Electroweak precision constraints on the Lee-Wick Standard Model
EZEQUIEL ALVAREZ; LEANDRO DA ROLD; CARLOS SCHAT; ALEJANDRO SZYNKMAN
JOURNAL OF HIGH ENERGY PHYSICS - (Online)
Lugar: Trieste, Italia.; Año: 2008 vol. 04 p. 2601 - 2601
We perform an analysis of the electroweak precision observables in the Lee-Wick Standard Model. The most stringent restrictions come from the S and T parametersthat receive important tree level and one loop contributions. In general the model predictsa large positive S and a negative T. To reproduce the electroweak data, if all the Lee-Wick masses are of the same order, the Lee-Wick scale is of order 5TeV. We show thatit is possible to find some regions in the parameter space with a fermionic state as lightas 2.4 − 3.5TeV, at the price of rising all the other masses to be larger than 5 − 8TeV.To obtain a light Higgs with such heavy resonances a fine-tuning of order a few per cent,at least, is needed. We also propose a simple extension of the model including a fourthgeneration of Standard Model fermions with their Lee-Wick partners. We show that inthis case it is possible to pass the electroweak constraints with Lee-Wick fermionic massesof order 0.4 − 1.5TeV and Lee-Wick gauge masses of order 3TeV.