Jet energy scale determination in the D0 experiment

TL;DR

This work delivers a comprehensive, data-driven jet energy scale calibration for the D0 Run II detector, using gamma+jet, Z+jet, and dijet events to map calorimeter jet energy to the particle level. The methodology combines absolute MPF-based response measurements with relative eta-dependent corrections, along with flavor-dependent tuning, zero-suppression, topology, and showering corrections, all validated via closure tests in data and MC. Key outcomes are JES corrections of about 1.4-1.8% in the central region and up to 3.5% at forward eta, with total JES uncertainties in the 1.4-3.5% range depending on eta, cone size, and run period. The results significantly improve jet energy and missing transverse energy measurements, enhancing the accuracy of precision SM measurements and new-physics searches at the Tevatron. The analysis also provides detailed treatment of correlations among jet energies across pT and eta, facilitating robust physics interpretations and cross-section determinations.

Abstract

The calibration of jet energy measured in the \DZero detector is presented, based on ppbar collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Jet energies are measured using a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively. This paper describes the energy calibration of jets performed with photon+jet, Z+jet and dijet{} events, with jet transverse momentum pT > 6 GeV and pseudorapidity range |eta| < 3.6. The corrections are measured separately for data and simulation, achieving a precision of 1.4%-1.8% for jets in the central part of the calorimeter and up to 3.5% for the jets with pseudorapidity |eta| = 3.0. Specific corrections are extracted to enhance the description of jet energy in simulation and in particular of the effects due to the flavor of the parton originating the jet, correcting biases up to 3%-4% in jets with low pT originating from gluons and up to 6%-8% in jets from b quarks.

Figures (42)

• Figure 1: Side view of a quadrant of the D0 calorimeters showing the transverse and longitudinal segmentation. The alternating shading pattern indicates the cells for signal readout. The lines indicate the pseudorapidity intervals defined from the center of the detector. The inter-cryostat detector (ICD) is visible as a thin dark shaded tile between the cryostats, within $1.1< |{\eta_\textnormal{det}^{}}\xspace| <1.4$.
• Figure 2: Typical variation with time of the mass of $Z$ boson reconstructed in the $e^{+}e^{-}$ final state for a fraction of the Run II data (reference value from Ref. PDG).
• Figure 3: (color online) Average transverse energy per $i_{\eta}$ ring in ZB events selected as discussed in the text. Lines with various colors correspond to ${\mathcal{L}}\xspace = {\textnormal{$\!\times 10^{30}\,\textnormal{cm}^{-2}\textnormal{s}^{-1}$}}\xspace$.
• Figure 4: (color online) Average transversed energy in minimum bias events as a function of $i_{\eta}$. Lines with various colors correspond to ${n_{\textnormal{PV}}}\xspace=1$, ${n_{\textnormal{PV}}}\xspace=5$, ${n_{\textnormal{PV}}}\xspace=8$, and ${n_{\textnormal{PV}}}\xspace=11$.
• Figure 5: (color online) Minimum bias energy as a function of ${n_{\textnormal{PV}}}\xspace$ for one particular ring ${i_{\eta}}\xspace=20$. Lines correspond to different luminosities ${\mathcal{L}}\xspace = {\textnormal{$\!\times 10^{30}\,\textnormal{cm}^{-2}\textnormal{s}^{-1}$}}\xspace$.