text
stringlengths
89
2.49k
category
stringclasses
19 values
CP invariance of chiral gauge theories and Majorana-Yukawa couplings on the lattice: The construction of CP-invariant lattice chiral gauge theories and the construction of lattice Majorana fermions with chiral Yukawa couplings is subject to topological obstructions. In the present work we suggest lattice extensions o...
hep-lat
Lattice Gauge Fixing, Gribov Copies and BRST Symmetry: We show that a modification of the BRST lattice quantization allows to circumvent an old paradox, formulated by Neuberger, related to lattice Gribov copies and non-perturbative BRST invariance. In the continuum limit the usual BRST formulation is recovered.
hep-lat
Lattice field theory results for hybrid static potentials at short quark-antiquark separations and their parametrization: We present SU(3) lattice Yang-Mills data for hybrid static potentials from five ensembles with different small lattice spacings and the corresponding parametrizations for quark-antiquark separatio...
hep-lat
Can axial U(1) anomaly disappear at high temperature?: In our recent study of two-flavor lattice QCD using chiral fermions, we find strong suppression of axial U(1) anomaly above the critical temperature of chiral phase transition. Our simulation data also indicate suppression of topological susceptibility. In this tal...
hep-lat
String tensions of SU(N) gauge theories in 2+1 dimensions: We calculate the energy spectrum of closed strings in SU(N) gauge theories with N=2,3,4,6,8 in 2+1 dimensions to a high accuracy. We attempt to control all systematic errors, and this allows us to perform a precise comparison with different theoretical predicti...
hep-lat
Level spacings for weakly asymmetric real random matrices and application to two-color QCD with chemical potential: We consider antisymmetric perturbations of real symmetric matrices in the context of random matrix theory and two-color quantum chromodynamics. We investigate the level spacing distributions of eigenval...
hep-lat
Thermodynamics of free Domain Wall fermions: Studying various thermodynamic quantities for the free domain wall fermions for both finite and infinite fifth dimensional extent N_5, we find that the lattice corrections are minimum for $N_T\geq10$ for both energy density and susceptibility, for its irrelevant parameter M ...
hep-lat
Matrix elements of (delta S=2) operators with Wilson fermions: We test the recent proposal of using the Ward identities to compute the K0-K0bar mixing amplitude with Wilson fermions, without the problem of spurious lattice subtractions. From our simulations, we observe no difference between the results obtained with an...
hep-lat
Searching for continuous phase transitions in 5D SU(2) lattice gauge theory: We study the phase diagram of 5-dimensional $SU(2)$ Yang-Mills theory on the lattice. We consider two extensions of the fundamental plaquette Wilson action in the search for the continuous phase transition suggested by the $4+\epsilon$ expan...
hep-lat
What the Gribov copy tells on the confinment and the theory of dynamical chiral symmetry breaking: We performed lattice Landau gauge QCD simulation on \beta=6.0, 16^4, 24^4, 32^4 and \beta=6.4, 32^4, 48^4 and 56^4 by adopting the gauge fixing that minimizes the norm of the gauge field, and measured the running coupli...
hep-lat
Stout-smearing, gradient flow and $c_{\text{SW}}$ at one loop order: The one-loop determination of the coefficient $c_\text{SW}$ of the Wilson quark action has been useful to push the leading cut-off effects for on-shell quantities to $\mathcal{O}(\alpha^2 a)$ and, in conjunction with non-perturbative determinations of...
hep-lat
Gauge Invariance and Lattice Monopoles: The number and the location of monopoles in Lattice configurations depend on the choice of the gauge, in contrast to the obvious requirement that monopoles, as physical objects, have a gauge-invariant status. It is proved, starting from non-abelian Bianchi identities, that mono...
hep-lat
Lyapunov Spectra in SU(2) Lattice Gauge Theory: We develop a method for calculating the Lyapunov characteristic exponents of lattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is obtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with lattice size is found.
hep-lat
The pion_0 to gamma gamma decay and the chiral anomaly in the quark-composites approach to QCD: We evaluate the pion_0 into two gammas decay amplitude by an effective action derived from QCD in the quark composites approach, getting the standard value. We also verify that our effective action correctly reproduces the...
