Electroweak Unification at HERA

The HERA collider at the DESY laboratory in Hamburg has been colliding electrons and protons at very high energies since 1992. The goals of HERA are to study the structure of the proton at the smalles distances available, and to investigate the strong and electroweak interactions of particle physics. Any discrepancy between the data and the expectations of the "standard model" could be an exciting signal for new physics, such as quark substructure or a new force. The UCL group built a major part of the ZEUS general purpose detector at HERA and has been working on physics analysis since the beginning of the experiment.

Project Goals

Your team has been commissioned to analyse data from the ZEUS experiment at HERA. You should search through a series of high energy electron-proton scattering events, and sift out the high momentum-transfer events where electroweak unification is expected to be observable. You should count the number of neutral- and charged-current deep inelastic scattering events as a function of the momentum transfer. The result should be presented on a visually stimulating web page, with the meaning of the results explained and the events illustrated. The web page should be aimed at physics A level students.

1. Information Collection

You will need to understand the basic kinematics of deep inelastic scattering, as well as something about electroweak unification. You will also need to find information about the HERA accelerator and the ZEUS detector which collected the data you are analysing. The information gathered will inform the rest of the project: It will guide the analysis and the selection devised, and will provide material for the presentation.

Some references which you may find useful:

- The ZEUS home page: http://www-zeus.desy.de/

- The workshops on HERA physics, available in the Castilleo-Spreadbury

library (D17).

- "Particle Physics" by B.R.Martin and G.Shaw, Wiley.

- "Quarks, Leptons and the Big Bang", J.Allday, IoP Publishing.

2. Analysis Software

Accessing the data will require the use of some ZEUS software packages. You will need to learn how to run these and understand their results. You will also need to use CERN software to perform the analysis and make plots.

3. Presentation

You will need to investigate the best way of presenting the results. Various packages exist, including a Java-based 3D event display which you may wish to use to display your events.

Resources Available

You have 4 hours total of consultancy time available with the following people.

Jon Butterworth: Physics, ZEUS software. jmb@hep.ucl.ac.uk

Mark Hayes: Physics, ZEUS software, Event displays. meh@hep.ucl.ac.uk

Ondrej Pribyl: Software, Webpages. o.pribyl@ucl.ac.uk

Your board member is Dr. Jon Butterworth, phone 7318.