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Future of Kaon Physics Augusto Ceccucci/CERN

Future of Kaon Physics Augusto Ceccucci/CERN. CERN-SPS Rare K decays LFV Chiral dynamics. Frequent K decays. U-70. J-PARC L X hypernuclei K Rare Decay. F factory Hadron xsec K S decays N ff. CKM Unitarity and Rare Kaon Decays.

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Future of Kaon Physics Augusto Ceccucci/CERN

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  1. Future of Kaon PhysicsAugusto Ceccucci/CERN CERN-SPS Rare K decays LFV Chiral dynamics Frequent K decays U-70 J-PARC L X hypernuclei K Rare Decay F factory Hadron xsec KS decays N ff Augusto Ceccucci/CERN

  2. CKM Unitarity and Rare Kaon Decays The unitarity of the CKM matrix can be expressed by triangles in a complex plane. There are six triangles, one is more “triangular”: VudVub*+VcdVcb*+VtdVtb*=0 It is customary to employ the Wolfenstein parameterization: Vus ~lVcb ~ l2 A Vub ~ l3 A(r- ih) Vtd ~ l3 A(1-r- ih) Sensitive to |Vtd| CP • It is important to check that the unitary triangle is the • same for all heavy quarks. • The s-quark is just as important as the b-quark. • If experiment shows that there are differences between the • flavors this would be an important discovery. Augusto Ceccucci/CERN

  3. The Global Contest of Flavour and CPV Sin 2b (2f1) Re e’/e What will we learn next?? DmBs Dm Augusto Ceccucci/CERN

  4. Forward Look (Personal Choice) Year: 20XX Augusto Ceccucci/CERN

  5. K→pnn : SMTheoretical Prediction NLO Calculation: Buchalla & Buras: 1993, 1999 Misiak, Urban: 1999 charm contribution NNLO Buras, Gorbahn, Haisch, Nierste hep-ph/0508165 top contributions The uncertainty of the SM prediction is mostly due to uncertainty of the CKM parameters and not to hadronic matrix elements: • BR(K+p+nn)  (1.6×10-5)|Vcb|4[sh2+(rc-r)2]  (8.0 ± 1.1)×10-11 • BR(KLp0nn)  (7.6×10-5)|Vcb|4h2  (3.0 ± 0.6)×10-11 Augusto Ceccucci/CERN

  6. MFV: Sensitivity to Z0 Penguinfrom Bobeth et a. (2005) Eg> 1.8 GeV 1 < q2 (GeV2) < 6 0.04 < q2 (GeV2) < 1 14.4 < q2 (GeV2)< 25 Augusto Ceccucci/CERN

  7. K0Lp0nn • KOPIO @ BNL stopped • In Japan a step by step approach is proposed: • KEK: • E391a has completed data taking (three runs) • Present limit < 2.1 10-7 90%CL • Aim to reach the Grossman-Nir bound (~10-9) • J-PARC (>2010) • Proposal for the J-PARC hadron facility • Step I: move the improved E391a detector at J-PARC; To reach SM sensitivity Received J-PARC PAC stage I approval • Step II: build a new detector and a dedicated beam-line to be able reach ~ 100 SM events • CERN • Evaluating capabilities in the context of an upgraded proton complex Augusto Ceccucci/CERN

  8. K0Lp0nn at J-Parc • Improvements w.r.t. E391a: • CsI calorimeter with a finer granularity • New photon veto in the beam • Waveform digitization for higher rates

  9. K+→p+nn : setting the bar for the next generation of experiments E787/E949: BR(K+→ p+ nn ) = 1.47+1.30-0.89 × 10-10 Current constraint on r,hplane ? 100 events Mean=SM 100 events Mean=E787/949 Augusto Ceccucci/CERN

  10. Plans for K+→p+nn • Decays at rest: • There is a Letter of Intent to continue K+→p+nn studies with kaons decays at rest at J-PARC • The plan is to move the BNL-E949 detector to Japan to study Hadron Nuclear Spectroscopy at the Spring-8 LEPS2 photon source • Then, the detector could be moved to J-PARC when/if a low energy K+ line becomes available • Decays in flight: • Not anymore pursued at FNAL • There is a proposal with a sensitivity to collect about 80 SM events in two years at the CERN-SPS • The proposal (P-326) builds on the infrastructure of the current CERN kaon experiment (NA48/2) and is also known as NA48/3 Augusto Ceccucci/CERN

