منابع مشابه
Gauge invariance and unstable particles.
A gauge-independent approach to resonant transition amplitudes with nonconserved external currents is presented, which is implemented by the pinch technique. The analytic expressions derived with this method are U(1)em invariant, independent of the choice of the gauge-fixing parameter, and satisfy a number of required theoretical properties, including unitarity. Although special attention is pa...
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When computing the properties of reactions involving unstable charged particles care has to be taken to use a gauge invariant amplitude. In this talk we present methods to (automatically) obtain such an amplitude, both at the tree level and in one-loop calculations, using only a minimal number of diagrams. The numerical difference with gauge variant methods commonly used will be discussed for t...
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Recently, calculations which consider the implications of anomalous trilinear gauge-boson couplings, both at tree-level and in loop-induced processes, have been criticized on the grounds that the lagrangians employed are not SU L (2) × U Y (1)gauge invariant. We prove that, in fact, the general Lorentz-invariant and U (1) em invariant but not SU L (2) × U Y (1) invariant action is equivalent to...
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Electromagnetic properties of off-shell particles are discussed on the sis of a purely electromagnetic reaction: virtual Compton scattering off a proton. It is shown that the definition of off-shell electromagnetic form factors is not gauge invariant and they cannot be investigated in practice. Using only fundamental requirements of gauge invariance it is demonstrated that off-shell effects are...
متن کاملGauge Invariance and Noncommutativity *
The role of the gauge invariance in noncommutative field theory is discussed. A basic introduction to noncommutative geometry and noncommutative field theory is given. Background invariant formulation of Wilson lines is proposed. Duality symmetries relating various noncommutative gauge models are being discussed. ∗Work supported by RFBR grant #, INTAS grant # and Scientific School Support grant #.
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 1995
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.75.3060