512,112 research outputs found

    Exclusive decay of Υ\Upsilon into J/ψ+χc0,1,2J/\psi+\chi_{c0,1,2}

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    We study the Υ\Upsilon exclusive decay into double charmonium, specifically, the SS-wave charmonium J/ψ J/\psi plus the PP-wave charmonium χc0,1,2\chi_{c0,1,2} in the NRQCD factorization framework. Three distinct decay mechanisms, i.e., the strong, electromagnetic and radiative decay channels are included and their interference effects are investigated. The decay processes Υ(1S,2S,3S)J/ψ+χc1,0\Upsilon(1S,2S,3S)\to J/\psi+\chi_{c1,0} are predicted to have the branching fractions of order 10610^{-6}, which should be observed in the prospective Super BB factory.Comment: 22 pages, 9 figures, 3 table

    Digging for biosynthetic dark matter.

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    An analysis of bacterial communities in soil samples from around the world reveals unexplored diversity in biosynthetic enzymes

    Long-range correlations in proton-lead collisions at sqrt{s_NN} = 5.02 TeV from ATLAS

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    Two-particle correlations in relative azimuth Δϕ\Delta\phi and relative pseudorapidity Δη\Delta\eta are studied in p+Pb collisions at sqrt{s_NN}=5.02 TeV with the ATLAS detector at LHC. The correlations are studied as a function of charged particle pT and the collision E_T^fcal summed over 3.1 < eta < 4.9 in the direction of the Pb beam. After subtracting the known sources of correlations such as dijets, resonances and momentum conservation, estimated using events with low E_T^fcal, the resulting correlations exhibit a Δϕ\Delta\phi modulation that is flat in Δη\Delta\eta out to Δη=5|\Delta\eta|=5. The modulation is comparable in magnitude to similar modulations observed in heavy ion collisions, and can be described by a 1+2c2cos2Δϕ+2c3cos3Δϕ1+2c_2\cos2\Delta\phi+2c_3\cos3\Delta\phi function over 0.5<pT<7 GeV in broad ranges of E_T^fcal. The correlation analysis is repeated for event classes defined by the number of reconstructed charged particles N_ch^rec. This analysis gives nearly the same result as the analysis based on E_T^fcal for the long-range correlation at the near-side (Δϕ 0\Delta\phi~0), but leads to biases in the long-range correlations at the away-side (Δϕπ\Delta\phi\sim\pi). HIJING simulation suggests that this bias is mainly associated with the contributions from dijets which are correlated strongly with the N_ch^rec.Comment: Proceedings for the 29th Winter Workshop On Nuclear Dynamics, February 3-10, 2013, Squaw Valley, California, US
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