Search

The equivalence of cooling to the gradient flow when the cooling step nc and the continuous flow step of gradient flow τ are matched is generalized to gauge actions that include rectangular terms. By expanding the link variables up to subleading terms in perturbation theory, we relate nc and τ and show that the results for the topological charge become equivalent when rescaling τ ≃ nc/ (3 - 15c1), where c1 is the Symanzik coefficient multiplying the rectangular term. We, subsequently, apply cooling and the gradient flow using the Wilson, the Symanzik tree-level improved, and the Iwasaki gauge actions to configurations produced with N f = 2 + 1 + 1 twisted mass fermions. We compute the topological charge, its distribution, and the correlators between cooling and gradient flow at three values of the lattice spacing demonstrating that the perturbative rescaling τ ≃ nc/ (3 - 15c1) leads to equivalent results. [ABSTRACT FROM AUTHOR]

We employ a novel method to analyze Euclidean correlation functions entering the calculation of hadron energies in lattice QCD. The method is based on the sampling of all possible solutions allowed by the spectral decomposition of the hadron correlators. We demonstrate the applicability of the method by studying the nucleon excited states in the positive- and negative-parity channels over a pion mass range of about 400 to 150 MeV. The results are compared to the standard variational approach routinely used to study excited states within lattice QCD. The main advantage of our new approach is its ability to unambiguously determine all excited states to which the Euclidean time correlation function is sensitive. [ABSTRACT FROM AUTHOR]

The masses of the low-lying baryons are evaluated using a total of ten ensembles of dynamical twisted mass fermion gauge configurations. The simulations are performed using two degenerate flavors of light quarks, and a strange and a charm quark fixed to approximately their physical values. The light sea quarks correspond to pseudo scalar masses in the range of about 210 to 430 MeV. We use the Iwasaki improved gluonic action at three values of the coupling constant corresponding to lattice spacing a = 0.094, 0.082 and 0.065 fm determined from the nucleon mass. We check for both finite volume and cutoff effects on the baryon masses. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. We performed a chiral extrapolation of the forty baryon masses using SU(2) χPT. After taking the continuum limit and extrapolating to the physical pion mass our results are in good agreement with experiment. We provide predictions for the mass of the doubly charmed Ξ*cc, as well as of the doubly and triply charmed Os that have not yet been determined experimentally. [ABSTRACT FROM AUTHOR]

We investigate the excited states of the nucleon using Nf=2 twisted mass gauge configurations with pion masses in the range of about 270 to 450 MeV and one ensemble of Nf=2 Clover fermions at almost physical pion mass. We use two different sets of variational bases and study the resulting generalized eigenvalue problem. We present results for the two lowest positive and negative parity states. [ABSTRACT FROM AUTHOR]

We perform a high statistics calculation of disconnected fermion loops on graphics processing units for a range of nucleon matrix elements extracted using lattice QCD. The isoscalar electromagnetic and axial vector form factors, the sigma terms and the momentum fraction and helicity are among the quantities we evaluate. We compare the disconnected contributions to the connected ones and give the physical implications on nucleon observables that probe its structure. [ABSTRACT FROM AUTHOR]

A method suitable for extracting resonance parameters of unstable baryons in lattice QCD is examined. The method is applied to the strong decay of the Δ to a pion-nucleon state, extracting the πNΔ coupling constant and Δ decay width. [ABSTRACT FROM AUTHOR]

We present results on the axial and the electromagnetic form factors of the nucleon, as well as on the first moments of the nucleon generalized parton distributions using maximally twisted mass fermions. We analyze two Nf = 2 + 1 + 1 ensembles having pion masses of 213 MeV and 373 MeV each at a different value of the lattice spacing. The lattice scale is determined using the nucleon mass computed on a total of 17 Nf = 2+1 + 1 ensembles generated at three values of the lattice spacing, a. The renormalization constants are evaluated nonperturbatively with a perturbative subtraction of O(a²) terms. The moments of the generalized parton distributions are given in the MS scheme at a scale of μ = 2 GeV. We compare with recent results obtained using different discretization schemes. The implications on the spin content of the nucleon are also' discussed. [ABSTRACT FROM AUTHOR]

