Contributions of charm anihilation to the hyperfine splitting in charmonium

Levkova, L.; DeTar, C.

doi:10.48550/arxiv.0809.5086

Cited by 4 publications

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“…Charm annihilation processes give a possible additional correction to the charmonium hyperfine splitting. DeTar and Levkova (2007) and Levkova and DeTar (2009) have started to study these quark-line disconnected diagrams using MILC ensembles with lattice spacings a ≈ 0.06 and 0.09 fm. They use stochastic estimators with unbiased subtraction (Mathur and Dong, 2003) to compute the disconnected contribution to the η c propagator.…”

Section: Onia With Fermilab Quarksmentioning

confidence: 99%

“…They use stochastic estimators with unbiased subtraction (Mathur and Dong, 2003) to compute the disconnected contribution to the η c propagator. They find that annihilation processes increase the η c mass a small amount (by 5.5(8) MeV for a fine lattice and 3.4(3) MeV for superfine), thereby decreasing slightly the predicted hyperfine splitting (Levkova and DeTar, 2009).…”

Section: Onia With Fermilab Quarksmentioning

confidence: 99%

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Nonperturbative QCD simulations with2+1flavors of improved staggered quarks

et al. 2010

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Dramatic progress has been made over the last decade in the numerical study of quantum chromodynamics (QCD) through the use of improved formulations of QCD on the lattice (improved actions), the development of new algorithms and the rapid increase in computing power available to lattice gauge theorists. In this article we describe simulations of full QCD using the improved staggered quark formalism, "asqtad" fermions. These simulations were carried out with two degenerate flavors of light quarks (up and down) and with one heavier flavor, the strange quark. Several light quark masses, down to about 3 times the physical light quark mass, and six lattice spacings have been used. These enable controlled continuum and chiral extrapolations of many low energy QCD observables. We review the improved staggered formalism, emphasizing both advantages and drawbacks. In particular, we review the procedure for removing unwanted staggered species in the continuum limit. We then describe the asqtad lattice ensembles created by the MILC Collaboration.All MILC lattice ensembles are publicly available, and they have been used extensively by a number of lattice gauge theory groups. We review physics results obtained with them, and discuss the impact of these results on phenomenology. Topics include the heavy quark potential, spectrum of light hadrons, quark masses, decay constant of light and heavy-light pseudoscalar mesons, semileptonic form factors, nucleon structure, scattering lengths and more. We conclude with a brief look at highly promising future prospects. PACS numbers: 12.38.Gc, 11.15.Ha 3. Staggered fermions 16 4. Chirally invariant fermions 21 C. Numerical simulations 25 D. Asqtad improved staggered fermions 29 E. Highly improved staggered fermions 32 III. Staggered chiral perturbation theory and "rooting" 34 A. Chiral effective theory for staggered quarks 34 B. Extensions of staggered chiral perturbation theory 41 C. The issue of rooting 45 IV. Overview of the MILC lattice ensembles 56 A. Algorithms and algorithm tests 57 B. The static potential and determining the lattice spacing 62 C. Tuning the strange quark mass 68 D. The topological susceptibility 68 V. Spectroscopy of light hadrons 71 A. Hadron mass computations 72 B. Correlated fits 76 C. Results for some light hadrons 79 3 D. Flavor singlet spectroscopy 83 E. Scalar mesons f 0 and a 0 84 F. Summary 88 VI. Results for the light pseudoscalar mesons 88 A. Motivation 88 B. From correlators to lattice masses and decay constants 88 C. Other computations of f π and f K 95 VII. Heavy-light mesons: masses and decay constants 96 A. Heavy quarks on the lattice 97 1. Nonrelativistic QCD 98 2. Wilson fermions with the Fermilab interpretation 98 3. The HISQ action 99 B. Lattice calculations of masses and decay constants 100 C. Results for masses, decay constants, and CKM matrix elements 104 VIII. Semileptonic form factors 107 A. D → πℓν and D → Kℓν 107 B. B → πℓν and |V ub | 109 C. B → Dℓν and B → D * ℓν 113 IX. Other computations using MILC lattices 116 A. Determination of ...

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Section: Onia With Fermilab Quarksmentioning

confidence: 99%

Section: Onia With Fermilab Quarksmentioning

confidence: 99%

Nonperturbative QCD simulations with2+1flavors of improved staggered quarks

et al. 2010

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“…However, the unrealistically heavy pion mass might have affected our conclusion. Runs on 24 3 × 48 lattices with m π ≈ 400 MeV will clarify this issue. Furthermore, mixing with other states like glueballs deserves future attention.…”

Section: The Mixingmentioning

confidence: 99%

Investigation of the $\eta'$-$\eta_c$-mixing with improved stochastic estimators

Ehmann¹,

Bali²

2009

Proceedings of the XXVI International Symposium on Lattice Field Theory — PoS(LATTICE 2008)

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Charmonia are flavour singlet mesons and thus in principle contributions from disconnected quark line diagrams might affect their masses, either directly or via mixing with other flavour singlet channels. We present a first study that takes both effects into account. We employ improved stochastic all-to-all propagator techniques (including new methods) to calculate the diagrams that appear within the mixing matrix between the η ′ and the η c . The runs are initially performed on N f = 2 16 3 × 32 configurations with the non-perturbatively improved Sheikholeslami-Wilson action, both for valence and sea quarks.

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“…Nonetheless, there are situations that require tuning the quarkonium rest mass. For our companion study of charmonium annihilation effects, mixing between quarkonium states and glueball states could be important [9]. In this case it is important to arrange for a correct placement of the unmixed charmonium and glueball eigenenergies of the lattice hamiltonian, i.e., the unmixed rest masses [10].…”

Section: Tuning the Heavy Quark Massesmentioning

confidence: 99%

“…The contribution to the charmonium correlator and mass from quark line disconnected diagrams is expected to be small, so they are usually ignored. Because it is so small, it is a challenge to calculate it [9]. Our most recent results are given in Table 3.1.…”

Section: Charmonium Hyperfine Splittingmentioning

confidence: 99%

Quarkonium mass splittings with Fermilab heavy quarks and 2+1 flavors of improved staggered sea quarks

Burch,

DeTar,

Di Pierro

et al. 2009

Preprint

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We present results from an ongoing lattice study of the lowest lying charmonium and bottomonium level splittings using the Fermilab heavy quark formalism. Our objective is to test the performance of this action on MILC-collaboration ensembles of (2 + 1) flavors of light improved staggered (asqtad) quarks. Measurements are done on 16 ensembles with degenerate up and down quarks of various masses, thus permitting a chiral extrapolation, and over lattice spacings ranging from 0.09 fm to 0.18 fm, thus permitting study of lattice-spacing dependence. We examine combinations of the mass splittings that are sensitive to components of the effective quarkonium potential.

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Contributions of charm anihilation to the hyperfine splitting in charmonium

Cited by 4 publications

References 0 publications

Nonperturbative QCD simulations with2+1flavors of improved staggered quarks

Nonperturbative QCD simulations with2+1flavors of improved staggered quarks

Investigation of the $\eta'$-$\eta_c$-mixing with improved stochastic estimators

Quarkonium mass splittings with Fermilab heavy quarks and 2+1 flavors of improved staggered sea quarks

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