Determination of the Absolute Jet Energy Scale in the DZERO Calorimeters

TL;DR

The paper presents an in situ determination of the absolute jet energy scale for the DØ calorimeters using γ–jet momentum balance and a comprehensive set of corrections. It systematically accounts for offsets from the underlying event, uranium noise, pile-up, detector nonuniformities (cryostat and IC), energy dependence, and showering losses, leveraging data-driven methods and Monte Carlo validation to extend calibration to high energies. The result is a jet energy scale correction with quantified uncertainties that are verified through closure tests, enabling more precise jet cross-section and mass measurements at the Tevatron. The methodology provides a robust framework for translating calorimeter jet energies to particle-level jets across ET and η ranges at two center-of-mass energies, with explicit treatment of correlations and systematic errors.

Abstract

The DZERO detector is used to study proton-antiproton collisions at the 1800 GeV and 630 GeV center-of-mass energies available at the Fermilab Tevatron. To measure jets, the detector uses a sampling calorimeter composed of uranium and liquid argon as the passive and active media respectively. Understanding the jet energy calibration is not only crucial for precision tests of QCD, but also for the measurement of particle masses and the determination of physics backgrounds associated with new phenomena. This paper describes the energy calibration of jets observed with the DZERO detector at the two proton-antiproton center-of-mass energies in the transverse energy and pseudorapidity range ET>8 GeV and pseudorapidity<3.

Figures (52)

• Figure 1: General view of DØ calorimeters.
• Figure 2: Diagram of a DØ calorimeter unit cell.
• Figure 3: Side view of the DØ calorimeters (one quadrant). The numbers indicate position in units of pseudorapidity.
• Figure 4: The ratio $e/\pi$ as measured from test beam data and determined from a Monte Carlo simulation. Note that the Monte Carlo $e/\pi$ ratio (open squares) changes faster and flattens out earlier than the test beam ratio (full circles).
• Figure 5: Measured test beam energy versus particle momentum for electrons and pions. The solid and dashed lines are fits to the electron and pion data, respectively. Good linearity between reconstructed and test beam energy is achieved with the DØ calorimeters.