The masses of the low-lying strange and charm baryons are evaluated using two degenerate flavors of twisted mass sea quarks for pion masses in the range of about 260 to 450 MeV. The strange and charm valence quark masses are tuned to reproduce the masses of the kaon and D meson at the physical point. The tree-level Symanzik improved gauge action is employed. We use three values of the lattice spacing, corresponding to β=3.9, β=4.05 and β=4.2, with r0/a=5.22(2), r0/a=6.61(3) and r0/a=8.31(5), respectively. We examine the dependence of the strange and charm baryons on the lattice spacing and the strange and charm quark masses. The pion mass dependence is studied and physical results are obtained using heavy-baryon chiral perturbation theory to extrapolate to the physical point. [ABSTRACT FROM AUTHOR]

Perturbative and nonperturbative results are presented on the renormalization constants of the quark field and the vector, axial-vector, pseudoscalar, scalar, and tensor currents. The perturbative computation, carried out at one-loop level and up to second order in the lattice spacing, is performed for a fermion action, which includes the clover term and the twisted mass parameter yielding results that are applicable for unimproved Wilson fermions, as well as for improved clover and twisted mass fermions. We consider ten variants of the Symanzik improved gauge action corresponding to ten different values of the plaquette coefficients. Nonperturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations are performed for pion masses in the range of 480-260 MeV and at three values of the lattice spacing, a, corresponding to &BGR; = 3.9, 4.05, 4.20. For each renormalization factor computed nonpertur-batively we subtract its perturbative …(a2) terms so that we eliminate part of the cutoff artifacts. The renormalization constants are converted to MS at a scale of &mgr; -- 2 GeV. The perturbative results depend on a large number of parameters and are made easily accessible to the reader by including them in the distribution package of this paper, as a MATHEMATICA input file. [ABSTRACT FROM AUTHOR]

We present results on the lower moments of the nucleon generalized parton distributions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with three different values of the lattice spacings, namely, a=0.089??fm, a=0.070??fm, and a=0.056??fm, allowing the investigation of cutoff effects. The volume dependence is examined using simulations on two lattices of spatial length L=2.1??fm and L=2.8??fm. The simulations span pion masses in the range of 260 to 470 MeV. Our results are renormalized nonperturbatively, and the values are given in the MS¯ scheme at a scale μ=2??GeV. They are chirally extrapolated to the physical point in order to compare with the experiment. The consequences of these results on the spin carried by the quarks in the nucleon are investigated. [ABSTRACT FROM AUTHOR]

We present results on the nucleon electromagnetic 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. Cutoff effects are investigated using three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm. The nucleon magnetic moment, Dirac and Pauli radii are obtained in the continuum limit and chirally extrapolated to the physical pion mass allowing for a comparison with experiment. [ABSTRACT FROM AUTHOR]

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 three different values of the lattice spacings, namely a = 0.089 fm, a = 0.070 fm and a = 0.056 fm. The nucleon axial charge is obtained in the continuum limit and chirally extrapolated to the physical pion mass enabling comparison with experiment. [ABSTRACT FROM AUTHOR]

Perturbative and nonperturbative results on the renormalization constants of the fermion field and the twist-2 fermion bilinears are presented with emphasis on the nonperturbative evaluation of the one-derivative twist-2 vector and axial-vector operators. Nonperturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations have been performed for pion masses in the range of about 450-260 MeV and at three values of the lattice spacing a corresponding to β=3.9, 4.05, 4.20. Subtraction of O(a2) terms is carried out by performing the perturbative evaluation of these operators at 1-loop and up to O(a2). The renormalization conditions are defined in the RI′-MOM scheme, for both perturbative and nonperturbative results. The renormalization factors, obtained for different values of the renormalization scale, are evolved perturbatively to a reference scale set by the inverse of the lattice spacing. In addition, they are translated to MS at 2 GeV using 3-loop perturbative results for the conversion factors. [ABSTRACT FROM AUTHOR]