  11. CERN-SPSC-2005-013 SPSC-P-326 Proposal to Measure the Rare Decay K+p+ n n at the CERN SPS CERN, Dubna, Ferrara, Florence, Frascati, Mainz, Merced, Moscow, Naples, Perugia, Protvino, Pisa, Rome, Saclay, San Luis Potosi, Sofia, Turin • Presented at the CERN SPSC in September 2005 • R&D endorsed by CERN Research Board on December 2005 • Test beams in Oct-Nov 2006 • Seeking more groups to join • Aims to complete R&D by the end of 2007…. • …to start data taking in 2011 Augusto Ceccucci/CERN

  12. CERN Proton Complex CERN Proton Complex NA48 SPS LHC CNGS Augusto Ceccucci/CERN

  13. NA48 Augusto Ceccucci/CERN

  14. P-326 Detector Layout K+p+ n n p+ K+ ~11 MHz of K+ decays n (KABES) • SPS primary p: 400 GeV/c • Secondary beam: • 75 GeV/c • 800 MHz • p/K/p (~6% K+) n SPIBES: Si mpixel X/X0 << 1% per station Pixel size ~ 300 x 300 mm excellent time resolution Augusto Ceccucci/CERN

  15. Background rejection 1) Kinematical Rejection 2)Photon vetoes to reject K+ p+p0 : P(K+)= 75 GeV/c Requiring P(p+) < 35 GeV/c P(p0) > 40GeV/c It can be hardly missed in the calorimeters!! 3) PID (RICH) for K+ m+n rejection Augusto Ceccucci/CERN

  16. Signal & backgrounds from K decays / year* *Before taxes. Proposal quotes a more conservative 40 evt/year @BR=10-10 • SPS used as LHC injector (so it will run in the future) • No flagrant time overlap with CNGS • P-326 fully compatible with the rest of CERN fixed target • Conservative beam request based on decennial NA48 experience at SPS Augusto Ceccucci/CERN

  17. Photon E=11 GeV Pion P=42 GeV/c Cluster not reconstructed Eg = 22 GeV Expected position LKr inefficiency measured with data LKr ineff. per g (Eg > 10 GeV): h ~ 7 × 10-6 (preliminary) p+ track and lower energy g are use to predict the position of the other g K+p+ p0 selected kinematically • Just collected tagged g to measure • for Eg < 10 GeV using an e- beam and the NA48 DCH’s as active target Augusto Ceccucci/CERN

  18. Other Physics Opportunities • The situation is similar to NA48, which was designed to measure “only” e’/e but produced many more measurements • Accumulating ~100 times the flux of NA48/2 will allow us to address, for instance: • Cusp like effects (p-p scattering) • K+ p+p0 p0 , K+ p0 p0 e+n • Lepton Flavour Violation K+ p+ m+ e- , K+p- m+ e+, RK= G(K+ e+ n )/ G(K+m+ n) • Search for new low mass particles • K+ p+ X • K+p+ p0 P (pseudoscalar sGoldstino) • Study rare p+ & p0 decays • Improve greatly on rare radiative kaon decays • Compare K+ and K- (alternating beam polarity) • K+/- p+/-p0g (CPV interference) • T-odd Correlations in Kl4 • And possibly, given the quality of the detector, topics in hadron spectroscopy Example I Example I I Augusto Ceccucci/CERN

  19. Example I:Observation of p-p scattering effect in K→3p decays NA48/2 has made the first observation the of the charge exchange process+00in the K00decay. 1 bin = 0.00015 GeV2 30M events NA48/2 PLB 633 (2006) hep-ex/0511056 4mπ+2 K±±00 4mπ+2 G~|M0+M1|2 N. Cabibbo, hep-ph/0405001 PRL 93121801 (2004) N. Cabibbo and G. Isidori, hep-ph/0502130 JHEP 503 (2005) G. Colangelo, J. Gasser, et al. hep-ph/0604084 PLB 638 (2006) M2(00) (GeV/c 2)2 Augusto Ceccucci/CERN

  20. Difference between p-p scattering length in I=0 and I=2 states NA48/2 PLB 633 (2006) hep-ex/0511056 (a0 – a2)m+ = 0.268 ± 0.010(stat) ± 0.004(syst) ± 0.013(theor) In agreement with theory (a0 – a2)m+ = 0.265 ± 0.004 (Colangelo 2001) Augusto Ceccucci/CERN

  21. EXAMPLE II: RK=G(K+ e+n) /G(K+m+n) NA48/2 EPS05 Masiero, Paradisi, Petronzio, hep-ph/0511289 Augusto Ceccucci/CERN

  22. P-326 Project • CORE Cost ~26 MCHF • Including about 3.7 MCHF for online/offline computing • Cost drivers: • Photon Vetoes: 5.0 MCHF • RICH: 3.0 MCHF • Magnets: 3.0 MCHF • Gigatracker: 2.9 MCHF (0.13 mm CMOS) • Completion of R&D and TDR submission during 2007 • Construction time 2008-2010 • It is a window of opportunity between the completion of the LHC detectors and before the LHC upgrade (SLHC) • A step-by-step upgrade of the to experimental setup allows one to address LFNV and other topics before the full construction of P-326 • Data taking with full detector from 2011 • The consolidation/upgrade of the CERN proton complex enthuses to also think about an K0Lp0nn Augusto Ceccucci/CERN

