348fb-1 collected at the Υ(4S) resonance with the BABAR detector. The branching fraction and charge asymmetry are measured to be (8.0-1.3+1.4±0.6)×10-6 and (-12.2±16.6±2.0)%, respectively, where the first uncertainty is statistical and the second is systematic. The charge asymmetry is defined by Ach=(ΓB - ΓB+)/(ΓB-+ΓB+) with ΓB± the B± decay rate. The significance of the observed branching fraction, including systematic uncertainties, is 7.9 standard deviations. © 2007 The American Physical Society.
Measurements of neutralBdecay branching fractions toKS0π+π−final states and the charge asymmetry ofB0→K*+π−
2006
Branching fraction measurements using B-meson decays to Kspi+pi- are presented. These measurements were obtained by analyzing a data sample of 88.9 million Y(4S) --> BB decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. Using a maximum likelihood fit, the following branching fraction results were obtained: Br(B0 -> K0pi+pi- = (43.7 +/- 3.8 +/- 3.4) * 10^-6, Br(B0 --> K{*+}pi-) = (12.9 +/- 2.4 +/- 1.4) * 10$^-6} and Br(B0 --> D-(--> Kspi-)pi+ = (42.7 +/- 2.1 +/- 2.2) * 10^{-6}. The CP violating char ge asymmetry A(K*pi} for the decay B0 --> $K{*+}pi-$ was measured to be A(K*pi} = 0.23 +/- $0.18^{+0.09}_{-0.06}$. For all these measurements the first error…
Measurements of absolute branching fractions forΛc+→Ξ0K+and Ξ(1530)0K+
2018
Abstract We report the first measurements of absolute branching fractions for the W -exchange-only processes Λ c + → Ξ 0 K + and Λ c + → Ξ ( 1530 ) 0 K + with the double-tag technique, by analyzing an e + e − collision data sample, that corresponds to an integrated luminosity of 567 pb −1 collected at a center-of-mass energy of 4.6 GeV by the BESIII detector. The branching fractions are measured to be B ( Λ c + → Ξ 0 K + ) = ( 5.90 ± 0.86 ± 0.39 ) × 10 − 3 and B ( Λ c + → Ξ ( 1530 ) 0 K + ) = ( 5.02 ± 0.99 ± 0.31 ) × 10 − 3 , where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.
A Novel Method for the Measurement of Half-Lives and Decay Branching Ratios of Exotic Nuclei
2019
A novel method for simultaneous measurement of masses, Q-values, isomer excitation energies, half-lives and decay branching ratios of exotic nuclei has been demonstrated. The method includes first use of a stopping cell as an ion trap, combining containment of precursors and decay-recoils for variable durations in a cryogenic stopping cell (CSC), and afterwards the identification and counting of them by a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). Feasibility has been established by recording the decay and growth of $^{216}$Po and $^{212}$Pb (alpha decay) and of $^{119m2}$Sb (t$_{1/2}$ = 850$\pm$90 ms) and $^{119g}$Sb (isomer transition), obtaining half-lives and bran…
Half-life, branching-ratio, andQ-value measurement for the superallowed0+→0+β+emitterTi42
2009
The half-life, the branching ratio, and the decay $Q$ value of the superallowed $\ensuremath{\beta}$ emitter $^{42}\mathrm{Ti}$ were measured in an experiment performed at the JYFLTRAP facility of the Accelerator Laboratory of the University of Jyv\"askyl\"a. $^{42}\mathrm{Ti}$ is the heaviest ${T}_{z}=\ensuremath{-}1$ nucleus for which high-precision measurements of these quantities have been tried. The half-life (${T}_{1/2}=208.14\ifmmode\pm\else\textpm\fi{}0.45$ ms) and the $Q$ value [${Q}_{\mathrm{EC}}=7016.83(25)$ keV] are close to or reach the required precision of about 0.1%. The branching ratio for the superallowed decay branch [$\mathrm{BR}=47.7(12)%$], a by-product of the half-lif…
Beta decay of 40Sc to proton and alpha-particle unbound states in 40Ca
1982
Delayed charged particle emission associated with the precursor nuclide 40Sc was studied by use of the He-jet technique. Altogether 40 proton groups (1.0 MeV < Ep < 3.7 MeV) and 21 α-particle groups (2.0 MeV < Eα < 4.6 MeV) were observed. Total proton and α-particle branching ratios were measured to be (4.4±0.7) × 10−3 and (0.17±0.05) × 10−3, respectively. Association of the delayed particle emitting levels with the levels observed in resonance reaction studies is discussed. The fact that the most prominent α-particle groups do not have a counterpart in resonance reaction data suggests collectivity or a cluster configuration for the emitting levels. Log ft values (upper limits) for β+ trans…
Consistent large-scale shell-model analysis of the two-neutrino ββ and single β branchings in 48Ca and 96Zr
2020
Abstract Two-neutrino double-beta-decay matrix elements M 2 ν and single beta-decay branching ratios were calculated for 48Ca and 96Zr in the interacting nuclear shell model using large single-particle valence spaces with well-tested two-body Hamiltonians. For 48Ca the matrix element M 2 ν = 0.0511 is obtained, which is 5.5% smaller than the previously reported value of 0.0539. For 96Zr this work reports the first large-scale shell-model calculation of the nuclear matrix element, yielding a value M 2 ν = 0.0747 with extreme single-state dominance. These matrix elements, combined with the available ββ-decay half-life data, yield effective values of the weak axial coupling which in turn are u…
Measurement of the W-pair cross section in $e^+ e^-$ collisions at 172 GeV
1997
The e(+)e(-) --> W+W- cross section is measured in a data sample collected by ALEPH at a mean centre-of-mass energy of 172.09 GeV, corresponding to an integrated luminosity of 10.65 pb(-1). Cross sections are given for the three topologies, fully leptonic, semi-leptonic and hadronic of a W-pair decay. Under the assumption that no other decay modes are present, the W-pair cross section is measured to be 11.7 +/- 1.2(stat.) +/- 0.3(syst.) pb. The existence of the triple gauge boson vertex of the Standard Model is clearly preferred by the data. The decay branching ratio of the W boson into hadrons is measured to be B(W --> hadrons) = 67.7 +/- 3.1(stat.) +/- 0.7(syst.) %, allowing a determinati…
Search for charged Higgs bosons in $e^+ e^-$ collisions at centre-of-mass energies from 130 to 172 GeV
1998
Abstract The data collected at centre-of-mass energies ranging from 130 to 172 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 27.5 pb−1, are analysed in a search for pair-produced charged Higgs bosons H±. Three analyses are employed to select the τ + ν τ τ − ν τ , c s τ − ν τ and c s s c final states. No evidence for a signal is found. Mass limits are set as a function of the branching fraction B (τν) for H±→τν. Charged Higgs bosons with masses below 52 GeV/c2 are excluded at 95% C.L. independently of B (τν) , thus significantly improving on existing limits.