Eur. Phys. J. C (2012) 72: 1887
https://doi.org/10.1140/epjc/s10052-012-1887-3

Regular Article - Theoretical Physics

CP asymmetries in the supersymmetric trilepton signal at the LHC

¹ Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, 87131, USA
² Bethe Center for Theoretical Physics and Physikalisches Institut der Universität Bonn, Nussallee 12, 53115, Bonn, Germany
³ Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil
⁴ Fakultät für Physik, TU Dortmund, Otto-Hahn-Str. 4, 44221, Dortmund, Germany
⁵ ARC Centre of Excellence for Particle Physics at the Terascale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, 5005, Australia
⁶ Departamento de Física Teórica y del Cosmos and CAFPE, Universidad de Granada, 18071, Granada, Spain

^* e-mail: kittel@th.physik.uni-bonn.de

Received: 29 November 2011
Revised: 2 December 2011
Published online: 1 March 2012

Abstract

In the CP-violating Minimal Supersymmetric Standard Model, we study the production of a neutralino–chargino pair at the LHC. For their decays into three leptons, we analyze CP asymmetries which are sensitive to the CP phases of the neutralino and chargino sector. We present analytical formulas for the entire production and decay process, and identify the CP-violating contributions in the spin correlation terms. This allows us to define the optimal CP asymmetries. We present a detailed numerical analysis of the cross sections, branching ratios, and the CP observables. For light neutralinos, charginos, and squarks, the asymmetries can reach several 10%. We estimate the discovery potential for the LHC to observe CP violation in the trilepton channel.