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تسجيل مستخدم جديدEvidence for the decay $X(3872)rightarrowpsi(2S)gamma$
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Evidence for the decay mode $X(3872)rightarrowpsi(2S)gamma$ in $B^+rightarrow X(3872)K^+$ decays is found with a significance of 4.4 standard deviations. The analysis is based on a data sample of proton-proton collisions, corresponding to an integrated luminosity of 3fb$^{-1}$ collected with the LHCb detector, at centre-of-mass energies of 7 and 8TeV. The ratio of the branching fraction of the $X(3872)topsi(2S)gamma$ decay to that of the $X(3872)rightarrow J/psi gamma$ decay is measured to be $$ frac{Br(X(3872)rightarrowpsi(2S)gamma)}{Br(X(3872)rightarrow J/psigamma)} = 2.46pm0.64pm0.29, %pm0.06,$$ where the first uncertainty is statistical and the second is systematic. The measured value agrees with expectations for a pure charmonium interpretation of the $X(3872)$ state and a mixture of charmonium and molecular interpretations. However, it does not support a pure $Dbar{D}^{*}$ molecular interpretation of the $X(3872)$state.
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First observations of the $B^0_s rightarrow psi(2S) eta$, $B^0 rightarrow psi(2S) pi^+ pi^-$ and $B^0_s rightarrow psi(2S) pi^+ pi^-$ decays are made using a dataset corresponding to an integrated luminosity of 1.0~$fb^{-1}$ collected by the LHCb exp
eriment in proton-proton collisions at a centre-of-mass energy of $sqrt{s}=7$ TeV. The ratios of the branching fractions of each of the $psi(2S)$ modes with respect to the corresponding $J/psi$ decays are [ frac{mathcal{B}(B^0_s rightarrow psi(2S) eta) }{mathcal{B}(B^0_s rightarrow J/psi eta)} =0.83pm0.14,(stat)pm0.12,(syst)pm0.02,(mathcalB}), ] [ frac{mathcal{B}(B^0 rightarrow psi(2S) pi^+ pi^-)}{mathcal{B}(B^0 rightarrow J/psi pi^+ pi^-)} =0.56pm0.07,(stat)pm0.05,(syst)pm0.01,(mathcal{B}), ] [ frac{mathcal{B}(B^0_s rightarrow psi(2S) pi^+ pi^-)}{mathcal{B}(B^0_s rightarrow J/psi pi^+ pi^-)} =0.34pm0.04,(stat)pm0.03,(syst)pm0.01,(mathcal{B}), ] where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the $J/psi$ and $psi(2S)$ meson decays.
We report the results of a search for the decay $B^0 to X(3872)(to J/psi pi^+ pi^-) gamma$. The analysis is performed on a data sample corresponding to an integrated luminosity of $711,{rm fb}^{-1}$ and containing $772 times 10^6 Bbar{B}$ pairs, coll
ected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider running at the $Upsilon(4S)$ resonance energy. We find no evidence for a signal and place an upper limit of $mathcal{B}(B^0 to X(3872)gamma)times mathcal{B}(X(3872) to J/psi pi^+ pi^-) < 5.1 times 10^{-7}$ at 90% confidence level.
Using data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.178 to 4.600 GeV, we study the process $e^+e^-rightarrowpi^{0}X(3872)gamma$ and search for $Z_c(4020)^{0}rightarrow X(3872)ga
mma$. We find no significant signal and set upper limits on $sigma(e^+e^-rightarrowpi^{0}X(3872)gamma)cdotmathcal{B}(X(3872)rightarrowpi^{+}pi^{-}J/psi)$ and $sigma(e^+e^-rightarrowpi^{0}Z_c(4020)^{0})cdotmathcal{B}(Z_c(4020)^{0}rightarrow X(3872)gamma)cdotmathcal{B}(X(3872)rightarrowpi^{+}pi^{-}J/psi)$ for each energy point at $90%$ confidence level, which is of the order of several tenths pb.
We report a study of $Bto (J/psi gamma) K$ and $Bto (psi gamma)K$ decay modes using $772times 10^{6}$ $Bbar{B}$ events collected at the Upsilon(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. We observe $X(387
2) to J/psi gamma$ and report the first evidence for $chi_{c2} to J/psi gamma$ in $Bto (X_{cbar{c}}gamma) K$ decays, while in a search for $X(3872) to psi gamma$ no significant signal is found. We measure the branching fractions, $mathcal{B}(B^{pm} to X(3872) K^{pm}) mathcal{B}(X(3872) to J/psigamma)$ $=$ $(1.78^{+0.48}_{-0.44}pm 0.12)times 10^{-6}$, $mathcal{B} (B^{pm} tochi_{c2} K^{pm})$$=$ $(1.11^{+0.36}_{-0.34} pm 0.09) times 10^{-5}$, $mathcal{B}(B^{pm} to X(3872) K^{pm}) mathcal{B}(X(3872) to psigamma)$ $<$ $3.45times 10^{-6}$ (upper limit at 90% C.L.) and also provide upper limits for other searches.
Using a total of $9.0~mathrm{fb}^{-1}$ of $e^+e^-$ collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes $e^+e^-to gamma X(3872)$ with $X(3872)topi^0chi_{cJ}$ for $J=0,1,2$
. We report the first observation of $X(3872)topi^{0}chi_{c1}$, a new decay mode of the $X(3872)$, with a statistical significance of more than 5$sigma$. Normalizing to the previously established process $e^+e^-to gamma X(3872)$ with $X(3872)topi^+pi^-J/psi$, we find ${cal B}(X(3872) to pi^0 chi_{c1})/{cal B}(X(3872) to pi^+pi^- J/psi) = 0.88^{+0.33}_{-0.27}pm0.10$, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to $pi^0chi_{c0}$ and $pi^0chi_{c2}$ of 19 and 1.1, respectively.
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