Search

In this work, we study masses and other static properties of triply heavy tetraquarks in the unified framework of the MIT bag which incorporates chromomagnetic interactions and enhanced binding energy. The masses, magnetic moments and charge radii of all strange and nonstrange (ground) states of triply heavy tetraquarks are computed, suggesting that all of triply heavy tetraquarks are above the respective two-meson thresholds. We also estimate relative decay widths of main decay channels of two-heavy mesons for these tetraquarks. [ABSTRACT FROM AUTHOR]

Inspired by the observation of the X(6900) by LHCb and the X(6600) (with mass 6552 ± 10 ± 12 MeV) recently by CMS and ATLAS experiments of the LHC in the di- J / Ψ invariant mass spectrum, we systemically study masses of all ground-state configurations of the hidden heavy-flavor tetraquarks q 1 Q 2 q ¯ 3 Q ¯ 4 and Q 1 Q 2 Q ¯ 3 Q ¯ 4 (Q = c , b ; q = u , d , s) containing two and four heavy quarks in the MIT bag model with chromomagnetic interaction and enhanced binding energy. Considering color-spin mixing due to chromomagnetic interaction, our mass computation indicates that the observed X(6600) is likely to be the 0 + + ground states of hidden-charm tetraquark c c c ¯ c ¯ with computed masses 6572 MeV, which has a 0 + + color partner around 6469 MeV. The fully bottom system of tetraquark b b b ¯ b ¯ has masses of 19685 MeV and 19717 MeV for the 0 + + ground states. Further calculation of the tetraquark systems s c s ¯ c ¯ , s b s ¯ b ¯ , c b c ¯ b ¯ , n c n ¯ c ¯ and n b n ¯ b ¯ shows that Z c (4200) is a 1 + - state of tetraquark n c n ¯ c ¯ and Z(4020) is a 1 + - state of tetraquark n c n ¯ c ¯ with a mass of 4079 MeV. All of these tetraquarks are above their lowest thresholds of two mesons and unstable against the strong decays. [ABSTRACT FROM AUTHOR]

Inspired by the observation of a resonant state X(6600) of fully charm tetraquark by the CMS experiment of LHCb Collaboration in double J / ψ decay channel, we perform a systematical study of all configurations of fully heavy pentaquarks P Q 1 Q 2 Q 3 Q 4 Q 5 ¯ ( Q i = c , b , i = 1 , 2 , 3 , 4 , 5 ) in their ground states in unified framework of MIT bag model. The color-spin wavefunctions of pentaquarks, classified via Young tableau and presented in terms of the Young–Yamanouchi bases, are used to compute masses and magnetic moments of fully heavy pentaquarks via numerical variational method, predicting a set of masses ranging from 8.229 GeV for the P c c c c c ¯ to 24.770 GeV for the P b b b b b ¯ . Combining with computed masses of fully heavy mesons and baryons, we find that masses of fully heavy hadrons(mesons, baryons, tetraquarks and pentaquarks) with identical flavor rise almost linearly with the number of valence quarks in hadrons, being consistent with the heavy quark symmetry in the heavy-quark limit. [ABSTRACT FROM AUTHOR]