Related papers: Anomalous gamma gamma interaction
Anomalous quartic couplings between the electroweak gauge bosons may contribute to the vv gamma gamma and qq gamma gamma final states produced in e+e- collisions. This analysis uses the LEP2 OPAL data sample at centre-of-mass energies up to…
The search for quartic anomalous gauge couplings at LEP requires appropriate predictions for the radiative processes e+ e- \to \nu\bar\nu \gamma\gamma, e+ e- \to q\bar{q}\gamma\gamma and e+ e- \to 4 fermions+\gamma. Matrix elements are…
Open heavy flavour production at $e^+e^-$ colliders in deeply inelastic $e\gamma$ scattering has an interesting feature: the structure function $F_2(x,Q^2)$ for this process is calculable for $x>0.01$, and is essentially proportional to the…
The associated production of a photon and a top-antitop quark pair ($t\bar{t}\gamma$) is important for measuring the top-quark charge and probing the top-photon interaction, and it requires improved theoretical predictions. We focus on the…
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…
Observations by the PHENIX and STAR collaborations suggest that a strongly coupled quark-gluon plasma is produced in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC). After a brief introduction to heavy-ion physics,…
The production of charm and beauty quarks in $\gamma \gamma$ collisions at LEP, $ep$ collisions at HERA and $p \bar{p}$ collisions at the Tevatron is discussed. The comparison with predictions of next-to-leading-order QCD and the issues it…
New results reported at the Moriond-QCD 2003 conference from the experiments ALEPH, DELPHI, L3, and OPAL on the structure of the photon as well as heavy quark production in gammagamma collisions are presented. The hadronic structure of the…
Recent theories propose that quantum gravity effects may be observable at LEP energies via gravitons that couple to Standard Model particles and propagate into extra spatial dimensions. The associated production of a graviton and a photon…
We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in the single top production at a high energy e\gamma collider. We analyzed all possible dimension-six CP-conserving…
It is very likely that in 3-4 years the construction of one or two linear colliders with c.m.s energy up to 0.5--1.5 TeV will be started. Besides e^+e^- collisions, linear colliders give a unique possibility to study gamma-gamma and…
We explore the capability of the Tevatron and LHC as well as other future hadron colliders to place limits on the possible existence of flavor-independent $q \bar q \gamma\gamma$ contact interactions which can lead to an excess of high…
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W -> lnu+gamma production in egamma and mugamma final states. Using data corresponding to an integrated luminosity of 4.2 fb-1…
We study the prospects of testing the $WW\gamma$ vertex in $e^- p\to\nu\gamma X$ and $e^+ p\to\nu\gamma X$ at HERA and LEP/LHC. Destructive interference effects between the Standard Model and the anomalous contributions to the amplitude…
Observing the production of the Higgs particle in the $\gamma$-$\gamma$ mode of a linear $e^+e^-$ collider allows for the measurement of the $H\gamma\gamma$ coupling. We point out that for the intermediate Higgs mass range this measurement…
Deep-inelastic e^\pm p scattering at high squared momentum transfer Q^2 up to 30000 GeV^2 is used to search for eq contact interactions associated to scales far beyond the HERA centre of mass energy. The neutral current cross section…
The hypothetic R--resonance production (anomalous "$l\bar l\gamma\gamma$" events at LEP) with 60 GeV mass at FNAL hadron collider has been considered. The cross-section of this R-resonance production with the consequent decay $R \to…
Enhancement of strangeness production has since long been proposed as a promising signal of quark-gluon plasma production. A convenient indicator for it is the Wroblewski parameter which has been shown to be about a factor two higher in…
The processes $pp/ pbar p \to Z \gamma + X \to \ell^+ \ell^- \gamma + X$ ($\ell=e, \mu$) and $pp/ pbarp \to Z \gamma + X \to \bar\nu\nu\gamma + X$ are calculated to ${\cal O}(\alpha_s)$ for general $ZZ\gamma$ and $Z\gamma\gamma$ couplings.…
We have estimated the sensitivity to the anomalous couplings of the $\gamma\gamma\gamma Z$ vertex in the $\gamma\gamma\rightarrow\gamma Z$ scattering of the Compton backscattered photons at the CLIC. Both polarized and unpolarized…