In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3...

A phase-space generation algorithm, capable to efficiently integrate the squared amplitude of any scattering process, is presented. The algorithm has been implemented in a Monte Carlo program, PHEGAS, which, using HELAC, a helicity amplitude computational package, can be used for automatic cross-section computation and event generation. Results for several scattering processes with four, five a...

Inverse methods form the basis of biomedical imaging applications, especially when they involve optical and near infrared radiation where multiple scattering tends to blur an image. This paper summarizes some of the recent literature on optical property reconstruction and on the use of fluorescence-induced signals for imaging. NOMENCLATURE cn Speed of light at refractive index n D Diffusion coe...

In this paper we estimate the event rates of neutralino-nucleus scattering leading to electron emission by the atomic ionization. We find that the branching ratio for detecting electrons vis a vis the traditional neutralino nucleus elastic scattering sensitively depends on the threshold energy. In the case of a light target and a neutralino mass of 100 GeV we estimate it to be around 10 percent...

Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb−1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q2 < 20 480GeV and 6 × 10−4 < x < 0.6, where Q2 is the ...

This article reviews the status of event-shape studies in ee annihilation and DIS. It includes discussions of perturbative calculations, of various approaches to modelling hadronisation and of comparisons to data.

We present subdivision next-event estimation (SNEE) for unbiased Monte Carlo simulation of subsurface scattering. Our technique is designed to sample high frequency illumination through geometrically complex interfaces with highly directional scattering lobes enclosing a scattering medium. This case is difficult to sample and a common source of image noise. We explore the idea of exploiting the...

A Monte Carlo event generator is presented. An original algorithm is developed to simulate electron–positron scattering at energies and momentum transferred much more than the electron mass. The first-order electroweak radiative corrections are included completely. Higher order corrections are taken into account by means of electron structure functions. PACS: 12.20.–m Quantum electrodynamics, 1...

We investigate the power-suppressed corrections to the mean values of various quantities that characterise the shapes of final states in deep inelastic lepton scattering. Our method is based on an analysis of one-loop Feynman graphs containing a massive gluon, which is equivalent to the evaluation of leading infrared renormalon contributions. As in e + e − annihilation, we find that the leading...

Deep inelastic ep scattering data taken with the H detector at HERA are used to study event shape variables over a large range of relevant energy Q between GeV and GeV Previously published analyses on thrust jet broadening jet mass and C parameter are substantially re ned and updated di erential two jet rates treated as event shapes are presented for the rst time The Q dependence of the mean va...