Five-flavor udscb¯ molecular pentaquarks from heavy-quark and local hidden gauge symmetries
Year: 2026
Type: article
Abstract: We study a family of genuinely exotic five-flavor molecular pentaquark states containing the five quark flavors u, d, s, c, b that form experimentally accessible hadrons. We construct the meson-baryon interaction from the local hidden gauge symmetry combined with heavy-quark spin symmetry, following the chiral unitary description that reproduces the LHCb hidden-charm strange pentaquarks. Heavy-quark flavor symmetry allows us to obtain the u d s c b ¯ sector by replacing the anti-charm quark in the meson with an anti-bottom quark while keeping the charm quark in the baryon. As a result, we obtain ten threshold-associated isoscalar poles with J P = 1 / 2 − , 3 / 2 − , 5 / 2 − in the range 7.72 to 7.96 GeV. They are narrow and organized into heavy-quark spin multiplets with predicted near-degeneracies. The loop subtraction constant, the single scheme parameter, is not adjusted by hand. Requiring the loop function at threshold to be independent of the heavy flavor fixes a ≃ − 3.2 to − 3.4 from the charm sector, consistent with the value a = − 3.1 used in the earlier two-sector study, and the predicted masses move by several tens of MeV when a varies between − 2.9 and − 3.2 . There are four states that overlap with the earlier two-sector study in the literature to about 2 MeV, which shows that the separate-sector treatment is recovered as a limit of this work. Moreover, the strongly coupled B *Ξ c and B s * Λ c channels support additional deeply bound poles. We show that their number and positions depend on the regularization scheme, and we quantify this dependence by comparing dimensional regularization with a cutoff scheme. The resulting states provide a signal that can be searched for at LHCb in the B c Λ and B s * Λ c invariant mass spectra in the window 7.60 to 7.77 GeV.
Source: Physics Letters B
Institution: Khon Kaen University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7221797949