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Finite-width effects in the near-threshold ZZZ and ZWW production at ILC

We calculate the cross-section of the near-threshold off-shell ZZZ and ZW+W- production at the International Linear Collider taking into account their instability and the principal part of next-to-leading order corrections. The calculations are performed in the framework of the model of unstable particles with smeared mass-shell. We show that the contribution of the finite Z/W and H widths (their

Hard diffraction and parton rescattering

We present a new model where hard diffraction is an effect of soft gluon rescattering between partons emerging from the hard interaction and the color field of the proton. A resummation to all orders of multiple gluon exchanges leads to an overall color singlet exchange amplitude which reproduces the precise HERA data on diffractive deep inelastic scattering.

Associated central exclusive production of charged Higgs bosons

We propose central exclusive production of a charged Higgs boson in association with a W boson as a possible signature of certain types of extended Higgs sectors. We calculate the cross section and find that the rate at the LHC could be large enough to allow observation in some models with two-Higgs doublets, where the charged Higgs and at least one of the neutral scalars can be light enough. We u

Soft color screening effects in diffractive DIS

We construct a QCD-based model where soft gluon rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. The model successfully describes the precise HERA data on the diffractive deep inelastic structure function in the whole available kinematical range.

Exclusive production of χ c(0 +) meson and its measurement in the π +π - channel

We report on the results of a theoretical study of the central exclusive production of scalar χ c(0 +) meson via χ c0→π +π - decay in high-energy hadron collisions at the RHIC, Tevatron and LHC. The corresponding amplitude for exclusive double-diffractive χ c0 meson production was obtained within the k t-factorization approach including virtualities of active gluons and the cross section is calcul

QCD rescattering mechanism for diffractive deep inelastic scattering

We present a QCD-based model where rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. In the framework of this model the amplitude for multiple gluon exchanges is calculated in the eikonal approximation to all orders in perturbation theory. Both large and small invariant mass MX limits are considered. The model succe

Factorization effect and near-threshold boson production at linear colliders

We calculate cross-section of the near-threshold three-boson production at the ILC with an account of their instability and a principal part of NLO corrections. The calculations are fulfilled within the framework of the model of unstable particles with smeared mass. We show that the contribution of finite width (instability) is large in the resonance Higgs-mass range and should be taken into accou

Diffractive exclusive production of heavy quark pairs at high energy proton-proton collisions

We discuss exclusive double diffractive (EDD) production of heavy quark - heavy antiquark pairs at high energies. Differential distributions for cc̄ at √s = 1.96 GeV and for bb̄ at √s = 14 TeV are shown and discussed. Irreducible leading-order bb̄ background to Higgs production is calculated in several kinematical variables. The signal-to-background ratio is shown and several improvements are sugg

Exclusive double-diffractive production of open charm in proton-proton and proton-antiproton collisions

We calculate differential cross sections for exclusive double diffractive (EDD) production of open charm in proton-proton and proton-antiproton collisions. Sizeable cross sections are found. The EDD contribution constitutes about 1% of the total inclusive cross section for open charm production. A few differential distributions are shown and discussed. The EDD contribution falls faster both with t

Soft gluon rescattering in diffractive DIS

We construct a QCD-based model where soft gluon rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. The model successfully describes the precise HERA data on the diffractive deep inelastic structure function in the whole available kinematical range.

Exclusive bb̄ pair production and irreducible background to the exclusive Higgs boson production

We calculated the cross section for the exclusive double-diffractive bb̄ production in pp→p(bb̄)p reaction at LHC. Large cross sections are obtained (3-10nb). This process constitutes the irreducible background to the exclusive Higgs production and is of particular importance in the upcoming Higgs boson searches. The distribution in invariant mass of the bb̄ pair is calculated and compared with th

Nonperturbative and spin effects in the central exclusive production of the tensor χc(2+) meson

We discuss central exclusive production (CEP) of the tensor χc(2 +) meson in proton-(anti)proton collisions at Tevatron, RHIC, and LHC energies. The amplitude for the process is derived within the kt-factorization approach. Differential and total cross sections are calculated for several unintegrated gluon distribution functions (UGDFs). We compare exclusive production of all charmonium states χc(

Nucleon spin structure and perturbative QCD frontier on the move

We discuss the interplay between higher orders of the perturbative QCD expansion and higher-twist contributions in the analysis of recent Jefferson Lab data on the lowest moments of spin-dependent proton and neutron structure functions Γ1p,n(Q2) and Bjorken sum rule function Γ1p-n(Q2) at 0.05

Nucleon spin structure at low momentum transfers

The generalized Gerasimov-Drell-Hearn sum rule is known to be very sensitive to QCD radiative and power corrections. We improve the previously developed QCD-inspired model for the Q2 dependence of the Gerasimov-Drell-Hearn sum rule. We take into account higher order radiative and higher-twist power corrections extracted from precise Jefferson Lab data on the lowest moment of the spin-dependent pro

Central exclusive χc production

The amplitudes of the central exclusive production of χc mesons are calculated using different unintegrated gluon distribution functions (UGDFs). The procedure of generalisation of UGDF for non-forward case by saturation of positivity constraints is suggested. We compare exclusive production of all charmonium states χc(0+), χc(1+) and χc(2 +) including branching fraction for radiative J/ψ+γ decay

Near-threshold boson pair production in the model of smeared-mass unstable particles

Near-threshold production of boson pairs is considered within the framework of the model of unstable particles with smeared mass. We describe the principal aspects of the model and consider the strategy of calculations including the radiative corrections. The results of calculations are in good agreement with LEP II data and Monte-Carlo simulations. Suggested approach significantly simplifies calc

Diffractive production of χc(0+,1 +,2+) mesons at LHC, Tevatron and RHIC

We consider exclusive double diffractive production of scalar χc(0+), axial-vector χc(1+) and tensor χc(2+) charmonia in proton-(anti)proton collisions at different energies. The corresponding amplitudes for these processes are derived within the kt -factorisation approach and the corresponding cross section is calculated with different unintegrated gluon distribution functions (UGDFs) known from

Elastic double diffractive production of axial-vector χc (1+ +) mesons and the Landau-Yang theorem

We discuss exclusive elastic double diffractive axial-vector χc (1+) meson production in proton-antiproton collisions at the Tevatron. The amplitude for the process is derived within the kt-factorization approach with unintegrated gluon distribution functions (UGDFs). We show that the famous Landau-Yang theorem is not applicable in the case of off-shell gluons. Differential cross sections for diff

Neutralinonucleon interaction in the split susy scenario of the dark matter

The split SUSY scenario with light Higgsino states is treated as an application to the dark matter problem. We have considered the structure of the neutralinonucleon interaction and calculated cross-section of the neutralinonucleon scattering. The decay properties of the lightest chargino and next lightest neutralino are analyzed in details.