Related papers: Off-diagonal helicity density matrix elements for …
We study the properties of charmed, nonstrange, $\rm D$ mesons produced in continuum $\rm {e^+}{e^-}$ annihilations. The $ \rm {e^+}{e^-}$ collisions were generated in the energy region of the $ \rm \Upsilon(3S)$ and $ \rm \Upsilon(4S)$…
Recently, the moments of multiplicity distributions in e+e- annihilation and the ratios H_q (cumulant over factorial moments K_q/F_q) have been determined both for the hadronic final state and for jets at variable resolution. These ratios…
We present model independent measurements of the helicity basis form factors in the decay D+ -> K- pi+ e+ nu_e obtained from about 2800 decays reconstructed from a 281 pb^{-1} data sample collected at the psi(3770) center-of-mass energy…
Diffractive photoproduction of rho, phi and J/psi was studied in the BFKL approach to hard colour singlet exchange. Differential cross sections, the energy dependence and spin density matrix elements were calculated and compared to data…
We present the non-relativistic QCD (NRQCD) prediction for the polarization of the J-Psi produced in b to J-Psi + X, as well as the helicity-summed production rate. We propose that these observables provide a means of measuring the three…
We report the first observation of $e^+e^-$ annihilations into states of positive $C$-parity, namely $\rho^0 \rho^0$ and $\phi\rho^0$. The two states are observed in the $\pip\pim\pip\pim$ and $K^+K^-\pip\pim$ final states, respectively, in…
We present studies of the angular and momentum distributions of charged particles in hadronic final states of e+e- annihilation. Some results are derived from reanalysis of data of the JADE experiment operating at the PETRA e+e- collider at…
Top quark polarization in $e^+e^-$ annihilation into $t\bar t$ is calculated for linearly polarized beams. The Green function formalism is applied to this reaction near threshold. The Lippmann--Schwinger equations for the $S$-wave and…
We investigate selectron pair production and decay in e-e- scattering and e+e- annihilation with polarized beams taking into account neutralino mixing as well as ISR and beamstrahlung corrections. One of the main advantages of having both…
We develop a formalism for studying vector meson ($V$) photo-production at the proton ($p$) with polarized photons, $\vec\gamma p \to V p $, through an analysis of the decay distribution in the channel $V\to\pi^0\gamma$. We show that this…
Dilepton production from both pion-pion and kaon-antikaon annihilation in heavy-ion collisions is studied using the relativistic transport model. The formation of a rho meson from pion-pion annihilation and a phi meson from kaon-antikaon…
The electroweak production processes of vector bosons, $e^+ e^- \rightarrow Z \gamma$, $\gamma e \rightarrow Ze$, and $\gamma e \rightarrow W \nu$ are considered simultaneousely and in the Standard model the covariant polarization density…
In the framework of non-perturbative QCD we calculate high-energy diffractive production of vector mesons $\rh, \rh'$ and $\rh''$ by real and virtual photons on a nucleon. The initial photon dissociates into a $q\bar{q}$-dipole and…
A study of the decay channels Lambda_{b}-->Lambda V, where V is a vector meson (1^-), has been done by putting together kinematical and dynamical analysis. An intensive use of the helicity formalism is involved on the kinematical side,…
The general structure of the $1/m$ corrections at zero recoil is studied. The relevant matrix elements are forward matrix elements of local higher dimensional operators and their time ordered products with higher order terms from the…
In this paper, we study total and differential observables of electro- and photoproduction of light $\rho$, $\omega$ and $\phi$ mesons as functions of the center-of-mass energy of the $\gamma p$ collision and momentum transfer squared…
The study of the pi^- p -> rho^0 n and pi^- p -> omega n amplitudes close and below the vector meson production threshold (1.2< sqrt(s) <1.8 GeV) reveals a rich dynamics arising from the presence of specific baryon resonances in this energy…
The differential cross sections and unpolarized spin-density matrix elements for the reaction $\gamma p\to p\omega$ were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV.…
We present a unified description of the vector meson and dilepton production in elementary and in heavy ion reactions. The production of vector mesons ($\rho,\omega$) is described via the excitation of nuclear resonances ($R$). The…
Photons emitted from the electromagnetic fields of relativistic heavy ions can fluctuate into quark anti-quark pairs and scatter from a target nucleus, emerging as vector mesons. These coherent interactions are identifiable by final states…