Search NASAβŒ• Search

Engineering topics

Miller, Nolan

Publications and source records attributed to Miller, Nolan.

Scale setting the MΓΆbius domain wall fermion on gradient-flowed HISQ action using the omega baryon mass and the gradient-flow scales 𝑑 0 and 𝑀 0

We report on a subpercent scale determination using the omega baryon mass and gradient-flow methods. The calculations are performed on 22 ensembles of 𝑁 𝑓 =2 +1 +1 highly improved, rooted staggered sea-quark configurations generated by the MILC and CalLat Collaborations. The valence quark action used is MΓΆbius domain wall fermions solved on these configurations after a gradient-flow smearing is applied with a flowtime of 𝑑 gf = 1 in lattice units. The ensembles span four lattice spacings in the range 0.06 ≲ π‘Ž ≲0.15 fm, six pion masses in the range 130 ≲ π‘š πœ‹ ≲ 400 MeV and multiple lattice volumes. On each ensemble, the gradient-flow scales 𝑑 0 /π‘Ž 2 and 𝑀 0 /π‘Ž and the omega baryon mass π‘Žβ’π‘š Ξ© are computed. The dimensionless product of these quantities is then extrapolated to the continuum and infinite volume limits and interpolated to the physical light, strange and charm quark mass point in the isospin limit, resulting in the determination of $\sqrt{t}_0$ = 0.1422⁒(14) fm and 𝑀 0 = 0.1709⁒(11) fm with all sources of statistical and systematic uncertainty accounted for. The dominant uncertainty in both results is the stochastic uncertainty, though for $\sqrt{t}_0$ there are comparable continuum extrapolation uncertainties. For 𝑀 0 , there is a clear path for a few-per-mille uncertainty just through improved stochastic precision, as recently obtained by the Budapest-Marseille-Wuppertal Collaboration.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

𝐹 𝐾 ⁑/𝐹 πœ‹ from MΓΆbius domain-wall fermions solved on gradient-flowed HISQ ensembles

We report the results of a lattice quantum chromodynamics calculation of 𝐹 𝐾 ⁑/𝐹 πœ‹ using MΓΆbius domain-wall fermions computed on gradient-flowed 𝑁 𝑓 =2 +1 +1 highly improved staggered quark (HISQ) ensembles. The calculation is performed with five values of the pion mass ranging from 130 ≲ π‘š πœ‹ ≲ 400 MeV , four lattice spacings of π‘Ž ∼ 0.15, 0.12, 0.09 and 0.06 fm and multiple values of the lattice volume. The interpolation/extrapolation to the physical pion and kaon mass point, the continuum, and infinite volume limits are performed with a variety of different extrapolation functions utilizing both the relevant mixed-action effective field theory expressions as well as discretization-enhanced continuum chiral perturbation theory formulas. We find that the π‘Ž ∼ 0.06 fm ensemble is helpful, but not necessary to achieve a subpercent determination of 𝐹 𝐾 ⁑/𝐹 πœ‹ . We also include an estimate of the strong isospin breaking corrections and arrive at a final result of 𝐹 $\hat{K}$ + ⁑ /𝐹 $\hat{πœ‹}$ + = 1.1942⁒(45) with all sources of statistical and systematic uncertainty included. This is consistent with the Flavour Lattice Averaging Group average value, providing an important benchmark for our lattice action. Combining our result with experimental measurements of the pion and kaon leptonic decays leads to a determination of |𝑉 𝑒⁒𝑠 |/|𝑉 𝑒⁒𝑑 | = 0.2311⁒(10).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