hep-lat
Gradient Flow Coupling in the SU(2) gauge theory with two adjoint fermions: We study SU(2) gauge theory with two fermion flavors in the adjoint representation. Using a clover improved HEX smeared action and the gradient flow running coupling allows us to simulate with larger lattice size than before. We find an infra...
hep-lat
Physical observables from boundary artifacts: scalar glueball in Yang-Mills theory: By relating the functional averages of a generic scalar operator in simulations with Open (O) and Periodic (P) boundary conditions (BCs) respectively for $SU(3)$ lattice gauge theory, we show that the scalar glueball mass and the glue...
hep-lat
Controlling Residual Chiral Symmetry Breaking in Domain Wall Fermion Simulations: At stronger gauge-field couplings, the domain wall fermion (DWF) residual mass, a measure of chiral symmetry breaking, grows rapidly. This measure is largely due to near zero fermion eigenmodes of logarithm of the 4D transfer matrix alo...
hep-lat
Developing and testing the density of states FFA method in the SU(3) spin model: The Density of States Functional Fit Approach (DoS FFA) is a recently proposed modern density of states technique suitable for calculations in lattice field theories with a complex action problem. In this article we present an explorator...
hep-lat
Non-perturbative improvement of nHYP smeared Wilson fermions: Using Schroedinger functional techniques, we determine the coefficient of the clover term necessary for non-perturbative O(a) improvement of hypercubic smeared Wilson fermions on a quenched plaquette action background. Unlike for unsmeared Wilson fermions, t...
hep-lat
Excited states of massive fermions in a chiral gauge theory: It is shown numerically, in a chiral U(1) gauge Higgs theory in which the left and right-handed fermion components have opposite U(1) charges, that the spectrum of gauge and Higgs fields surrounding a static fermion contains both a ground state and at least o...
hep-lat
Type of dual superconductivity for the $SU(2)$ Yang--Mills theory: We investigate the type of dual superconductivity responsible for quark confinement. For this purpose, we solve the field equations of the $U(1)$ gauge-scalar model to obtain the static vortex solution in the whole range without restricting to the long-...
hep-lat
Critical Behavior of the Schwinger Model with Wilson Fermions: We present a detailed analysis, in the framework of the MFA approach, of the critical behaviour of the lattice Schwinger model with Wilson fermions on lattices up to $24^2$, through the study of the Lee-Yang zeros and the specific heat. We find compelling e...
hep-lat
Aharonov--Bohm Effect in 3D Abelian Higgs Theory: We study a field--theoretical analogue of the Aharonov--Bohm effect in the 3D Abelian Higgs Model: the corresponding topological interaction is proportional to the linking number of the vortex and the particle world trajectories. We show that the Aharonov--Bohm effect g...
hep-lat
Multicanonical simulation of 3D dynamical triangulation model and a new phase structure: We apply the multicanonical technique to the three dimensional dynamical triangulation model, which is known to exhibit a first order phase transition with the Einstein-Hilbert action. We first clarify the first order nature of t...
hep-lat
Clock model interpolation and symmetry breaking in O(2) models: Motivated by recent attempts to quantum simulate lattice models with continuous Abelian symmetries using discrete approximations, we define an extended-O(2) model by adding a $\gamma \cos(q\varphi)$ term to the ordinary O(2) model with angular values restr...
hep-lat
Measurement of hadron masses in 2-color finite density QCD: We investigate hadron spectra in 2-color QCD using lattice simulation with $N_{f}=2$ at low temperature and finite density in which there appears not only the hadronic phase but also the superfluid phase. We first calculate the pion and rho meson spectrum, whi...
hep-lat
Lambda(1405) and Negative-Parity Baryons in Lattice QCD: We review briefly recent studies of the Lambda(1405) spectrum in Lattice QCD. Ordinary three-quark pictures of the Lambda(1405) in quenched Lattice QCD fail to reproduce the mass of the experimental value, which seems to support the penta-quark picture for the La...
hep-lat
A Noisy Monte Carlo Algorithm: We propose a Monte Carlo algorithm to promote Kennedy and Kuti's linear accept/reject algorithm which accommodates unbiased stochastic estimates of the probability to an exact one. This is achieved by adopting the Metropolis accept/reject steps for both the dynamical and noise configurati...
