Continuum limit of overlap valence quarks on a twisted mass sea

Cichy, Krzysztof; Herdoíza, Gregorio; Jansen, Karl

doi:10.1016/j.nuclphysb.2011.01.021

Cited by 17 publications

(37 citation statements)

References 60 publications

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“…There have been a few other choices for mixed actions all utilizing overlap [80,81] valence-fermions on a variety of sea-quark configurations. These include Wilson sea-fermions [82], twisted-mass sea-fermions [83,84], domain-wall sea fermions [85,86], and HISQ sea fermions [87]. Mixed-action calculations are inherently unitarity violating with partially quenched effects only vanishing in the continuum limit.…”

Section: Details Of the Lattice Calculation And Numerical Resultsmentioning

confidence: 99%

Scalar strange content of the nucleon from lattice QCD

2013

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The scalar strange-quark matrix element of the nucleon is computed with lattice QCD. A mixedaction scheme is used with domain-wall valence fermions computed on the staggered MILC seaquark configurations. The matrix element is determined by making use of the Feynman-Hellmann theorem which relates this strange matrix element to the change in the nucleon mass with respect to the strange-quark mass. The final result of this calculation is m s N |ss|N = 49 ± 10 ± 15 MeV and, correspondingly f s = m s N |ss|N /m N = 0.053 ± 0.011 ± 0.016.Given the lack of a quantitative comparison of this phenomenologically important quantity determined from various lattice QCD calculations, we take the opportunity to present such an average. The resulting conservative determination is f s = 0.043 ± 0.011.Typeset by REVT E X 1

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Section: Details Of the Lattice Calculation And Numerical Resultsmentioning

confidence: 99%

Scalar strange content of the nucleon from lattice QCD

2013

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“…[40,41] to the partially quenched theory. It would also be interesting to compare results obtained using (51) with those from other recently proposed methods for determining W ′ 8 , which are based on using a mixed action [42] or on partially quenched pion scattering amplitudes [43].…”

Section: Discussionmentioning

confidence: 99%

Constraint on the low energy constants of Wilson chiral perturbation theory

Hansen

Sharpe

2012

Phys. Rev. D

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Wilson chiral perturbation theory (WChPT) is the effective field theory describing the longdistance properties of lattice QCD with Wilson or twisted-mass fermions. We consider here WChPT for the theory with two light flavors of Wilson fermions or a single light twisted-mass fermion. Discretization errors introduce three low energy constants (LECs) into partially quenched WChPT at O(a 2 ), conventionally called W ′ 6 , W ′ 7 and W ′ 8 . The phase structure of the theory at non-zero a depends on the sign of the combination 2W ′ 6 + W ′ 8 , while the spectrum of the lattice Hermitian Wilson-Dirac operator depends on all three constants. It has been argued, based on the positivity of partition functions of fixed topological charge, and on the convergence of graded group integrals that arise in the ǫ-regime of ChPT, that there is a constraint on the LECs arising from the underlying lattice theory. In particular, for W ′ 6 = W ′ 7 = 0, the constraint found is W ′ 8 ≤ 0. Here we provide an alternative line of argument, based on mass inequalities for the underlying partially quenched theory. We find that W ′ 8 ≤ 0, irrespective of the values of W ′ 6 and W ′ 7 . Our constraint implies that 2W ′ 6 > |W ′ 8 | if the phase diagram is to be described by the first-order scenario, as recent simulations suggest is the case for some choices of action.

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“…The simulations considered in this work [65,87] were performed at three values of the lattice gauge coupling β = 3.90, 4.05 and β = 4.20, corresponding to values of the lattice spacing a ≈ 0.08 fm, 0.07 fm and 0.05 fm, respectively. The charged pion mass M π ± approximately ranges from 310 MeV to 460 MeV.…”

Section: N F = 2 Wtm Fermions With Tlsym Gauge Actionmentioning

confidence: 99%