arXiv subjects

R. Decker

Publications and source records attributed to R. Decker.

8 recordsLinked to original sources

arXiv2021

Kink-antikink stripe interactions in the two-dimensional sine-Gordon equation

The main focus of the present work is to study quasi-one-dimensional kink-antikink stripes embedded in the two-dimensional sine-Gordon equation. Using variational techniques, we reduce the interaction dynamics between a kink and an antikink stripe on their respective time and space dependent widths and locations. The resulting reduced system of coupled equations is found to accurately describe the width and undulation dynamics of a single kink stripe as well as that of interacting ones. As an aside, we also discuss two related topics: the computational identification of the kink center and its numerical implications and alternative perturbative and multiple scales approaches to the transverse direction induced dynamics for a single kink stripe in the two-dimensional realm.

nlin.PS↗

arXiv2018

{\phi}^4 Solitary Waves in a Parabolic Potential: Existence, Stability, and Collisional Dynamics

We explore a {\phi}^4 model with an added external parabolic potential term. This term dramatically alters the spectral properties of the system. We identify single and multiple kink solutions and examine their stability features; importantly, all of the stationary structures turn out to be unstable. We complement these with a dynamical study of the evolution of a single kink in the trap, as well as of the scattering of kink and anti-kink solutions of the model. We see that some of the key characteristics of kink-antikink collisions, such as the critical velocity and the multi-bounce windows, are sensitively dependent on the trap strength parameter, as well as the initial displacement of the kink and antikink.

math-ph↗

arXiv2017

Kink Dynamics in a Parametric $\phi^6$ System: A Model With Controllably Many Internal Modes

We explore a variant of the $\phi^6$ model originally proposed in Phys.\ Rev.\ D {\bf 12}, 1606 (1975) as a prototypical, so-called, "bag" model in which domain walls play the role of quarks within hadrons. We examine the steady state of the model, namely an apparent bound state of two kink structures. We explore its linearization, and we find that, as a function of a parameter controlling the curvature of the potential, an {\it effectively arbitrary} number of internal modes may arise in the point spectrum of the linearization about the domain wall profile. We explore some of the key characteristics of kink-antikink collisions, such as the critical velocity and the multi-bounce windows, and how they depend on the principal parameter of the model. We find that the critical velocity exhibits a non-monotonic dependence on the parameter controlling the curvature of the potential. For the multi-bounce windows, we find that their range and complexity decrease as the relevant parameter decreases (and as the number of internal modes in the model increases). We use a modified collective coordinates method [in the spirit of recent works such as {Phys.\ Rev.\ D} {\bf 94}, 085008 (2016)] in order to capture the relevant phenomenology in a semi-analytical manner.

nlin.PS↗

arXiv2005

Lepton Self-Mass, Higgs Scalar and Heavy Quark Masses

This paper has been presented at the DESY Workshop, October 22-24, 1979. Assuming cancellation of lepton self-mass ultraviolet divergences in the SU(2) x U(1) gauge theory, we predict heavy quark t and Higgs scalar masses. In Eq.(6), the mass sum rule necessary to the vanishing of quadratic divergences is formulated.

hep-ph↗

arXiv1995

Tau Decays into Four Pions

We compute branching ratios and invariant mass distributions of the tau decays into four pions. The hadronic matrix elements are obtained by starting from the structure of the hadronic current in chiral limit and then implementing low-lying resonances in the different channels. Reasonable agreement with experiment is obtained both for the $τ\to ν_τ + (4 π) $ decay rates and the $e^+e^- \to (4 π) $ cross sections. Furthermore we supply an interface to use our matrix elements within the Tauola Monte-Carlo program.

hep-ph↗

arXiv1993

Radiative Tau Decays with One Pseudoscalar Meson

We have calculated the decay $τ\rightarrow νπ(K) γ$. We present the photon energy spectrum, the meson-photon invariant mass spectrum and the integrated rate as a function of a photon energy cut or an invariant mass cut. Both the internal bremsstrahlung and the structure dependent radiation have been taken into account. To this aim we have parametrized the form factors $F_V$ and $F_A$, which determine the structure dependent radiation. Observables especially suited for the measurement of the structure dependent form factors are found and implications on the width of the $a_1$ discussed.

hep-ph↗

arXiv1993

Dominant Three-Body Decays of a Heavy Higgs and Top Quark

We calculate the dominant three body Higgs decays, $H \to W^+W^-(Z^0, γ)$ and $H \to t\overline{t}(Z^0,γ,g)$, in the Standard Model. We find that the branching ratios of these decays are of the order of few percent for large Higgs masses. We comment on the behaviour of the partial decay width $Γ(H \to t\overline{b}W^-)$ below the $t\overline{t}$ threshold. Numerical results of the following three body top decays, $t \to W^+b(γ,g,Z^0)$ and $t \to W^+bH$, are also given. We discuss the feasibility of observing these Higgs and top decays at future high energy colliders.

hep-ph↗

arXiv1993

Measuring the Wess-Zumino Anomaly in Tau Decays

We propose to measure the Wess-Zumino anomaly contribution by considering angular distributions in the decays $τ\toν_τηπ^{-}π^{0}$, $τ\toν_τK^- π^{-} K^+ $ and $τ\toν_τK^- π^- π^+$. Radial excitations of the $K^*$, which cannot be seen in $e^++e^-$, should be observed in the $ K^- π^+ π^-$ decay channel.

hep-ph↗