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Register a new user$Upsilon(nl)$ decay into $ B^{(*)} bar B^{(*)}$
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We have evaluated the decay modes of the $Upsilon(4s), Upsilon(3d), Upsilon(5s), Upsilon(6s)$ states into $Bbar B, Bbar B^*+c.c., B^* bar B^*, B_s bar B_s, B_s bar B^*_s +c.c., B^*_s bar B_s^* $ using the $^3P_0$ model to hadronize the $bbar b$ vector seed, fitting some parameters to the data. We observe that the $Upsilon(4s)$ state has an abnormally large amount of meson-meson components in the wave function, while the other states are largely $bbar b$. We predict branching ratios for the different decay channels which can be contrasted with experiment for the case of the $Upsilon(5s)$ state. While globally the agreement is fair, we call the attention to some disagreement that could be a warning for the existence of more elaborate components in the state.
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In this work, we preform a systematic investigation about hidden heavy and doubly heavy molecular states from the $D^{(*)}bar{D}^{(*)}/B^{(*)}bar{B}^{(*)}$ and $D^{(*)}D^{(*)}/bar{B}^{(*)}bar{B}^{(*)}$ interactions in the quasipotential Bethe-Salpeter equation (qBSE) approach. With the help of the Lagrangians with heavy quark and chiral symmetries, interaction potentials are constructed within the one-boson-exchange model in which we include the $pi$, $eta$, $rho$, $omega$ and $sigma$ exchanges, as well as $J/psi$ or $Upsilon$ exchange. Possible bound states from the interactions considered are searched for as the pole of scattering amplitude. The results suggest that experimentally observed states, $Z_c(3900)$, $Z_c(4020)$, $Z_b(10610)$, and $Z_b(10650)$, can be related to the $Dbar{D}^{*}$, $D^*bar{D}^{*}$, $Bbar{B}^{*}$, and $B^*bar{B}^{*}$ interactions with quantum numbers $I^G(J^P)=1^+(1^{+})$, respectively. The $Dbar{D}^{*}$ interaction is also attractive enough to produce a pole with $0^+(0^+)$ which is related to the $X(3872)$. Within the same theoretical frame, the existence of $Dbar{D}$ and $Bbar{B}$ molecular states with $0(0^+)$ are predicted. The possible $D^*bar{D}^*$ molecular states with $0(0^+, 1^+, 2^+)$ and $1(0^+)$ and their bottom partners are also suggested by the calculation. In the doubly heavy sector, no bound state is produced from the $DD/bar{B}bar{B}$ interaction while a bound state is found with $0(1^+)$ from $DD^*/bar{B}bar{B}^*$ interaction. The $D^*D^*/bar{B}^*bar{B}^*$ interaction produces three molecular states with $0(1^+)$, $0(2^+)$ and $1(2^+)$.
The comparison between parameterisations of the perturbation results for the decay width of the Standard Model Higgs boson to bar{b}b-quarks pairs, based on application of bar{MS}-scheme running quark mass and pole b-quark mass, are presented. In the case of the latter parameterisation taking into account of order O(alpha_s^3) term is rather important. It is minimising deviations of the results obtained at the O(alpha_s^2) level from the results, which follow from the running quark mass approach
We perform a quantitative analysis of the $bbbar{b}bar{b}$ tetraquark decays into hidden- and open-bottom mesons and calculate, for the first time, the $bbbar{b}bar{b}$ tetraquark total decay width. On the basis of our results, we propose the $bbbar{b}bar{b} to B^{+} B^{-} (B^0 bar{B}^0) (B_s^0 bar{B}_s^0) to l^{+} l^{-}+text{X}$ decays as the most suitable channels to observe the $bbbar{b}bar{b}$ tetraquark states, since the calculated two-lepton cross section upper limit, $simeq 39 $ fb, is so large as to be potentially detectable with the 2018 LHCb sensitivity, paving the way to the observation of the $bbbar{b}bar{b}$ tetraquark in the future LHCb upgrade. The $4mu$ signal for the ground state, $J^{PC}=0^{++}$, is likely to be too small even for the upgraded LHCb, but it may not be hopeless for the $J^{PC}=2^{++}$ fully-bottom state.
We compute the mass-spectra of all bottom tetraquarks [$bb][bar{b}bar{b}$] and heavy-light bottom tetraquarks [$bq][bar{b}bar{q}$] (q=u,d), that are considered to be compact and made up of diquark-antidiquark pairs. The fully bottom tetraquark [$bb][bar{b}bar{b}$] has been studied in $eta_{b}(1S)eta_{b}(1S)$, $eta_{b}(1S)Upsilon(1S)$ and $Upsilon(1S)Upsilon(1S)$ S-wave channels, as well as a few orbitally excited channels, with masses ranging from 18.7 GeV to 19.8 GeV. The masses of heavy-light bottom tetraquarks are studied in the $B^{pm}B^{pm}$, $B^{pm}B^{*}$ and $B^{*}B^{*}$ channels, with masses ranging from 10.4 GeV to 10.5 GeV. Two charged resonances, $Z_{b}(10610)$ and $Z_{b}(10650)$, both with the quantum number $1^{+-}$, have also been investigated.
We report the observation of $Upsilon(2S)togammaeta_{b}(1S)$ decay based on analysis of the inclusive photon spectrum of $24.7$ fb$^{-1}$ of $e^+ e^-$ collisions at the $Upsilon(2S)$ center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure a branching fraction of $mathcal{B}(Upsilon(2S)togammaeta_{b}(1S))=(6.1^{+0.6+0.9}_{-0.7-0.6})times 10^{-4}$, and derive an $eta_{b}(1S)$ mass of $9394.8^{+2.7+4.5}_{-3.1-2.7}$ MeV/$c^{2}$, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.
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