Axigluon production at ep colliders

We study the prospects for the production of axigluons, the massive color-octet gauge bosons present in all chiral-color models, in ep collisions. We find that HERA will likely be able to exclude the currently allowed “window” of light axigluon masses, 25 GeV < M_A < 125 GeV.     

Exotic hadron bound state production at hadron colliders

The non-relativistic wave function framework is applied to study the production and decay of exotic hadrons, which can be effectively described as bound states of other hadrons. Employing the factorized formulation,with the help of event generators, we investigate the production of exotic hadrons in multiproduction processes at high energy hadron colliders. This study provides crucial information for the measurements of the relevant exotic hadrons.     

High-p T lepton pair production at ep colliders: comparison between various production mechanisms

High-p _T lepton pair production under the conditions of HERA is studied in order to compare the respective contributions of several different production mechanisms, among them the γγ and the Drell-Yan effects. Various distributions are considered. It is shown that the γγ process systematically and largely dominates. Therefore this type of experiment may allow one to determine the equivalent-photon spectrum of the proton.     

Supersymmetric left-right model and its tests in linear colliders

We investigate phenomenological implications of a supersymmetric left-right model based on SU(2)_L × SU(2)_R × U(1)_B–L gauge symmetry testable in the next generation linear colliders. We concentrate in particular on the doubly charged SU(2)_R triplet higgsino , which we find very suitable for experimental search. We estimate its production rate in e⁺e⁻, e⁻e⁻, e⁻γ and γγ collisions and consider its subsequent decays. These processes have a clear discovery signature with a very low background from other processes.     

Muon-pair production in the left-right symmetric model at a Z~0-factory

The potential for probing the impacts of the left-right symmetric model (LRM) on the process e + e-→μ + μ-at a proposed Z 0-factory is investigated.Under different electron-positron polarization collision modes,we calculate and compare the deviations of various observables in the framework of the LRM from the standard model (SM) predictions,such as the total cross section,the distribution of the transverse momentum of μ-,and the forward-backward charge asymmetry of μ-.In addition,we present the relations between the observables and the LRM parameters.We conclude that it is possible to observe the effects of the LRM on the process e + e-→μ + μ-by using optimal observables and favorable parameters at a Z 0-factory.     

Charmonium production at high-energy colliders

I review inclusive charmonium production at the high-energy colliders Tevatron and HERA.     

Tau lepton production in ep collisions at HERA

The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994–2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.     

g_1 at low x and low Q^2 with Polarized ep colliders

Measurements of at low x and low are expected to provide a sensitive probe of the transition from Regge to perturbative QCD dynamics, offering a new testing ground for models of small x physics. We discuss the potential of polarized ep colliders (Polarized HERA and eRHIC) to investigate this physics – varying between 0.01 and 1 GeV– and to constrain the high-energy part of the Drell-Hearn-Gerasimov sum-rule for polarized photoproduction. Received: 28 August 2000 / Revised version: 9 November 2000 / Published online: 21 December 2000     

Hadron production by ep collisions at HERA

TheP distribution of hadrons from deep-inelastic ep collisions of the H1 experiment determines for the hadrons in the final state, a temperature 277±14 MeV220 MeV of the critical temperature predicted by QCD, suggesting the formation of quark-gluon plasma (QGP). From their forward to backward ratio, it is found an excess of hadrons arising from the deconfinement of quarks inside the proton.     

Associate Higgs and gauge boson production at hadron colliders in a model with vector resonances

Motivated by new models of dynamical electroweak symmetry breaking that predict a light composite Higgs boson, we build an effective Lagrangian which describes the standard model (with a light Higgs) and vector resonances. We compute the cross section for the associate production of a Higgs and a gauge boson. For some values of model parameters we find that the cross section is significantly enhanced with respect to the standard model. This enhancement is similar at the LHC (large hadron collider) and the Tevatron for the same range of resonance mass. PACS 12.60.Nz