We calculate the electromagnetic, axial, and pseudoscalar form factors of the nucleon to δ(1232) transition using two dynamical light degenerate quarks and a dynamical strange quark simulated with the domain wall fermion action. Results are obtained at lattice spacings a=0.114 fm and a=0.084??fm, with corresponding pion masses of 330 MeV and 297 MeV, respectively. High statistics measurements are achieved by utilizing the coherent sink technique. The dominant electromagnetic dipole form factor, the axial form factors and the pseudoscalar coupling are extracted to a good accuracy. This allows the investigation of the nondiagonal Goldberger-Treiman relation. Particular emphasis is given on the extraction of the subdominant electromagnetic quadrupole form factors and their ratio to the dominant dipole form factor, REM and RSM, measured in experiment. [ABSTRACT FROM AUTHOR]

We present a determination of the ratio of kaon and pion leptonic decay constants in isosymmetric QCD (ISOQCD), fK/fπ, making use of the gauge ensembles produced by the Extended Twisted Mass Collaboration with Nf = 2 + 1 + 1 flavors of Wilson-clover twisted-mass quarks, including configurations close to the physical point for all dynamical flavors. The simulations are carried out at three values of the lattice spacing ranging from ~0.068 to ~0.092 fm with linear lattice size up to L~5.5 fm. The scale is set by the particle data group (PDG) value of the pion decay constant, fISO QCDπ = 130.4(2) MeV, at the ISOQCD pion point, MISO QCDπ = 135.0(2) MeV, obtaining for the gradient-flow scales the values w 0 = 0.17383(63) fm, √t0 = 0.14436(61) fm and t0/w0 = 0.11969(62) fm. The data are analyzed within the framework of SU(2) chiral perturbation theory without resorting to the use of renormalized quark masses. At the ISOQCD kaon point MISO QCDK = 494.2(4) MeV we get (fK/fπ) ISO QCD = 1.1995(44), where the error includes both statistical and systematic uncertainties. Implications for the Cabibbo-Kobayashi-Maskawa matrix element |Vus| and for the first-row Cabibbo-Kobayashi-Maskawa unitarity are discussed. [ABSTRACT FROM AUTHOR]

We present a calculation of the up, down, strange, and charm quark masses performed within the lattice QCD framework. We use the twisted-mass fermion action and carry out simulations that include in the sea two light mass-degenerate quarks, as well as the strange and charm quarks. In the analysis, we use gauge ensembles simulated at three values of the lattice spacing and with light quarks that correspond to pion masses in the range from 350 MeV to the physical value, while the strange and charm quark masses are tuned approximately to their physical values. We use several quantities to set the scale in order to check for finite lattice spacing effects, and in the continuum limit, we get compatible results. The quark mass renormalization is carried out nonperturbatively using the (modified) Regularization Independent Momentum Subtraction (RI'-MOM) method converted into the MS scheme. For the determination of the quark masses, we use physical observables from both the meson and the baryon sectors, obtaining mud = 3.636(66) (+60-57) MeV and ms = 98.7(2.4)(+4.0-3.2) MeV in the MS (2 GeV) scheme and mc = 1036 (17) (+15-8) MeV in the MS (3 GeV) scheme, where the first errors are statistical and the second ones are combinations of systematic errors. For the quark mass ratios, we get m s / m u d = 27.17(32) (+56-38) and mc/ms = 11.48(12) (+25-19). [ABSTRACT FROM AUTHOR]

We present results on the isoscalar form factors including the disconnected contributions, as well as on the strange and charm quark form factors. Using previous results on the isovector form factors, we determine the flavor decomposition of the nucleon axial form factors. These are computed using an ensemble of Nf = 2 + 1 + 1 twisted mass fermions simulated with physical values of quark masses. We investigate the SU(3) flavor symmetry and show that there is up to 10% breaking for the axial and up to 50% for the induced pseudoscalar form factors. By fitting the Q2 -dependence, we determined the corresponding root mean square radii. The pseudoscalar coupling of the η meson and the nucleon is found to be gηNN = 3.7(1.0)(0.7), and the Goldberger-Treiman discrepancy for the octet combination about 50%. [ABSTRACT FROM AUTHOR]

