Over the past several decades, many extensions and alterations to the standard model (SM) of particle physics have been proposed. These take the form of concrete modifications or extensions to the known particle spectrum and interactions; resulting in predictions that are testable at the energy and intensity frontiers found in high energy colliders. Particle experimentalists design and conduct searches for new physics at these colliders, which requires a significant investment of time and resources. Often these searches are sensitive to a broader class of models than they were originally designed to test, thus it is natural to ask
What impact does an existing analysis have on an alternative signal hypothesis?
The ability to accurately answer this question would extend the impact of our existing searches with little additional effort. If one sacrifices the optimality of a dedicated search, then one can reuse the estimates of backgrounds and systematic uncertainties from the original search as well as the observations in data. The only piece of information necessary to recast the results of an existing analysis into the context of a new theory is the expected signal yield for that model. We call this technique recasting, and in our paper we consider several examples where this has been successfully done. The advantages of this approach are that it
- extends the impact of existing results from experimental collaborations,
- provides accurate interpretation of existing searches in the context of alternative models,
- does not require access to or reprocessing of the data,
- does not involve design of new event selection criteria, and
- does not require additional estimates of background rates or systematic uncertainties.
Despite the simplicity of the question above, and its in principle straightforward resolution, it is presently difficult to answer in practice. This difficulty is not the result of a lack of tools, which are to a large extent available, but rather it is because a framework where such a question can be easily asked and accurately answered is not currently available. In our paper we present RECAST, a framework designed to facilitate this type of analysis. The framework has been designed so that it will
- connect those interested in alternative signals with those responsible for relevant searches,
- standardize the format of such requests,
- maintain collaborations’ control over the approval of new results,
- allow new models to be considered even after a search is completed, and
- complement data archival efforts.
The impact of RECAST depends entirely on the incorporation and integration of existing analyses into the framework. It builds on the efforts of experimental searches by extending and expanding their relevance to the community, all under the auspices of the collaborations. The design and considerations put forth here work aim to initiate a community wide effort to bring such a framework to life.