Related papers: Probing the QCD pomeron in doubly tagged e^+ e^- c…
We derive the analytic expression of the two one-loop dipole contributions to the elastic 4-gluon amplitude in QCD. The first one corresponds to the double QCD pomeron exchange, the other to an order alpha^2 correction to one-pomeron…
Using the QCD dipole picture of the BFKL pomeron, the gluon contribution to the cross-section for single diffractive dissociation in deep-inelastic high-energy scattering is calculated. The resulting contribution to the proton diffractive…
The novel possibilities of probing the photon structure and high energy limit of QCD at photon colliders are summarised. We discuss the photon structure function $F_2^{\gamma}(x,Q^2)$, the gluon distribution in the photon and the spin…
The process e+e- to 2 (or 3) gammas is studied using data recorded with the OPAL detector at LEP. The data sample taken at a centre-of-mass energy of 189 GeV corresponds to a total integrated luminosity of 178 pb-1. The measured…
The contribution of the QCD Pomeron to the process AA -> AA J/Psi J/Psi is discussed. We focus on the photon-photon collision, with the quasi-real photon coming from the Weizsacker - Williams spectrum of the nuclei. We calculate the cross…
A measurement of the cross-section for Z-boson production in the forward region of pp collisions at 8TeV centre-of-mass energy is presented. The measurement is based on a sample of $\rm Z\rightarrow e^+e^-$ decays reconstructed using the…
The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models.…
We study the reactions $\gamma^*(Q^2)p\to\rho^0 p$ and $\gamma^*(Q^2)p\to\gamma^*(Q^2) p$ at large Q^2 and $W^2/Q^2$ and small momentum transfer, $\kappa^2_\perp$, to the nucleon where the pomeron exchange dominates. At large Q^2 the…
This paper describes a measurement of the $Z/\gamma^*$ boson transverse momentum spectrum using ATLAS proton-proton collision data at a centre-of-mass energy of $\sqrt{s}$ = 7 TeV at the LHC. The measurement is performed in the $Z/\gamma^*…
Within the framework of the perturbative QCD approach, we calculate the time-like $B_cB_c(B_c^*)$ form factors $F(Q^2)$ and $A_2(Q^2)$. We include relativistic corrections and QCD corrections, either of which can give about $20\%$…
Production of a single doubly charged Higgs boson $Delta^{--}$ in polarized $e^+e^-$ and $e^+\gamma$ collision modes of the linear collider have been investigated. The mass range of $Delta^{--}$ to be probed extends up to the collision…
We study the production of gauge boson pairs at the next generation of linear $e^+e^-$ colliders operating in the $e\gamma$ mode. The processes $e\gamma \rightarrow VV^\prime F$ ($V,V^\prime =W$, $Z$, or $\gamma$ and $F=e$ or $\nu$) can…
The double vector meson production in two photon collisions is addressed assuming that the color singlet $t$-channel exchange carries large momentum transfer. We consider the non-forward solution of the BFKL equation at high energy and…
We discuss the process $\ell^+\ell^- \to N W^{\pm} \ell^{\mp}$, where $N$ is a heavy Majorana neutrino and $\ell = e, \mu$. Large cross sections are expected for these processes at high center-of-mass energies, which can be reached at…
The process e^+e^- -> Z gamma gamma -> q q~ gamma gamma is studied in 0.5 fb-1 of data collected with the L3 detector at centre-of-mass energies between 130.1 GeV and 201.7 GeV. Cross sections are measured and found to be consistent with…
Inclusive D^{*+-} production in two-photon collisions is studied with the L3 detector at LEP, using 683 pb^{-1} of data collected at centre-of-mass energies from 183 to 208 GeV. Differential cross sections are determined as functions of the…
In a strongly-interacting electroweak sector with an isosinglet vector state, such as the techni-omega, $\omega_T$, the direct $\omega_T Z \gamma $ coupling implies that an $\omega_T$ can be produced by $Z \gamma$ fusion in $e\gamma$…
In a strongly-interacting electroweak sector with an isosinglet vector state, such as the techni-omega, $\omega_T$, the direct $ \omega_T Z \gamma $ coupling implies that an $\omega_T$ can be produced by $Z \gamma$ fusion in $e \gamma$…
We study dilepton, proton-antiproton and diphoton production in ultraperipheral lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 and 5.5 TeV. The nuclear calculations are based on equivalent photon approximation in the impact…
We study the interface between soft and hard QCD at high energy and small momentum transfer. At LHC and SSC energies, we find that a cutoff BFKL equation leads one to expect a measurable perturbative component in traditionally soft…