Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the ...first search for a stable, doubly strange six-quark state in Υ→S$\bar{Λ}\bar{Λ}$ decays based on a sample of 90×10$^{6}$Υ(2S) and 110×106Υ(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined Υ(2S,3S) → S$\bar{Λ}\bar{Λ}$ branching fraction in the range (1.2-1.4) × 10-7 are derived for mS < 2.05 GeV. These bounds set stringent limits on the existence of such exotic particles.
A search is presented for the four-body decay ${B}^{0}{\rightarrow}pp\overline{p}\overline{p}$ in a sample of 471 million $B\overline{B}$ pairs collected with the BABAR detector, operated at the SLAC ...PEP-II asymmetric-energy ${e}^{+}{e}^{{-}}$ collider. The center-of-mass energy is 10.58 GeV. From a fit to the distribution of the energy-substituted mass ${m}_{\mathrm{ES}}$, the branching fraction $\mathcal{B}({B}^{0}{\rightarrow}pp\overline{p}\overline{p})=(1.1\pm{}0.5\pm{}0.2)\times{}{10}^{{-}7}$ is extracted, where the first uncertainty is statistical and the second is systematic. The significance of the signal, including the systematic uncertainty, is 2.9 standard deviations. The upper limit on the branching fraction is determined to be $2.0\times{}{10}^{{-}7}$ at 90% confidence level.
A search is presented for the four-body decay B0→ppp¯p¯ in a sample of 471 million BB¯ pairs collected with the BABAR detector, operated at the SLAC PEP-II asymmetric-energy e+e− collider. The ...center-of-mass energy is 10.58 GeV. From a fit to the distribution of the energy-substituted mass mES, the branching fraction B(B0→ppp¯p¯)=(1.1±0.5±0.2)×10−7 is extracted, where the first uncertainty is statistical and the second is systematic. The significance of the signal, including the systematic uncertainty, is 2.9 standard deviations. The upper limit on the branching fraction is determined to be 2.0×10−7 at 90% confidence level.
We study the ϒ(1S) radiative decays to γπ+π− and γK+K− using data recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e− collider at center-of-mass energies at the ϒ(2S) ...and ϒ(3S) resonances. The ϒ(1S) resonance is reconstructed from the decay ϒ(nS)→π+π−ϒ(1S), n=2, 3. Branching fraction measurements and spin-parity analyses of ϒ(1S) radiative decays are reported for the I=0 S-wave and f2(1270) resonances in the π+π− mass spectrum, the f2′(1525) and f0(1500) in the K+K− mass spectrum, and the f0(1710) in both.
A new dark sector antibaryon, denoted ψ_{D}, could be produced in decays of B mesons. This Letter presents a search for B^{+}→ψ_{D}+p (and the charge conjugate) decays in e^{+}e^{-} annihilations at ...10.58 GeV, using data collected in the BABAR experiment. Data corresponding to an integrated luminosity of 398 fb^{-1} are analyzed. No evidence for a signal is observed. Branching fraction upper limits in the range from 10^{-7}-10^{-5} are obtained at 90% confidence level for masses of 1.0<m_{ψ_{D}}<4.3 GeV/c^{2}. The result is also reinterpreted to provide the first limits on a supersymmetric model with R-parity violation and a light neutralino.
We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing ...Electron-Positron Collider.
Based on the full BABAR data sample of 466.5 million $B\bar{B}$ pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to ...distinguish Cabibbo-Kobayashi-Maskawa (CKM) suppressed B → Xueν decays from the CKM-favored B → Xceν decays, and from various other backgrounds, and determine the total semileptonic branching fraction B (B → Xeν) = ( 10.34 ± 0.04stat ± 0.2 6syst)%, averaged over B± and B0 mesons. We determine the spectrum and branching fraction for charmless B → Xueν decays and extract the CKM element | Vub| , by relying on four different QCD calculations based on the heavy quark expansion. While experimentally, the electron momentum region above 2.1 GeV / c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and the extraction of the CKM matrix element |Vub| are presented, with the lower limit on the electron momentum varied from 0.8 GeV / c to the kinematic endpoint. We determine |Vub| using each of these different calculations and find, |Vub| = ( 3.794 ± 0.107exp $+ 0.292\atop{ - 0.219 SF}$ $+ 0.078 \atop{- 0.068 theory}$ ) × 10- 3 (De Fazio and Neubert), (4.563 ± 0.126exp $+ 0.230\atop {- 0.208 SF}$ $+ 0.162\atop{- 0.163 theory}$ ) ×10-3 (Bosch, Lange, Neubert, and Paz), (3.959 ± 0.104exp $+ 0.164\atop{- 0.154 SF}$ $+ 0.042\atop{ - 0.079 theory}$ ) × 10-3 (Gambino, Giordano, Ossola, and Uraltsev), (3.848 ± 0.108exp $+ 0.084\atop{ - 0.070 theory}$) × 10-3 (dressed gluon exponentiation), where the stated uncertainties refer to the experimental uncertainties of the partial branching fraction measurement, the shape function parameters, and the theoretical calculations.
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