Physics Priorities S. Dawson July 11, 2007 Fermilab Steering Committee Meeting

Priorities: Recent committees (EPP2010 and P5) have addressed the priorities of US HEP Both stressed the importance of a diverse program Priority doesn’t mean you only do the items at the top of the list Both EPP2010 and P5 assumed a fast decision on ILC construction (2010) and a technically driven schedule for ILC construction

EPP2010 Priorities (in order) The energy frontier LHC (including upgrades) ILC Emphasis on US bid to host The particle/astro connection Emphasis on dark matter/dark energy Neutrinos Focus was on a global program Flavor physics

P5 Priorities 60% of new investments to ILC R&D / 40% to smaller initiatives Attempt to quantify importance of diverse program Recommendations are for projects which will complete construction by 2012 to allow flexibility with ILC construction Recommendations for review of longer term (SNAP/LSST) items, along with flavor physics at end of decade, after review of new physics results from the LHC

P5 Recommendations DES CDMS, 25 kg Daya Bay Nova For the long term, LSST & SNAP development Should more money be available…first priority is enhanced ILC development Particle/astro Neutrinos

Priorities The energy frontier LHC will (almost certainly) discover the nature of EWSB, supersymmetry (if it exists), new heavy particles…. We expect great discoveries from the LHC ILC will explore the nature of these new particles Exploring the energy frontier is (and has been) the top priority of our field But there are many fundamental questions which are not best studied at the energy frontier

Our understanding of what particle physics is has broadened in recent years Quantum Universe questions: Are there undiscovered principles of nature: new symmetries, new physical laws? Are there extra dimensions of space? These are questions for the energy frontier

High priority to the connection with astrophysics How can we solve the mystery of dark energy? What is dark matter? Can we make it in the laboratory? How did the universe come to be? These questions cannot be completely answered at the energy frontier

Neutrinos Do all the forces become one? Answering this question most likely requires a large proton decay experiment Proton decay experiment is likely to be part of a future very long baseline neutrino experiment What are neutrinos telling us? A focused program to explore neutrino masses, mixing, CP violation in the neutrino sector needed to answer this question

Opportunities for Neutrino Physics Priorities spelled out by NuSaG Next generation of long baseline neutrino experiments will measure  13, CP violation, mass hierarchy Wait until we know  13 before starting a large neutrino experiment? More protons are better!

Questions naturally answered with dedicated experiments Why are there so many kinds of particles? What happened to the anti-matter? These questions can be addressed by dedicated experiments on the flavor frontier P5 recommended that experiments on the flavor frontier be revisited in 2012 in light of LHC results

Mid-term Physics Program at Fermilab Will the physics be important in a global context when the experiment is done? Can it be done uniquely or substantially better at Fermilab than at other labs? Compare JPARC neutrino/flavor physics program Is there a community for these experiments? Is the experiment unique in its physics reach? Will the experiment answer questions not answered at the LHC?

Muon and Electron Number Violation  - N → e - N Current limit from SINDRUM2 at PSI: R  e < 6x Limited by backgrounds around Sensitive to Beyond the Standard Model Physics Compositeness to 3000 TeV scale Supersymmetric models predict R μe ~ for weak scale SUSY

Kaon Physics in 2012 Physics Drivers are Beyond the SM Physics CKM matrix well established by 2012 K + →π + νν Expect 3-4% theory error on SM prediction in 2012 NA48/3 expects 100 K + →π + νν events by events/year with SNuMi (KTEV-III) K L 0 →π 0 νν Expect 1-2% theory error on SM prediction in 2012 JPARC expects 5 K L 0 →π 0 νν events 20 events/year with SNuMi (KTeV-III), K0PI0 LOI BSM can give large (model dependent) enhancements

Kaons and BSM Physics

Conclusions Neutrino/flavor physics offers rich menu of physics Window to high energy scales in some scenarios Physics reach is complementary to energy frontier The problem of flavor is difficult to study at the LHC How does this fit with the priorities of our field?