hep-lat
Non-perturbative results for the coefficients b_m and b_a-b_p in O(a) improved lattice QCD: We determine the improvement coefficients b_m and b_a-bp in quenched lattice QCD for a range of beta-values, which is relevant for current large scale simulations. At fixed beta, the results are rather sensitive to the precise...
hep-lat
Calculation of the pion charge radius from an improved model-independent method: We propose a new improved model-independent method for calculating the pion charge radius. In a recently-proposed model-independent method for the pion charge radius, we find it difficult to compute the pion charge radius for small pole ...
hep-lat
Inclusion of isospin breaking effects in lattice simulations: Isospin symmetry is explicitly broken in the Standard Model by the mass and electric charge of the up and down quarks. These effects represent a perturbation of hadronic amplitudes at the percent level. Although these contributions are small, they play a cru...
hep-lat
2+1 flavour Domain Wall Fermion simulations by the RBC and UKQCD collaborations: We review simulations of dynamical domain wall fermions at a fixed inverse lattice spacing of 1.73GeV and with pion masses as light as 330MeV and spatial dimensions as large as 2.7fm performed by the RBC and UKQCD collaborations. These r...
hep-lat
Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model: We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the H...
hep-lat
On the type of the temperature phase transition in phi-4 model: The temperature induced phase transition is investigated in the one-component scalar field \phi^4 model on a lattice by using Monte Carlo simulations. Using the GPGPU technology a huge amount of data is collected that gives a possibility to determine the L...
hep-lat
Chiral symmetry restoration in QCD with many flavours: We discuss the phases of QCD in the parameter space spanned by the number of light flavours and the temperature with respect to the realisation of chiral and conformal symmetries. The intriguing interplay of these symmetries is best studied by means of lattice simu...
hep-lat
Distributing the chiral and flavour components of Dirac-Kahler fermions across multiple lattices: We use a specific implementation of discrete differential geometry to describe Dirac-Kahler fermions in such a way that we can separate their chiral and flavour components. The formulation introduces additional lattices ...
hep-lat
Exotic phases of finite temperature SU(N) gauge theories with massive fermions: F, Adj, A/S: The phase diagrams at high temperature of SU(N) gauge theories with massive fermions are calculated by numerically minimizing the one-loop effective potential. We consider fermions in the Fundamental (F), Adjoint (Adj), Antis...
hep-lat
From C to Parton Sea: Bjorken-x Dependence of the PDFs: Studying the structure of nucleons is not only important to understanding the strong interactions of quarks and gluons, but also to improving the precision of new-physics searches. Since a broad class of experiments, including the LHC and dark-matter detection, re...
hep-lat
Axial Nucleon form factors from lattice QCD: We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length $L=2.1$ fm and $L=2.8$ fm. Cut-off effects are investigated using thr...
hep-lat
Lattice calculation of matrix elements relevant for Delta I=1/2 rule and epsilon-prime: We have gained enough statistical precision to distinguish signal from noise in matrix elements of all operators relevant for the Delta I=1/2 rule in kaon decays and for the direct CP violation parameter epsilon-prime. We confirm ...
hep-lat
Acceleration of the Arnoldi method and real eigenvalues of the non-Hermitian Wilson-Dirac operator: In this paper, we present a method for the computation of the low-lying real eigenvalues of the Wilson-Dirac operator based on the Arnoldi algorithm. These eigenvalues contain information about several observables. We ...
hep-lat
How the Quark Number fluctuates in QCD at small chemical potential: We discuss the distribution of the quark number over the gauge fields for QCD at nonzero quark chemical potential. As the quark number operator is non-hermitian, the distribution is over the complex plane. Moreover, because of the fermion determinant, ...
hep-lat
A calculation of the $B_{B}$ parameter in the static limit: We calculate the $B_{B}$ parameter, relevant for $\overline{B}^0$ -- $B^0$ mixing, from a lattice gauge theory simulation at $\beta = 6.0$. The bottom quarks are simulated in the static theory, the light quarks with Wilson fermions. Improved smearing functions...
hep-lat
UV divergence of the quasi-PDF operator under the lattice regularization: Even since the "quasi" parton distribution function (PDF) was proposed under the large-momentum effective theory (LaMET) framework, its renormalization under the lattice regularization has been a central challenge to be solved due to the linear d...
