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Large computing clusters used for scientific processing suffer from systemic failures when operated over long continuous periods for executing workflows. Diagnosing job problems and faults leading to eventual failures in this complex environment is difficult, specifically when the success of an entire workflow might be affected by a single job failure. In this paper, we introduce a model-based, hierarchical, reliable execution framework that encompass workflow specification, data provenance, execution tracking and online monitoring of each workflow task, also referred to as participants. The sequence of participants is described in an abstract parameterized view, which is translated into a concrete data dependency based sequence of participants with defined arguments. As participants belonging to a workflow are mapped onto machines and executed, periodic and on-demand monitoring of vital health parameters on allocated nodes is enabled according to pre-specified rules. These rules specify conditions that must be true pre-execution, during execution and post-execution. Monitoring information for each participant is propagated upwards through the reflex and healing architecture, which consists of a hierarchical network of decentralized fault management entities, called reflex engines. They are instantiated as state machines or timed automatons that change state and initiate reflexive mitigation action(s) upon occurrence of certain faults. We describe how this cluster reliability framework is combined with the workflow execution framework using formal rules and actions specified within a structure of first order predicate logic that enables a dynamic management design that reduces manual administrative workload, and increases cluster-productivity.

We present the first computation in a program of lattice-QCD baryon physics using staggered fermions for sea and valence quarks. For this initial study, we present a calculation of the nucleon mass, obtaining \\(964\\pm16\\) MeV with all sources of statistical and systematic errors controlled and accounted for. This result is the most precise determination to date of the nucleon mass from first principles. We use the highly-improved staggered quark action, which is computationally efficient. Three gluon ensembles are employed, which have approximate lattice spacings \\(a=0.09\\) fm, \\(0.12\\) fm, and \\(0.15\\) fm, each with equal-mass \\(u\\)/\\(d\\), \\(s\\), and \\(c\\) quarks in the sea. Further, all ensembles have the light valence and sea \\(u\\)/\\(d\\) quarks tuned to reproduce the physical pion mass, avoiding complications from chiral extrapolations or nonunitarity. Our work opens a new avenue for precise calculations of baryon properties, which are both feasible and relevant to experiments in particle and nuclear physics.

We present lattice-QCD calculations of the hadronic form factors for the semileptonic decays \\(D\\to\\pi\\ell\\nu\\), \\(D\\to K\\ell\\nu\\), and \\(D_s\\to K\\ell\\nu\\). Our calculation uses the highly improved staggered quark (HISQ) action for all valence and sea quarks and includes \\(N_f=2+1+1\\) MILC ensembles with lattice spacings ranging from \\(a\\approx0.12\\) fm down to \\(0.042\\) fm. At most lattice spacings, an ensemble with physical-mass light quarks is included. The HISQ action allows all the quarks to be treated with the same relativistic light-quark action, allowing for nonperturbative renormalization using partial conservation of the vector current. We combine our results with experimental measurements of the differential decay rates to determine \\(|V_{cd}|^{D\\to\\pi}=0.2238(11)^{\\rm Expt}(15)^{\\rm QCD}(04)^{\\rm EW}(02)^{\\rm SIB}[22]^{\\rm QED}\\) and \\(|V_{cs}|^{D\\to K}=0.9589(23)^{\\rm Expt}(40)^{\\rm QCD}(15)^{\\rm EW}(05)^{\\rm SIB}[95]^{\\rm QED}\\) This result for \\(|V_{cd}|\\) is the most precise to date, with a lattice-QCD error that is, for the first time for the semileptonic extraction, at the same level as the experimental error. Using recent measurements from BES III, we also give the first-ever determination of \\(|V_{cd}|^{D_s\\to K}=0.258(15)^{\\rm Expt}(01)^{\\rm QCD}[03]^{\\rm QED}\\) from \\(D_s\\to K \\ell\\nu\\). Our results also furnish new Standard Model calculations of the lepton flavor universality ratios \\(R^{D\\to\\pi}=0.98671(17)^{\\rm QCD}[500]^{\\rm QED}\\), \\(R^{D\\to K}=0.97606(16)^{\\rm QCD}[500]^{\\rm QED}\\), and \\(R^{D_s\\to K}=0.98099(10)^{\\rm QCD}[500]^{\\rm QED}\\), which are consistent within \\(2\\sigma\\) with experimental measurements. Our extractions of \\(|V_{cd}|\\) and \\(|V_{cs}|\\), when combined with a value for \\(|V_{cb}|\\), provide the most precise test of second-row CKM unitarity, finding agreement with unitarity at the level of one standard deviation.

