LHC-

-CERN 25/26 July 2005

Information Letter

We are all eagerly awaiting data from the LHC that will point to how the electroweak symmetry is broken, perhaps confirm that superpartners exist, or more generally provide signals of physics beyond the Standard Model that can focus our attention and give us clues to the underlying theory.

Once there is a discovery there will be celebrations and champagne. Then what? Theorists and experimenters have increasingly begun to realize that we could be more prepared for finding and for learning to interpret the (hoped for) signals of physics beyond the Standard Model. Experimenters have already done some mock data challenges, but mostly in the context of very minimal mSUGRA models with limited connections to underlying theories, and with very special signatures. Theorists are less prepared. Some theorists and experimenters have been working on the very important studies of the SM signals that will be needed to recognize physics beyond the SM. Many theorists who are eager to have data pointing to how the SM will be extended have not yet developed the techniques to participate in the process of discovery, and it will take time to do that.

For simplicity let's assume supersymmetry is what is discovered to concretely discuss the issues - if it is something else there will be similar challenges. Experimenters report cross sections times decay branching ratios, and some kinematical distributions that are related to masses. In practice it may be possible to measure at most a few superpartner masses if any. How do we figure out the physics implications of the data, how supersymmetry is broken, whether there is evidence for the 4D physics being determined by the existence of small extra dimensions, etc?

In order to focus attention on such issues, and begin to make progress, a meeting will be held at CERN on July 25-26, 2005, dubbed the LHC Olympics. By mid May 2005, the `results' from the first year of LHC running will be posted at the web site. Anyone can then have access to the `data', which will be in a form like that it might have from a real detector. A group of people will then be formed who will analyze the data, discover signals of new physics, and report the results at the CERN meeting. It is hoped that a number of experimenters and theorists will then try to interpret the reported signals, and develop and improve techniques to learn the implications from the limited amount of hadron collider observables. If there is interest alternative `results' of the first year may be posted to allow additional studies.

We believe such an exercise will be very valuable for particle physics. It is hoped that this meeting will generate widespread enthusiasm and interest in such studies, which will lead to a second meeting some months later where people can present their interpretations of the data, and learn the actual theory that was used to generate the `LHC results'. For this process to work it is important that the initial meeting have a critical mass of participants, so we hope you will participate and distribute this message to anyone who might be interested.

News

A "Primer" that non-experts can use to help connect a theory and "data" is accessible here in its minimal form. Please, have a look on the pdf-file or the the ps-file. We will keep upgrading it.