We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding ...to approximately 260,000 signal events. We use these data to extract the non-radiative sigma(e+e- ->pi+pi-pi+pi-) cross section in the energy range from 0.6 to 4.5 Gev. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
We use 111+/-1 million Upsilon(3S) and 89+/-1 million Upsilon(2S) events recorded by the BaBar detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions between bottomonium ...states using photons that have been converted to e+e- pairs by the detector material. We observe Upsilon(3S) -> gamma chi_b0,2(1P) decay, make precise measurements of the branching fractions for chi_b1,2(1P,2P) -> gamma Upsilon(1S) and chi_b1,2(2P) -> gamma Upsilon(2S) decays, and search for radiative decay to the eta_b(1S) and eta_b(2S) states.
We report a measurement of the inclusive semileptonic branching fraction of the B_s meson using data collected with the BaBar detector in the center-of-mass (CM) energy region above the Upsilon(4S) ...resonance. We use the inclusive yield of phi mesons and the phi yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B_s mesons relative to all B mesons as a function of CM energy. The inclusive semileptonic branching fraction of the B_s meson is determined to be B(B_s to l nu X)=9.5 (+2.5/-2.0)(stat)(+1.1/-1.9)(syst)%, where l indicates the average of e and mu.
Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the \(h_b(1P)\) spin-singlet partner of the ...P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).
We search for hadronic decays of a light Higgs boson (A0) produced in radiative decays of an Upsilon(2S) or Upsilon(3S) meson, Upsilon --> gamma A0. The data have been recorded by the BABAR ...experiment at the Upsilon(3S) and Upsilon(2S) center of mass energies, and include (121.3 \pm 1.2) x 10^6 Upsilon(3S) and (98.3 \pm 0.9) x 10^6 Upsilon(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions B(Upsilon(nS)-->gamma A0) x B(A0-->hadrons) (n=2 or 3) that range from 1 x 10^{-6} for an A0 mass of 0.3 GeV/c^2 to 8 x 10^{-5} at 7 GeV/c^2.
We study the decay \(\bar{B}^{0}\rightarrow\Lambda_{c}^{+}\bar{p}\pi^{+}\pi^{-}\), reconstructing the \Lambda_{c}^{+} baryon in the \(p K^{-}\pi^{+}\) mode, using a data sample of \(467\times ...10^{6}\) \(B\bar{B}\) pairs collected with the BaBar detector at the PEP-2 storage rings at SLAC. We measure branching fractions for decays with intermediate \(\Sigma_{c}\) baryons to be \({\cal B}\bar{B}^{0}\rightarrow\Sigma_{c}(2455)^{++}\bar{p}\pi^{-}=(21.3 \pm 1.0 \pm 1.0 \pm 5.5) \times 10^{-5}\), \({\cal B}\bar{B}^{0}\rightarrow\Sigma_{c}(2520)^{++}\bar{p}\pi^{-}=(11.5\pm 1.0 \pm 0.5 \pm 3.0)\times 10^{-5}\), \({\cal B}\bar{B}^{0}\rightarrow\Sigma_{c}(2455)^{0}\bar{p}\pi^{+}=(9.1 \pm 0.7 \pm 0.4 \pm 2.4)\times10^{-5}\), and \({\cal B}\bar{B}^{0}\rightarrow\Sigma_{c}(2520)^{0}\bar{p}\pi^{+}= (2.2 \pm 0.7 \pm 0.1\pm 0.6) \times 10^{-5}\), where the uncertainties are statistical, systematic, and due to the uncertainty on the \(\Lambda_{c}^{+}\rightarrow\proton\Km\pi^{+}\) branching fraction, respectively. For decays without \(\Sigma_{c}(2455)\) or \(\Sigma_{c}(2520)\) resonances, we measure \({\cal B}\bar{B}^{0}\rightarrow\Lambda_{c}^{+}\bar{p}\pi^{+}\pi^{-}_{\mathrm{non-\Sigma_{c}}}=(79 \pm 4 \pm 4 \pm 20)\times10^{-5}\). The total branching fraction is determined to be \({\cal B}\bar{B}^{0}\rightarrow\Lambda_{c}^{+}\bar{p}\pi^{+}\pi^{-}_{\mathrm{total}}=(123 \pm 5 \pm 7 \pm 32)\times10^{-5}\). We examine multibody mass combinations in the resonant three-particle \(\Sigma_{c}\bar{p}\pi\) final states and in the four-particle \(\Lambda_{c}^{+}\bar{p}\pi^{+}\pi^{-}\) final state, and observe different characteristics for the \(\bar{p}\pi\) combination in neutral versus doubly-charged \(\Sigma_{c}\) decays.
: Vomiting and abdominal symptoms are uncommonly seen in children with Prader–Willi syndrome (PWS). A case is described of a child with PWS who presented with vomiting, abdominal distension and ...abdominal pain due to a duodenal web causing gross gastric distension. Prompt attention to the onset of such clinical features in children with PWS may prevent excess morbidity and complications.
Search for CP Violation in the Decay D+/- to Ks pi del Amo Sanchez, P.; Lees, J.P.; Poireau, V. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
08/2011, Letnik:
83, Številka:
7
Journal Article
Recenzirano
Odprti dostop
We report on a search for CP violation in the decay D{sup {+-}} {yields} K{sub S}{sup 0}{pi}{sup {+-}} using a data set corresponding to an integrated luminosity of 469 fb{sup -1} collected with the ...BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay rate asymmetry A{sub CP} is determined to be (-0.44 {+-} 0.13(stat) {+-} 0.10(syst))%, consistent with zero at 2.7 {sigma} and with the standard model prediction of (-0.332 {+-} 0.006)%. This is currently the most precise measurement of this parameter.
We report the observation of the decay $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}$ based on $342 \mathrm {\,fb}^{-1}}$ of data collected at the $\Y4S$ resonance with the BABAR ...detector at the PEP-II $e^{+}e^{-}$ storage rings at SLAC. A simultaneous fit to three $D^{+}_{s}$ decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}$ with a significance greater than five standard deviations (including systematic uncertainties) and measure its branching fraction to be $\BR(B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}) = 6.13^{+1.04}_{-1.03}(\mathrm{stat.})\pm0.43(\mathrm{syst.}) \pm 0.51(\BR(D_{s}))\times10^{-4}$, where the last error reflects the limited knowledge of the $D_{s}$ branching fractions.
We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle $\gamma$ through a Dalitz plot analysis of neutral $D$ meson decays to $K_S^0 \pi^+ \pi^-$ and $K_S^0 K^+ K^-$ produced ...in the processes $B^\mp \to D K^\mp$, $B^\mp \to D^{*} K^\mp$ with $D^* \to D \pi^0,D \gamma$, and $B^\mp \to D K^{*\mp}$ with $K^{*\mp} \to K_S^0 \pi^\mp$, using 468 million $B\bar{B}$ pairs collected by the BABAR detector at the PEP-II asymmetric-energy $e^+e^-$ collider at SLAC. We measure $\gamma=(68 \pm 14 \pm 4 \pm 3)^\circ$ ({\rm mod $180^\circ$}), where the first error is statistical, the second is the experimental systematic uncertainty and the third reflects the uncertainty in the description of the neutral $D$ decay amplitudes. This result is inconsistent with $\gamma = 0$ (no direct CP violation) with a significance of 3.5 standard deviations.
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