Van der Waals potentials describing interactions between color-singlet mesons and/or baryons vanish at leading order in potential nonrelativistic quantum chromodynamics (pNRQCD). This result and constraints from Gauss's law are used to prove that weakly-coupled pNRQCD van der Waals potentials in generic non-Abelian gauge theories with only heavy quarks are too weak to form bound states whose color state is a product of color-singlets. Quantum Monte Carlo calculations of four, five, and six quarks with equal masses provide numerical evidence that exotic color configurations are higher energy than products of color-singlet hadrons, suggesting that equal-mass fully-heavy tetraquark, pentaquark, and hexaquark bound states do not exist at next-to-leading order in pNRQCD and at all orders in QCD-like theories in which all quark masses are asymptotically large. Mechanisms for generating hadron-hadron bound states are identified, which necessarily involve large quark-mass hierarchies, relativistic effects arising from the presence of sufficiently light quarks, or nonperturbative effects outside the scope of weakly-coupled pNRQCD.

The gradient-flow scale w0 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 w0 1/4 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 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 logenhancement 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 all;SD 48.139(11)stat(91)syst[92]total x 10-10 and all;W mu (conn) = 206.90(14)stat(61)syst[63]total x 10-10. We use Bayesian model averaging to fully estimate the covariance matrix between the individual contributions. aW mu = 236.45(17)stat(83)syst[85]total x 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.

We propose to use interpolating operators for lattice quantum chromodyanmics (QCD) calculations of highly-boosted pions and nucleons with kinematically-enhanced ground-state overlap factors at large momentum. Because this kinematic enhancement applies to the signal but not the variance of the correlation function, these interpolating operators can achieve better signal-to-noise ratios at large momentum. We perform proof-of-principle calculations with boosted pions and nucleons using close-to-physical and larger quark masses to explore the utility of our proposal. Results for effective energies and matrix elements, as well as Lanczos ground-state energy estimators, are consistent with theoretical expectations for signal-to-noise improvement at large momenta.

We report on the ongoing effort of improving the determination of the gradient flow scale on the (2+1+1)-flavor HISQ ensembles generated by the MILC collaboration. We compute the scales $\sqrt{t_0}/a$ and $w_0/a$ with the Wilson and Symanzik flow using three discretizations for the action density: clover, Wilson and tree-level Symanzik improved. For the absolute scale setting, we intend to employ the $\Omega$-baryon mass, but are also using the pion decay constant while the $\Omega$-mass calculations are in progress.

Neutrinos are the most poorly understood particles in the Standard Model but may be key to understanding fundamental mysteries of the universe, including matter-antimatter asymmetry. Most experiments to improve our knowledge of neutrinos depend on neutrino interactions with hadronic matter and therefore rely on a solid theoretical understanding of these interactions. Lattice QCD offers a first-principles, model-independent method of analyzing hadronic systems and their responses to external currents, including the electroweak currents induced by neutrino interactions. In this talk, I will discuss my work on using lattice QCD to understand the hadronic systems needed for both neutrino oscillation and neutrinoless double-beta decay experiments and the impact of this work on neutrino physics.

Neutrinoless double-beta (0νββ) decay is a heretofore unobserved process which, if observed, would imply that neutrinos are Majorana particles. Interpretations of the stringent experimental constraints on 0νββ-decay half-lives require calculations of nuclear matrix elements. This work presents the first lattice quantum chromodynamics (LQCD) calculation of the matrix element for 0νββ decay in a multinucleon system, specifically the nn→ppee transition, mediated by a light left-handed Majorana neutrino propagating over nuclear-scale distances. This calculation is performed with quark masses corresponding to a pion mass of mπ=806 MeV at a single lattice spacing and volume. The statistically cleaner Σ−→Σ+ee transition is also computed in order to investigate various systematic uncertainties. The prospects for matching the results of LQCD calculations onto a nuclear effective field theory to determine a leading-order low-energy constant relevant for 0νββ decay with a light Majorana neutrino are investigated. This work, therefore, sets the stage for future calculations at physical values of the quark masses that, combined with effective field theory and nuclear many-body studies, will provide controlled theoretical inputs to experimental searches of 0νββ decay. Published by the American Physical Society 2024

