相关论文: Initial State Radiation in Resolved Photon Interac…
The current methods to determine the primary energy in surface arrays are different when dealing with hadron or photon initiated showers. In this work, we adapt a method previously developed for photon-initiated showers to hadron primaries.…
In view of the new (preliminary) search results for instanton-induced events at HERA from the H1 collaboration, we present a brief discussion of (controllable) theoretical uncertainties, both in the event topology and the calculated rate.
The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb^-1 collected by the H1…
We present a method for calculating the photoproduction of jets at HERA based on Next to Leading Logarithm QCD calculations. It is implemented in a Monte-Carlo generator which allows us to easily compute any infra-red safe cross sections…
We present results of a global tuning of general purpose Monte Carlo models to published measurements of photon-proton -> jets at HERA and photon-photon -> jets at LEP and TRISTAN. The principle free parameters in the tuning are the…
General-purpose Monte Carlo event generators have become important tools in particle physics, allowing the simulation of exclusive hadronic final states. In this article we examine the Pythia 8 generator, in particular focusing on its…
We implement a comprehensive simulation of photon surface interactions using a Monte Carlo approach. This is effective in simulating the interaction of light with telescope mirrors and lenses. We use a full electromagnetic solution to…
Coherent QCD radiation in the hadroproduction of top quark pairs leads to a forward--backward asymmetry that grows more negative with increasing transverse momentum of the pair. This feature is present in Monte Carlo event generators with…
The atmospheric scattering of light has a significant influence on results of optical observations of air showers. It causes attenuation of direct light from the shower, but also contributes a delayed signal to the observed light. The…
The measurement of forward jet cross sections has been suggested as a promising probe of new small x parton dynamics and the question is whether the new HERA data provide an indication of this. In this paper the influence of resolved photon…
The mediated photon-photon interaction due to the resonant Kerr nonlinearity in an inhomogeneously broadened atomic vapor is considered. The time-scale for photon-photon scattering is computed and found to be determined by the inhomogeneous…
This lecture discusses the physics implemented by Monte Carlo event generators for hadron colliders. It details the construction of parton showers and the matching of parton showers to fixed-order calculations at higher orders in…
Wrong Monte-Carlo computations are used to study the propagation of light in low pressure gas of nebulae. We recall that the incoherent interactions required for Monte Carlo calculations and hindering coherent interactions are due to…
We describe the program HERWIRI2.1, which implements order alpha-squared photonic radiative corrections exponentiated at the amplitude level (initial state, final state, and initial-final interference) and electroweak corrections to the…
After a brief introduction into the phenomenology of instantons, results from instanton perturbation theory applied to deep-inelastic electron proton scattering are summarized. Based on event signatures derived from Monte Carlo studies,…
The polarization of real photons emitted from early-time heavy-ion collisions is calculated, concentrating on the contribution from bremsstrahlung and quark-antiquark annihilation processes at leading order in the strong coupling. The…
After giving a very brief introduction to the resolved photon processes, I will summarise the latest experimental information from HERA, on resolved photon contribution to large pt jet production as well as to direct photon production. I…
Results are presented on the production of isolated prompt photons in photoproduction (virtuality Q^2 < 1 GeV^2) and in deep inelastic scattering (Q^2 > 35 GeV^2). The results are reasonably well described by pQCD calculations in next to…
Results on isolated prompt photon production are presented. The measurements were performed at HERA in deep inelastic ep scattering and photoproduction, as well as at LEP in photon photon collisions. Differential cross sections are shown…
The status of HERA data on jet photoproduction is reviewed, and some suggestions and prospects for further work are given.