Solving Mysteries with Rare Kaon Decays 2/8 Douglas Bryman - PowerPoint PPT Presentation

Solving Mysteries with Rare Kaon Decays 2/8 Douglas Bryman University of British Columbia 1

→ Tevatron LHC; TeV Energy Scale New Physics High Mass High Mass Scales? Scales? Rare Decays and CP violation COSMOLOGICAL Symmetry Violation EVOLUTION, BBN NEUTRINO PHYSICS LEPTOGENESIS? 2

The Memoirs of Sherlock Holmes by Sir Arthur Conan Doyle "Excellent!" [Watson] cried. "Elementary," said [Holmes]. " The Crooked Man " Doug Bryman FNAL Accelerator 3 Workshop October 20, 2009

Five Special Rare Decay Experiments Probe new physics at the 1-1000 TeV Scales! State of the art: : 10 -12 Exotic Lepton Flavor Violation: Searches- μ → γ <1.2 10 -11 e New physics if seen since SM effects are μ − − → <7.8 10 -13 N e N negligible. ⎧ ⎫ SM Parameters + + + π → ν ( K ) e ⎨ ⎬ ***±0.4% and BSM + + + π → μ ν ⎩ ⎭ ( K ) Physics ***10 -10 : + + → π νν ⎧ ⎫ K 7events ⎪ ⎪ New physics if − ⎨ ⎬ deviations from well- 8 < → π νν 6.7 10 x 0 0 K ⎪ ⎪ calculated SM ⎩ ⎭ 4 L predictions occur.

Experiments Experiments Prospects for 10-1000 x improvements. + + → π νν K → π νν Lepton Flavor Violation 0 0 K L + → + π ν / K e Precision 7 90% CL 100 + → e ν + K (2006) 10 − 11 1000 0.4% 10 − − 13/ 17 0.06% Doug Bryman FNAL Accelerator 5 Workshop October 20, 2009

Intensity Frontier at Fermilab: Now and in the Future Now: Main Injector Neutrino Program (MINOS,Miniboone,Minerva,NOVA) -16 8 GeV Booster Proposals: Mu2E (10 ), g-2 (4x), ... + + → π νν Tevatron Stretcher Proposal: K Future: 2/8 GeV Linac Project X Doug Bryman FNAL Accelerator 6 Workshop October 20, 2009

Tevatron Stretcher Mike Syphers • Tevatron stretcher: 150 GeV beams to Fermilab switch yard. • MI: 1.33 s cycle time, 2(of 30) pulses->Tevatron • 100 Tp stored in Tevatron for slow, resonant extraction • 10% of the available MI beam � 80 kW with 95% duty factor, 27.3 s cycle time. MI+Tevatron K flux: ~ 2.5 AGS Doug Bryman FNAL Accelerator 7 Workshop October 20, 2009

Project X ICD-2 Kaon Production vs . T P K + 0 K 1 mA 100% d.f. σ 2 GeV 1 K K production (<1 GeV): ~ 30 σ 24 GeV K ICD-2 p beam intensity: ~ 300 AGS ICD-2 Doug Bryman FNAL Accelerator 8 K flux: ~10 Workshop October 20, 2009 AGS

→ πνν K FCNC! ..the curious incident of the dog in the night-time... "The dog did nothing in the night-time." "That was the curious incident," remarked Sherlock Holmes. Sherlock Holmes in "Silver Blaze" Doug Bryman FNAL Accelerator 9 Workshop October 20, 2009

→ πνν K in the SM 2 nd order weak: proceeds very slowly! u c t λ η λ * 2 5 Standard Model ( Buras ): I m =Im V V = A t ts td λ 2 ⎛ ⎞ − − → π νν I m 0 0 10 11 = = ± B K t ⎜ ⎟ ( ) 1 .8 x 1 0 X x ( ) 2.5 0.40 10 x λ L t ⎝ ⎠ 5 ( ) ± → ± 16% 12% + + − − → π νν ( ) ⎡ ⎤ = 10 11 η + ρ − ρ 2 ± B K ∼ 4 2 ( ) 1.0 1 x 0 A 8.5 0 .7 10 x ⎣ ⎦ 0 ( ) ± → ± 8% 6% Kronfeld 10

→ πνν K : Great Discovery Potential ± → πνν → mass scale 1000TeV! 10% measurements K ~ Two Examples: SUSY: Rare meson decays Minimal Flavor Violation e.g. into light neutralinos Littlest Higgs Model with T-parity + + → π νν K + + → π νν → π νν 0 0 B K ( ) vs . B( K ) → L 5 x SM 11 H. K. Dreiner et al. Bonn-TH-2009-04 M. Blanke, et al., arXiv:hep-ph/0610298 .

