How much do charm sea quarks affect the charmonium spectrum?

Abstract

The properties of charmonium states are or will be intensively studied by the B-factories Belle II and BESIII, the LHCb and PANDA experiments and at a future Super-c-tau Factory. Precise lattice calculations provide valuable input and several results have been obtained by simulating up, down and strange quarks in the sea. We investigate the impact of a charm quark in the sea on the charmonium spectrum, the renormalization group invariant charm-quark mass and the scalar charm-quark content of charmonium. The latter is obtained by the direct computation of the mass-derivatives of the charmonium masses. We do this investigation in a model, QCD with two degenerate charm quarks. The absence of light quarks allows us to reach very small lattice spacings down to 0.023 fm. By comparing to pure gauge theory we find that charm quarks in the sea affect the hyperfine splitting at a level below 2%. The most significant effects are 5% in the quark mass and 3% in the value of the charm quark content of the eta_c meson. Given that we simulate two charm quarks these estimates are upper bounds for the contribution of a single charm quark. We show that lattice spacings <0.06 fm are needed for safe continuum extrapolations of the charmonium spectrum with O(a) improved Wilson quarks. A useful relation for the projection to the desired parity of operators in two-point functions computed with twisted mass fermions is proven.

arXiv comment25 pages, 8 figures

References in corpus (34)

• Observation of a narrow charmonium-like state in exclusive B+ -> K+ pi+pi- J/psi decays
• Observation of a New Narrow Charmonium State in Exclusive B+-->K+ pi+pi- J/psi Decays
• Observation of $J/\psi p$ resonances consistent with pentaquark states in ${\Lambda }_b^0\to J/\psi K^{-}p$ decays
• Highly Improved Staggered Quarks on the Lattice, with Applications to Charm Physics
• Non-perturbative O(a) improvement of lattice QCD
• Perturbative analysis of the gradient flow in non-abelian gauge theories
• Chirally improving Wilson fermions - I. O(a) improvement
• Trivializing maps, the Wilson flow and the HMC algorithm
• Infinite N phase transitions in continuum Wilson loop operators
• Speeding up the Hybrid-Monte-Carlo algorithm for dynamical fermions
• Critical slowing down and error analysis in lattice QCD simulations
• Excited and exotic charmonium spectroscopy from lattice QCD
• Non-perturbative determination of the axial current normalization constant in O(a) improved lattice QCD
• Lattice QCD with open boundary conditions and twisted-mass reweighting
• Lattice QCD without topology barriers
• The strange quark mass and Lambda parameter of two flavor QCD
• Evidence of Two Resonant Structures in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{h}_c$
• Computation of the strong coupling in QCD with two dynamical flavours
• Excited and exotic charmonium, $D_s$ and $D$ meson spectra for two light quark masses from lattice QCD
• Solution of the Dirac equation in lattice QCD using a domain decomposition method
• Non-perturbative renormalization of the axial current with dynamical Wilson fermions
• Adaptive Aggregation-based Domain Decomposition Multigrid for Twisted Mass Fermions
• High precision renormalization of the flavour non-singlet Noether currents in lattice QCD with Wilson quarks
• A precise determination of the charm quark's mass in quenched QCD
• The eta' meson from lattice QCD
• Charm annihilation effects on the hyperfine splitting in charmonium
• Masses of $D$ mesons, $D_s$ mesons and charmonium states from twisted mass lattice QCD
• On the effects of heavy sea quarks at low energies
• Power corrections from decoupling of the charm quark
• How perturbative are heavy sea quarks?
• Identifying spin and parity of charmonia in flight with lattice QCD
• Splittings of low-lying charmonium masses at the physical point
• Charmonium and exotics from lattice QCD
• Non-perturbative tests of continuum HQET through small-volume two-flavour QCD

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• FLAG Review 2021
• Doubly Charmed Tetraquark $T_{cc}^{+}$ from Lattice QCD near Physical Point
• FLAG Review 2024
• Past, present, and future of precision determinations of the QCD coupling from lattice QCD
• Optimising creation operators for charmonium spectroscopy on the lattice
• Determination of the charm quark mass in lattice QCD with $2+1$ flavours on fine lattices
• Scale setting for $N_f=3+1$ QCD
• Constructing static quark-anti-quark creation operators from Laplacian eigenmodes
• Quark flavor physics and lattice QCD
• Charm sea effects on charmonium decay constants and heavy meson masses