  23. Augusto Ceccucci/CERN

  24. Why should CH Participate • Outstanding physics opportunity • The importance of rare kaon decays has been recognised by the theoretical community since a long time. If these experiments are not done, we will arguably lack the cleanest test of the SM flavour sector • It is a “no lose situation”. If new particles exists, their effect must appear in loops • No other clean way to study the FCNC d  s transitions • Complementary with LHCb • Cost-effective alternative to Super-F factories • With a moderate investment CH could play an essential role • The time scale is well matched to bridge the current round of LHC experiments and the ILC/SLHC construction • Small risk • The SPS is here to stay and the CERN proton complex will be consolidated • Projects such as this one add breath to the CERN Physics programme  low strategic/schedule risk • The experiment is feasible with some more R&D  moderate technical risk • The exploitation of existing CERN infrastructure keeps the tag price low  low financial risk Augusto Ceccucci/CERN

  25. Summary • J-PARC • Hypernuclei studies (K1.8 line “day one” experiments) • P14: K0Lp0 nn (K0 beam-line, >2010) • P6: Transverse m polarisation (K+ p0 m+ n, m+ g n) (K1.1BR beam-line) • P9: K+p+ nn at rest (>2013) • CERN-SPS: P-326 (NA48/3) • K+p+ nn in-flight (Precise SM prediction, Test of MFV) • LFNV: RK= G(K+ e+ n )/ G(K+m+ n) , K+p+m+e-, K+p+m-e+,… • Chiral dynamics (Ke4, Km4, radiative and non-leptonic kaon decays) • pp Scattering • Search for new low energy particles • T-odd correlations • Other labs (“frequent” decays) • IHEP Protvino (in-flight separated beam) • Frascati F factory (hadronic x-sections, K Interferometry, nucleon ff) Augusto Ceccucci/CERN

  26. SPARES Augusto Ceccucci/CERN

  27. Plans at the Frascati f-factory • Last KLOE run: 2006 • DAFNE runs until 2008 for other experiments: FINUDA +SIDDHARTA • Plans for Luminosity and Energy upgrades (DANAE) • DANAE Motivation: • Kaon interferometry (QM) • Nuclear Physics • N N form factor • Synchrotron radiation • R&D Augusto Ceccucci/CERN

  28. IHEP Protvino: RF-separated beam @U-70 Main beam parameters : Primary proton beam energy 65-70 GeV Primary proton beam intensity 1013 ppp Secondary beam momentum 12.5 or 18 GeV Length of the beam line ~200m K+ intensity at the end 5 x 106 +, p contamination <25% Muon halo <100 % Beamline was built in 2001-2004 and commissioned in December 2004 End of the beamline Deflector in the beamline

  29. Expected Backgrounds (J-PARC-Step1)For 7 SM events: S/B~1.4 Augusto Ceccucci/CERN

  30. P-326 RICH performance RICH Radiator: STP Ne: (n-1)x106=67.1 L=18 m P from straws Augusto Ceccucci/CERN

  31. Theory vs. Experiment Adapted from U. Haisch @ Flavour in the LHC era, 6-8 Feb 06, CERN Augusto Ceccucci/CERN

  32. T-violating Transverse Muon Polarization in K+→p0m+n Decays • Non-zero PT is a clear signal of • T violation • Standard Model contribution to PT: PT (SM) < 10-7 • Effects from final state interactions (FSI) : PT (FSI) < 10-5 • A large window for new physics in the region of PT = 10-3 ~ 10-5 KEK-PS E246 result PT = - 0.0017 ± 0.0023(stat) ± 0.0011(syst) ( |PT | < 0.0050 : 90% C.L. ) Imx = - 0.0053 ± 0.0071(stat) ± 0.0036(syst) ( |Imx | <0.016 : 90% C.L. ) E246 Augusto Ceccucci/CERN

  33. Upgraded E246 experiment at J-PARC E246 detector • Sensitivity goal = dPT ~10-4 • dPTstat ~0.05 dPTstat (E246) ~10-4 • dPTsyst ~ 0.1 dPTsyst (E246) ~10-4 • Stopped K+ decay • SC Toroidal spectrometer • Active muon polarimeter etc. Augusto Ceccucci/CERN

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