Related papers: Selected topics in e^+e^- collisions
The decay width, forward-backward asymmetry and lepton longitudinal and transversal polarization for the exclusive K^* -> l^+ l^- decay in a two Higgs doublet model are computed. It is shown that all these quantities are very effective…
"Twisted particles" refer to non-plane-wave states of photons, electrons, hadrons, or any other particle which carry non-zero, adjustable orbital angular momentum with respect to their average propagation direction. Twisted photons and…
We report the first double differential cross sections of two charged pions and kaons ($e^+e^- \rightarrow hhX$) in electron-positron annihilation as a function of the fractional energies of the two hadrons for any charge and hadron…
The methods allowing to extract the coherent component of pion emission conditioned by the formation of a quasi-classical pion source in heavy ion collisions are suggested. They exploit a nontrivial modification of the quantum statistical…
Sine-Gordon deformed defects that exhibit unusual phenomenological features on the topological charge are investigated. The possibility of a smooth and continuous transition between topological (non null charge) and non-topological (null…
We study the radiative pion decay pi+ -> e+ nu_e gamma within nonlocal chiral quark models that include wave function renormalization. In this framework we analyze the momentum dependence of the vector form factor F_V(q^2), and the slope of…
Tensor form factors encode essential information about the internal spin structure and tensor dynamics of baryons. In this work, we investigate the tensor form factors of the baryon hyperons $\Omega^-$, $\Sigma^{*+}$, and $\Xi^{*-}$ within…
This paper summarizes some recent progress and future perspectives in the experimental investigation of the Standard Model (and physics beyond it) using charged kaon decays, except for the important mode K+ -> pi+ nu nubar discussed in…
We summarize recent work in determining the transition form factor (TFF) of the neutral pion ($\pi^0 \to \gamma^*\gamma^*$), by solving the non-perturbative Dyson-Schwinger and Bethe-Salpeter equations. We first study the transition form…
C o n t e n t s 1. Introduction. 2. General Relations. 3. Small $x$ Domain -- Regge Behaviour. 4. The Parton Model. 5. Sum Rules in the Parton Model. 6. QCD Corrections to Sum Rules. 7. Nucleon Axial Coupling Constants. 8. The Experimental…
We prove factorization theorem for the processes $\pi\gamma^*\to\gamma$ and $\pi\gamma^*\to\pi$ to leading twist in the covariant gauge by means of the Ward identity. Soft divergences cancel and collinear divergences are grouped into a pion…
A summary of results obtained from e^+e^- annihilations at LEP is given. The precision measurements around the Z resonance, the results from charged gauge boson production and searches for new particles are reviewed. Particular emphasis is…
A unified and consistent phenomenological approach to single transverse spin asymmetries in the framework of perturbative QCD, with the inclusion of a new class of spin and k_T dependent distribution and fragmentation functions, is…
As one of the simplest hadronic processes, $\gamma\gamma\rightarrow M^{+}M^{-}$ ($M=\pi,K$) could be a good testing ground for our understanding of the perturbative and nonperturbative structure of QCD, and will be studied with high…
In this talk some of the theoretical aspects of $b \to s \gamma$ transitions are discussed. The focus is on inclusive decays, since these can be computed more reliably. Topics covered are (1) perturbative QCD corrections, (2)…
We review the Standard Model predictions of CP violation in kaon decays. We present an elementary introduction to Chiral Perturbation Theory, four--quark effective hamiltonians and the relation among them. Particular attention is devoted to…
We calculate the $O(p^6)$ corrections to the anomalous form factors appearing in $\pi^+$, $K^+ \to e^+ \nu \gamma,\ \mu^+\nu\gamma$ and $K_{l4}$ decays in Chiral Perturbation Theory. The relevant dimension $6$ terms of the lagrangian are…
An overview is presented of the talks in the working group on Goldstone Bosons. Topics touched on are CP-violation in the Kaon system, rare Kaon decays, $\pi\pi$-scattering, $\phi$-meson decays, scalar mesons, form-factors and…
Off-forward structure functions of the pion are investigated in twist-two and twist-three approximation. A simple model is used for the pion, which allows to introduce finite size effects, while preserving gauge invariance. Results for the…
The most general amplitude for the radiative pion decay pi -> e nu gamma including terms beyond V-A theory is considered. The experimental constraints on the decay amplitude components are discussed. A model independent presentation of the…