Heavy and Light Quarks With Lattice Chiral Fermions

We introduce a stochastic method with low-mode substitution to evaluate the connected threepoint functions. The isovector matrix elements of the nucleon for the axial-vector coupling g 3 A , scalar couplings g 3 S and the quark momentum fraction x u−d are calculated with overlap fermion on 2+1 flavor domain-wall configurations on a 24 3 ×64 lattice at mπ = 330 MeV with lattice spacing a = 0.114 fm.

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“…To assess this error, we shall calculate the 3pt function at three values of t 2 so that we can fit all four terms in Eq. (30).…”

Section: Resultsmentioning

confidence: 99%

Stochastic method with low mode substitution for nucleon isovector matrix elements

et al. 2016

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“…The values of Z QQ R QQ for three lattice spacings are plotted in the left panel of Fig. 4, and the values at a 2 p 2 = 0 limit are obtained based on linear extrapolation of the data in the range a 2 p 2 ∈ [4,8]. It turns out that the a 2 p 2 dependence is small by usingp µ in the definition of the tree level operator and projection, when the chosen momenta are along the body-diagonal direction.…”

Section: Numerical Setupmentioning

confidence: 99%

“…4, the other two terms needed by the singlet quark EMT renormalization, δZ QQ R QQ and Z QG R GQ for the disconnected contribution, are plotted. Regardless of the simulation details of the Z QG which will be addressed later, the contribution of second term is much smaller than the first term, and thus the a 2 p 2 extrapolation can be carried out with the δZ QQ R QQ term alone in the a 2 p 2 ∈ [4,8] range, considering the value of the other term as a systematic uncertainty which is ∼0.001. Note that the CDER technique [18] is applied to the correlation function of δZ QQ with the cutoff r 0 ∼ 1 fm, In our previous investigation of the glue EMT renormalization [19], we chose the momenta with two transverse components to calculate Z GG :…”

Section: Numerical Setupmentioning

confidence: 99%

Proton Mass Decomposition from the QCD Energy Momentum Tensor

et al. 2018

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We report results on the proton mass decomposition and also on related quark and glue momentum fractions. The results are based on overlap valence fermions on four ensembles of N f = 2 + 1 DWF configurations with three lattice spacings and three volumes, and several pion masses including the physical pion mass. With fully non-perturbative renormalization (and universal normalization on both quark and gluon), we find that the quark energy and glue field energy contribute 33(4)(4)% and 37(5)(4)% respectively in the M S scheme at µ = 2 GeV. A quarter of the trace anomaly gives a 23 (1)(1)% contribution to the proton mass based on the sum rule, given 9(2)(1)% contribution from the u, d, and s quark scalar condensates. The u, d, s and glue momentum fractions in the M S scheme are in good agreement with global analyses at µ = 2 GeV.Introduction: In the standard model, Higgs boson provides the origin of quark masses. But how it is related to the proton mass and thus the masses of nuclei and atoms is another question. The masses of the valence quarks in the proton are just ∼3 MeV per quark which is directly related to the Higgs boson, while the total proton mass is 938 MeV. The percentage of the quark and gluon contributions to the proton mass can only be provided by solving QCD non-perturbatively, and/or with information from experiment. With phenomenological input, the first decomposition was carried out by Ji [1]. As in Refs. [1,2], the Hamiltonian of QCD can be decomposed asin the rest frame of the hadron state where M is the hadron mass, T µν is the energy momentum tensor of QCD with T 44 as its expectation value in the hadron, and the trace anomaly gives

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“…The effective quark propagator of the massive overlap fermion is the inverse of the operator (D c + m) [10,11], where D c is chiral, i.e. {D c , γ 5 } = 0 [12], and is expressed in terms of the overlap operator D ov as (14) where is the matrix sign function and D w is the Wilson Dirac operator with a negative mass characterized by the parameter ρ = 4 − 1/2κ for κ c < κ < 0.25.…”

Section: Numerical Detailsmentioning

confidence: 99%

Meson mass decomposition from lattice QCD

et al. 2015

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Hadron masses can be decomposed as a sum of quark and glue components which are defined through hadronic matrix elements of QCD operators. The components consist of the quark mass term, the quark energy term, the glue energy term, and the trace anomaly term. We calculate these components for mesons with lattice QCD for the first time. The calculation is carried out with overlap fermion on 2 + 1 flavor domain-wall fermion gauge configurations. We confirm that ∼ 50% of the light pion mass comes from the quark mass term and ∼ 10% comes from the quark energy; whereas, while for the ρ meson, the quark energy contributes roughly half of its mass but the quark mass term contributes little. The combined glue components contribute ∼ 40 − 50% for both mesons. It is interesting to observe that the quark mass contribution to the mass of the vector meson is almost linear in quark mass over a large quark mass region below the charm quark mass. For heavy mesons, the quark mass term dominates the masses, while the contribution from the glue components is about 200 MeV (a bare value around 2 GeV) for the heavy pseudoscalar and vector mesons. The charmonium hyperfine splitting is found to be dominated by the quark energy term which is consistent with the picture of the quark potential model.

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Heavy and Light Quarks With Lattice Chiral Fermions

Cited by 45 publications

References 39 publications

Stochastic method with low mode substitution for nucleon isovector matrix elements

Stochastic method with low mode substitution for nucleon isovector matrix elements

Proton Mass Decomposition from the QCD Energy Momentum Tensor

Meson mass decomposition from lattice QCD

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