We use the operator-product expansion to find coefficient of $〈{G}^{2}〉$ in Cornwall's minimally gauge-dependent effective gluon propagator lowest order ${\ensuremath{\alpha}}_{s}$. This contribution is explicitly shown be gauge invariant. The running mass generated by this condensate obtained ${m}_{\mathrm{gluon}}^{2}\ensuremath{\approx}\frac{{(640 \mathrm{MeV})}^{4}}{{Q}^{2}}$. Quark effects are insignificant.

We demonstrate that QED exhibits a previously unobserved noncovariant, nonlocal symmetry. Some consequences are discussed.Received 31 March 1993DOI:https://doi.org/10.1103/PhysRevLett.71.3758©1993 American Physical Society

A compact 14 MeV neutron detector using an array of scintillating fibers has been tested on the TFTR tokamak under conditions a high gamma background. This uses fiber-matrix geometry, magnetic field-insensitive phototube with active HV base and pulse-height discrimination to reject low-level pulses from 2.5 neutrons intense gammas. Laboratory calibrations have performed at EG&G Las Vegas pulsed DT generator 30 kCi 60Co source as background, PPPL sources, LANL energetic deuterium beam...

When the electroweak action is rewritten in terms of SU(2) gauge invariant variables, Higgs can be interpreted as a conformal metric factor. We show that asymptotic flatness required to avoid Gribov problem: without it, new variables fail nonperturbatively invariant. also clarify relations between this approach and unitary fixing, existence similar transformations other theories.

We bring together for the first time coefficients in covariant gauges of all condensates dimension four or less operator product expansion (OPE) quark, gluon and ghost propagators. It is stressed that contrary to general belief do not enter OPE propagators gauge-invariant combinations like [Formula: see text] 〈G 2 〉. The results are presented arbitrary lowest order light quark masses SU (N c ) internal symmetry group. All terms which, through equations motion, may be viewed as being...

A crucial element of scattering theory and the LSZ reduction formula is assumption that coupling vanishes at large times. This known not to hold for theories Standard Model in general such asymptotic dynamics well understood. We give a description field which incorporates important features weak convergence physical boundary conditions. Applications with three four point interactions are presented results shown be completely consistent perturbation theory.

We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A describing flux tube between quarks as a thin string of glue is found to be poor description continuum state; infinitesimal thickness leads UV artifacts which suppress overlap with state. Contrastingly, surrounds non-Abelian Coulomb fields have good for all charge separations. In fact, increases lattice regulator removed. This opens up possibility that true limit.

We consider two very different models of the flux tube linking heavy quarks: a string matter fields and Coulombic description separately gauge invariant charges. compare how close they are to unknown true ground state in compact U(1) SU(2) Higgs model. Simulations show that is better confined phase but best deconfined phase; last result shown agree with analytical calculations. Surprisingly nonabelian theory both phases. This indicates significant difference width tubes theories.

The canonical quantization of a charged particle in an intense laser background is developed and the associated two-point function calculated. It shown how causal propagator can be extracted. We provide interpretation this terms degenerate quantum processes. spectral properties are derived, we show multipole structures emerge as perturbative feature. also calculate multiple wave-function renormalizations to all orders perturbation theory. Our calculations for both circular linearly polarized...

We investigate the properties of a dressed electron which reduces, in particular class gauges, to usual fermion. A one loop calculation propagator is presented. show explicitly that an infra-red finite, multiplicative, mass shell renormalisation possible for this electron, or, equivalently, fermion abovementioned gauges. The results are complete accord with previous conjectures.

New results for the fermion propagator in a laser background are presented. We show that all orders electron can be written compact and appealing form as sum of sideband poles with matrix wave function renormalization valued mass shift. This last result is essential fermionic theory if we to maintain both its square pick up correction only at order ${e}^{2}$. A perturbative verification our carried out.

We study the approach, initiated by Marinari et al., to static interquark potential based on Polyakov lines of finite temporal extent, evaluated in Coulomb gauge. show that, at small spatial separations, can be understood as being between two separately gauge invariant color charges. At larger separations Gribov copies obstruct nonperturbative identification individually states. demonstrate, for first time, how invariance maintained quite generally averaging over copies. This allows us...

The reduced Hamiltonian system on T*(SU(3)∕SU(2)) is derived from a Riemannian geodesic motion the SU(3) group manifold parametrized by generalized Euler angles and endowed with bi-invariant metric. Our calculations show that metric defined flow orbit space SU(3)∕SU(2)≃S5 not isometric or even geodesically equivalent to standard five-sphere S5 embedded into R6.