Related papers: $N^*$ Production from $e^+e^-$ Annihilations
The BESIII experiment at the Beijing Electron Positron Collider (BEPCII) has accumulated the world's largest samples of direct $e^+e^-$ collisions in the $\tau$-charm region. From the collected samples, which include $e^+e^-$ annihilations…
E831-FOCUS is a photoproduction experiment which collected data during the 1996/1997 fixed target run at Fermilab. More than 1 million charm particles have been reconstructed. Using this sample we measure the lifetimes of all the weakly…
We estimate the power corrections (infrared renormalon contributions) to the coefficient functions for the transverse, longitudinal and asymmetric fragmentation functions in $e^+e^-$ annihilation, using a method based on the analysis of…
We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) >~ sigma(e+e- --> pbar p). We discuss an interpretation in terms of…
A summary of charm hadron production fractions is given, as measured at e+e- storage rings and at HERA, taking into account the newest values of charmed hadron decay branching ratios.
A class of meson decay modes sensitive to only one quark topology at leading G_F order (annihilation of valence quarks through a W) is described. No experimental observations, nor even upper limits, have been reported for these decays. This…
The leptonic tensor for the process $e^+ e^- \to \gamma+\gamma^*$, which describes the next-to-leading order virtual and soft QED corrections to initial state radiation in $e^+ e^-$ annihilation with emission of an extra virtual photon…
The production of the vector meson pairs $B_s^* \bar B_s^*$ in the $e^+e^-$ annihilation is generally contributed by two $P$ wave amplitudes with different total spin $S$ of the mesons, $S=0$ and $S=2$, and also by an $F$ wave amplitude.…
The aim of this work is to give a pedagogical derivation of polarization observables for the annihilation reaction $e^+ + e^- \to N+ \bar N$. The reaction mechanism is one photon + two photon exchange, the last is described by axial…
The form factors of the $K^+ \to \gamma$ transition are studied in the light-front quark model and chiral perturbation theory of $O(p^6)$. The decay spectrum of $K^+ \to e^+ \nu_{e}\gamma$, dominated by the structure dependent contribution,…
The process $e^+e^- \to q \bar q \gamma$ contains radiation zeros, i.e. configurations of the four-momenta for which the scattering amplitude vanishes. We calculate the positions of these zeros for $u$--quark and $d$--quark production and…
We report on a complete calculation of electroweak production of top quark pairs in $e^+e^-$ annihilation at next-to-next-to-leading order in Quantum Chromodynamics. Our setup is fully differential and can be used to calculate any…
In this work we study the e^{+}e^{-}\to\phi K^{+}K^{-} reaction. The leading order electromagnetic contributions to this process involve the \gamma*\phi\ K^{+}K^{-} vertex function with a highly virtual photon. We calculate this function at…
Forward-backward (charge) asymmetry in the processes of $e^+e^-$ annihilation into a pair of charged pseudoscalar mesons is recalculated in the one-loop approximation. The exact dependence on the meson masses is taken into account. Results…
We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) is somewhat greater than sigma(e+e- --> pbar p). We discuss an…
Based on the S-matrix approach, we introduce a modified formula for the $\pi^{\pm}$ electromagnetic form factor which describes very well the experimental data in the energy region $2m_{\pi} \leq \sqrt{s} \leq 1.1$ GeV. Using the CVC…
The production of charmonium in heavy-ion collisions is investigated based on Boltzmann-type transport model for charmonium evolution and langevin equation for charm quark evolution. Charmonium suppression and regeneration in both…
We consider the process of annihilation of e^+ e^- to three pion final state for the case of moderately high energies. The final state emission of virtual and real photon is considered explicitly. The calculations are performed in frames of…
We study the charmonium coherent photoproduction and hadroproduction consistently with modifications from both cold and hot nuclear matters. The strong electromagnetic fields from fast moving nucleus interact with the other target nucleus,…
Using the operator product expansion and nonrelativistic QCD we study the production of charmonium hybrids in B decays. We express the decay rate in terms of a few matrix elements which eventually will be fixed by experimental measurements…