20.500.12556/RUL-182132 Electromagnetic form factors and structure of the $T_{bb}$ tetraquark from lattice QCD We present the first lattice QCD determination of the electromagnetic form factors of the exotic tetraquark ▫$T_{bb}(bb\overline{u}\overline{d})$▫ with quantum numbers ▫$I(J^P) = 0(1^+)$▫. The extracted form factors encode information about its internal structure, including the charge distribution and the magnetic dipole moments, determined separately for the light and heavy quarks. Our results provide evidence in favor of it being a bound state consisting of a compact heavy diquark [▫$BB$▫] in a color-antitriplet with spin one and a light antidiquark [▫$\overline{u}\overline{d}$▫] in a color-triplet with spin zero. The charge radius of ▫$T_{bb}$▫ is found to be significantly smaller than the combined charge radii of ▫$B$▫ and ▫$B^*$▫ mesons. These two comprise the lowest-lying threshold ▫$BB^*$▫ in the channel that we are considering, and their electric charge form factors are also determined. The computations were performed on a single ensemble, generated by the Coordinated Lattice Simulations effort, with ▫$N_f = 2 + 1$▫ dynamical quarks and a lattice spacing of approximately ▫$a \approx 0.064$▫ fm at the pion mass ▫$m_\Pi \approx 290$▫ MeV. lattice QCD tetraquarks form factors magnetic moment kvantna kromodinamika na mreži tetrakvarki oblikovni faktorji magnetni moment true false true Angleški jezik Slovenski jezik Članek v reviji 2026-04-24 14:35:46 2026-04-24 14:35:47 2026-06-02 10:11:11 0000-00-00 00:00:00 2026 0 0 Str. 161901-1-161901-9 iss. 16 Vol. 136 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.120 0031-9007 10.1103/jnsy-5nhj 276531715 https://journals.aps.org/prl/abstract/10.1103/jnsy-5nhj 1 ddd3af3c-3fd9-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=233105 jnsy-5nhj.pdf jnsy-5nhj.pdf 1 324EBAFCA07D6CD3E86051FA6D4DF20E 0b5a1039925c45a1aa152afa2679a4fe04e816f697ca6e304c041208f4941136 0f3712fe-3fda-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=233106 Fakulteta za matematiko in fiziko 0 0 0