hep-lat
Partially Quenched QCD with Non-Degenerate Dynamical Quarks: We discuss the importance of using partially quenched theories with three degenerate quarks for extrapolating to QCD, and present some relevant results from chiral perturbation theory.
hep-lat
The Weak-Coupling Limit of Simplicial Quantum Gravity: In the weak-coupling limit, kappa_0 going to infinity, the partition function of simplicial quantum gravity is dominated by an ensemble of triangulations with the ratio N_0/N_D close to the upper kinematic limit. For a combinatorial triangulation of the D--sphere t...
hep-lat
Perturbative renormalization functions of local operators for staggered fermions with stout improvement: In this paper we present the perturbative computation of the renormalization functions for the quark field and for a complete set of ultra-local fermion bilinears. The computation of the relevant Green's functions...
hep-lat
Light-quark connected intermediate-window contributions to the muon $g-2$ hadronic vacuum polarization from lattice QCD: We present a lattice-QCD calculation of the light-quark connected contribution to window observables associated with the leading-order hadronic vacuum polarization contribution to the anomalous mag...
hep-lat
Study of the finite temperature transition in 3-flavor QCD using the R and RHMC algorithms: We study the finite temperature transition in QCD with three flavors of equal masses using the R and RHMC algorithm on lattices with temporal extent N_{\tau}=4 and 6. For the transition temperature in the continuum limit we fi...
hep-lat
Fast Partitioning of Pauli Strings into Commuting Families for Expectation Value Measurements of Dense Operators: The cost of measuring quantum expectation values of an operator can be reduced by grouping the Pauli string ($SU(2)$ tensor product) decomposition of the operator into maximally commuting sets. We detail ...
hep-lat
Domain-wall and overlap fermions at nonzero quark chemical potential: We have recently given a construction of the overlap Dirac operator at nonzero quark chemical potential. Here, we introduce a quark chemical potential in the domain-wall fermion formalism and show that our earlier result is reproduced if the extent o...
hep-lat
Vacuum structure of gauge theory on lattice with two parallel plaquette action: We perform Monte Carlo simulations of a lattice gauge system with an action which contains two parallel plaquettes. The action is defined as a product of gauge group variables over two parallel plaquettes belonging to a given three-dimens...
hep-lat
$Λ(1405)$ from lattice QCD: Low-lying $\Lambda$ baryons with spin 1/2 are analyzed in two-flavor lattice QCD. In order to extract two low-lying states for each parity, we construct $2 \times 2$ cross correlators from flavor SU(3) ``octet'' and ``singlet'' baryon operators, and diagonalize them. Two-flavor CP-PACS gauge...
hep-lat
Applying Integrability to Gauge Theories: Lattice Yang-Mills theories in any dimension may be regarded as coupled 1+1-dimensional integrable field theories. These integrable systems decouple at large center-of-mass energies, where the action becomes effectively anisotropic. This effective action is the high-energy cent...
hep-lat
Flavor Twisted Boundary Conditions in the Breit Frame: We use a generalization of chiral perturbation theory to account for the effects of flavor twisted boundary conditions in the Breit frame. The relevant framework for two light flavors is an SU(6|4) partially quenched theory, where the extra valence quarks differ on...
hep-lat
Formal Developments for Lattice QCD with Applications to Hadronic Systems: Lattice quantum chromodynamics (QCD) will soon become the primary theoretical tool in rigorous studies of single- and multi-hadron sectors of QCD. It is truly ab initio meaning that its only parameters are those of standard model. The result o...
hep-lat
A Study of PCAC for the Nonperturbative Improvement of the Wilson Action: We present an exploratory study for the nonperturbative determination of the coefficient of the ${\cal O}(a)$ improvement term to the Wilson action, $c_{SW}$. Following the work by L\"{u}scher et al., we impose the PCAC relation as a nonperturbat...
hep-lat
Spectrum of the Hermitian Wilson Dirac operator: Recent results on the spectral properties of the Hermitian Wilson-Dirac operator are presented.
