The 2009 Europhysics Conference on High Energy Physics

Inclusive production of D* mesons in deep inelastic scattering at HERA is studied. The data were taken with the H1 detector in the years 2004 to 2007 and correspond to an integrated luminosity of ~350 pb^-1. D* mesons are reconstructed in their decays D* -> D0 + pi_slow -> K + pi + pi_slow. The visible range for the measurements covers the pseudorapidity interval |eta(D*)| <1.5,...

The inclusive charm and beauty cross sections as well as the charm and beauty jet cross sections are measured in $e^-p$ and $e^+p$ collisions at HERA II in deep inelastic scattering. The data were collected with the H1 detector in 2006 and 2007 corresponding to an integrated luminosity of 189 pb^-1. The amount of charm and beauty events is determined using variables reconstructed by...

The production of charm and beauty quarks in ep interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange Q^2>20 GeV^2, using an integrated luminosity of 126 pb^-1. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta p_T^{mu}>1.5 GeV and pseudorapidities ...

Charm and beauty photoproduction has been studied in ep collisions at HERA with the ZEUS and H1 detectors. Heavy quarks were identified using different experimental techniques. Charm was identified via the reconstruction of D* mesons, while beauty was tagged via its semi-leptonic decay into leptons or using lifetime tagging techniques. Differential cross sections were measured and...

The charm fragmentation function has been measured in D* photoproduction with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The fragmentation function is measured versus z, the ratio of E+p_parallel for the D* meson and that for the associated jet, where E is the energy and p_parallel the longitudinal momentum relative to the jet axis. Jets were reconstructed...

The Large Hadron Collider (LHC) will open up a new era in high energy physics.
The expected large cross sections for heavy-flavour production in proton-proton collisions at √s = 14 TeV will allow detailed studies of production mechanisms and an extensive test of QCD. Since charm and beauty has been proposed as a good probe to study hot QCD matter (the so-called Quark-Gluon Plasma), the...

We present a first precision analysis of the transverse-momentum spectrum of gaugino pairs produced at the Tevatron and the LHC with center-of-mass energies of 1.96 and 10 or 14 TeV, respectively. Our calculation is based on a universal resummation formalism at NLL order, which is consistently matched to the perturbative prediction at O(\alpha_s). Numerical results are given for the...

We present a factorization formula for the production of pairs of heavy coloured particles in hadronic collision at the production threshold. We construct a basis in colour space that diagonalizes the soft function appearing in the factorization formula to all orders in perturbation theory. We perform a resummation of soft gluon effects in momentum space and present results for the example...

Although the choice of a factorization scheme is as important as the choice of a factorization scale, the dependence of theoretical predictions (at finite order) on the choice of a factorization scheme has been little investigated. This is due to the fact that the freedom in the choice of a factorization scheme is enormous, even at NLO. Every factorization scheme can be unambiguously specified...

The parton shower algorithms sums up large logarithms. In general we can say that they are able to sum up the leading logarithmic contributions almost for all important quantities but we have less confidence when we want to say something about the next-to-leading logarithmic contributions. In this talk I will discuss a strategy how to validate parton shower algorithms against some know...

Three- and four-jet production is measured in deep-inelastic ep scattering at low x and Q^2 with the H1 detector using an integrated luminosity of 44.2 pb^-1. Several phase space regions are selected for the three-jet analysis in order to study the underlying parton dynamics from global topologies to the more restrictive regions of forward jets close to the proton direction. The measurements...

We are interested in processes which probe partonic structure where the partons carry a small fraction of the protons momentum. In particular the physics of forward jets and production of W,Z, bosons allows for this studies. In our approach we apply kt factorisation framework and perform simulations using Monte Carlo generator CASCADE.

Feasibility studies are presented on forward jet production at the LHC with the CMS detector, assuming the integrated luminosity 1 pb-1, together with studies of inclusive Z and W production, as well as low-mass Drell Yan with the LHCb detector. The potential sensitivity of the CMS and the LHCb experiments to the proton PDFs at low x_Bj is discussed. The feasibility of observing hard...

The TOTEM experiment at the LHC is designed and optimized to measure the total pp cross section with a precision down to 1-2%, to study the nuclear elastic pp cross section over a wide range of the squared four-momentum transfer and to perform a comprehensive physics program on diffractive dissociation processes partially in cooperation with the CMS experiment. In order to fulfill its...

Double diffractive events are a direct test of BFKL resummations at Tevatron and LHC. In this new study, we compute for the first time the BFKL NLL cross section for two jet events with a large rapidity gap between jets. The BFKL NLL formalism leads to a good description of D0 data, and we provide in addition some predictions for LHC.

The LHC experiments provide an unprecedented coverage in pseudo-rapidity. This advantage and high LHC luminosity allows for interesting studies of exclusive diffractive production, probing gluon physics and testing pQCD, and which can eventually lead to discovery physics. The talk is focused on the CMS program, the ATLAS is also mentioned briefly, and includes discussion of the exclusive...

The dissociation of virtual photons, gamma* p -> X p, in events with a large rapidity gap between X and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA, using data collected in the years 1999-2000. New measurements with a leading proton detected in the Forward Proton Spectrometer have been performed by...

Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb-1. The measurements were made in the kinematic range Q2 < 1 GeV2 , 0.20 < y < 0.85 and xIP < 0.025, where Q2 is the photon virtuality, y is the inelasticity and xIP is the fraction of the proton momentum taken by the diffractive exchange. The two jets with...

The most promising QCD based approach to DIS diffraction is formulated in terms of dipole models. In this analysis, we consider two important parameterisations of the dipole scattering amplitude, called GBW and CGC in which parton saturation results are built in. We present a precise comparison of the results of the dipole models using these two parameterisations with the newest data from...