Hadron structure from lattice QCD

Green, Jeremy R.

doi:10.1063/1.4938624

Cited by 8 publications

(7 citation statements)

References 50 publications

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“…This is indeed the case for g A , which has been measured precisely [82,83] and for which there are ongoing LQCD efforts [84], with results in the physical point currently at the few-percent level [85][86][87]. As recently pointed out in ref.…”

Section: Jhep12(2016)052mentioning

confidence: 77%

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Global effective-field-theory analysis of new-physics effects in (semi)leptonic kaon decays

González–Alonso

Camalich

2016

J. High Energ. Phys.

129

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We analyze the decays K → π ν and P → ν (P = K, π, = e, µ) using a low-energy Effective-Field-Theory approach to parametrize New Physics and study the complementarity with baryon β decays. We then provide a road map for a global analysis of the experimental data, with all the Wilson coefficients simultaneously, and perform a fit leading to numerical bounds for them and for V us . A prominent result of our analysis is a reinterpretation of the well-known V ud −V us diagram as a strong constraint on new physics. Finally, we reinterpret our bounds in terms of the SU(2) L × U(1) Y -invariant operators, provide bounds to the corresponding Wilson coefficients at the TeV scale and compare our results with collider searches at the LHC.

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Section: Jhep12(2016)052mentioning

confidence: 77%

“…• Using the values in the table 2 we find log C QCD = 0.2073 (84). The correlation between this number and the quantities f K ± /f π ± and f + (0) is taken into account.…”

Section: Jhep12(2016)052mentioning

confidence: 99%

Global effective-field-theory analysis of new-physics effects in (semi)leptonic kaon decays

González–Alonso

Camalich

2016

J. High Energ. Phys.

129

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“…e.g. [17][18][19][20] and references therein). The problem is particularly acute for the axial charge of the nucleon, which is both of fundamental importance for testing the limits of the Standard Model and well known experimentally, but for which lattice results differ amongst themselves by several standard deviations and show a discrepancy of about 10% from the experimental value when extrapolated to the physical point.…”

Section: Introductionmentioning

confidence: 99%

Nucleon matrix elements from lattice QCD with all-mode-averaging and a domain-decomposed solver: An exploratory study

et al. 2017

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We study the performance of all-mode-averaging (AMA) when used in conjunction with a locally deflated SAP-preconditioned solver, determining how to optimize the local block sizes and number of deflation fields in order to minimize the computational cost for a given level of overall statistical accuracy. We find that AMA enables a reduction of the statistical error on nucleon charges by a factor of around two at the same cost when compared to the standard method. As a demonstration, we compute the axial, scalar and tensor charges of the nucleon in N f = 2 lattice QCD with non-perturbatively O(a)-improved Wilson quarks, using O(10,000) measurements to pursue the signal out to source-sink separations of t s ∼ 1.5 fm. Our results suggest that the axial charge is suffering from a significant amount (5-10%) of excited-state contamination at source-sink separations of up to t s ∼ 1.2 fm, whereas the excited-state contamination in the scalar and tensor charges seems to be small.

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“…The methodology for the lattice QCD calculations of the various matrix elements within the nucleon is well developed for most of these quantities [1][2][3][4][5]. Generation of background gauge configurations with (2+1) or (2+1+1) flavors is now standard.…”

Section: Introductionmentioning

confidence: 99%

“…The challenges to obtaining precise results for matrix elements within the nucleon ground state are the following [1][2][3][4][5]:…”

Section: Introductionmentioning

confidence: 99%

Controlling excited-state contamination in nucleon matrix elements

et al. 2016

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We present a detailed analysis of methods to reduce statistical errors and excited-state contamination in the calculation of matrix elements of quark bilinear operators in nucleon states. All the calculations were done on a 2 þ 1-flavor ensemble with lattices of size 32 3 × 64 generated using the rational hybrid Monte Carlo algorithm at a ¼ 0.081 fm and with M π ¼ 312 MeV. The statistical precision of the data is improved using the all-mode-averaging method. We compare two methods for reducing excited-state contamination: a variational analysis and a 2-state fit to data at multiple values of the source-sink separation t sep . We show that both methods can be tuned to significantly reduce excited-state contamination and discuss their relative advantages and cost effectiveness. A detailed analysis of the size of source smearing used in the calculation of quark propagators and the range of values of t sep needed to demonstrate convergence of the isovector charges of the nucleon to the t sep → ∞ estimates is presented.

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Hadron structure from lattice QCD

Cited by 8 publications

References 50 publications

Global effective-field-theory analysis of new-physics effects in (semi)leptonic kaon decays

Global effective-field-theory analysis of new-physics effects in (semi)leptonic kaon decays

Nucleon matrix elements from lattice QCD with all-mode-averaging and a domain-decomposed solver: An exploratory study

Controlling excited-state contamination in nucleon matrix elements

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