hep-lat
QCD Thermodynamics with an almost realistic quark mass spectrum: We will report on the status of a new large scale calculation of thermodynamic quantities in QCD with light up and down quarks corresponding to an almost physical light quark mass value and a heavier strange quark mass. These calculations are currently be...
hep-lat
Moments of Ioffe time parton distribution functions from non-local matrix elements: We examine the relation of moments of parton distribution functions to matrix elements of non-local operators computed in lattice quantum chromodynamics. We argue that after the continuum limit is taken, these non-local matrix element...
hep-lat
B-Bbar Mixing and Matching with Fermilab Heavy Quarks: We discuss the matching procedure for heavy-light 4-quark operators using the Fermilab method for heavy quarks and staggered fermions for light quarks. These ingredients enable us to construct the continuum-limit operator needed to determine the oscillation frequen...
hep-lat
A Numerical Test of KPZ Scaling: Potts Models Coupled to Two-Dimensional Quantum Gravity: We perform Monte Carlo simulations using the Wolff cluster algorithm of the q=2 (Ising), 3, 4 and q=10 Potts models on dynamical phi-cubed graphs of spherical topology with up to 5000 nodes. We find that the measured critical ex...
hep-lat
Relativistic Lattice Boltzmann Methods: Theory and Applications: We present a systematic account of recent developments of the relativistic Lattice Boltzmann method (RLBM) for dissipative hydrodynamics. We describe in full detail a unified, compact and dimension-independent procedure to design relativistic LB schemes c...
hep-lat
Improved thermodynamics of SU(2) gauge theory: In this work we present the results of our investigation about the thermodynamics of SU(2) gauge theory. We employ a Symanzik improved action to reduce strongly the discretisations effects, and we use the scaling relations to take into account the finite volume effects clo...
hep-lat
Three dimensional vacuum domains in four dimensional SU(2) gluodynamics: Performing lattice simulations of the four dimensional SU(2)gluodynamics we find evidence for existence of three-dimensional domains whose total volume scales in physical units. Technically, the domains are defined in terms of the minimal density ...
hep-lat
$|V_{cb}|$ using lattice QCD: Lattice QCD calculations of hadronic matrix elements allow one to draw inferences about quark flavor interactions from measurements of hadron decays. Within the context of the Standard Model, the magnitude of the charm-bottom quark coupling $V_{cb}$ can be determined from semileptonic deca...
hep-lat
A no-go theorem for the Majorana fermion on a lattice: A variant of the Nielsen--Ninomiya no-go theorem is formulated. This theorem states that, under several assumptions, it is impossible to write down a doubler-free Euclidean lattice action of a single Majorana fermion in $8k$ and $8k+1$ dimensions.
hep-lat
N=1 super Yang-Mills on the lattice: We present results from a numerical study of N=1 supersymmetric Yang-Mills theory using domain wall fermions. A set of dynamical simulations were performed for the gauge group SU(2) using the Wilson gauge action on 8^3x8 and 16^3x32 lattices. We considered a range of gluino masses (...
hep-lat
Spectral Functions of Hadrons in Lattice QCD: Using the maximum entropy method, spectral functions of the pseudo-scalar and vector mesons are extracted from lattice Monte Carlo data of the imaginary time Green's functions. The resonance and continuum structures as well as the ground state peaks are successfully obtaine...
hep-lat
Determination of the renormalized heavy-quark mass in Lattice QCD: We study on the lattice the correlator of heavy-quark currents in the vicinity of vanishing momentum. The renormalized charmed quark mass, the renormalized strong coupling constant and gluon condensate can be defined in terms of the derivatives of that ...
hep-lat
Field Theory Simulations on a Fuzzy Sphere - an Alternative to the Lattice: We explore a new way to simulate quantum field theory, without introducing a spatial lattice. As a pilot study we apply this method to the 3d \lambda \phi^4 model. The regularisation consists of a fuzzy sphere with radius R for the two spatia...
hep-lat
Lattice QCD calculation of hadronic light-by-light scattering: We perform a lattice QCD calculation of the hadronic light-by-light scattering amplitude in a broad kinematical range. At forward kinematics, the results are compared to a phenomenological analysis based on dispersive sum rules for light-by-light scattering...