In the near-future noisy intermediate-scale quantum (NISQ) era of quantum computing technology, applications of quantum computing will be limited to calculations of very modest scales in terms of the number of qubits used. The need to represent numeric quantities using limited resources leads to digitization errors which must be taken into account. As a first step towards quantum simulations of realistic high-energy physics problems, we explore classically the effects of digitizing elements of the \\(\\mathrm{SU}(2)\\) gauge group to a finite set. We consider several methods for digitizing the group, finding the best performance from an action-preserving projection onto a mesh. Working in (3+1) dimensions, we find that using \\(\\sim 7\\) (qu)bits to represent each \\(\\mathrm{SU}(2)\\) gauge link induces a digitization error on the order of \\(10\\%\\) in short-distance observables and \\(2\\%\\) in long-distance observables. Promisingly, our results indicate that each \\(\\mathrm{SU}(2)\\) gauge link can be represented by \\(\\mathcal{O}(10)\\) (qu)bits, from which we estimate that a \\(16^3\\) \\(\\mathrm{SU}(2)\\) lattice could be simulated with no more than \\(\\mathcal{O}(10^5)\\) (qu)bits. Our results on digitization are also of interest as a form of lossy compression that could be used in high-performance classical computing to alleviate communications bottlenecks.

We present high-precision results from lattice QCD for the mass splittings of the low-lying charmonium states. For the valence charm quark, the calculation uses Wilson-clover quarks in the Fermilab interpretation. The gauge-field ensembles are generated in the presence of up, down, and strange sea quarks, based on the improved staggered (asqtad) action, and gluon fields, based on the one-loop, tadpole-improved gauge action. We use five lattice spacings and two values of the light sea quark mass to extrapolate the results to the physical point. An enlarged set of interpolating operators is used for a variational analysis to improve the determination of the energies of the ground states in each channel. We present and implement a continuum extrapolation within the Fermilab interpretation, based on power-counting arguments, and thoroughly discuss all sources of systematic uncertainty. We compare our results for various mass splittings with their experimental values, namely, the 1S hyperfine splitting, the 1P-1S splitting and the P-wave spin-orbit and tensor splittings. Given the uncertainty related to the width of the resonances, we find excellent agreement.

We present results for the dominant light-quark connected contribution to the long-distance window (LD) of the hadronic vacuum polarization contribution (HVP) to the muon \\(g-2\\) from lattice quantum chromodynamics (QCD). Specifically, with a new determination of the lattice scale on MILC's physical-mass HISQ ensembles, using the \\(^-\\) baryon mass, we obtain a result of \\(400.2(2.3)_stat(3.7)_syst[4.3]_total 10^-10\\). Summing this result with our recent determinations of the light-quark connected contributions to the short- (SD) and intermediate-distance (W) windows, we obtain a sub-percent precision determination of the light-quark-connected contribution to HVP of \\(655.5(2.3)_stat(3.9)_syst[4.5]_total 10^-10\\). Finally, as a consistency check, we verify that an independent analysis of the full contribution is in agreement with the sum of individual windows. We discuss our future plans for improvements of our HVP calculations to meet the target precision of the Fermilab \\(g-2\\) experiment.

