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Register a new userEvidence for the decay $B^0to pbar{p}pi^0$
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We report a search for the charmless baryonic decay $B^0to pbar{p}pi^0$ with a data sample corresponding to an integrated luminosity of 711~$rm fb^{-1}$ containing $(772pm 10)times 10^6$ $B^0bar{B}^0$ pairs. The data was collected by the Belle experiment running on the $Upsilon(4S)$ resonance at the KEKB $e^+e^-$ collider. We measure a branching fraction $mathcal{B}(B^0to pbar{p}pi^0)= (5.0pm1.8pm0.6 )times 10^{-7}$, where the first uncertainty is statistical and the second is systematic. The signal has a significance of 3.1 standard deviations and constitutes the first evidence for this decay mode. We also search for the intermediate two-body decays $B^{0}toDelta^+bar{p}$ and $B^0tobar{Delta}^-p$, and set an upper limit on the branching fraction: $mathcal{B}(B^0to Delta^+bar{p})+mathcal{B}(B^0tobar{Delta}^-p)<1.6times10^{-6}$ at 90% confidence level.
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An amplitude analysis of ${B^0to (pi^+pi^-) (K^+pi^-)}$ decays is performed in the two-body invariant mass regions ${300 < m(pi^+pi^-)<1100}$ MeV/$c^2$, accounting for the $rho^0$, $omega$, $f_0(500)$, $f_0(980)$ and $f_0(1370)$ resonances, and ${750 < m(K^+pi^-)<1200}$ MeV/$c^2$, which is dominated by the $K^{*}(892)^0$ meson. The analysis uses 3 fb$^{-1}$ of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The $CP$ averages and asymmetries are measured for the magnitudes and phase differences of the contributing amplitudes. The $CP$-averaged longitudinal polarisation fractions of the vector-vector modes are found to be $tilde{f}^0_{rho K^{*}} = 0.164 pm 0.015 pm 0.022$ and $tilde{f}^0_{omega K^{*}} = 0.68 pm 0.17 pm 0.16$, and their $CP$ asymmetries, $mathcal{A}^0_{rho K^{*}} = -0.62 pm 0.09 pm 0.09$ and $mathcal{A}^0_{omega K^{*}} = -0.13 pm 0.27 pm 0.13$, where the first uncertainty is statistical and the second systematic.
We report a study of the suppressed decay B^- -> DK^-, D -> K^+pi^-pi^0, where D denotes either a D^0 or a bar{D}^0 meson. The decay is sensitive to the CP-violating parameter phi_3. Using a data sample of 772 x 10^6 Bbar{B} pairs collected at the Upsilon(4S) resonance with the Belle detector, we measure the ratio of branching fractions of the above suppressed decay to the favored decay B^- -> DK^-, D -> K^-pi^+pi^0. Our result is R_{DK} = [1.98 +/- 0.62(stat.) +/- 0.24(syst.)] x 10^{-2}, which indicates the first evidence of the signal for this suppressed decay with a significance of 3.2 standard deviations. We measure the direct CP asymmetry between the suppressed B^- and B^+ decays to be A_{DK} = 0.41 +/- 0.30 (stat.) +/- 0.05 (syst.). We also report measurements for the analogous quantities R_{Dpi} and A_{Dpi} for the decay B^- -> Dpi^-, D -> K^+pi^-pi^0.
The reaction pbar p -> pbar p pi+ pi- has been studied with high statistics at CERN-LEAR with incident pbar momenta from 1.65 to 2.0 GeV/c by the JETSET (PS202) experiment. The aim of this paper is to search for narrow resonances decaying to pbar p. No evidence for such structures is found. In particular, an upper limit for the production of a 2.02 GeV state with a width of Gamma = 20 MeV, having been seen in other hadroproduction experiments, is established. Our results restrict the cross section for such a peak to be below 200 nb at the 95% confidence level.
The first observation of the rare decay$B^0_s to phipi^+pi^-$ and evidence for $B^0 to phipi^+pi^-$ are reported, using $pp$ collision data recorded by the LHCb detector at centre-of-mass energies $sqrt{s} = 7$ and 8~TeV, corresponding to an integrated luminosity of $3{mbox{,fb}^{-1}}$. The branching fractions in the $pi^+pi^-$ invariant mass range $400<m(pi^+pi^-)<1600{mathrm{,Mekern -0.1em V!/}c^2}$ are $[3.48pm 0.23pm 0.17pm 0.35]times 10^{-6}$ and $[1.82pm 0.25pm 0.41pm 0.14]times 10^{-7}$ for $B^0_s to phipi^+pi^-$ and $B^0 to phipi^+pi^-$ respectively, where the uncertainties are statistical, systematic and from the normalisation mode $B^0_s to phiphi $. A combined analysis of the $pi^+pi^-$ mass spectrum and the decay angles of the final-state particles identifies the exclusive decays $B^0_s to phi f_0(980) $, $B_s^0 to phi f_2(1270) $, and $B^0_s to phirho^0$ with branching fractions of $[1.12pm 0.16^{+0.09}_{-0.08}pm 0.11]times 10^{-6}$, $[0.61pm 0.13^{+0.12}_{-0.05}pm 0.06]times 10^{-6}$ and $[2.7pm 0.7pm 0.2pm 0.2]times 10^{-7}$, respectively.
We report a search for the charmless hadronic decay $B^0toeta pi^0$ with a data sample corresponding to an integrated luminosity of 694 $rm fb^{-1}$ containing $753times10^6$ $Bbar{B}$ pairs. The data were collected by the Belle experiment running on the $Upsilon(4S)$ resonance at the KEKB $e^+e^-$ collider. We measure a branching fraction $mathcal{B}(B^0toetapi^0)=(4.1^{+1.7+0.5}_{-1.5-0.7})times 10^{-7}$, where the first uncertainty is statistical and the second is systematic. Our measurement gives an upper limit of $mathcal{B}(B^0toetapi^0)<6.5times 10^{-7}$ at 90% confidence level. The signal has a significance of $3.0$ standard deviations and constitutes the first evidence for this decay mode.
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