相关论文: Helicity Amplitudes and Angular Decay Distribution…
Using the helicity formalism, we calculate the combined angular distribution function of the two gamma photons ($\gamma_1$ and $\gamma_2$) and the electron ($e^-$) in the triple cascade process…
Recently we considered the electromagnetic decays of the orbitally-excited SU(6) 70-plet baryons in large-N_c QCD, fitting to the helicity amplitudes measured in photoproduction experiments. Using the results of this analysis, we predict…
We derive the expressions for the full angular distributions of $\bar B\to D\ell\bar \nu_\ell$ and $\bar B\to D^{\ast }\ell\bar \nu_\ell$ decays and discuss the spectra on each angle separately. The coefficient functions, depending on…
We study the two-body decays of mesons using the covariant helicity formalism. In particular, we show how the partial wave analysis of decays constrains the interacting terms entering the Lagrangian describing the decays of mesons with…
The decay of the D meson into multibody final states is a complex process that provides valuable insights into the fundamental interactions within the Standard Model of particle physics. This study focuses on the decay cascade $D^{+}\to…
We discuss the polar angle decay distribution in the decay of on-shell and off-shell polarized (W,Z) gauge bosons into massive quark pairs. In particular for the off-shell decays in $H \to (W,Z) + (W^\ast,Z^\ast) (\to q_1\bar q_2)$ it is…
We discuss general on-shell couplings of a scalar with two Z bosons using an operator analysis. In addition to the operator originated from the Higgs mechanism, two dimension-five operators, one CP-even and one CP-odd, are generated only at…
We calculate the independent helicity amplitudes in the decays $B \to K^* \ell^+ \ell^-$ and $B \to \rho \ell \nu_\ell$ in the so-called Large-Energy-Effective-Theory (LEET). Taking into account the dominant $O(\alpha_s)$ and SU(3)…
We derive the four-fold angular distribution for the semileptonic decay $\bar{B}\to D_2^*(\to D \pi)\,\ell \bar{\nu}$ where $D_2^*$(2460) is a tensor meson. We start with the most general beyond the Standard Model (SM) dimension-six…
We give a brief overview of phenomenological developments in the analysis of angular observables for exclusive decay modes of $B$ mesons and $\Lambda_b$ baryons, with focus on recent results and some important aspects related to the…
In the 5-component representation of weak bosons, the first four components make a Lorentz four vector, representing the transverse and longitudinal polarizations excluding the scalar component of the weak bosons, whereas its fifth…
We present a prescription to calculate manifestly gauge invariant tree-level helicity amplitudes for arbitrary scattering processes with off-shell initial-state gluons within the kinematics of high-energy scattering. We show that it is…
In a helical flow there is a subrange of the inertial range in which there is a cascade of both energy and helicity. In this range the scaling exponents associated with the cascade of helicity can be defined. These scaling exponents are…
In these lectures we give, first, the model-independent analysis of the exclusive rare decays B -> K l(bar) l and B_c -> D(D*) l(bar) l with special emphasis on the cascade decay B_c -> D(*)(-> D pi) l(bar) l. We derive a four-fold angular…
The modularity property of the helicity formalism is used to provide amplitude expressions and stage-two spin-correlation functions which can easily be used in direct experimental searches for electro-weak symmetries and dynamics in the…
We perform a helicity amplitude analysis for the processes of $e^+e^-$$\rightarrow$$J/\psi,\psi(2S)\rightarrow\Xi(1530)\bar\Xi(1530)\rightarrow\pi\pi\Xi\bar\Xi\rightarrow\Lambda\bar\Lambda4\pi\rightarrow p\bar{p}6\pi$. The joint angular…
We present results for the helicity amplitudes of the lowest-lying hyperon resonances Y*, computed within the framework of the Bonn constituent-quark model, which is based on the Bethe-Salpeter approach. The seven parameters entering the…
We develop a new theoretical framework for the description of leading twist light-cone baryon distribution amplitudes which is based on integrability of the helicity $\lambda=3/2$ evolution equation to leading logarithmic accuracy. A…
We present the general expression of helicity amplitudes for generic multi-body particle decays characterised by multiple decay chains. This is achieved by addressing for the first time the issue of the matching of final particle spin…
We calculate the independent helicity amplitudes in the decays B --> K^* ell^+ ell^- and B --> rho ell nu_ell in the so-called Large-Energy-Effective-Theory (LEET). Taking into account the dominant O(alpha_s) and SU(3) symmetry-breaking…