Related papers: $N^*$ Production from $e^+e^-$ Annihilations
Measurements by the Belle Collaboration of the exclusive production of two charmonia in e^+ e^- annihilation differ substantially from theoretical predictions. Till now, no conclusive explanation for this remarkable discrepancy has been…
The dominance of chi_0 in the data for e+e- to psi + chi_J(c\bar{c}) is shown to violate OZI factorization. Single gluon exchange gives a non-factorizing effective S.L interaction that generates a large scalar production amplitude. This…
Using a sample of >10^5 J/psi to mu+mu- decays, Fermilab experiment 789 has studied production of J/psi and psi-prime in 800-GeV proton-nucleon collisions. Differential cross sections and nuclear dependences have been measured for…
We confront the generally small cross sections for gluino pair production in e^+e^- annihilation with the much larger ones in photon-photon scattering at a multi-TeV linear collider like CERN CLIC. The larger rates and the steeper rise of…
Charmonium productions in $p-p$ and $A-B$ collisions have been estimated within the ambit of colour evaporation model (CEM). The model parameters have been fixed by fitting the theoretical results with CDF data. The method is then applied…
Recent theoretical results on heavy flavor production and decay in the framework of perturbative QCD are reviewed. This includes calculations for top production at hadron colliders, inclusive charmonium production and the comparison between…
A short review of the history and a 'slide-show' of QCD tests in $e^+e^-$ annihilation is given. The world summary of measurements of $\alpha_s$ is updated.
Recently, the BESIII experiment performed a measurement of the energy-dependent Born cross section and the effective form factor for the $e^+e^-\to\Omega^-\bar\Omega^+$ reaction at center-of-mass energies ranging from 3.4 to 4.7 GeV. A fit…
We discuss the momentum distributions of inclusively produced particles in $e^+e^-$ annihilation. We show that the dependence of the position of the maxima of the $\xi=\ln(1/z)$ spectra on the mass of the produced particles follows…
We study the production processes e^+ e^- -> chi^+_i chi^-_j, i,j=1,2, and e^+ e^- -> chi^0_m chi^0_n, m,n=1,...,4, working out the advantages of polarizing both beams. For e^+ e^- -> chi^+_1 chi^-_1 with chi^-_1 -> chi^0_1 e^- nu and e^+…
The multiple hadron production in the events induced by the heavy primary quarks in $e^+e^-$ annihilation is reconsidered with account of corrected experimental data. New value for the multiplicity in $b\bar{b}$ events is presented on the…
Analytic formulae are derived for the complete photon energy spectrum due to QED corrections to fermion pair production in case of a limited angular acceptance for the final state fermions. After a numerical integration over the energy of…
Within the framework of nonrelativistic QCD (NRQCD) factorization, we investigate the relativistic corrections to the production of double $B_c$ mesons in $e^+e^-$ annihilation. The study covers center-of-mass energies from the production…
In this paper the relevance of non-spectator decays of charm particles is analysed and some crucial tests for it are suggested.
In the presented paper production of charmonium state $\mathcal{Q}$ in exclusive $W\to\mathcal{Q} D_{s}^{(*)}$ decays is analyzed in the framework of both leading order Nonrelativistic Quantum Chromodynamics (NRQCD) and light-cone expansion…
We study the production of neutralinos e^+ e^- ->chi^0_i \chi^0_j with polarized beams and the subsequent decays chi^0_i -> chi^0_k l^+ l^- and chi^0_j -> chi^0_l l^+ l^-, including the complete spin correlations between production and…
The study of electron-positron collisions at center-of-mass energies corresponding to charmonium production has reached new levels of sensitivity thanks to experiments by the BES and CLEO Collaborations. Final states $\gamma P$, where $P$…
We calculate the longitudinal contribution to the alignment polarization $\Pl$ of quarks produced in $e^+e^-$ annihilation. In the Standard Model, the longitudinal alignment polarization vanishes at the Born term level and thus receives its…
In this paper we study inclusive production of vector charmonium states $J/\psi$ or $\psi(2S)$ in two-photon $\epem$-annihilation at $\sqrt s=10.6 \rm GeV$ using color-singlet model. Analytic expressions for differential cross sections,…
We research on the neutrino pair annihilation $\nu+\overline{\nu}\longrightarrow e^{-}+e^{+}$ around a massive source in asymptotic safety. Since neutrinos and photons have the same geodesic equation around black holes, we can estimate the…