* A wide range of non-SM possibilities.. .. (Me s c a ) i → π νν + → π νν + 0 0 B K ( ) vs . B ( K ) * From G. Isidori, PoS L KAON, 064 (2008) [arXiv:0709.2438 [hep- ph]]. SM + + → π νν Deviations in B( K ) as small as σ 30% from SM could be observed at 5 ! Doug Bryman FNAL Accelerator 12 Workshop October 20, 2009

→ πνν Experiments K + + → π νν K + + + − → π νν = • 1.15 10 B( ) 1.73 10 K x BNL E787/949: − 1.05 • CERN NA62; New Technique • New proposal: Fermilab P996 • Fermilab Proje ct X? → π ν ν 0 0 K L − 8 • → π ν ν < 0 0 KEK E391a: B( K ) 6.7 10 x L • JPARC KOTO • Fermilab Project X? Doug Bryman FNAL Accelerator 13 Workshop October 20, 2009

+ + → μ ν γ K ( ) Special Features of + + → π π 0 K 64% 21% Measuring + + → π νν K Background processes exceed I II signal by >10 10 • Determine everything possible about the K + and π + * Measure momentum, energy, range, decay sequences * π + / μ + particle ID better than 10 6 ( π + - μ + -e + ) • Eliminate events with extra charged particles or photons * π 0 inefficiency < 10 -6 • Suppress backgrounds well below the expected signal (S/N~5-10) * Predict backgrounds from data : dual independent cuts * Use “Blind analysis” techniques * Test predictions with “outside-the-box” measurements 14 • Evaluate candidate events with S/N function

“… when you have eliminated the impossible, whatever remains, however improbable , must be the truth ? ” Sherlock Holmes in The Sign of the Four (1890) Doug Bryman FNAL Accelerator 15 Workshop October 20, 2009

BNL E787/949 Measurement of + + → π νν K Doug Bryman FNAL Accelerator 16 Workshop October 20, 2009

E787/E949 Final Result: 7 events + + + − → π νν = 1.15 10 B( K ) 1.73 x 10 observed − 1.05 (Standard Model: + + − → π νν = ± 10 B( K ) (0.85 0.07) 10 x ) Probability for all 7 events to be due to background: 0.001 Doug Bryman FNAL Accelerator 17 Workshop October 20, 2009

+ → π νν + New Approach to K : Decay-in-flight at 75 GeV/c CERN Proposal Goal: 10 x E949 50 events/yr; Bkg. 14% New technique Doug Bryman FNAL Accelerator 18 Workshop October 20, 2009

New Proposal P996: + → π νν + Measurement of K Decay at Fermilab • 150 GeV MI beam (10% of available current) + Tevatron stretcher (after Run II) � 95% d.f. • New short K + beam at P=550 MeV/c : 7 x K + flux relative to LESB3 at the AGS 3 x efficiency for stopping kaons • Detector Improvements > 10 x acceptance of E949 . • Goal: >100 x E949 • Proven technique. Doug Bryman FNAL Accelerator 19 Workshop October 20, 2009

20 Doug Bryman FNAL Accelerator Workshop October 20, 2009 Magnetic Field: B=1.25 T

P996: Incremental Improvements to E949 Technique +3.25 Acceptance Gain Factor: 11.28 13.7 m K+ beam at 550 MeV/c -2.22 ⎡ ⎤ K ~ 3 ⎢ ⎥ π ⎣ ⎦ + 89 194 events/yr Estimated sensitivity at the SM level: . − 79 Can reach precision <5%, comparable to future improvements expected for SM prediction. Doug Bryman FNAL Accelerator 21 Workshop October 20, 2009

+ + → π νν K Prospects MI+Tevatron Project X Stretcher ICD-2 (P996) (Rough est.) Events/yr “500” 194 + 89 − 79 S/N ~4 ~4 Precision 5% 3% attainable Doug Bryman FNAL Accelerator 22 Workshop October 20, 2009

→ π νν 0 0 The Challenge: K L _ • B(K L →π 0 νν ) ~ 2.5 × 10 -11 Need huge flux of K’s -> high rates • Weak neutral particle kinematic signature 2 particles missing • Backgrounds with π 0 up to 10 9 times larger • Veto inefficiency on extra particles must be ≤ 10 -4 • Neutrons dominate the beam – make π 0 off residual gas – requires high vacuum – halo must be very small – hermeticity requires photon veto in the beam • Need convincing measurement of background Doug Bryman FNAL Accelerator 23 Workshop October 20, 2009

Sherlock Holmes in "The Crooked Man" • " You know my methods, Watson. … And it ended by my discovering traces, but very different ones from those which I had expected. Doug Bryman FNAL Accelerator 24 Workshop October 20, 2009

→ π νν 0 0 K L KEK PS E391a � JPARC KOTO with KTEV CsI − 8 → π νν < 0 0 E391a Result: B( K ) 6.7 10 x (90% CL ) L Features: • Pencil Beam , High P T selection • High acceptance • Reliance on high photon veto efficiency • Sensitivity goal: ~SM level: 2.8 events S/B~1 Doug Bryman FNAL Accelerator 25 Workshop October 20, 2009

Hajime Nanjo ( Kyoto ) Doug Bryman FNAL Accelerator 26 Workshop October 20, 2009

→ π νν 0 0 Project X ICD-2: K Experiment Concept L a la KOPIO 2 GeV Protons <50 ps → π νν 0 0 K L • 0 Use TOF to work in the K c.m. system L • → π π 0 0 0 Identify main 2-body background K L • π → γγ 0 Reconstruct decays with pointing calorimeter • π 4 solid angle photon and charged particle vetos 27