April 17th, 2006


Z → e+e- + jets production

Oriol Saltó, Monica D'Onofrio, Mario Martínez
IFAE - Barcelona

We want to make a precise measurement of the Z → ee + jets cross section to estimate the Z → νν + jets irreductible background on the searches for monojet signatures. While looking for a MC simulation that properly describes the event topology and the jets, we present some PR plots comparing different observables in data and MC simulations.



PR plots



Number of events with ≥ n jets

GIF figure
EPS figure

ΔR distance between Z and the leading jet

GIF figure
EPS figure

PTin
Sum of the component of the momentum parallel of the tracks to the plane defined by the beam axis and the Z particle direction.

GIF figure
EPS figure

PTout
Sum of the component of the momentum of the tracks transerval to the plane defined by the beam axis and the Z particle direction.

GIF figure
EPS figure

PT profile of the events Z → ee + ≥1 jet
Profile of the pT of the calorimeter towers in φ (taking the Z0 direction as φ = 0). The calorimeter towers used are from the central part of the calorimeter |Y| < 0.7
The event selection requires only one reconstructed vertex in the event.

GIF figure
EPS figure

Differential Jet Shape
Differential shape of the jets in steps of ΔR = 0.1 using the calorimeter towers. Jets reconstructed with MidPoint algorithm with R = 0.7.
The event selection requires only one reconstructed vertex in the event.

GIF figure
EPS figure

Integrated Jet Shape
Integrated shape of the jets using the calorimeter towers. Jets reconstructed with MidPoint algorithm with R = 0.7.
The event selection requires only one reconstructed vertex in the event.

GIF figure
EPS figure

Inclusive jet production (Pythia)
Comparison of the jet production, as a function of the pT of the jet, in data and in Pythia Tune A. Every Pythia distribution has been normalized to the number of entries in the data.
The distributions have been scaled to split them for a better visualization.

GIF figure
EPS figure

Inclusive jet production (Alpgen+Herwig)
Comparison of the jet production, as a function of the pT of the jet, in data and in Alpgen+Herwig. Every Alpgen+Herwig distribution has been normalized to the number of entries in the data.
The distributions have been scaled to split them for a better visualization.

GIF figure
EPS figure

Invariant Mass Z-jet

GIF figure
EPS figure




Oriol Salto