Campos, F. de [UNESP]Éboli, O. J. P. [UNESP]García-Jareño, M. A.Valle, J. W. F.2014-05-272014-05-271999-04-26Nuclear Physics B, v. 546, n. 1-2, p. 33-51, 1999.0550-3213http://hdl.handle.net/11449/65764We study chargino pair production at LEP II in supersymmetric models with spontaneously broken R-parity. We perform signal and background analyses, showing that a large region of the parameter space of these models can be probed through chargino searches at LEP II. In particular, we determine the attainable limits on the chargino mass as a function of the magnitude of the effective bilinear R-parity violation parameter ∈, demonstrating that LEP II is able to unravel the existence of charginos with masses almost up to their kinematical limit even in the case of R-parity violation. This requires the study of several final state topologies since the usual MSSM chargino signature is recovered as ∈ → 0. Moreover, for sufficiently large ∈ values, for which the chargino decay mode χ ± → τ ± J dominates, we find through a dedicated Monte Carlo analysis that the χ ± mass bounds are again very close to the kinematic limit. Our results establish the robustness of the chargino mass limit, in the sense that it is basically model-independent. They also show that LEP II can establish the existence of spontaneous R-parity violation in a large region of parameter space should charginos be produced. © 1999 Elsevier Science B.V.33-51engArtigo10.1016/S0550-3213(99)00032-2WOS:000080276500003Acesso restrito2-s2.0-0033606022