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Register a new userSearch for beautiful tetraquarks in the $Upsilon(1S)mumu$ invariant-mass spectrum
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The $Upsilon(1S)mu^+mu^-$ invariant-mass distribution is investigated for a possible exotic meson state composed of two $b$ quarks and two $overline{b}$ quarks, $X_{boverline{b}boverline{b}}$. The analysis is based on a data sample of $pp$ collisions recorded with the LHCb detector at centre-of-mass energies $sqrt{s} =$ 7, 8 and 13 TeV, corresponding to an integrated luminosity of 6.3 fb$^{-1}$. No significant excess is found, and upper limits are set on the product of the production cross-section and the branching fraction as functions of the mass of the $X_{boverline{b}boverline{b}}$ state. The limits are set in the fiducial volume where all muons have pseudorapidity in the range $[2.0,5.0]$, and the $X_{boverline{b}boverline{b}}$ state has rapidity in the range $[2.0,4.5]$ and transverse momentum less than 15 GeV/$c$.
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We report the first search for the $J^{PC}=0^{--}$ glueball in $Upsilon(1S)$ and $Upsilon(2S)$ decays with data samples of $(102pm2)$ million and $(158pm4)$ million events, respectively, collected with the Belle detector. No significant signals are observed in any of the proposed production modes, and the 90% credibility level upper limits on their branching fractions in $Upsilon(1S)$ and $Upsilon(2S)$ decays are obtained. The inclusive branching fractions of the $Upsilon(1S)$ and $Upsilon(2S)$ decays into final states with a $chi_{c1}$ are measured to be $BR(Upsilon(1S)to chi_{c1}+ anything) = (1.90pm 0.43(stat.)pm 0.14(syst.))times 10^{-4}$ with an improved precision over prior measurements and $BR(Upsilon(2S)to chi_{c1}+ anything) = (2.24pm 0.44(stat.)pm 0.20(syst.))times 10^{-4}$ for the first time.
We search for the $J^{PC}=0^{--}$ and $1^{+-}$ light tetraquark states with masses up to 2.46~GeV/$c^2$ in $Upsilon(1S)$ and $Upsilon(2S)$ decays with data samples of $(102pm 2)$ million and $(158pm 4)$ million events, respectively, collected with the Belle detector. No significant signals are observed in any of the studied production modes, and 90% credibility level (C.L.) upper limits on their branching fractions in $Upsilon(1S)$ and $Upsilon(2S)$ decays are obtained. The inclusive branching fractions of the $Upsilon(1S)$ and $Upsilon(2S)$ decays into final states with $f_1(1285)$ are measured to be ${cal B}(Upsilon(1S)to f_1(1285)+anything)=(46pm28({rm stat.})pm13({rm syst.}))times 10^{-4}$ and ${cal B}(Upsilon(2S)to f_1(1285)+anything)=(22pm15({rm stat.})pm6.3({rm syst.}))times 10^{-4}$. The measured $chi_{b2} to J/psi + anything$ branching fraction is measured to be $(1.50pm0.34({rm stat.})pm0.22({rm syst.}))times 10^{-3}$, and 90% C.L. upper limits for the $chi_{b0,b1} to J/psi + anything$ branching fractions are found to be $2.3times 10^{-3}$ and $1.1times 10^{-3}$, respectively. For ${cal B}(chi_{b1} to omega + anything)$, the branching fraction is measured to be $(4.9pm1.3({rm stat.})pm0.6({rm syst.}))times 10^{-2}$. %($<3.68times 10^{-2}$ at 90% C.L.). All results reported here are the first measurements for these modes.
The branching fractions of the $Upsilon(1S)$ inclusive decays into final states with a $J/psi$ or a $psi(2S)$ are measured with improved precision to be $BR(Upsilon(1S)to J/psi + {rm anything})=(5.25pm 0.13(mathrm{stat.})pm 0.25(mathrm{syst.}))times 10^{-4}$ and $BR(Upsilon(1S)to psi(2S) + {rm anything})=(1.23pm 0.17(mathrm{stat.})pm 0.11(mathrm{syst.}))times 10^{-4}$. The first search for $Upsilon(1S)$ decays into $XYZ$ states that decay into a $J/psi$ or a $psi(2S)$ plus one or two charged tracks yields no significant signals for $XYZ$ states in any of the examined decay modes, and upper limits on their production rates in $Upsilon(1S)$ inclusive decays are determined.
Using data samples of $102times10^6$ $Upsilon(1S)$ and $158times10^6$ $Upsilon(2S)$ events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays $Upsilon(1S,2S)rightarrow J/psi(psi)+X$, where $X=eta_c$, $chi_{cJ} (J=~0,~1,~2)$, $eta_c(2S)$, $X(3940)$, and $X(4160)$. No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/psi$ or $psi$ except for the evidence of $chi_{c1}$ production with a significance of $4.6sigma$ for $Upsilon(1S)rightarrow J/psi+chi_{c1}$. The measured branching fraction $BR(Upsilon(1S)rightarrow J/psi+chi_{c1})$ is $(3.90pm1.21(rm stat.)pm0.23 (rm syst.))times10^{-6}$. The $90%$ confidence level upper limits on the branching fractions of the other modes having a significance of less than $3sigma$ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.
The $B_s^0pi^pm$ invariant mass distribution is investigated in order to search for possible exotic meson states. The analysis is based on a data sample recorded with the LHCb detector corresponding to $3$ fb$^{-1}$ of $pp$ collision data at $sqrt{s} = 7$ and $8$ TeV. No significant excess is found, and upper limits are set on the production rate of the claimed $X(5568)$ state within the LHCb acceptance. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the $B_s^0pi^pm$ final state. The same limits also apply to a possible exotic meson decaying through the chain $B_s^{*0}pi^pm$, $B_s^{*0} to B_s^0 gamma$ where the photon is excluded from the reconstructed decays.
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