P. Ribarics

Beam tests and calibration of the H1 liquid argon calorimeter with electrons

Results are presented on the energy calibration of the H1 liquid argon calorimeter modules with electrons from a test beam in the energy range of 3.7 GeV to 80 GeV. The method to determine the calibration for the Hl experiment from these measurements by the use of detailed simulations is described . Various systematic checks of this calibration are given. The calorimeter response is uniform in space within ±1% and linear with energy within ±1%. An average energy resolution of about 11.5%/ E [GeV] is achieved .

Electron / pion separation with the H1 LAr calorimeters

Abstract The performances of the H1 liquid argon calorimeter modules for the energy measurements and identification of electrons are studied with test data taken at CERN in the energy range 5 to 166 GeV. Various electron identification estimators exploiting global or detailed shower characteristics are studied and compared. The usage of impact position measurements is also discussed. A best combination of robust shower estimators leads typically to π-misidentification probabilities in the range 1.5 to 5.0 × 10−3 at 30 GeV for 95% electron detection efficiency. This further reduces to ∼ 10−4 for these pions to be misidentified as electrons below 25 GeV.

Exclusive rho 0 and phi production in deep inelastic muon scattering

Data are presented on exclusive ρ0 and ϕ production in deep inelastic muon scattering from a target consisting mainly of nitrogen. The ratio of the total cross sections for ρ0 and ϕ production is found to be 9∶(1.6±0.4) at 〈Q2〉=7.5 GeV2, consistent with theSU(3) prediction of 9∶2. Thet dependence for exclusive ρ0 production is found to become shallover asQ2 increases and, for largeQ2, thet dependence is typical of that for a hard scattering process. Furthermore, the ratio of the cross sections for coherent: incoherent production from nitrogen is found to decrease rapidly withQ2. Such behaviour indicates that even for exclusive vector meson production the virtual photon behaves predominantly as an electromagnetic probe.

Study of a novel electromagnetic liquid argon calorimeter — the TGT

Abstract The concept and the basic design of a fast, highly granular and compact electromagnetic liquid argon calorimeter are described. This novel calorimeter offers uniform energy response and constant energy resolution independent of the production angle of an impinging particle and of its impact position at the calorimeter. An example of a calorimeter with full rapidity coverage in an application in a collider detector is given. An important aspect of the concept is the electronics for fast signal processing matched to the short charge collection time. We report on the experience with the realization of a prototype calorimeter module and on its performance in a testbeam exposure.

Artificial Neural Networks as a Level-2 Trigger for the H1 Experiment: Status of the Hardware Implementation

Triggering at the HERA ep collider is challenging because of the high bunch crossing rate and an expected large background. In the H1 experiment, a trigger decision is made in four steps (level 1–4), stepwise decreasing the event rate and allowing for more sophisticated trigger decisions. The time available for L2 is about 20 μs. We have proposed to use an artificial neural network (ANN) for the L2 trigger based on the CNAPS-1064 chip available from Adaptive Solutions, (Oregon, USA). The intrinsic parallelism of the ANN algorithm together with the dedicated hardware offers fast processing of the trigger informations. The trigger system uses up to 10 decision units, each consisting of a Pattern Recognition Module (PRM) and a Data Distribution Board (DDB). A DDB receives the L2 data stream and generates the network inputs used by the algorithms on the PRM. A PRM is a commercial VME board carrying the CNAPS processors.

A comparison of the energy distributions of hadrons produced in deep inelastic scattering of muons on hydrogen and deuterium targets

The energy distribution of inclusive hadrons produced by 280 GeV muons on hydrogen and deuterium targets are compared. The sum of the scaled energy distributions of the positive and negative hadrons is found to be the same for the two targets. The difference of these distributions is observed to factorise inx andz and thez-dependence is found to be independent of the target type and have a form (1−z)2.1±0.2. The net charge of the hadronic jet is positive at highx even in the case when the scattering takes place on the neutron. These results are in good agreement with the expectations of the Quark Parton Model.