The Tevatron’s beam-beam legacy

Vladimir Shiltsev

Vladimir Shiltsev, director of the Accelerator Physics Center, wrote this column.

Although the Tevatron was shut down more than 18 months ago, scientists continue to analyze the data it produced, discover important results and publish papers. When you read this, you probably think immediately of the scientists who are still sifting through the high-energy physics data. Well, accelerator physicists are sifting through Tevatron data as well. While the CDF and DZero collaborations continue to extract a wealth of results from the proton-antiproton collisions the Tevatron produced, we in the Accelerator Physics Center continue to analyze and learn new things from the Tevatron beam data.

From the point of view of an accelerator scientist, the Tevatron collider was arguably the most complex accelerator facility in the world because of a combination of factors such as the use of superconducting magnet technology, the acceleration of both protons and antiprotons and the rather complicated beam dynamics in the machine.

Beam-beam effects (BB)—usually unpleasant phenomena stemming from the electromagnetic interaction of colliding bunches—were a significant part of the Tevatron’s everyday life and subject of careful studies by a number of physicists. During Tevatron Run I (1987-1996), some 15 people were involved in BB studies and optimization, if one counts those who authored corresponding scientific publications. During Tevatron Run II (2001-2011), more than 25 people were involved.

Several APC members took part in a recent ICFA mini-workshop on beam-beam effects in hadron colliders, which was held at CERN from March 18 to 22. That workshop was the successor to similar workshops held at CERN in April 1999 and at Fermilab in June 2001. Alex Valishev, Giulio Stancari and I reviewed the past and present theoretical understanding of BB effects in the Tevatron, compared it with experimental observations, showed our fascinating progress in BB modeling tools and discussed numerous results from the beam-beam compensation experiments carried out with Tevatron electron lenses. All these aspects are important for planning additional research with the goal of further improving the already strong performance of the LHC and for studies that are needed for the planned LHC upgrade projects, such as the high-luminosity LHC and the proposed LHeC for proton-electron collider experiments. They are also important for our own future accelerator projects, including a future muon collider.