Related papers: Valley Method Versus Instanton-Induced Effective L…
Based on the new valley equation, we propose the most plausible method for constructing instanton-like configurations in the theory where the presence of a mass scale prevents the existence of the classical solution with a finite radius. We…
We calculate the cross sections of the baryon and lepton number violating processes. The proper valley method enables us to calculate the multi-boson processes, which have the possibility to observation. The mass corrections of the gauge…
The valley method for computing the total high-energy anomalous cross section $S_{anom}$ is the extension of the optical theorem to the case of instanton-antiinstanton backgrounds. As a toy model for baryon number violation in Electroweak…
Instanton theory is an established method to calculate rate constants of chemical reactions including atom tunneling. Technical and methodological improvements increased its applicability. Still, a large number of energy and gradient…
The instanton configuration in the SU(2)-gauge system with a Higgs doublet is constructed by using the new valley method. This method defines the configuration by an extension of the field equation and allows the exact conversion of the…
We show why and how the $I\bar I$ valley trajectory commonly used in the literature so far is in fact unsatisfactory. A better $I\bar I$ valley is suggested. We also give analytic expressions for the multiple instanton-antiinstanton…
We present some recent advances in the computational study of baryon number violation in high energy electroweak collisions. We examine classically allowed processes above the sphaleron barrier and, using a stochastic search procedure, we…
It is known since 1980's that the instanton-induced 't Hooft effective Lagrangian not only can solve the so called $U(1)a$ problem, by making the $\eta'$ meson heavy etc, but it can also lead to chiral symmetry breaking. In 1990's it was…
We develop a systematic treatment for the quasi-zero modes, which play an important role in nonabelian gauge theories. It can be used to derive the analytic forms for the constrained instantons in the \ymh theory. This will automatically…
Within the framework of the instanton approach we present analytical results for the following model problems: (i) particle penetration through a parabolic potential barrier, where the instanton solution practically coincides with the exact…
We estimate the contribution of a class of multiinstanton ladder graphs to baryon and lepton number violating processes in the standard model. We find that this contribution is negligible and does not alter the high energy behavior of the…
We study the path-integral formalism in the imaginary-time to show its validity in a case with a metastable ground state. The well-known method based on the bounce solution leads to the imaginary part of the energy even for a state that is…
Large deviation theory and instanton calculus for stochastic systems are widely used to gain insight into the evolution and probability of rare events. At its core lies the realization that rare events are, under the right circumstances,…
Electroweak instantons are a prediction of the Standard Model and have been studied in great detail in the past although they have not been observed. Earlier calculations of the instanton production cross section at colliders revealed that…
Baryon number is an accidental symmetry of the Standard Model at the Lagrangian level. Its violation is arguably one of the most compelling phenomena predicted by physics beyond the Standard Model. Furthermore, there is a large experimental…
We extend the worldline instanton technique to compute the vacuum pair production rate for spatially inhomogeneous electric background fields, with the spatial inhomogeneity being genuinely two or three dimensional, both for the magnitude…
Canonical instanton theory is known to overestimate the rate constant close to a system-dependent crossover temperature and is inapplicable above that temperature. We compare the accuracy of the reaction rate constants calculated using…
The transition from the instanton-dominated quantum regime to the sphaleron-dominated classical regime is studied in the $d=2$ abelian-Higgs model when the spatial coordinate is compactified to $S^1$. Contrary to the noncompactified case,…
We review some promising numerical techniques for calculating high energy baryon number violating cross sections in the standard model. As these lectures are designed to be self- contained, we present in some detail the formalism of…
The N=2 supersymmetric gauge theory with gauge group SU(2) is considered. The instanton field is calculated explicitly using the superfield formalism. The instanton-induced effects are encoded in the effective vertex in the Lagrangian. This…