V. A. Khoze

Production and decay properties of ultra-heavy quarks☆

Abstract The widths of ultra-heavy quarks that can be decay into W, Z or Higgs bosons are discussed. If the lifetimes become much shorter than the typical strong interaction time scale Λ −1 QCD ∼ 10 −23 s, then open-flavor hadrons and quarkonium bound states cannot be formed any more. Consequences for the jet evolution are investigated. On the other hand, if such quarks can decay only through tiny mixing angles - as it could happen for sequential down-type quarks and for SU(2) singlet quarks in E 6 models - then these bound states do form. Production rates for quarkonia in e + e - annihilation and in hadronic collisions are estimated and their decay signatures are discussed.

Prospects for new physics observations in diffractive processes at the LHC and Tevatron

Abstract. We study the double-diffractive production of various heavy systems (e.g. Higgs, dijet,

THE STRING EFFECT AND QCD COHERENCE

t\bar{t}

Similarity of parton and hadron spectra in QCD jets

and SUSY particles) at LHC and Tevatron collider energies. In each case we compute the probability that the rapidity gaps, which occur on either side of the produced system, survive the effects of soft rescattering and QCD bremsstrahlung effects. We calculate both the luminosity for different production mechanisms, and a wide variety of subprocess cross sections. The results allow numerical predictions to be readily made for the cross sections of all these processes at the LHC and the Tevatron collider. For example, we predict that the cross section for the exclusive double-diffractive production of a 120 GeV Higgs boson at the LHC is about 3 fb, and that the QCD background in the

Can the Higgs be seen in rapidity gap events at the Tevatron or the LHC

b\bar{b}

Perturbative-QCD Approach to Multiparticle Production

decay mode is about 4 times smaller than the Higgs signal if the experimental missing-mass resolution is 1 GeV. For completeness we also discuss production via

Soft diffraction and the elastic slope at Tevatron and LHC energies: a multi-Pomeron approach

\gamma\gamma

Double-diffractive processes in high-resolution missing-mass experiments at the Tevatron

or WW fusion.

Ways to detect a light Higgs boson at the LHC.

Abstract In the framework of the idea of local parton-hadron duality we discuss the asymptotic predictions of QCD perturbation theory for angular distributions of hadron flows in three-jet events, e + e - → q q g → hadrons. The coherence of soft gluon emission provides the QCD explanation of the string effect observed in experiments.

Probabilities of rapidity gaps in high energy interactions.

A possible existence of the local correspondence between parton and hadron distributions in hard processes (local parton-hadron duality) is discussed. First comparison is made to check up local duality at modern energies. It is shown, in particular, that an account of essential single-logarithmic corrections to leading double-logarithmic approximation proves sufficient to fit π± spectra ine+e− annihilation atW≳20GeV by theoretical perturbative spectra of QCD partons. Rapidity spectra versus the normalized rapidity appear to be similar for π,K, p. Further tests of local duality as well as effects of chromodynamical coherence are suggested.