We extract the neutron electric dipole moment |→dN| within the lattice QCD formalism. We analyze one ensemble of Nf=2+1+1 twisted mass clover-improved fermions with lattice spacing of a≃0.08 fm and physical values of the quark masses corresponding to a pion mass mπ≃139 MeV. The neutron electric dipole moment is extracted by computing the CP-odd electromagnetic form factor F3(Q2→0) through small θ-expansion of the action. This approach requires the calculation of the topological charge for which we employ a fermionic definition by means of spectral projectors while we also provide a comparison with the gluonic definition accompanied by the gradient flow. We show that using the topological charge from spectral projectors leads to absolute errors that are more than two times smaller than those provided when the field theoretic definition is employed. We find a value of |→dN|=0.0009(24)θ e⋅fm when using the fermionic definition, which is statistically consistent with zero. [ABSTRACT FROM AUTHOR]

We compute the nucleon axial and induced pseudoscalar form factors using three ensembles of gauge configurations, generated with dynamical light quarks with mass tuned to approximately their physical value. One of the ensembles also includes the strange and charm quarks with their mass close to physical. The latter ensemble has large statistics and finer lattice spacing and it is used to obtain final results, while the other two are used for assessing volume effects. The pseudoscalar form factor is also computed using these ensembles. We examine the momentum dependence of these form factors as well as relations based on pion pole dominance and the partially conserved axial-vector current hypothesis. [ABSTRACT FROM AUTHOR]

We determine the nucleon axial, scalar and tensor charges within lattice quantum chromodynamics including all contributions from valence and sea quarks. We analyze three gauge ensembles simulated within the twisted mass formulation at approximately physical value of the pion mass. Two of these ensembles are simulated with two dynamical light quarks and lattice spacing a=0.094  fm and the third with a=0.08  fm includes in addition the strange and charm quarks in the sea. After comparing the results among these three ensembles, we quote as final values our most accurate analysis using the latter ensemble. For the nucleon isovector axial charge we find 1.286(23) in agreement with the experimental value. We provide the flavor decomposition of the intrinsic spin 1/2ΔΣq carried by quarks in the nucleon obtaining for the up, down, strange and charm quarks 1/2ΔΣu=0.431(8), 1/2ΔΣd=-0.212(8), 1/2ΔΣs=-0.023(4) and 1/2ΔΣc=-0.005(2), respectively. The corresponding values of the tensor and scalar charges for each quark flavor are also evaluated providing valuable input for experimental searches for beyond the standard model physics. In addition, we extract the nucleon σ-terms and find for the light quark content σπN=41.6(3.8)  MeV and for the strange σs=45.6(6.2)  MeV. The y-parameter that is used in phenomenological studies we find y=0.078(7). [ABSTRACT FROM AUTHOR]

We evaluate the gluon and quark contributions to the spin of the proton using an ensemble of gauge configurations generated at physical pion mass. We compute all valence and sea quark contributions to high accuracy. We perform a nonperturbative renormalization for both quark and gluon matrix elements. We find that the contribution of the up, down, strange, and charm quarks to the proton intrinsic spin is 1/2∑q=u,d,s,cΔΣq+=0.191(15) and to the total spin ∑q=u,d,s,cJq+=0.285(45)(10). The gluon contribution to the spin is Jg=0.187(46)(10) yielding J=Jq+Jg=0.473(71)(14) confirming the spin sum. The momentum fraction carried by quarks in the proton is found to be 0.618(60) and by gluons 0.427(92), the sum of which gives 1.045(118) confirming the momentum sum rule. All scale and scheme dependent quantities are given in the MS̄ scheme at 2 GeV. [ABSTRACT FROM AUTHOR]

