Related papers: Polarization effects in e^+e^- annihilation proces…
We present the higher order QCD corrections to the fragmentation functions and the corresponding cross sections.
Recent experiments have found spin alignment of $J/\psi$ with respect to event plane in heavy ion collisions, suggesting a medium effect that is spin dependent. We propose a possible mechanism with polarized dissociation from the motion of…
We compute the next-to-next-to-leading order (NNLO) QCD corrections to the six most important event shape variables related to three-particle final states in electron-positron annihilation. The corrections are sizeable for all variables,…
We study the effects of gluon radiation on top production and decay processes at an $e^+e^-$ collider.The matrix elements are computed without any approximations, using spinor techniques. We use a Monte Carlo event generator which takes…
The longitudinal polarization of hyperons in $e^+e^-$ annihilation at high energies depends on the longitudinal polarization of the quark produced at the $e^+e^-$ annihilation vertex whereas the spin alignment of vector mesons is…
Polarization and spin correlations in diboson systems serve as powerful tools for precision tests and searches for new physics. Recently, interpreting these observables through the lens of quantum information, for instance by examining…
We present a computation of QCD next-to-leading order corrections to the top production and decay process at linear colliders. The top quarks are allowed to be off-shell and the production and decay subprocesses are treated together, thus…
Recent measurements, in particular those on $\Lambda$ polarization and spin alignment of vector mesons in $e^+e^-$ annihilation at LEP, and those on the azimuthal asymmetry at HERA, have attracted much attention on the spin effects in high…
We report the first observation of $e^+e^-$ annihilations into hadronic states of positive $C$-parity, $\rho^0 \rho^0$ and $\phi\rho^0$. The angular distributions support two-virtual-photon annihilation production. We also report the…
We developed a method to analyze the polarization correlations of two baryons $B_{1}\bar{B}_{2}$ with various spin combinations in the annihilation process. We established spin density matrices for arbitrary spins in standard and Cartesian…
We provide complete analytic expressions for the inclusive prompt photon production cross section in hadronic final states of $e^+e^-$ annihilation reactions through one-loop order in quantum chromodynamics perturbation theory. Computed…
A polarization analysis is performed for the recent observation of $Z_{cs}$ exotic state in the $e^+e^-$ annihilation experiment with motivation for measuring its spin quantum number in the future. Starting with the unpolarized electron and…
Linear polarization of gluons inside unpolarized hadrons affects the transverse momentum distribution of produced spin-0 particles, such as of the Higgs or (pseudo-)scalar quarkonium states at LHC. Despite the currently unknown amount of…
We show that the longitudinal polarization of the top quarks produced in the annihilation of e+ e- or mu+ mu- into tbar t at energies near the threshold is not affected by the large Coulomb-type corrections, which greatly modify the total…
The complete set of matrix elements for all polarization configurations in top quark decays is presented including higher order QCD corrections. The analysis is done in the framework of the helicity formalism. The results can be used in a…
We point out that the fragmentation of a strange quark into nucleons versus antinucleons is not necessarily identical $D_{p/s}(z,Q^2) \neq D_{\bar p/s}(z,Q^2)$, even though the perturbative contributions from gluon splitting and evolution…
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 final-state interaction effects on the inclusive two-particle production in electron-positron annihilation are investigated within the context of the one-photon annihilation approximation. Such effects are characterized by one structure…
The process of $e^+ e^-$ annihilation into $\pi^+ \pi^-$ pair with radiation of the photon is considered. The amplitude of the reaction $e^+ e^- \to \pi^+ \pi^- \gamma$ consists of the model independent initial-state radiation (ISR) and…
We show that measurements of the proton's polarization in electron-positron annihilation to a proton-antiproton pair $e^+ e^- \to p \bar p$ strongly discriminate between the analytic forms of models which fit the proton form factors in the…