hep-lat
Multigrid for Chiral Lattice Fermions: Domain Wall: Critical slowing down for the Krylov Dirac solver presents a major obstacle to further advances in lattice field theory as it approaches the continuum solution. We propose a new multi-grid approach for chiral fermions, applicable to both the 5-d domain wall or 4-d Ove...
hep-lat
Effective Monopole Potential for SU(2) Lattice Gluodynamics in Spatial Maximal Abelian Gauge: We investigate the dual superconductor hypothesis in finite-temperature SU(2) lattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more physical than the ordinary Maximal Abelian gauge due to absence of n...
hep-lat
Finite-volume effects in long-distance processes with massless leptonic propagators: In Ref. [1], a method was proposed to calculate QED corrections to hadronic self energies from lattice QCD without power-law finite-volume errors. In this paper, we extend the method to processes which occur at second-order in the we...
hep-lat
Dirac sheets and gauge fixing in $U(1)$ lattice gauge theory: Photon correlators in $~U(1)~$ pure gauge theory for different lattice actions are considered under the Lorentz gauge condition. They are shown to depend strongly on the gauge fixing ambiguity and on the corresponding existence of Dirac sheets. For the Coulo...
hep-lat
Non-Perturbative Gauge-Higgs Unification in Five Dimensions: We study the phase diagram and mass spectrum of an $SU(2)$ Gauge-Higgs Unification scenario on a five-dimensional orbifold.We observe spontaneous symmetry breaking within the Higgs phase of the theory and, in the vicinity of a newly discovered phase, we find ...
hep-lat
Models of Walking Technicolor on the Lattice: We study QCD with 2 colour-sextet quarks as a walking-Technicolor candidate. As such it provides a description of the Higgs sector of the standard model, in which the Higgs field is replaced by the Goldstone `pions' of this QCD-like theory, and the Higgs itself is the $\sig...
hep-lat
Lattice study of the simplified model of M-theory for larger gauge groups: Lattice discretization of the supersymmetric Yang-Mills quantum mechanics is dis cussed. First results of the quenched Monte Carlo simulations, for D=4 and with higher g auge groups (3 <= N <= 8), are presented. We confirm an earlier (N=2) evi...
hep-lat
SU(3)-breaking ratios for $D_{(s)}$ and $B_{(s)}$ mesons: We present results for the $SU(3)$ breaking ratios of decay constants $f_{D_s}/f_D$ and $f_{B_s}/f_B$ and - for the first time with physical pion masses - the ratio of bag parameters $B_{B_s}/B_{B_d}$, as well as the ratio $\xi$, forming the ratio of the nonpetu...
hep-lat
Euclidean lattice simulation for the dynamical supersymmetry breaking: The global supersymmetry is spontaneously broken if and only if the ground-state energy is strictly positive. We propose to use this fact to observe the spontaneous supersymmetry breaking in euclidean lattice simulations. For lattice formulations th...
hep-lat
Staggered domain wall fermions: Staggered Domain Wall Fermions (SDWF) combine the attractive chiral properties of staggered fermions with those of domain wall fermions. SDWF describe four flavors with exact U(1)xU(1) flavor chiral symmetry. An extra lattice dimension is introduced and the full SU(4)xSU(4) flavor chiral...
hep-lat
I=2 $π$-$π$ scattering length with dynamical overlap fermion: We report on a lattice QCD calculation of the I=2 $\pi\pi$ scattering length using the overlap fermion formulation for both sea and valence quarks. We investigate the consistency of the lattice data with the prediction of the next-to-next-to-leading order ch...
hep-lat
Role of chiral symmetry in the nucleon excitation spectrum: The origin of the low-lying nature of the $N$*(1440), or Roper resonance, has been the subject of significant interest for many years, including several investigations using lattice QCD. The majority of lattice studies have not observed a low-lying excited sta...
hep-lat
Matching effective chiral Lagrangians with dimensional and lattice regularization: We compute the free energy in the presence of a chemical potential coupled to a conserved charge in effective O($n$) scalar field theory (without explicit symmetry breaking terms) to NNL order for asymmetric volumes in general $d$--dim...