{Delta}u-{Delta}d} are in agreement with experiment, and show only very mild quark mass dependence. The second, RBC/UK, set of ensembles employs one strange and two degenerate (up and down) dynamical DWF quarks and Iwasaki gauge action. The strange quark mass is set at 0.04, and three up/down mass values of 0.03, 0.02 and 0.01 in lattice units are used. The lattice cutoff is a{sup -1} {approx} 1.6GeV and the spatial volume is about (3.0fm){sup 3}. Even with preliminary statistics of 25-30 gauge configurations, the ratios g{sub A}/g{sub V} and {sub u-d}/{sub {Delta}u-{Delta}d} are consistent with experiment and show only very mild quark mass dependence. Another structure function moment, d{sub 1}, though yet to be renormalized, appears small in both sets.

which may then be used as input for nuclear many-body calculations of the relevant experimental decays. Contributions from short-range operators may prove to be equally important to, or even more important than, those from long-range Majorana neutrino exchange.

Neutrino oscillation experiments require accurate reconstructions of neutrino energies, which depend in part on a theoretical understanding of the axial $N \rightarrow \Delta$ transition form factors. Lattice QCD studies of this transition require construction of all hadronic states with energies up to the mass of the $\Delta$ resonance, which includes $N\pi$ and $N\pi\pi$ for physical quark mass values. Building interpolating operators from sparse grids of source and sink points is a versatile method of approximating all-to-all quark propagators that has been successfully used in other multi-hadron calculations. This work will discuss applications of this method to $N\pi$ and $N\pi\pi$ systems and present preliminary results.

Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA The NSF AI Institute for Artificial Intelligence and Fundamental Interactions RIKEN Center for Computational Science, Kobe 650-0047, Japan Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan Centre for Theoretical and Computational Physics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan

The pion light-cone distribution amplitude (LCDA) is a central non-perturbative object of interest for the calculation of high-energy exclusive processes in quantum chromodynamics. This article describes the progress in the lattice QCD calculation of the fourth Mellin moment of the pion LCDA using a heavy-quark operator product expansion (HOPE).

The pion light-cone distribution amplitude (LCDA) is a central non-perturbative object of interest for the calculation of high-energy exclusive processes in quantum chromodynamics. In this article, we discuss the calculation of the second and fourth Mellin moment of the pion LCDA using a heavy-quark operator product expansion. The resulting value for the second Mellin moment is $ \langle{ \xi^2 }\rangle(\mu = 2~\text{GeV})= 0.210 \pm 0.013\text{ (stat.)} \pm 0.034\text{ (sys.)}$. This result is compatible with those from previous determinations of this quantity.

Parton distribution functions (PDFs) and light cone distribution amplitudes (LCDAs) are central nonperturbative objects of interest in high-energy inelastic and elastic scattering, respectively. As a result, an ab initio determination of these objects is highly desirable. In this paper we present theoretical details for the calculation of the PDFs and LCDAs using a heavy-quark operator product expansion method. This strategy was proposed in a previous paper [Phys. Rev. D 73, 014501 (2006)] for computing higher moments of the PDFs using lattice QCD. Its central feature is the introduction of a fictitious, valence heavy quark. In the current article, we show that the operator product expansion of the hadronic matrix element we study can also be expressed as the convolution of a perturbative matching kernel and the corresponding light cone distribution, which in principle can be inverted to determine the parton momentum fraction dependence. Regarding the extraction of higher moments, this work also provides the one-loop Wilson coefficients in the operator product expansion formulas for the unpolarized PDF, helicity PDF and pseudoscalar meson LCDAs. Although theseWilson coefficients for the PDFs can be inferred from existing results in the literature, those for the LCDAs are new.

