Search results for "Gauge"
showing 10 items of 710 documents
Unitarity, Becchi-Rouet-Stora-Tyutin symmetry, and Ward identities in orbifold gauge theories
2004
We discuss the use of BRST symmetry and the resulting Ward identities as consistency checks for orbifold gauge theories in an arbitrary number of dimensions. We demonstrate that both the usual orbifold symmetry breaking and the recently proposed Higgsless symmetry breaking are consistent with the nilpotency of the BRST transformation. The corresponding Ward identities for four-point functions of the theory engender relations among the coupling constants that are equivalent to the sum rules from tree level unitarity. We present the complete set of these sum rules also for inelastic scattering and discuss applications to six-dimensional models and to incomplete matter multiplets on orbifold f…
Asymptotic freedom in massive Yang-Mills theory
2007
An effective field theory model of the massive Yang-Mills theory is considered. Assuming that the renormalized coupling constants of 'non-renormalizable' interactions are suppressed by a large scale parameter it is shown that in analogy to the non-abelian gauge invariant theory the dimensionless coupling constant vanishes logarithmically for large values of the renormalization scale parameter.
Canonical Neutral Current Predictions From The Weak Electromagnetic Gauge Group SU(3) X U(1)
1980
A straightforward SU(3) x U(1) model in which there is effectively one new neutral-current parameter (denoted by R) is shown to give the canonical neutrino neutral-current predictions for all values of R. For small R the ''low-energy'' theory is essentially SU(2) x U(1) while for R of the order of one it has a much richer ''low-energy'' gauge-boson mass spectrum. Even in the latter case, the predicted e-d asymmetry agrees with experiment. It is interesting that the atomic-physics parity violation depends sensitively on R.
Constraining new interactions with leptonic tau decays
1995
13 páginas, 10 tablas.-- PACS number(s): 13.35.Dx, 12.60.Cn, 12.60.Fr
Massless Spectra and Gauge Couplings at One-Loop on Non-Factorisable Toroidal Orientifolds
2018
So-called `non-factorisable' toroidal orbifolds can be rewritten in a factorised form as a product of three two-tori by imposing an additional shift symmetry. This finding of Blaszczyk et al., arXiv:1111.5852, provides a new avenue to Conformal Field Theory methods, by which the vector-like massless matter spectrum - and thereby the type of gauge group enhancement on orientifold invariant fractional D6-branes - and the one-loop corrections to the gauge couplings in Type IIA orientifold theories can be computed in addition to the well-established chiral matter spectrum derived from topological intersection numbers among three-cycles. We demonstrate this framework for the $\mathbb{Z}_4 \times…
The Negele-Vautherin density matrix expansion applied to the Gogny force
2010
We use the Negele-Vautherin density matrix expansion to derive a quasi-local density functional for the description of systems of fermions interacting with short-ranged interactions composed of arbitrary finite-range central, spin-orbit, and tensor components. Terms that are absent in the original Negele-Vautherin approach owing to the angle averaging of the density matrix are fixed by employing a gauge invariance condition. We obtain the Kohn-Sham interaction energies in all spin-isospin channels, including the exchange terms, expressed as functions of the local densities and their derivatives up to second (next to leading) order. We illustrate the method by determining the coupling consta…
Continuity equation and local gauge invariance for the N3LO nuclear energy density functionals
2011
Background: The next-to-next-to-next-to-leading order (N3LO) nuclear energy density functional extends the standard Skyrme functional with new terms depending on higher-order derivatives of densities, introduced to gain better precision in the nuclear many-body calculations. A thorough study of the transformation properties of the functional with respect to different symmetries is required, as a step preliminary to the adjustment of the coupling constants. Purpose: Determine to which extent the presence of higher-order derivatives in the functional can be compatible with the continuity equation. In particular, to study the relations between the validity of the continuity equation and invari…
Infinite matter properties and zero-range limit of nonrelativistic finite-range interactions
2016
We discuss some infinite matter properties of two finite-range interactions widely used for nuclear structure calculations, namely Gogny and M3Y interactions. We show that some useful informations can be deduced for the central, tensor and spin-orbit terms from the spin-isospin channels and the partial wave decomposition of the symmetric nuclear matter equation of state. We show in particular that the central part of the Gogny interaction should benefit from the introduction of a third Gaussian and the tensor parameters of both interactions can be deduced from special combinations of partial waves. We also discuss the fact that the spin-orbit of the M3Y interaction is not compatible with lo…
A three body state with J=3 in the ρB*B̅N* interaction
2016
We study the ρB * BN * system solving the Faddeev equations in the fixed center approximation. The B * BN * system will be considered forming a cluster, and using the two-body ρB * unitarized scattering amplitudes in the local Hidden Gauge approach we find a new I ( J PC ) = 1(3 −− ) state. The mass of the new state corresponds to a two particle invariant mass of the ρB * system close to the resonant energy of the B * 2 (5747), indicating that the role of this J = 2 resonance is important in the dynamical generation of the new state.
An educational path for the magnetic vector potential and its physical implications
2013
We present an educational path for the magnetic vector potential A aimed at undergraduate students and pre-service physics teachers. Starting from the generalized Ampere–Laplace law, in the framework of a slowly varying time-dependent field approximation, the magnetic vector potential is written in terms of its empirical references, i.e. the conduction currents. Therefore, once the currents are known, our approach allows for a clear and univocal physical determination of A, overcoming the mathematical indeterminacy due to the gauge transformations. We have no need to fix a gauge, since for slowly varying time-dependent electric and magnetic fields, the ‘natural’ gauge for A is the Coulomb o…