Spectroscopy of doubly charmed baryons from lattice QCD

Abstract

We present the ground and excited state spectra of doubly charmed baryons from lattice QCD with dynamical quark fields. Calculations are performed on anisotropic lattices of size 16 3 ×128, with inverse spacing in temporal direction a −1 t = 5.67(4) GeV and with a pion mass of about 390 MeV. A large set of baryonic operators that respect the symmetries of the lattice yet which retain a memory of their continuum analogues are used. These operators transform as irreducible representations of SU(3)F symmetry for flavor, SU(4) symmetry for Dirac spins of quarks and O(3) for spatial symmetry. The distillation method is utilized to generate baryon correlation functions which are analysed using the variational fitting method to extract excited states. The lattice spectra obtained have baryonic states with well-defined total spins up to 7 2 and the pattern of low lying states does not support the diquark picture for doubly charmed baryons. On the contrary the calculated spectra are remarkably similar to the expectations from models with an SU(6)× O(3) symmetry. Various spin dependent energy splittings between the extracted states are also evaluated.

Low-lying baryon masses using Nf=2 twisted mass clover-improved fermions directly at the physical pion mass

“…8 and 9 we illustrate the lattice QCD results mentioned above for the spin-1/2 and spin-3/2 charmed baryons, respectively, omitting the results from Ref. [31] that were not extrapolated to the physical point. As in the octet and decuplet case, the error bar in our results denotes the statistical and systematic errors added in quadrature, however in most cases it is too small to be visible.…”

“…Two values of the lattice spacing, a = 0.085 and 0.112 fm and seven values of the pion mass were employed, and chiral and continuum extrapolations were performed. In addition, the Hadron Spectrum Collaboration (HSC) obtained results on the doubly charmed baryons from gauge ensembles using the tree-level Symanzik-improved gauge action and clover fermions using an anisotropic lattice with the lattice spacing in the temporal direction a t = 0.035 fm and in the spatial directions a s = 0.12 fm, at a single pion mass of m π = 390 MeV [31]. Finally, the RQCD group [30] has calculated the singly and doubly charmed baryon spectrum from N f = 2 + 1 non-perturbatively improved Wilson-clover fermions in a pion mass range of m π = 260 ∼ 460 MeV and a = 0.075 fm.…”

“…Many of these calculations perform chiral and continuum extrapolations. Recently, the study was extended to the higher spins of 5/2 and 7/2 and excited states using an ensemble of clover fermions on an asymmetric lattice at a pion mass of m π = 391 MeV [31]. We make a thorough discussion of the various lattice calculations and how they compare with our results and the experimental values in Sec.…”

From deep inelastic scattering to heavy-flavor semileptonic decays: Total rates into multihadron final states from lattice QCD

“…Providing estimates of the lifetime of the doubly charmed baryons Ξ + cc [47] and Ξ ++ cc would help their search at LHCb. The spectroscopy of these heavy baryons has recently been studied on the lattice [48].…”

Meson resonances on the lattice

“…also in a number of other calculations performed by the Hadron Spectrum Collaboration, including the determination of the gross features of excited light meson spectrum [4,5], the flavor structure of isoscalar mesons [11,12], the excited spectrum of charmonium and charmed mesons [13,14], decay constants of excited pions [15], and the spectrum of baryons [16,17,18,19,20]. …”