We present results for the moments of nucleon isovector vector and axial generalized parton distribution functions computed within lattice QCD. Three ensembles of maximally twisted mass clover-improved fermions simulated with a physical value of the pion mass are analyzed. Two of these ensembles are generated using two degenerate light quarks. A third ensemble is used having, in addition to the light quarks, strange and charm quarks in the sea. A careful analysis of the convergence to the ground state is carried out that is shown to be essential for extracting the correct nucleon matrix elements. This allows a controlled determination of the unpolarized, helicity, and tensor second Mellin moments. The vector and axial-vector generalized form factors are also computed as a function of the momentum transfer square up to about 1 GeV². The three ensembles allow us to check for unquenching effects and to assess lattice finite volume effects. [ABSTRACT FROM AUTHOR]

We determine the strange electromagnetic form factors of the nucleon within the lattice formulation of quantum chromodynamics using simulations that include light, strange and charm quarks in the sea all tuned to their physical mass values. We employ state-of-the-art techniques to accurately extract the form factors for values of the momentum transfer square up to 0.8  GeV². We find that both the electric and magnetic form factors are statistically nonzero. We obtain for the strange magnetic moment μs=-0.017(4)(+10)(+50), the strange magnetic radius ⟨r²M⟩s=-0.015(9)(+30)(+40)  fm², and the strange charge radius ⟨r²E⟩s=-0.0048(6)(0-8)(+120) fm², where the first error is statistical, and the second and third systematic. [ABSTRACT FROM AUTHOR]

The electromagnetic form factors of the proton and the neutron are computed within lattice QCD using simulations with quark masses fixed to their physical values. Both connected and disconnected contributions are computed. We analyze two new ensembles of Nf=2 and Nf=2+1+1 twisted mass clover-improved fermions and determine the proton and neutron form factors, the electric and magnetic radii, and the magnetic moments. We use several values of the sink-source time separation in the range of 1.0 to 1.6 fm to ensure ground state identification. Disconnected contributions are calculated to an unprecedented accuracy at the physical point. Although they constitute a small correction, they are non-negligible and contribute up to 15% for the case of the neutron electric charge radius. [ABSTRACT FROM AUTHOR]

Using Nf=2+1+1 lattice QCD, we determine the fermionic connected contributions to the first and second moments of the pion parton distribution function. Based on gauge configurations from the European Twisted Mass Collaboration, chiral and continuum extrapolations are performed using pion masses in the range of 230 to 500 MeV and three values of the lattice spacing. Finite volume effects are investigated using different volumes. In order to avoid mixing under renormalization for the second moment, we use an operator with two nonzero spatial components of momentum. Momenta are injected using twisted boundary conditions. Our final values read 〈x〉physR=0.2075(106) and 〈x²〉physR=0.163(33), determined at 2 GeV in the M®S scheme and with systematic and statistical uncertainties summed in quadrature. [ABSTRACT FROM AUTHOR]

We evaluate the strange nucleon electromagnetic form factors using an ensemble of gauge configurations generated with two degenerate maximally twisted mass clover-improved fermions with mass tuned to approximately reproduce the physical pion mass. In addition, we present results for the disconnected light quark contributions to the nucleon electromagnetic form factors. Improved stochastic methods are employed leading to high-precision results. The momentum dependence of the disconnected contributions is fitted using the model-independent z-expansion. We extract the magnetic moment and the electric and magnetic radii of the proton and neutron by including both connected and disconnected contributions. We find that the disconnected light quark contributions to both electric and magnetic form factors are nonzero and at the few percent level as compared to the connected. The strange form factors are also at the percent level but more noisy yielding statistical errors that are typically within one standard deviation from a zero value. [ABSTRACT FROM AUTHOR]

We present an investigation of the electromagnetic pion form factor, Fp(Q²), at small values of the four-momentum transfer Q² (≲0.25 GeV²), based on the gauge configurations generated by the European Twisted Mass Collaboration with Nf=2 twisted-mass quarks at maximal twist including a clover term. Momentum is injected using nonperiodic boundary conditions and the calculations are carried out at a fixed lattice spacing (a≃0.09 fm) and with pion masses equal to its physical value, 240 MeV and 340 MeV. Our data are successfully analyzed using chiral perturbation theory at next-to-leading order in the light-quark mass. For each pion mass two different lattice volumes are used to take care of finite size effects. Our final result for the squared charge radius is ⟨r²⟩p=0.443(29) fm², where the error includes several sources of systematic errors except the uncertainty related to discretization effects. The corresponding value of the SU(2) chiral low-energy constant l6 is equal to l6=16.2(1.0). [ABSTRACT FROM AUTHOR]