Recently $SU(2)$ Yang-Mills theory with one massless adjoint Dirac quark flavor emerges as a novel critical theory that can describe the evolution between a trivial insulator and a topological insulator in AIII class in $3+1$ dimensions. There are several classes of conjectured infrared dynamics for this theory. One possibility is that the theory undergoes spontaneous chiral symmetry breaking, with two massless Goldstone bosons (the scalar diquark and its antiparticle) in the infrared. Another scenario, which is suggested by previous lattice studies by Athenodorou et al., is that the IR sector of the theory is a strongly interacting conformal field theory as the quark mass vanishes. The most recent theoretical proposals argue for a case that in the infrared a composite fermion composed of two quarks and an antiquark becomes massless and non-interacting as the quark mass goes to zero, while other sectors are decoupled from this low-energy fermion. This work expands upon previous studies by including the composite fermion to investigate which of these three potential scenarios captures the infrared behavior of this theory.

We explore the feasibility of determining Mellin moments of the pion's light cone distribution amplitude using the heavy quark operator product expansion (HOPE) method. As the first step of a proof of principle study we pursue a determination of the second Mellin moment. We discuss our choice of kinematics which allows us to successfully extract the moment at low pion momentum. We describe the numerical simulation, and describe the data analysis, which leads us to a preliminary determination of the second Mellin moment in the continuum limit in the quenched approximation as ⟨ξ^2⟩=0.19(7) in the M̅S̅ scheme at 2 GeV.

The charge radius of the proton has been measured in scattering and spectroscopy experiments using both electronic and muonic probes. The electronic and muonic measurements are discrepant at $5\sigma$, giving rise to what is known as the proton radius puzzle. With the goal of resolving this, we introduce a novel method of using lattice QCD to determine the isovector charge radius -- defined as the slope of the electric form factor at zero four-momentum transfer -- by introducing a mass splitting between the up and down quarks. This allows us to access timelike four-momentum transfers as well as spacelike ones, leading to potentially higher accuracy in determining the form factor slope at $Q^2 = 0$ by interpolation. In this preliminary study, we find a Dirac isovector radius squared of $0.320 \pm 0.074$ fm$^2$ at quark masses corresponding to $m_\pi = 450$ MeV. We compare the feasibility of this method with other approaches of determining the proton charge radius from lattice QCD.

A real‐time, isothermal micro‐Raman spectroscopy was developed as a single technique for monitoring the solid state kinetics of dehydration and measuring its activation energy. The technique comprises of acquisition and numerical analysis of a set of isothermal time‐dependent Raman spectra. α‐FeOOH transformation to Fe2O3 in N2 atmosphere was continuously monitored for up to 16 h at three temperatures. Dehydration activation energy of 1.4(1) eV was estimated. The Raman band evolution of two modes with different symmetries (B1g ~ 240 cm−1 and Ag ~ 400 cm−1) and the intensity decay of B1g mode at ~540 cm−1 are analyzed independently utilizing kinetic model‐free approach. The study opens new possibilities for developing versatile solid state chemical and bio‐chemical Raman sensors and advances the field of analytical micro‐Raman spectroscopy. Copyright © 2017 John Wiley & Sons, Ltd.

A novel, real-time, in-situ, micro-Raman technique was developed for the monitoring and physicochemical kinetics characterization of solid-state reactions. The technique comprises the acquisition and analysis of a set of time-dependent, isothermal Raman spectra. The pertinence of the technique is demonstrated by the contributions to the study of the dehydration of synthetic goethite (FeOOH) to hematite (Fe2O3). The process was monitored for up to 16 hrs in N2 atmosphere at temperatures of 220, 230 and 240 oC. The Raman spectral range of 200 to 700 cm-1 was deconvoluted using an iterative fitting algorithm. The isothermal, time-dependent mode analysis yields values for the reaction rates, which exhibit first-order kinetic behavior. The energy barriers of a two-step dehydration process are estimated to be 105 ± 19 kJ/mol and 74 ± 7 kJ/mol in agreement with molecular dynamic simulations (Wen-Juan Zhang et al, J. Mol. Struct.: THEOCHEM, 950 (2010) 20–26). Our study concurs with other reports on the activation energy of the same process in air, employing infrared spectroscopy, thermogravimetry, and differential scanning calorimetry (Walter D., Thermochim. Acta 445 (2006) 195 -199; Prasad et al., J. Asian Earth Sci. 27 (2006) 503-511). This in-situ, Raman spectroscopic experiment is a promising, non-destructive, real-time analysis technique with applications to various kinetic solid-state processes such as oxidation, dehydration, and phase transformations.