hep-lat
2+1 Flavor QCD simulated in the epsilon-regime in different topological sectors: We generated configurations with the parametrized fixed-point Dirac operator D_{FP} on a (1.6 fm)^4 box at a lattice spacing a=0.13 fm. We compare the distributions of the three lowest k=1,2,3 eigenvalues in the nu= 0,1,2 topological sec...
hep-lat
Calculation of $ρ$ meson decay width from the PACS-CS configurations: We present preliminary results on the $\rho$ meson decay width from $N_f=2+1$ full QCD configurations generated by PACS-CS Collaboration. The decay width is estimated from the $P$-wave scattering phase shift for the isospin $I=1$ two-pion system. The...
hep-lat
Non-perturbative renormalisation of left-left four-fermion operators with Neuberger fermions: We outline a general strategy for the non-perturbative renormalisation of composite operators in discretisations based on Neuberger fermions, via a matching to results obtained with Wilson-type fermions. As an application, w...
hep-lat
Transversity PDFs of the proton from lattice QCD with physical quark masses: We present a lattice QCD calculation of the transversity isovector- and isoscalar-quark parton distribution functions (PDFs) of the proton utilizing a perturbative matching at next-to-leading-order (NLO) accuracy. Additionally, we determine ...
hep-lat
Influence of Fermions on Vortices in SU(2)-QCD: Gauge fields control the dynamics of fermions, also a back reaction of fermions on the gauge field is expected. This back reaction is investigated within the vortex picture of the QCD vacuum. We show that the center vortex model reproduces the string tension of the full t...
hep-lat
Provenance for Lattice QCD workflows: We present a provenance model for the generic workflow of numerical Lattice Quantum Chromodynamics (QCD) calculations, which constitute an important component of particle physics research. These calculations are carried out on the largest supercomputers worldwide with data in the m...
hep-lat
Complete Monopole Dominance of the Yang-Mills Confining Potential: We continue our investigation of quark confinement using a particular variant of the Cho-Duan-Ge gauge independent Abelian decomposition. The decomposition splits the gauge field into a restricted Abelian part and a coloured part in a way that preserves...
hep-lat
Quarkonium mass splittings in three-flavor lattice QCD: We report on calculations of the charmonium and bottomonium spectrum in lattice QCD. We use ensembles of gauge fields with three flavors of sea quarks, simulated with the asqtad improved action for staggered fermions. For the heavy quarks we employ the Fermilab in...
hep-lat
Linear Covariant Gauges on the Lattice: Linear covariant gauges, such as Feynman gauge, are very useful in perturbative calculations. Their nonperturbative formulation is, however, highly non-trivial. In particular, it is a challenge to define linear covariant gauges on a lattice. We consider a class of gauges in latti...
hep-lat
Hyperon sigma terms for 2+1 quark flavours: QCD lattice simulations determine hadron masses as functions of the quark masses. From the gradients of these masses and using the Feynman-Hellmann theorem the hadron sigma terms can then be determined. We use here a novel approach of keeping the singlet quark mass constant i...
hep-lat
Towards an algebraic approach to the discretisation of fermions: A discretisation scheme for differential geometry is applied to the problem of constructing lattice actions, the naive and staggered action are thus derived. It is found that after specifying an ansatz for the space of fields, the corresponding lattice ac...
hep-lat
Improved Perturbation Theory for Improved Lattice Actions: We study a systematic improvement of perturbation theory for gauge fields on the lattice; the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed for the Wilson gluon...
hep-lat
High-accuracy two-loop computation of the critical mass for Wilson fermions: We test an algebraic algorithm based on the coordinate-space method, evaluating with high accuracy the critical mass for Wilson fermions in lattice QCD at two loops. We test the results by using different types of infrared regularization.
hep-lat
Duality and scaling in 3-dimensional scalar electrodynamics: Three-dimensional scalar electrodynamics, with a local U(1) gauge symmetry, is believed to be dual to a scalar theory with a global U(1) symmetry, near the phase transition point. The conjectured duality leads to definite predictions for the scaling exponents...
hep-lat
Neutron Electric Dipole Moment on the Lattice: a Theoretical Reappraisal: We present a strategy for a lattice evaluation of the neutron electric dipole moment induced by the strong CP violating term of the QCD Lagrangian. Our strategy is based on the standard definition of the electric dipole moment, involving the char...
hep-lat