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Register a new userStudy of X(3872) in $B$ meson decays
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Belle collaboration
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We present results on the X(3872), produced in $B^+ to X(3872) K^+$ and $B^0 to X(3872) K^0_S$ decays where $X(3872) to J/psi pi^+ pi^-$. We report the first statistically significant observation of $B^0 to X(3872) K^0_S$ and measure the ratio of branching fractions to be $frac{{cal B}(B^0 to X(3872)K^0)} {{cal B}(B^+ to X(3872)K^+)} = 0.82 pm 0.22 pm 0.05$, consistent with unity. The mass difference between the X(3872) states produced in $B^+$ and $B^0$ decay is found to be $delta M equiv M_{XK^+} - M_{XK^0} = (+0.18 pm 0.89 pm 0.26)$ MeV/$c^2$, consistent with zero. In addition, we search for the X(3872) in the decay $B^0 to X(3872)K^+pi^-$, $X(3872) to J/psi pi^+ pi^-$. We measure ${cal B}(B^0 to X(3872) (K^+ pi^-)_{NR}) times {cal B}(X(3872) to J/psi pi^+ pi^-) = (8.1 pm 2.0 ^{+1.1}_{-1.4})times 10^{-6}$ and we set the 90% C.L. limit, ${cal B}(B^0 to X(3872)K^{*}(892)^0) times {cal B}(X(3872) to J/psi pi^+ pi^-) < 3.4 times 10^{-6}$. The analysis is based on a 605 fb$^{-1}$ data sample collected at the $Upsilon(4S)$ with the Belle detector at the KEKB collider.
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We report the first observation of $B^0 to X(3872) (K^{+}pi^{-})$ and evidence for $B^+ to X(3872) (K^{0}pi^{+})$. We measure the product of branching fractions for the former to be ${cal B}(B^0 to X(3872) (K^+ pi^-)) times {cal B}(X(3872) to J/psi pi^+ pi^-) = (7.9 pm 1.3(mbox{stat.})pm 0.4(mbox{syst.})) times 10^{-6}$ and find that $B^{0}to X(3872) K^{*}(892)^{0}$ does not dominate the $B^{0}to X(3872)K^{+}pi^{-}$ decay mode. We also measure ${cal B}(B^+ to X(3872) (K^0 pi^+)) times {cal B}(X(3872) to J/psi pi^+ pi^-) = (10.6 pm 3.0(mbox{stat.}) pm 0.9(mbox{syst.})) times 10^{-6}$. This study is based on the full data sample of 711~fb$^{-1}$ ($772times 10^6 Bbar B$ pairs) collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB collider.
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 $X(3872) to J/psi gamma$ 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.
We present measurements of the decays B+ -> X(3872) K+ and B0 -> X(3872) K0 with X(3872) -> Jpsi pi+ pi-. The data sample used, collected with the BABAR detector at the PEP-II e+e- asymmetric-energy storage ring, corresponds to 455 x 10^6 BBbar pairs. Branching fraction measurements of BF(B+ -> X(3872) K+) x BF(X(3872) -> Jpsi pi+ pi-) = (8.4 +/- 1.5 +/- 0.7) x 10^{-6} and BF(B0 -> X(3872) K0) x BF(X(3872) -> Jpsi pi+ pi- = (3.5 +/- 1.9 +/- 0.4) x 10^{-6} are obtained. We set an upper limit on the natural width of the X(3872) of Gamma < 3.3 MeV/c^2 at the 90% confidence level.
We discuss how the latest data on X(3872) in B and B_s decays speak about its tetraquark nature. The established decay pattern, including the up to date observations by CMS, are explained by the mixing of two quasi-degenerate, unresolvable, neutral states. The same mechanism also explains isospin violations in X decays and strongly suggests that the lurking charged partners are required to have very small branching fractions in J/psi rho^pm, well below the current experimental limits. In addition, a new prediction on the decay into J/psi omega final states is attained. The newest experimental observations are found to give thrust to the simplest tetraquark picture and call for a definitive, in-depth study of final states with charged rho mesons.
The processes $X(3872)to D^{*0}bar{D^{0}}+c.c.,~gamma J/psi,~gamma psi(2S),$ and $gamma D^{+}D^{-}$ are searched for in a $9.0~rm fb^{-1}$ data sample collected at center-of-mass energies between $4.178$ and $4.278$ GeV with the BESIII detector. We observe $X(3872)to D^{*0}bar{D^{0}}+c.c.$ and find evidence for $X(3872)togamma J/psi$ with statistical significances of $7.4sigma$ and $3.5sigma$, respectively. No evident signals for $X(3872)togammapsi(2S)$ and $gamma D^{+}D^{-}$ are found, and upper limit on the relative branching ratio $R_{gamma psi} equivfrac{mathcal{B}(X(3872)togammapsi(2S))}{mathcal{B}(X(3872)togamma J/psi)}<0.59$ is set at 90$%$ confidence level. Measurements of branching ratios relative to decay $X(3872)topi^+pi^- J/psi$ are also reported for decays $X(3872)to D^{*0}bar{D^{0}}+c.c., ~gammapsi(2S),~gamma J/psi$, $gamma D^{+}D^{-}$, as well as the non-$D^{*0}bar{D}^{0}$ three-body decays $pi^0 D^{0}bar{D}^{0}$ and $gamma D^{0}bar{D}^{0}$.
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