Possible reduction of the total uncertainty on the W boson mass measured at LEP2

TL;DR

This paper proposes a new W boson mass estimator at LEP2 that reduces total uncertainty by about 30% compared to standard methods, by balancing statistical and systematic uncertainties related to Colour Reconnection effects.

Contribution

It introduces an alternative estimator for the W mass that optimizes uncertainty balance and provides an indirect measurement of the Colour Reconnection model parameter.

Findings

Total uncertainty reduced by ~30% with the new estimator.

An indirect measurement of the Colour Reconnection parameter kappa.

Preliminary results show improved precision over standard estimators.

Abstract

An alternative W mass estimator in e+e- -> WW -> qqqq events at LEP2 is designed to optimize the balance between the statistical uncertainty and the systematic uncertainty due to a possible Colour Reconnection effect. The preliminary result for the total uncertainty on the W mass in this channel is roughly 30 % lower then those obtained with the standard estimators, based on the SKI implementation of Colour Reconnection. Also an indirect measurement of the SKI Colour Reconnection model parameter kappa is inferred from the difference between both W mass estimators.