Kaon Physics at Hadron Machines Augusto Ceccucci/CERN KAON’07, Frascati, May 24, 2007 Panel Discussion

Kaon Physics at Hadron Machines has been tremendously successful CP-Violation Direct CP-Violation Stringent test of LFV Ultra-Rare Decays Strong interactions (pp scattering, cPT ) CKM …

K  p nn decays Example 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

NP Reach of the K  p nn decays F. Mescia CKM 2006

These K  p nn measurements must be done… These K  p nn measurements must be done…. …and require proton machines to make enough kaons

Proton Machines are Very Versatile CERN:PS, SPS,(PS2?), LHC IHEP: U-70 J-PARC: 30 (50) GeV FNAL: MI, Tevatron

NA48

Proposal to Measure the Rare Decay K+p+ n n at the CERN SPS 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 I & II, Saclay, San Luis Potosi, Sofia, TRIUMF, Turin Approved R&D Programme Approved 2007 run to study KE2 & to test prototype detectors Seek to start data taking in 2011 Experiment description: see G. Ruggiero’s talk tomorrow morning Unseparated 800 MHz beam (kaon fraction ~5-6%)

K+p+p+p- and other 3-tracks bckg. P-326: K+p+ n n Events/year Total Region I Region II Signal (SM) 65 16 49 K+p+p0 2.7±0.2 1.7±0.2 1.0±0.1 Km2 1.2±0.3 1.1±0.3 <0.1 Ke4 2±2 negligible K+p+p+p- and other 3-tracks bckg. 1±1 Kp2g 1.3±0.4 Km2g 0.4±0.1 0.2±0.1 Ke3, Km3 ,others - Total bkg 9±3 3.0±0.2 6±3 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

P-326 Status and Prospects 2007 Activities: Continue R&D Long run at SPS to measure RK=G(K+  e+ n) /G(K+m+n) to ~0.3% Converge towards the technology choices Seek approval Aim to data taking in 2011

P-326 R&D

Gigatracker: R&D program 300 mm  300 mm Si pixel with ~200 ps time resolution Readout chip: 1st MPW submission in 0.13mm Submitted in February 07 Analogue FE blocks for the "CFD" option (Torino) FE amplifier discriminator NINO, LVDS driver (CERN) Wafers delivery ≈ end May 07 ASICs characterization (t resolution, jitter, time walk) Tests card in progress (results by September) Irradiated test diode Si diode irradiation tests Prototype wafers (200µm thick) produced by itc-IRST using ALICE pixel layout 3 mm × 3 mm and 7 mm × 7 mm test-diodes Test diodes irradiated with n and p (Ljubljana, CERN) Fluences: 1E12 to 2E14 1MeV n cm-2 (range P326) Pre and post irradiation measurements (annealing) to study diode characteristics itc-IRST wafer, 200µm Si diode characterization with pulsed IR laser system

LKr calorimeter: R&D program Measurement of the inefficiency K+ data taken in a dedicated NA48 test run in 2004 using K+p+p0 h < 10-5 (@90% C.L., Eg>10 GeV) Tagged g using an SPS electron beam (2006) Inefficiency measured for Eg > 2.5 GeV > 10 GeV, h < 10-5 confirmed < 10 GeV analysis in progress Energy deposition in LKr electron x Energy GeV z g X LKr cm

Spectrometer: R&D program Chosen technology: tube of mylar (25 mm, D=1 cm, L=2.1 m) 100 straws produced in Dubna Tests on gas leakage Tests on tube expansion in vacuum Prototype assembled & cosmic ray tests October 2007: Prototype integration in NA48 set-up and test on beam

RICH: R&D program Design, construction and test of a RICH prototype Full length prototype (17 m, 0.6 m diameter, stainless steel tube at CERN) Mirror built, delivered and under test in Firenze Endcap with 96 Hamatsu PMs readout through Winston’s cones PMs tested at SPS (2006) and Firenze (with laser) Measured FWHM per single g per phototube: 390ps (150 ps electronics and 110 ps laser included) FWHM 0.375 ps t ns November 2007: prototype integration in the K12 beam set up and test Simulation p K p+m

Large angle photon vetoes: R&D program KLOE-type lead/scintillating fiber: prototype constructed in Frascati 1 mm diameter scintillating fibers, 0.5 mm thick lead foils. Readout granularity: 18 cells Very well known and tested technology Under test at the Frascati BTF Fibers+lead wires: 9 X0 All fiber: 8 X0 16.8 cm 8.2 cm Lead scintillators tiles Aijimura et al. NIM Studies of the efficiency of detectors built with this technology available Fermilab prototype under test at BTF Outgassing tests performed at CERN on detectors built with same technology: they can be placed in the vacuum of the decay region (10-6 mbar)

RICH STRAW KE2

CERN Proton Complex *SPS: more than a LHC injector* SPS LHC The High Energy Frontier P-326 The rarity frontier SPS CNGS

SPARES

FT versus CNGS performance [CERN-HIP Working Group] CNGS request 4.5 1019 pot/year Double batch + Linac4 Without changes P-326 Request J J Double batch

K→p nn : SM Theoretical 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

LKr inefficiency measured with data p+ track and lower energy g are use to predict the position of the other g Cluster not reconstructed Eg = 22 GeV Pion P=42 GeV/c Photon E=11 GeV Expected position K+  p+ p0 selected kinematically Collected tagged g to measure for Eg < 10 GeV using an e- beam and the NA48 DCH’s as active target (Oct ’06)

P-326 Parameters K+ decays per year 1.0x1011 4.8x1012  48 Beam: Present (NA48/2) P-326 Factor wrt 2004 SPS protons per pulse on target 1 x 1012 3 x 1012 3.0 Duty cycle (s./s.) 4.8 / 16.8 1.0 Solid angle (msterad)  0.40  16 40 Av. K+momentum <pK> (GeV/c) 60 75 K+ ~ 1.5 Mom. band RMS: (Dp/p in %)  4  1 ~0.25 Total beam per pulse (x 107) per Effective spill length MHz MHz/cm2 (gigatracker) 5.5 18 2.5 250 800 ~45 (~27) ~24(~15) Eff. running time / yr (pulses) 3 x 105 K+ decays per year 1.0x1011 4.8x1012  48

CERN P-326: K+Decays in flight ~11 MHz n 800 MHz beam p/K/p n