Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMass spectra for the $ccbar{b}bar{b}$/$bbbar{c}bar{c}$ tetraquark states
102
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We have studied the masse spectra for the $ccbar{b}bar{b}$/$bbbar{c}bar{c}$ tetraquark states with quantum numbers $J^{P}=0^{pm},1^{pm}$, and $2^{+}$. We systematically construct the interpolating currents with various spin-parity quantum numbers and calculate their two-point correlation functions in the framework of QCD moment sum rule method. Our calculations show that the masses are about $12.3-12.4$ GeV for the positive parity $ccbar{b}bar{b}$ tetraquark ground states with $J^{P}=0^+, 1^+, 2^+$, while $12.8-13.1$ GeV for the negative parity channels with $J^{P}=0^-, 1^-$. The mass predictions for the positive parity $ccbar{b}bar{b}$ ground states are lower than the $B_{c}B_{c}$ threshold, implying that these tetraquarks can only decay via weak interaction and thus are expected to be stable and narrow.
rate research
Read More
We study the existence of fully-heavy hidden-flavor $bcbar{b}bar{c}$ tetraquark states with various $J^{PC}=0^{pm+}, 0^{--},1^{pmpm}, 2^{++}$, by using the moment QCD sum rule method augmented by fundamental inequalities. Using the moment sum rule analyses, our calculation shows that the masses for the S-wave positive parity $bcbar{b}bar{c}$ tetraquark states are about $12.2-12.4$ GeV in both $[mathbf{bar{3}_c}]_{bc}otimes[mathbf{3_c}]_{bar{b}bar{c}}$ and $[mathbf{6_c}]_{bc}otimes[mathbf{bar{6}_c}]_{bar{b}bar{c}}$ color configuration channels. Except for two $0^{++}$ states, such results are below the thresholds $T_{eta_ceta_b}/T_{Upsilonpsi}$ and $T_{B_cB_c}$, implying that these S-wave positive parity $bcbar{b}bar{c}$ tetraquark states are probably stable against the strong interaction. For the P-wave negative parity $bcbar{b}bar{c}$ tetraquarks, their masses in the $[mathbf{bar{3}_c}]_{bc}otimes[mathbf{3_c}]_{bar{b}bar{c}}$ channel are around $12.9-13.2$ GeV, while a bit higher in the $[mathbf{6_c}]_{bc}otimes[mathbf{bar{6}_c}]_{bar{b}bar{c}}$ channel. They can decay into the $cbar c+bbar b$ and $cbar b+bbar c$ final states via the spontaneous dissociation mechanism, including the $J/psiUpsilon$, $eta_cUpsilon$, $J/psieta_b$, $B_c^+B_c^-$ channels.
We give a brief comment on the possible tetraquark states $cc bar c bar c$ observed by the LHCb experiment.
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.
Using the data sample of 711 fb$^{-1}$ of $Upsilon(4S)$ on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays $B^{-} to bar{Lambda}_{c}^{-} Xi_{c}^{0}$, $B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2645)^{0}$, and $B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2790)^{0} $. The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against $bar{Lambda}_{c}^{-}$ baryons in selected $B^-$ candidates. The branching fraction of $B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2790)^{0}$ is measured to be $ (1.1 pm 0.4 pm 0.2)times 10^{-3}$, where the first uncertainty is statistical and the second systematic. The 90% credibility level upper limits on ${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}^{0})$ and ${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2645)^{0})$ are determined to be $6.5times 10^{-4}$ and $7.9times 10^{-4}$, respectively.
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.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
