Dear Colleagues:

Over the next year, the APS Division of Particles and Fields will sponsor a major study of opportunities for the future of high energy physics ("Snowmass 2013").  We are the organizers of the "Energy Frontier" segment of this study.   We are writing to bring you up to date on the plans and to strongly urge you to participate.

The kickoff meeting for this study will be at Fermilab, October 11-13, 2012.   We encourage you to be there. The web site for the meeting is:

https://indico.fnal.gov/conferenceDisplay.py?confId=5841

Registration is now available at this web page.   Please register and attend!

The Snowmass 2013 study will conclude in a 2-week meeting at the University of Minnesota in August 2012. An outline of the whole study can be found at:

http://www.snowmass2013.org/

The Snowmass 2013 study will be of great importance in guiding the future of high energy physics in the US.  It is an understatement to say that the future of this program is uncertain. The leadership of the DOE Office of High Energy Physics has just changed, and the leadership of Fermilab and the NSF Physics Division will turn over soon.   The current US plan for the future of high-energy physics is weak.  It is time to rethink the future of our program.

The Snowmass study will not involve a HEPAP subpanel, and this study will not have the power to make decisions.  In fact, this is an advantage.  This is an open, grassroots study that puts the physics first.  It is a chance to review where we are going and what the most important experiments are that high energy physicists should be involved in.

In the Energy Frontier part of the study, there are two questions that seem to us of great importance:

1. What are the properties of the Higgs Boson?

A Higgs-like particle has been discovered by ATLAS and CMS. Where do we go from here? What are the capabilities of the LHC experiments to learn about this particle in detail?  Can high luminosity running contribute to the precision experiments on the Higgs?   Do we need a lepton collider Higgs factory?  And, if so, what kind of accelerator is needed?

2. Where are the promised new particles at the TeV energy scale?

Many people say that the Standard Model is incomplete, but now the LHC experiments have excluded many proposed models of new physics.  What should be our strategy now?  What are the expectations for high LHC energies and luminosities?  It is possible that new particles are light and have escaped the LHC searches so far.  How can we find these particles in the current data?  How can a lepton collider contribute to this search?

Beyond, and strongly attached to, these questions, there are many others. How do we improve the precision of our predictions for the Standard Model at hadron colliders, and how can we test those predictions?  How does the top quark enter this story?  Will the new physics involve flavor in an essential way; will it be CP violating?

Many of these questions have been studied only in small communities.  The study of what can actually be done in the difficult conditions of the high-luminosity LHC is just beginning.  By the summer of 2013, we will have all of the data from the first run of the LHC, and we will be in a extended shutdown that will give us time to contemplate it.  It will be time to look seriously at the future of the LHC program and other possible high energy initiatives.

It is clear to us, for these reasons, that the Snowmass study will be interesting from a scientific point of view.  But it will also be important in another way.  Frontier energy physics is very expensive.  The machines that make it possible are now overseas, and the frontier experiments will continue there for the foreseeable  future.  It is easy to argue that this is not an area for further US investment.  Those who think differently need to develop a narrative that justifies continued US involvement in this program.  If you are in this group, you need to show up to the Snowmass study to make clear how large a community you represent.

The Fermilab meeting in October will be the first step into this study.  You will find the program at the web site above.  In particular, the Energy Frontier Group has the Ramsey Auditorium reserved for almost the whole day on Friday to present and discuss study questions on the topics relevant to the Energy Frontier.  Come, and get involved!  You might also contact directly the Energy Frontier subgroup convenors, whom you will find listed in the Energy Frontier pages of the Snowmass web site.

Thank you very much.

Chip Brock and Michael Peskin


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  Michael E. Peskin                           [log in to unmask]
  HEP Theory Group, MS 81                       -------
  SLAC National Accelerator Lab.        phone: 1-(650)-926-3250
  2575 Sand Hill Road                       fax:     1-(650)-926-2525
  Menlo Park, CA 94025 USA              www.slac.stanford.edu/~mpeskin/
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