We present results on the nucleon axial and induced pseudoscalar form factors using an ensemble of two degenerate twisted mass clover-improved fermions with mass yielding a pion mass of mπ = 130 MeV. We evaluate the isovector and the isoscalar, as well as the strange and the charm axial form factors. The disconnected contributions are evaluated using recently developed methods that include deflation of the lower eigenstates, allowing us to extract the isoscalar, strange, and charm axial form factors. We find that the disconnected quark loop contributions are nonzero and particularly large for the induced pseudoscalar form factor. [ABSTRACT FROM AUTHOR]

The masses of the low-lying baryons are evaluated using an ensemble with two degenerate light twisted mass clover-improved quarks with mass tuned to reproduce the physical pion mass. The Iwasaki improved gluonic action is employed. The coupling constant value corresponds to a lattice spacing of a=0.0938(3)(2) fm, determined from the nucleon mass. We find that the clover term supresses isospin symmetry breaking as compared to our previous results using Nf=2+1+1 twisted mass fermions. The masses of the hyperons and charmed baryons evaluated using this ensemble are in agreement with the experimental values. We provide predictions for the mass of the doubly charmed Ξ*cc, as well as of the doubly and triply charmed Ωs that have not yet been determined experimentally. [ABSTRACT FROM AUTHOR]

We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small, giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the z expansion, we extract the nucleon electric and magnetic radii, as well as the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations. [ABSTRACT FROM AUTHOR]

We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with N f = 2 flavors of twisted mass clover-improved fermions with a physical value of the pion mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed nonperturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are gSu = 5.20 (42) (15) (12), gSu = 4.27 (26) (15) (12), gSu = 0.33 (7) (1) (4), and gSu = 0.062 (13) (3) (5) and for the tensor charges gSu = 0.794 (16) (2) (13), gSu = - 0.210 (10) (2) (13), gSu = 0.00032 (24) (0), and gSu = 0.00062 (85) (0) in the MS scheme at 2 GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from estimating the contamination due to the excited states, when our data are precise enough to probe the first excited state. [ABSTRACT FROM AUTHOR]

We present physics results from simulations of QCD using Nf = 2 dynamical Wilson twisted mass fermions at the physical value of the pion mass. These simulations are enabled by the addition of the clover term to the twisted mass quark action. We show evidence that compared to previous simulations without this term, the pion mass splitting due to isospin breaking is almost completely eliminated. Using this new action, we compute the masses and decay constants of pseudoscalar mesons involving the dynamical up and down as well as valence strange and charm quarks at one value of the lattice spacing, a ~0.09 fm. Further, we determine renormalized quark masses as well as their scale-independent ratios, in excellent agreement with other lattice determinations in the continuum limit. In the baryon sector, we show that the nucleon mass is compatible with its physical value and that the masses of the baryons do not show any sign of isospin breaking. Finally, we compute the electron, muon and tau lepton anomalous magnetic moments and show the results to be consistent with extrapolations of older ETMC data to the continuum and physical pion mass limits. We mostly find remarkably good agreement with phenomenology, even though we cannot take the continuum and thermodynamic limits. [ABSTRACT FROM AUTHOR]

The axial couplings of the low lying baryons are evaluated using a total of five ensembles of dynamical twisted mass fermion gauge configurations. The simulations are performed using the Iwasaki gauge action and two degenerate flavors of light quarks, and a strange and a charm quark fixed to approximately their physical values at two values of the coupling constant. The lattice spacings, determined using the nucleon mass, are a=0.082??fm and a=0.065??fm, and the simulations cover a pion mass in the range of about 210 MeV to 430 MeV. We study the dependence of the axial couplings on the pion mass in the range of about 210 MeV to 430 MeV as well as the SU(3) breaking effects as we decrease the light quark mass toward its physical value. [ABSTRACT FROM AUTHOR]