Electroweak precision constraints on the Lee-Wick standard model

• Autores: Álvarez, E.; Schat, C.; Da Rold, L.; Szynkman, A.
• Año de publicación: 2008
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: J. High Energy Phys. 2008;2008(4)
• Materia: Beyond standard model; Higgs physics; Quark masses and SM parameters; Standard model
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

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 parameters that receive important tree level and one loop contributions. In general the model predicts a 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 5 TeV. We show that it is possible to find some regions in the parameter space with a fermionic state as light as 2.4-3.5 TeV, at the price of rising all the other masses to be larger than 5-8 TeV. 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 fourth generation of Standard Model fermions with their Lee-Wick partners. We show that in this case it is possible to pass the electroweak constraints with Lee-Wick fermionic masses of order 0.4-1.5 TeV and Lee-Wick gauge masses of order 3 TeV.
Fil:Szynkman, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.