We present complete results for the hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment \\(a_\\) in the short- and intermediate-distance window regions, which account for roughly 10% and 35% of the total HVP contribution to \\(a_\\), respectively. In particular, we perform lattice-QCD calculations for the isospin-symmetric connected and disconnected contributions, as well as corrections due to strong isospin-breaking. For the short-distance window observables, we investigate the so-called log-enhancement effects as well as the significant oscillations associated with staggered quarks in this region. For the dominant, isospin-symmetric light-quark connected contribution, we obtain \\(a^ll,\\,SD_(conn.) = 48.139(11)_stat(91)_syst[92]_total 10^-10\\) and \\(a^ll,\\,W_(conn.) = 206.90(14)_stat(61)_syst[63]_total 10^-10\\). We use Bayesian model averaging to fully estimate the covariance matrix between the individual contributions. Our determinations of the complete window contributions are \\(a^SD_ = 69.05(1)_stat(21)_syst[21]_total 10^-10\\) and \\(a^W_ = 236.45(17)_stat(83)_syst[85]_total 10^-10\\). This work is part of our ongoing effort to compute all contributions to HVP with an overall uncertainty at the few permille level.

The gradient-flow scale \\(w_0\\) in lattice QCD is determined using the mass of the \\(\\Omega^-\\) baryon to set the physical scale. Nine ensembles using the highly improved staggered quark (HISQ) action with lattice spacings of 0.15 fm down to 0.04 fm are used, seven of which have nearly physical light-quark masses. Electromagnetic corrections to the \\(\\Omega^-\\) mass are defined in order to compute a pure-QCD \\(\\Omega\\) mass. The final result is \\(w_0 = 0.17187(68)\\) fm, corresponding to a relative uncertainty of 0.40% and a central value in good agreement with previous calculations in the literature.

We present results for the dominant light-quark connected contribution to the long-distance window (LD) of the hadronic vacuum polarization contribution (HVP) to the muon \\(g-2\\) from lattice quantum chromodynamics (QCD). Specifically, with a new determination of the lattice scale on MILC's physical-mass HISQ ensembles, using the \\(\\Omega^-\\) baryon mass, we obtain a result of \\(a^{ll,\\,{\\mathrm{LD}}}_{\\mu}(\\mathrm{conn.}) = 401.2(2.3)_{\\mathrm{stat}}(3.6)_{\\mathrm{syst}}[4.3]_{\\mathrm{total}} \\times 10^{-10}\\). In addition, following up on our recent work on the short- (SD) and intermediate-distance (W) windows, we report updated values for these quantities with this new scale-setting determination. Summing these individual window contributions enables a sub-percent precision determination of the light-quark-connected contribution to HVP of \\(a^{ll}_{\\mu}(\\mathrm{conn.}) = 656.2(1.9)_{\\mathrm{stat}}(4.0)_{\\mathrm{syst}}[4.4]_{\\mathrm{total}} \\times 10^{-10}\\). Finally, as a consistency check, we verify that an independent analysis of the full contribution is in agreement with the sum of individual windows. We discuss our future plans for improvements of our HVP calculations to meet the target precision of the Fermilab \\(g-2\\) experiment.

We present complete results for the hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment \\(a_\\mu\\) in the short- and intermediate-distance window regions, which account for roughly 10% and 35% of the total HVP contribution to \\(a_\\mu\\), respectively. In particular, we perform lattice-QCD calculations for the isospin-symmetric connected and disconnected contributions, as well as corrections due to strong isospin-breaking. For the short-distance window observables, we investigate the so-called log-enhancement effects as well as the significant oscillations associated with staggered quarks in this region. For the dominant, isospin-symmetric light-quark connected contribution, we obtain \\(a^{ll,\\,{\\mathrm{SD}}}_{\\mu}(\\mathrm{conn.}) = 48.116(16)(94)[96] \\times 10^{-10}\\) and \\(a^{ll,\\,{\\mathrm{W}}}_{\\mu}(\\mathrm{conn.}) = 207.06(17)(63)[66] \\times 10^{-10}\\). We use Bayesian model averaging combined with a global bootstrap to fully estimate the covariance matrix between the individual contributions. Our determinations of the complete window contributions are \\(a^{{\\mathrm{SD}}}_{\\mu} = 69.01(2)(21)[21] \\times 10^{-10}\\) and \\(a^{{\\mathrm{W}}}_{\\mu} = 236.57(20)(94)[96] \\times 10^{-10}\\). This work is part of our ongoing effort to compute all contributions to HVP with an overall uncertainty at the few permille level.