Related papers: Unstable particles in One Loop Calculations
We present general one-loop contributions to the decay processes $H\rightarrow f\bar{f}\gamma$ including all possible the exchange of the additional heavy vector gauge bosons, heavy fermions, and charged (also neutral) scalar particles in…
We analyze properties of unstable systems at rest and in motion.
The naive implementation of finite width effects in processes involving unstable particles can violate gauge invariance. For the example of radiative $W$ production and decay, $q\bar q' \to \ell\nu\gamma$, at tree level, it is demonstrated…
Round-off errors arising from the difference between real numbers and their floating-point representation cause the control flow of conditional floating-point statements to deviate from the ideal flow of the real-number computation. This…
Using variational methods, we construct approximate solutions for the Gross-Pitaevski equation which concentrate on circles in $\R^3$. These solutions will help to show that the $L^2$ flow is unstable for the usual topology and for the…
We develop an unambiguous and practical method to calculate one-loop quantum corrections to the energies of classical time-independent field configurations in renormalizable field theories. We show that the standard perturbative…
We present a detailed non-perturbative analysis of the time-evolution of a well-known quantum-mechanical system - a particle between potential walls - describing the decay of unstable states. For sufficiently high barriers, corresponding to…
A general, two-way coupled, point-particle formulation that accounts for the disturbance created by the dispersed particles in obtaining the undisturbed fluid flow field needed for accurate computation of the force closure models is…
Time evolution of the decay process of unstable particles is investigated in field theory models. We first formulate how to renormalize the non-decay amplitude beyond perturbation theory and then discuss short-time behavior of very…
In this paper, we study the effects of the widths of unstable particles on the one-loop electroweak corrections for the $pp \to WW$ process at the TeV scale within the framework of the complex mass scheme. We also investigate, for this same…
We study gauge dependence of gravitational waves produced from a first-order phase transition in classical scale-invariant $U(1)'$ models. Accidental gauge independence of the one-loop effective potential in this class of models is spoiled…
The leading perturbative contributions into the two-point gauge-invariant correlator $Tr<gF(x)U(x,0)U(0,y)F(y)U(y,0)U(0,x)>$ are calculated at the one-loop order. It is shown, that nonlocal condensate is nonzero at this order. The relation…
We solve the one loop effective scalar field equations for spatial plane waves in massless, minimally coupled scalar quantum electrodynamics on a locally de Sitter background. The computation is done in two different gauges: a non-de Sitter…
We compute the one-loop quantum corrections to the gravitational potentials of a spinning point particle in a de Sitter background, due to the vacuum polarisation induced by conformal fields in an effective field theory approach. We…
Performing a stability analysis during the design of any electronic circuit is critical to guarantee its correct operation. A closed-loop stability analysis can be performed by analysing the impedance presented by the circuit at a…
We recently presented a new method for the evaluation of one-loop amplitude of arbitrary scattering processes, in which the reduction to scalar integrals is performed at the integrand level. In this talk, we review the main features of the…
Engineered systems naturally experience large disturbances that can disrupt desired operation because the system may fail to recover to a stable equilibrium point. It is valuable to determine the mechanism of instability when the system is…
We review mathematical methods for the treatment of a system of Bose particles with nonuniform density. Common pitfalls are pointed out.
We study QED corrections to operator matrix elements involving heavy composite particles (e.g., heavy-mesons, nuclei, and atoms). We define a new notion of reducible and irreducible graphs which is useful for systems with many discrete…
In honor of Dave Roper's 90th birthday, I present a pedagogical introduction to our modern understanding of unstable particles in Quantum Field Theory, based on the analytic structure of the propagator, with occasional remarks on the Roper…