Exotic physics looks at particles and phenomena that lie outside the Standard Model and beyond Supersymmetry. Exotic physics defies expectation and can be considered research into physics beyond the Standard Model that is not included in Supersymmetry. CoEPP concentrates on three specific areas of exotic physics, these include searches for new physics in multilepton final states, new heavy bosons and the search for and measurement of exotic Onia states.

The Adelaide and Melbourne groups are involved in analysis searches that can provide evidence for new phenomena. The production of multilepton events has been predicted by many models such as excited neutrino models, fourth-generation quark models and Supersymmetry models. The Adelaide group is involved in the physics analysis with collaboration of colleagues from NIKHEF (National Institute for Subatomic Physics, Netherlands) and LBNL (Lawrence Berkeley National Laboratory, USA).

The search is conducted in separate channels based on events containing at least four leptons. The estimation of various backgrounds is a crucial part of the search and Soni’s work provides the estimation of backgrounds from fake taus and the associated systematic uncertainties.

Heavy quark pairs - either a charm quark and antiquark, or a beauty quark and antiquark - form bound states under the strong interaction. The properties of these states can be successfully explained using a very simple potential form. Over the last 15 years, a number of new states have been observed which cannot be understood using this simple model, and are consequently categorised as exotica.

The best-established of these exotic states in the charm system is the X(3872). It is reasonable to assume that a similar state in the beauty system must exist, the so-called Xb. The discovery of the Xb would provide an important input for any model aiming to explain these exotic states. 


The decay of a lambda particle in the 32 cm hydrogen bubble chamber. Credit: CERN.