Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

Abstract

We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.

Figures (6)

• Figure 1: Annular regions around the $W$ boson and the tagged jet in $(\eta,\phi)$ space.
• Figure 2: Comparisons of data (points) with PYTHIA events with AO and SF (histogram) for (a) electron $E_T$, (b) event ${\hbox{$E$/}}_T$, (c) azimuthal separation of the $W$ boson and tagged jet, and (d) rapidity separation of the $W$ boson and tagged jet.
• Figure 3: (a) Calorimeter tower multiplicity around the jet and $W$ boson as a function of $\beta$. (b) Ratio of the tower multiplicity around the jet to the tower multiplicity around the $W$ boson as a function of $\beta$.
• Figure 4: Comparison of the Jet/$W$ boson tower multiplicity ratio from data to (a) PYTHIA with AO on and SF, (b) AO off and SF, (c) AO off and IF, and to the (d) MLLA+LPHD predictions. The predictions have been normalized to the data. All uncertainties are statistical only.
• Figure 5: $R_{\mathrm{sig}}$ for DØ data, PYTHIA with various coherence implementations, and a MLLA+LPHD QCD calculation. The errors are statistical only and the shaded band shows the statistical uncertainty on the $R_{\mathrm{sig}}$ variable for the data.