Douglas Bryman University of British Columbia APS May 3, 2011

2 COSMOLOGICAL EVOLUTION, BBN LEPTOGENESIS? New Physics Higher Mass Scales? Direct production of new particles

3 New Physics found at LHC New particles with unknown flavor- and CP-violating couplings New Physics NOT found at LHC Precision flavor-physics experiments needed to help sort out the flavor- and CP-violating couplings of the NP. Precision flavor-physics experiments needed -> sensitive to NP at mass scales beyond the reach of the LHC (through virtual effects).

4 A single effective operator Dominated by top quark (charm significant, but controlled) Hadronic matrix element shared with Ke3 Uncertainty from CKM elements (will improve) Remain clean in most New Physics models (unlike many other observables) Brod, Gorbahn, Stamou PR D83, (2011)

5 Summary of SM Theory Uncertainties CKM parameter uncertainties dominate the error budget today. U. Haisch, arXiv: With foreseeable improvements, expect total SM theory error ≤6%. Unmatched by any other FCNC process (K or B). A. Kronfeld 30% deviation from the SM would be a 5  signal of NP

General MSSM with R-parity SM E949 already provides a significant constraint. Buras et al, NP B714,103(2005) R Parity: R = (-1) 2j+3B+L.

7 7 E787/E Future?

8 Builds on NA-31/NA-48 Un-separated GHz beam Aim: ~40 events/yr at SM Under construction; start >2012 CERN NA-62 first generation decay-in-flight experiment. 75 GeV KOTO: 2 nd try with ~same setup as KEK ( ) Improved J-PARC Beam line (Eventually) higher power Aim: 2.8 events (S/B~1) at SM Under construction; start >2011 Next Generation Experiments

9 Determine everything possible about the K and   + /µ + particle ID better than 10 6 (  + → µ + → e + ) Work in the CM system (stopped K +, K L TOF) Eliminate events with extra charged particles or photons *   0 inefficiency < Suppress backgrounds well below the expected signal (S/N~10) * Predict backgrounds from data: dual independent cuts * Use “Blind analysis” techniques * Test predictions with outside-the-signal-region measurements Evaluate candidate events with S/N function Experimentally weak signatures: backgrounds exceed signals by >10 10 I II

10 E949 – 3 nd generation Photon Veto  4  Photon Veto  500 MHz digitizers Incremental Improvements 550 MeV/c K stopping rate x5 with comparable instantaneous rate Larger solid angle – Acceptance x 10 Finer segmentation, improved resolutions - Reduced backgrounds Overall > 100 x sensitivity P996 :4 th generation at FNAL MI

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12 3 GeV 1 mA Continuous Beam Fermilab Project X

Incremental Improvements 450 MeV/c K stopping rate x10 with comparable instantaneous rate as E949 Larger solid angle – Acceptance x 10 Finer segmentation, improved resolutions - Reduced backgrounds Overall > 250 x sensitivity 4 th Generation Detector 340 events/year Comparable or lower rates then in E949, despite much higher yield.

14 B(K L  0 ) ~ 2.4  Need huge flux of K’s -> high rates Weak neutral particle kinematic signature 2 particles missing Backgrounds with  0 up to 10 9 times larger Principal problem: K L  0  0 Veto inefficiency on each extra particle must be  Neutrons dominate the beam –make  0 off residual gas – requires high vacuum –halo must be very small –hermeticity may require photon veto in the beam Need convincing measurement of background

15 a la KOPIO

16 At Project X : High intensity allows small beam dimensions Symmetrical beam, detector; geometric acceptance maximized 2-D beam kinematic constraint increases S/B Upstream backgrounds, backgrounds in the fiducial volume reduced Same micro-bunch event spoilage reduced Random vetos reduced due to high duty factor Beam veto may be unnecessary Neutron rates high – could be problematic Ideal time structure for TOF-based experiment.

17 Project X Kaon Hall 3 GeV protons

18 GoalsKOTO * J-PARC Proj.X Events/yr ~1“200” S/N~15-10 Precision 5% * J-PARC plans a phase II to reach higher sensitivity. Goals NA62 CERN FNAL MI Proj.X Events/ yr S/N555 Precision 10%4%2%

19 A unique opportunity to search for new physics with Rare Kaon Decays