Chirally improving Wilson fermions - I. O(a) improvement

G.C. Rossi (Univ. Roma Tor Vergata); Milano); R. Frezzotti (INFN

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Chirally improving Wilson fermions - I. O(a) improvement

R. Frezzotti (INFN, Milano), G.C. Rossi (Univ. Roma Tor Vergata)

High Energy Physics - Lattice · Submitted 12 Jun 2003

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign.

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arXiv IDhep-lat/0306014 (version 3)

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CitationG.C. Rossi (Univ. Roma Tor Vergata), Milano), R. Frezzotti (INFN. "Chirally improving Wilson fermions - I. O(a) improvement." arXiv:hep-lat/0306014 (2003). https://pith.science/paper/IUHLHYSF

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What the abstract itself states, as probabilities: claims first 0.06 · states limitation 0.43 · human participants 0.01 · controlled comparison 0.32 · randomized assignment 0.01 · states quantitative result 0.24 · compares with prior results 0.78 · mentions code or data availability 0.02.

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We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign. Improved hadronic masses and matrix elements can be obtained by similarly averaging the corresponding physical quantities separately computed within the two regularizations. To deal with the problems related to the spectrum of the Wilson--Dirac operator, which are particularly worrisome when Wilson and mass terms are such as to give contributions of opposite sign to the real part of the eigenvalues, we propose to use twisted-mass lattice QCD for the actual computation of the quantities taking part to the averages. The choice $\pm \pi/2$ for the twisting angle is particularly interesting, as O($a$) improved estimates of physical quantities can be obtained even without averaging data from lattice formulations with opposite Wilson terms. In all cases little or no extra computing power is necessary, compared to simulations with standard Wilson fermions or twisted-mass lattice QCD.

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What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign.	contribution 0.68	0.87	0.85	asserted 0.67
s1	Improved hadronic masses and matrix elements can be obtained by similarly averaging the corresponding physical quantities separately computed within the two regularizations.	result 0.43	0.48	0.11	hedged possibility 0.51
s2	To deal with the problems related to the spectrum of the Wilson--Dirac operator, which are particularly worrisome when Wilson and mass terms are such as to give contributions of opposite sign to the real part of the eigenvalues, we propose to use twisted-mass lattice QCD for the actual computation of the quantities taking part to the averages.	method 0.87	0.39	0.09	hedged possibility 0.69
s3	The choice $\pm \pi/2$ for the twisting angle is particularly interesting, as O($a$) improved estimates of physical quantities can be obtained even without averaging data from lattice formulations with opposite Wilson terms.	result 0.62	0.65	0.21	asserted 0.78
s4	In all cases little or no extra computing power is necessary, compared to simulations with standard Wilson fermions or twisted-mass lattice QCD.	interpretation 0.56	0.46	0.06	asserted 0.95

What kind of paper the classifier reports this is: method or tool 0.92 · evidence from argument 0.51.

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Original abstract

We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign. Improved hadronic masses and matrix elements can be obtained by similarly averaging the corresponding physical quantities separately computed within the two regularizations. To deal with the problems related to the spectrum of the Wilson--Dirac operator, which are particularly worrisome when Wilson and mass terms are such as to give contributions of opposite sign to the real part of the eigenvalues, we propose to use twisted-mass lattice QCD for the actual computation of the quantities taking part to the averages. The choice $\pm \pi/2$ for the twisting angle is particularly interesting, as O($a$) improved estimates of physical quantities can be obtained even without averaging data from lattice formulations with opposite Wilson terms. In all cases little or no extra computing power is necessary, compared to simulations with standard Wilson fermions or twisted-mass lattice QCD.

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161 arXiv papers cite this in 259 sentences

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Papers whose main result relates to this one's

Found among the papers closest to this one by title and main claim. Pith's classifier compared each pair's main results and a second model family confirmed the relation; checked against two further families, shown conflicts agreed 118 times in 120 and shown same results 218 times in 239. The quoted sentence is the other paper's main claim.

States the same result 1 paper

It is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with standard and twisted Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign.

Chirally improving Wilson fermions · 0.84

Papers citing it · 159 sentences without a confident label

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Once the bare charm quark mass $μ_c$ is extracted, we renormalise it in the RI-MOM scheme: $m^RI-MOM_c = Z^RI-MOM_μμ_c$ where $Z^RI-MOM_μ=1/Z^RI-MOM_P$ in TmQCD [ref] .

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We calculate for the first time the bare matrix elements of all the relevant 4-quark operators for one ensemble of $N_f=2+1+1$ twisted mass fermions [ref] at maximal twist [ref] at pion mass $M_π = 260$ MeV generated by the Extended Twisted Mass Collaboration (ETMC) [ref] .

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According to Ref. [ref] , in order to guarantee the $O(a)$ improvement of the extracted matrix elements we consider the two kinematics with opposite spatial momenta of the parent and child mesons and perform the following average:

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In our work we used two gauge ensembles generated by the JLQCD collaboration [ref] and by the ETM collaboration [ref] , which use Domain Wall fermions and Twisted-Mass Wilson fermions respectively.

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It depends on [equation] The expression for $M_π^2$ explicitly verifies that $O(a)$-improvement of the pion mass requires both twist angles to be at maximal twist [ref] .

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We remark that the nonconserved local currents do not spoil the automatic $𝒪(a)$ improvement [ref] and the four-point function in Eq. ([ref]) is therefore $𝒪(a)$ improved.

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The presence of lattice artifacts brings in new types of mass terms, one of which is often referred to as a “twisted” mass [ref] .

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Moreover, another class of mixed actions involves using variants of the sea action in the valence sector, such as Osterwalder-Seiler quarks on a twisted mass sea [ref] .], namely using maximally twisted mass fermions [ref] in the sea sector and overlap fermions in the valence sector.

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In Sec. [ref] we move onto twisted-mass fermions, focusing first on the phase diagram and pion masses in the case of maximal twist, where most simulations have been done because of the property of automatic $𝒪(a)$ improvement [ref] .

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