CDF Multi-Muon Events and Singlet Extensions of the MSSM

TL;DR

This paper proposes a singlet-extended MSSM model to explain CDF multi-muon events through a cascade decay process involving a CP-odd scalar and multiple tau-lepton generations, differing from previous models.

Contribution

It introduces a specific singlet extension of the MSSM with detailed decay cascades that account for the observed multi-muon events and their unique features.

Findings

Large production cross section (~100 pb) from CP-odd scalar A.

Cascade decays produce up to 10 tau leptons per event.

Model predicts slow decay of a_2 leading to displaced vertices.

Abstract

We discuss a generalization of the minimal supersymmetric extension of the Standard Model in the form of three additional singlet superfields, which would explain the essential features of the CDF multi-muon events presented recently: a large production cross section of ~ 100 pb originates from the production of a CP-odd scalar A with a mass in the 70 - 80 GeV range and a large value of tan(beta) ~ 40. The CP-odd scalar A decays dominantly into CP-odd and CP-even scalars a_1 and h_1, which generate decay cascades h_1 -> 2 h_2 -> 4 a_2 -> 8 tau-leptons, and a_1 -> h_1 a_2 with h_1 decaying as above. The decay a_2 -> tau+ tau- is slow, leading to a lifetime of O(20) ps. The phenomenology of the model differs from similar scenarios presented before in that one of the two cascades leads to 10 instead of 8 tau-leptons, and additional production processes like associate A production with b b-bar pairs are relevant.