Highly improved staggered quarks on the lattice with applications to charm physics

By E. Follana, Q. Mason, C. Davies, K. Hornbostel, G. Peter Lepage, J. Shigemitsu, H. Trottier, K. Wong. 2006

376 citations recorded by the source corpus.

We use perturbative Symanzik improvement to create a new staggered-quark action (HISQ) that has greatly reduced one-loop taste-exchange errors, no tree-level order a{sup 2} errors, and no tree-level order (am){sup 4} errors to leading order in the quark's velocity v/c. We demonstrate with simulations that the resulting action has taste-exchange interactions that are 3-4 times smaller than the widely used ASQTAD action. We show how to bound errors due to taste exchange by comparing ASQTAD and HISQ simulations, and demonstrate with simulations that such errors are likely no more than 1% when HISQ is used for light quarks at lattice spacings of 1/10 fm or less. The suppression of (am){sup 4} errors also makes HISQ the most accurate discretization currently available for simulating c quarks. We demonstrate this in a new analysis of the {psi}-{eta}{sub c} mass splitting using the HISQ action on lattices where am{sub c}=0.43 and 0.66, with full-QCD gluon configurations (from MILC). We obtain a result of 111(5) MeV which compares well with the experiment. We discuss applications of this formalism to D physics and present our first high-precision results for D{sub s} mesons.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/de8d519edecd738c655f4e39f8096200cd972f3d

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Citations in the corpus

Review of lattice results concerning low-energy particle physics (2016, methodology): “An improvement program can be used to suppress tastechanging interactions, leading to “improved staggered fermions,” with the so-called “Asqtad” [715], “HISQ” [716], “Stout-smeared” [717], and “HYP” [478] actions as the most common versions.”
Charmed bottom baryon spectroscopy from lattice QCD (2014, background): “At leading order in perturbation theory, the resulting mass shift of the ηc can be expressed in terms of its hadronic width [78, 79],”
Light Hadron Masses from Lattice QCD (2012, background): “More recently, two steps of fat7 link smearing, the first one without the second one with Lepage term, with a gauge group projection after the first smearing step were suggested by (Follana et al., 2007).”
Excited and exotic charmonium spectroscopy from lattice QCD (2012, methodology): “Overlaps, Z i ≡ 〈n|O † i |0〉, for the lightest P-wave (left panel) and D-wave (right panel) supermultiplets with operators {π, ρ}NR ×D([1]) J=1 and {π, ρ}NR ×D [2] J=2 respectively.”
Probing Novel Scalar and Tensor Interactions from (Ultra)Cold Neutrons to the LHC (2011, background): “etails on the domain-wall fermion (DWF) formulation are given in Refs. [71, 72, 73, 74, 75]; clover fermions in Ref. [76]; twisted-mass fermions in Ref. [77]; and improved staggered fermions in Refs. [78, 79, 80]. Calculation of the isovector nuclear matrix elements requires two separate optimizatio”
FLAG Review 2019 (2019, methodology): “Although logically distinct from the light-quark improvement program for these actions, it is customary with the HISQ action to include an additional correction designed to reduce discretization errors for heavy quarks (in practice, usually charm quarks) [1010].”
Quarkonia and their transitions (2007, background): “For example, recent lattice calculations of the spin-splitting between J/ψ and ηc yield 111± 5 MeV (Follana et al., 2007), while the experimental value is 117.1± 1.2 MeV.”
Flavor Physics in the Quark Sector (2009, background): “The Highly Improved Staggered Quark (HISQ) action for charm quarks [866] eliminates the (mca) 2 term and results at three values of the lattice spacing then give an accurate extrapolation to a = 0 with a 2% final error [340].”
Leading hadronic contribution to the muon magnetic moment from lattice QCD (2020, background): “ix and we drop the avor index for simplicity. Equation (110) is just the conserved vector current of the staggered fermion action. Staggered bilinears can be assigned with a spin taste structure, see [67] for a modern treatment. In the case of the operator in (110), two such assignments can be given”
A Guide to Light-Cone PDFs from Lattice QCD: An Overview of Approaches, Techniques, and Results (2018, methodology): “Clover valence fermions were employed on an Nf=2+1+1 HISQ ensemble [213].”