Improved semileptonic form factor calculations in lattice QCD

Evans, Richard and Bali, Gunnar and Collins, Sara (2010) Improved semileptonic form factor calculations in lattice QCD. PHYSICAL REVIEW D, 82 (9): 094501. ISSN 2470-0010, 2470-0029

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Abstract

We investigate the computational efficiency of two stochastic based alternatives to the sequential propagator method used in lattice QCD calculations of heavy-light semileptonic form factors. In the first method, we replace the sequential propagator, which couples the calculation of two of the three propagators required for the calculation, with a stochastic propagator so that the calculations of all three propagators are independent. This method is more flexible than the sequential propagator method but introduces stochastic noise. We study the noise to determine when this method becomes competitive with the sequential propagator method, and find that for any practical calculation it is competitive with or superior to the sequential propagator method. We also examine a second stochastic method, the so-called "one-end trick,'' concluding it is relatively inefficient in this context. The investigation is carried out on two gauge field ensembles, using the nonperturbatively improved Wilson-Sheikholeslami-Wohlert action with N-f = 2 mass-degenerate sea quarks. The two ensembles have similar lattice spacings but different sea-quark masses. We use the first stochastic method to extract O(a)-improved, matched lattice results for the semileptonic form factors on the ensemble with lighter sea quarks, extracting f(+)(0).

Item Type: Article
Uncontrolled Keywords: ESTIMATOR; MATRIX;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Theroretical Physics > Chair Professor Schäfer > Group Gunnar Bali
Depositing User: Dr. Gernot Deinzer
Date Deposited: 07 Jul 2020 06:05
Last Modified: 07 Jul 2020 06:05
URI: https://pred.uni-regensburg.de/id/eprint/23893

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