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From the Director of Particle Physics & Astrophysics: Evolution of the SLAC Electron Research Program

(Photo - David MacFarlane)

Next week the electron-based Department of Energy research program at SLAC, Fermilab, and Lawrence Berkeley National Laboratory will be peer reviewed by an expert external committee. This is one of a series of rotating, every-three-year reviews of the High Energy Physics laboratory programs in the different research areas within the overall HEP portfolio. Our proposed program will have three elements: the ongoing BaBaR physics on matter-antimatter symmetries and rare decays heavy quarks now put on steroids with a SuperB Factory; an expansion of the design and exploration of the detector capabilities at the next high energy frontier machine, an e+e- or μ+μ- collider; and development of a new experiment at the Continuous Electron Beam Accelerator Facility to explore a recent explanation for the 25 percent share of the Universe made up of dark matter.

The electron research program has traditionally been a major component of the SLAC HEP effort, supporting the research staff on the flagship BaBaR experiment at the PEP-II B Factory. With the completion of data taking in April 2008, the focus of this effort has been on exploiting the opportunity offered by one of the world's great datasets. As of this week, BaBaR collaborators, including SLAC physicists as the host laboratory, have produced 420 journal papers while enabling 361 PhD theses. SLAC will continue to be the center-of-gravity for BaBaR for a number of years yet, and is working to create a long-term capability for access to the data.

The next scientific step for the flavor physics program pursued by BaBaR would be a giant leap forward in sensitivity enabled by the factor of 50 increase in event rate or luminosity planned for the SuperB project in Italy. SLAC has been a leader in developing the design for the machine and detector at SuperB, based on our experience with BaBaR and PEP-II. There is a compelling and complementary opportunity to use the unique capability of a very high luminosity B Factory to explore the flavor physics properties of any new physics discoveries at the Large Hadron Collider.

For the last five years, SLAC has played a central role in the Global Design Effort for the International Linear Collider. This includes an effort to design an optimized high-performance detector, the Silicon Detector, designed to achieve the physics performance goals for this energy frontier e+e- linear collider. A complete simulation and analysis tool kit has been developed to support this work, which culminated in a Letter of Intent last year.

Beyond the ILC, there are now a number of efforts underway to develop other technical pathways to an energy frontier e+e- or μ+μ- collider, with varying levels of maturity and understanding of the technical solutions. Recently, the five HEP laboratories (Argonne National Laboratory, Brookhaven National Laboratory, Fermilab, LBNL, and SLAC) in the US have developed a white paper that proposes to expand the ILC detector program to examine the broader physics goals for lepton colliders more generally. The physics goals for these concepts are all similar, even if the operational conditions may be extremely different. The white paper program is intended to ensure that DOE and the HEP community have available an objective comparison of the options in terms of physics performance as we define a strategic direction for a future energy frontier lepton collider. The plan provides a unified approach to these questions that also allows progress and accomplishments from one option to benefit all, and will provide the framework for discussion of the SLAC lepton collider effort at next week's review.

The final element of the future electron research program is a new idea to search for a potential dark matter candidate. The idea of extending the Standard Model with a new weakly mixed heavy photon as an explanation for observed cosmic ray electron and positron spectra can be directly explored with high rate beam dump experiments at the Continuous Electron Beam Accelerator Facility. A SLAC team is in the midst of designing a new experiment to explore this exciting idea.

We look forward to exploring these plans for the future of the electron research program at next week's DOE review in Washington.

óDavid MacFarlane
SLAC Today, June 18, 2010