Charmed bottom baryon spectroscopy from lattice QCD

Abstract

We calculate the masses of baryons containing one, two, or three heavy quarks using lattice QCD. We consider all possible combinations of charm and bottom quarks, and compute a total of 36 different states withþ . We use domain-wall fermions for the up, down, and strange quarks, a relativistic heavyquark action for the charm quarks, and nonrelativistic QCD for the bottom quarks. Our analysis includes results from two different lattice spacings and seven different pion masses. We perform extrapolations of the baryon masses to the continuum limit and to the physical pion mass using SUð4j2Þ heavy-hadron chiral perturbation theory including 1=m Q and finite-volume effects. For the 14 singly heavy baryons that have already been observed, our results agree with the experimental values within the uncertainties. We compare our predictions for the hitherto unobserved states with other lattice calculations and quark-model studies.

Two nucleon systems atmπ∼450 MeVfrom lattice QCD

“…The Lüscher-Weisz gauge action [30] was used with a clover-improved quark action [31] with one level of stout smearing (ρ = 0.125) [32]. The clover coefficient was set equal to its tree-level tadpole-improved value, a value that is consistent with an independent numerical study of the nonperturbative c SW in the Schrödinger functional scheme [33][34][35], reducing discretization errors from O(b) to O(b 2 ). The L = 24, 32 and 48 ensembles consist of 3.4 × 10 4 , 2.2 × 10 4 , and 1.5 × 10 4 HMC evolution trajectories, respectively.…”

Heavy-hadron interactions from Lattice QCD

“…One of the highlights from recent years has been the prediction of the mass of the Ξ cc (and of a number of other charmed baryons) by various groups [26][27][28][29][30][31][32], which has been presented in Section 2.…”

“…A number of years ago, an isospin partner to this state has been claimed by the SELEX collaboration [18,19] Before the observation by the LHCb collaboration, a number of lattice calculations yielded predictions for the mass of Ξ cc in the isospin limit. The most advanced of these determinations [26][27][28][29][30][31] are collected in Figure 2, together with the state claimed by SELEX (green circle) and the observation by LHCb (magenta vertical band). While having a sizeable uncertainty, which largely stems from the limited set of gauge configurations, the various lattice determinations agree within uncertainties and the more precise determinations show considerable tension with the observation by SELEX, but agree quite well with the observed mass from LHCb.…”

Diagonal and transition magnetic moments of negative parity heavy baryons in QCD sum rules

“…The properties of heavy baryons have been studied in framework of the various methods such as, relativistic quark model [2], variational approach [3], constituent quark model [4], lattice QCD model [5], QCD sum rules method [6]. Recent progress on this subject can be found in [7].…”