Quit Using Pseudorapidity, Transverse Energy, and Massless Constituents

TL;DR

This paper advocates replacing pseudorapidity with true rapidity, transverse energy with transverse momentum, and massless constituents with massive ones in jet analysis to improve precision in measurements.

Contribution

It introduces three specific recommendations for jet analysis that enhance accuracy by using true rapidity, transverse momentum, and massive constituents.

Findings

Using true rapidity improves event display accuracy.

Replacing transverse energy with transverse momentum preserves conservation laws.

Including massive constituents prevents underestimating jet mass.

Abstract

Use a massive jet's true-rapidity instead of its pseudorapidity, even for event displays and for determining if a jet is near a calorimeter edge. Use transverse momentum instead of transverse energy since only the former is conserved. Use massive constituents because using massless constituents reduces the jet mass by an amount proportional to the square of the number of hadrons in the jet, and can amount to several GeV. These three recommendations are important for precision measurements when jets are constructed by adding constituent 4-vectors.