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Register a new userObservation of the decay $B^0_s to phipi^+pi^-$ and evidence for $B^0 to phipi^+pi^-$
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LHCb collaboration: R. Aaij
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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.
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We search for annihilation decay modes of neutral $b$ mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb$^{-1}$ of integrated luminosity, we obtain the first evidence for the $B^0_s to pi^+pi^-$ decay, with a significance of $3.7sigma$, and a measured branching ratio $mathcal{B}(B^0_s to pi^+pi^-)= (0.57 pm 0.15 (stat) pm 0.10 (syst))times 10^{-6}$. A search for the $B^0 to K^+K^-$ mode in the same sample yields a significance of $2.0sigma$, and a central value estimate $mathcal{B}(B^0 to K^+K^-)= (0.23 pm 0.10 (stat) pm 0.10 (syst))times 10^{-6}$.
Proton-proton collision data recorded in 2011 and 2012 by the lhcb experiment, co-rres-pon-ding to an integrated luminosity of 3.0invfb, are a-na-lysed to search for the charmless ${B^0 to rho^0 rho^0}$ decay. More than 600 ${B^0 to (pi^+pi^-)(pi^+pi^-)}$ signal decays are selected and used to perform an amplitude analysis from which the ${B^0 to rho^0 rho^0}$ decay is observed for the first time with 7.1 standard deviations significance. The fraction of ${B^0 to rho^0 rho^0}$ decays yielding a longitudinally polarised final state is measured to be $fL = 0.745^{+0.048}_{-0.058} ({rm stat}) pm 0.034 ({rm syst})$. The ${B^0 to rho^0 rho^0}$ branching fraction, using the ${B^0 to phi K^*(892)^{0}}$ decay as reference, is also reported as ${BF(B^0 to rho^0 rho^0) = (0.94 pm 0.17 ({rm stat}) pm 0.09 ({rm syst}) pm 0.06 ({rm BF})) times 10^{-6}}$.
Using a sample of 1.31 billion $J/psi$ events collected with the BESIII detector at the BEPCII collider, the decays $J/psi to phi pi^{+}pi^{-}pi^{0}$ and $J/psi to phi pi^{0}pi^{0}pi^{0}$ are investigated. The isospin violating decay $J/psi to phi pi^{0} f_{0}(980)$ with $f_{0}(980) to pipi$, is observed for the first time. The width of the $f_{0}(980)$ obtained from the dipion mass spectrum is found to be much smaller than the world average value. In the $pi^{0} f_{0}(980)$ mass spectrum, there is evidence of $f_1(1285)$ production. By studying the decay $J/psi to phieta$, the branching fractions of $eta to pi^{+}pi^{-}pi^{0}$ and $eta to pi^{0}pi^{0}pi^{0}$, as well as their ratio, are also measured.
We present the results of a Dalitz plot analysis of D^0 to K^0_S pi^0 pi^0 using the CLEO-c data set of 818 inverse pico-barns of e^+ e^- collisions accumulated at sqrt{s} = 3.77 GeV. This corresponds to three million D^0 D^0-bar pairs from which we select 1,259 tagged candidates with a background of 7.5 +- 0.9 percent. Several models have been explored, all of which include the K^*(892), K^*_2(1430), K^*(1680), the f_0(980), and the sigma(500). We find that the combined pi^0 pi^0 S-wave contribution to our preferred fit is (28.9 +- 6.3 +- 3.1)% of the total decay rate while D^0 to K^*(892)^0 pi^0 contributes (65.6 +- 5.3 +- 2.5)%. Using three tag modes and correcting for quantum correlations we measure the D^0 to K^0_S pi^0 pi^0 branching fraction to be (1.059 +- 0.038 +- 0.061)%.
The time-integrated Dalitz plot of the three-body hadronic charmless decay ${{overline{B}}^0 to K_{mathrm{scriptscriptstyle S}}^0 pi^+ pi^-}$ is studied using a $pp$ collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of $3.0;mathrm{fb}^{-1}$. The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the ${overline{B}^0 to K_{mathrm{scriptscriptstyle S}}^0 pi^+ pi^-}$ decay branching fraction and CP asymmetries of the flavour-specific amplitudes are measured. The CP asymmetry between the conjugate ${overline{B}^0 to K^{*}(892)^{-}pi^+}$ and ${overline{B}^0 to K^{*}(892)^{+}pi^-}$ decay rates is determined to be $-0.308 pm 0.062$.
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