Related papers: Strong Interaction Effects in Scalar Top Productio…
We discuss perturbative and non-perturbative strong interaction effects in the pair production of stop squarks ($\tilde{t}_1$) at $e^+ e^-$ colliders. Events with an additional hard gluon allow to detect or exclude stop pair production even…
The exchange of gluons between heavy quarks produced in $e^+e^-$ interactions results in an enhancement of their production near threshold. We study QCD threshold effects in $\gamma\gamma$ collisions. The results are relevant to heavy quark…
We study gluon radiation in top quark production above threshold at high energy $e^+e^-$ colliders. We allow for the top quarks to be off-shell, considering radiation in both the top production and decay processes simultaneously. Our…
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…
We consider the effects in the production via gluon fusion in LHC collisions of one or two spin-zero new resonant particles $\Phi$ that decay into a top quark pair. We revisit previous analyses of the interferences between the heavy-fermion…
In this talk we present results of an exact calculation of gluon radiation in top production and decay at lepton colliders, including all spin correlations and interferences. We compare properties of gluons radiated in the production and…
In this talk we discuss gluon radiation in top production and decay. After reviewing results for hadron colliders we consider soft gluon radiation at lepton colliders and present gluon distributions that are potentially sensitive to…
Final-state interaction and screening have a great influence on $q \bar q$ production cross sections, which are important quantities in many problems in quark-gluon plasma physics. They lead to an enhancement of the cross section for a $q…
We present the results of an exact calculation of gluon radiation in top production and decay at high energy electron-positron colliders. We include all spin correlations and interferences, the bottom quark mass, and finite top width…
In these proceedings contribution we review our recent results of medium modifications to the coherence pattern between the initial and final state radiation. We study single gluon production off a highly energetic parton that undergoes a…
We report the first evidence of spin interference in exclusive $J/\psi \to e^+e^-$ photoproduction in ultraperipheral Au+Au and isobar (Ru+Ru, Zr+Zr) collisions ($\sqrt{s_{NN}} = 200$~GeV) at STAR. A negative $\cos(2\phi)$ modulation is…
The large width of the top quark influences the way gluons are radiated in top events, giving rise to interesting interference effects in top production and decay. We discuss top width effects in soft guon radiation in $\ee \to \tt$ at high…
We present the distributions for gluon radiation off stop-antistop particles produced in $e^+e^-$ annihilation: $e^+e^- \to \tilde t \bar{\tilde t} g$. For high energies the splitting functions of the fragmentation processes $\tilde t \to…
We study the possibility to detect heavy physics effects in the interactions of Higgs bosons and the top quark at future colliders using the effective Lagrangian approach. The modification of the interactions may enhance the production of…
An analysis of the spin correlation effects in top quark pair production at hadron colliders is presented with special emphasis for the Large Hadron Collider (LHC). At the LHC top quark pair production is dominated by gluon-gluon fusion.…
At $e^+e^-$ and $ep$ colliders, the large fluxes of almost on-shell photons accompanying the lepton beams lead to the photoproduction of jets. As the centre-of-mass energy is increased, regions of smaller $x$ in the parton densities are…
Initial-state and final-state interactions, which are conventionally neglected in the parton model, have a profound effect in QCD hard-scattering reactions. These effects, which arise from gluon exchange between the active and spectator…
We present the results of an exact calculation of gluon radiation in top production and decay at high energy electron-positron colliders. We include all spin correlations and interferences, the bottom quark mass, and finite top width…
In the Minimal Supersymmetric Standard Model, one of the scalar top quarks can be relatively light and its couplings to Higgs bosons strongly enhanced. I will discuss two consequences of this feature: 1) the effects of scalar top loops on…
We summarize our calculation of the total cross section for top quark production at hadron colliders within the context of perturbative quantum chromodynamics, including resummation of the effects of initial-state soft gluon radiation to…