H. Weerts

Improved parton distributions from global analysis of recent deep inelastic scattering and inclusive jet data

The impact of recent precision measurements of DIS structure functions and inclusive jet production at the Fermilab Tevatron on the global QCD analysis of parton distribution functions is studied in detail. Particular emphasis is placed on exploring the range of variation of the gluon distribution G(x,Q) allowed by these new data. The strong coupling of G(x,Q) with {alpha}{sub s} is fully taken into account. A new generation of CTEQ parton distributions, CTEQ4, is presented. It consists of the three standard sets [modified minimal subtraction ({ovr MS}), deep inelastic scattering (DIS), and leading order (LO)], a series that gives a range of parton distributions with corresponding {alpha}{sub s}`s, and a set with a low starting value of Q. Previously obtained gluon distributions that are consistent with the high E{sub t} jet cross section are also discussed in the context of this new global analysis. {copyright} {ital 1997} {ital The American Physical Society}

Global QCD analysis and the CTEQ parton distributions

The CTEQ program for the determination of parton distributions through a global QCD analysis of data for various hard scattering processes is fully described. A new set of distributions, CTEQ3, incorporating several new types of data is reported and compared to the two previous sets of CTEQ distributions. A comparison with current data is discussed in some detail. The remaining uncertainties in the parton distributions and methods to further reduce them are assessed. Comparisons with the results of other global analyses are also presented.

Design and Implementation of the New D0 Level-1 Calorimeter Trigger

Increasing luminosity at the Fermilab Tevatron collider has led the D0 collaboration to make improvements to its detector beyond those already in place for Run IIa, which began in March 2001. One of the cornerstones of this Run IIb upgrade is a completely redesigned level-1 calorimeter trigger system. The new system employs novel architecture and algorithms to retain high efficiency for interesting events while substantially increasing rejection of background. We describe the design and implementation of the new level-1 calorimeter trigger hardware and discuss its performance during Run IIb data taking. In addition to strengthening the physics capabilities of D0, this trigger system will provide valuable insight into the operation of analogous devices to be used at LHC experiments.

Hadron and Electron Response of Uranium Liquid Argon Calorimeter Modules for the D0 Detector

We present the results of tests made on two types of uranium/liquid argon calorimeter modules, one electromagnetic and one hadronic, constructed for the D0 detector at the Fermilab Tevatron Collider. For electrons and hadrons with energies between 10 and 150 GeV, we present measurements of energy resolution, linearity of response, electromagnetic to hadronic response ratio (e/π), and longitudinal hadronic shower development. We have also investigated the effects of adding small amounts of methane to the liquid argon.

Hadron and electron response in a uranium liquid argon calorimeter from 10 to 150 GeV

Abstract A uranium liquid argon calorimeter, with a total depth of nine absorption lengths, has been exposed to electrons and hadrons in the energy range of 10–150 GeV. Two configurations with different uranium plate thicknesses were successfully operated. In both cases the response was found to be linear over the entire energy regime. We present measurements of various contributions to energy resolution, differences in electron/hadronm/muon response, longitudinal and transverse shower profiles and electron position resolution.

Design, construction, and performance of the electromagnetic module of the DØ end calorimeter

Author(s): Aihara, H.; Arthur, A.A.; Dahl, O.I.; Eberhard, P.H.; Edwards, W.R.; Fulton, R.L.; Haughian, J.M.; Madaras, R.J.; Roe, N.A.; Shuman, D.B.; Spadafora, A.L.; Stevenson, M.L.; Taylor, J.D.; Wenzel, W.A.

Hadron showers in a low-density fine-grained flash chamber calorimeter

Abstract Hadronic showers at six incident particle energies from 33.8 to 415.4 GeV have been studied using the low-density fine-grained flash chamber calorimeter of the Lab C neutrino detector at Fermilab. Transverse distributions of unprecedented fine granularity have been obtained for a range of depths in the shower. Longitudinal energy distributions have been compared with those from iron-scintillator detectors. Some differences are observed which may be attributable to the different relative sensitivity of the two detector types to electromagnetic and hadronic shower components. Both longitudinal and transverse distributions have been parametrized. Fluctuations in energy deposition have been studied. The relative size of the fluctuations is largest near the starting vertex and in the tail of the shower, and falls slowly with increasing beam energy. Correlations between energy deposition in neighboring parts of the shower are observed, and anticorrelation is seen between energy deposition in the peak and in the tail of the shower. Containment lengths and widths have also been measured and parametrized.

Erratum to “hadron showers in a low-density fine-grained flash chamber calorimeter”☆

Abstract Our recent paper ∗ described an analysis of the energy deposition in hadronic showers at six incident particle energies from 33.8 to 415.4 GeV using the low-density fine-grained flash chamber calorimeter of the Lab C neutrino detector at Fermilab. More recent work on the subject has led us to revise some of the results presented for energies above 200 GeV. We present here revised results for the longitudinal and transverse energy deposition, and new coefficients for the parametrization of these curves.