The sensitivities to anomalous quartic photon couplings at the Large Hadron Collider are estimated using diphoton production via photon fusion. The tagging of the protons proves to be a very powerful tool to suppress the background and unprecedented
sensitivities down to $6 cdot 10^{-15}$gev$^{-4}$ are obtained, providing a new window on extra dimensions and strongly-interacting composite states in the multi-TeV range. Generic contributions to quartic photon couplings from charged and neutral particles with arbitrary spin are also presented.
We consider hard diffractive events in proton-proton collisions at the LHC, in which both protons escape the collision intact. In such double Pomeron exchange processes, we propose to measure dijets and photon-jet final states, and we show that it ha
s the potential to pin down the Pomeron quark and gluon contents, a crucial ingredient in the standard QCD description of hard diffraction. By comparing with predictions of the soft color interaction approach, we also show that more generally, the measurement of the photon-jet to di-jet cross section ratio can put stringent test on the QCD dynamics at play in diffractive processes in hadronic collisions.
Using the Quality Factor (QF) method, we analyse the scaling properties of deep-inelastic processes at HERA and fixed target experiments for x<10^{-2}.
In this short report, we discuss the Jet Physics results and perspectives at HERA, Tevatron and LHC.
The scaling properties at low $x$ of the proton DIS cross section and its charm component are analyzed with the help of the quality factor method. Scaling properties are tested both in the deep inelastic scattering data and in the structure functions
reconstructed from CTEQ, MRST and GRV parametrisations of parton density functions. The results for DIS cross sections are fully compatible between data and parametrisations. Even with larger error bars, the charm component data favors the same geometric scaling properties as the ones of inclusive DIS. This is not the case for all parametrisations of the charm component.
Central diffractive production of heavy states (massive dijets, Higgs boson) is studied in the exclusive mode using a new Hybrid Pomeron Model (HPM). Built from Hybrid Pomerons defined by the combination of one hard and one soft color exchanges, the
model describes well the centrally produced diffractive dijet data at the Tevatron. Predictions for the Higgs boson and dijet exclusive production at the LHC are presented.
We present a new method to test the Standard Model expectations at the LHC using photon-induced $WW$ production. Both $W$ decay in the main ATLAS or CMS detectors while scattered protons are measured in forward detectors. The sensitivity to anomalous
$WWgamma$ triple gauge coupling can be improved by more than a factor 5 or 30 compared to the present LEP or Tevatron sensitivity respectively.
In these lectures, we present and discuss the most recent results on inclusive diffraction at the Tevatron collider and give the prospects at the LHC. We also describe the search for exclusive events at the Tevatron. Of special interest is the exclus
ive production of Higgs boson and heavy objects ($W$, top, stop pairs) at the LHC which will require precise measurements and analyses of inclusive and exclusive diffraction to constrain further the gluon density in the pomeron. At the end of these lectures, we describe the projects to install forward detectors at the LHC to fulfil these measurements.
We propose a new set of measurements which can be performed at the LHC using roman pot detectors. This new method is based on exploiting excitation curves to measure kinematical properties of produced particles. We illustrate it in the case of central diffractive W pair production.
