The Time Reversal Experiment with Kaons (TREK) at J-PARC Hampton University, Hampton, VA, USA & Jefferson Lab, Newport News, VA, USA Michael Kohl OLYMPUS Collaboration Meeting, DESY, April 6-7, 2009

2 TREK/E06 New official website: T ime R eversal violation E xperiment with K aons: Search for New Physics beyond the Standard Model by Measurement of T-violating Transverse Muon Polarization in K +  μ + π 0 ν μ Decays

3 20 Institutions from 6 Countries CANADA University of Saskatchewan Department of Physics and Engineering University of British Columbia Department of Physics and Astronomy TRIUMF Universite de Montreal Laboratoire de Physique Nucleaire USA Massachusetts Institute of Technology (MIT) Laboratory for Nucl. Science & Bates Lin. Acc. Center University of South Carolina Department of Physics and Astronomy Iowa State University College of Liberal Arts & Sciences Hampton University Department of Physics Jefferson Laboratory RUSSIA Russian Academy of Sciences (RAS) Institute for Nuclear Research (INR) JAPAN Osaka University Department of Physics National Defense Academy Department of Applied Physics Tohoku University Laboratory of Nuclear Science High Energy Accel. Research Org. (KEK) Institute of Particle and Nuclear Studies Institute of Material Structure Science Accelerator Laboratory Kyoto University, Department of Physics Tokyo Institute of Technology (TiTech) Department of Physics VIETNAM University of Natural Sciences THAILAND Kasetsart University

4 TREK/E06 90%CL.

5 KEK-E246: P T = ± (stat) ± (sys)‏ ( |P T | < : 90% C.L. )‏ ●K + ➙ π 0 μ + ν Decay at rest T-odd correlation P T ≠0 ⇒ T violation (CPT theorem) ⇒ CP violation Transverse muon polarization M. Abe et al., PRL83 (1999) 4253 M. Abe et al., PRL93 (2004) M. Abe et al., PRD72 (2006)

6 Stopped K + decay at K5 Superconducting Toroidal Spectrometer KEK-PS E246 experiment: K + →π 0 μ + ν (K μ3 )

7 E246: Superconducting toroidal magnet

8 20 cm active length 6 mm ring counters 9 cm diameter 256 fibers 5x5 mm 2 E246: Active target and CsI calorimeter 768 CsI crystals, 75%4  sr 12 muon gaps 25 cm length PIN diode readout

9 Time Reversal Experiment with Kaons  TREK/E06: Upgrade of E246 setup  Reduce systematic errors by factor ~>10 - alignment with data - correction of systematics  Decrease statistical error by factor ~> x higher K + intensity at J-PARC - 10x larger polarimeter acceptance - >1.6x higher polarimeter sensitivity New proposal of P T (K  3 ) at J-PARC 10 -4

10 Upgrade proposal Charged tracking: –Addition of a new element C1 between C2 and TGT/RNG –Replacement of previous C1 chamber by cylindrical GEM –Finer segmentation of TGT fiber; use of helium bags Readout: MPPC (SiPMT) or MA-PMT π 0 detection: –New, faster readout of CsI(Tl): APD, MAPD –Operation of wave form analysis by FADC Muon polarimeter : –Active polarimeter –New magnet with a parallel field

Light guide : l Bicron 692 WLS or l Kuraray Y11 WLS or l Clear optical fiber Readout: SiPMT (HPK MPPC) or MA-PMT Estimated hits in the photon sensor: ~ 7 x10 7 particles/year 3 x 3 mm 492 fibers c.f. E246 Ring counters PSI FAST target Cross section Timing counters One element Active fiber target: Baseline design – 150 cm

12 Active Muon Polarimeter  10 times more acceptance  Full angular acceptance for positrons  Improved field alignment

13 TREK/E06 Tracking Upgrade  Planar GEMs (C1) between CsI and C2  Cylindrical GEM (C0)‏ in replacement of former C1 70 µm 140 µm GEM technology: In collaboration with Hampton U., MIT, and Jefferson Lab

14 C0 Cylindrical GEM for TREK 300 mm 140 mm160 mm  Vertex tracking near target, δ < 0.1 mm  Very high rate capability 25 kHz/mm 2 (COMPASS)  Radiation-hardness 4 x10 10 MIPs/mm 2 (COMPASS)  TREK: Rates <250 Hz/mm 2 (halo <5 Hz/mm 2 ), total dose: 7 x10 7 particles

15 Tracking upgrade: Geant4 Target/C0 C1 C2 GOALS: Realistic geometry of upgraded TREK apparatus Realistic tracking performance Obtain design criteria for Sizes and locations of new elements Intrinsic resolutions for C0 and C1 Angular and spatial resolution of tracks Optimization of material budget Geant4 studies initiated in summer 2008

16 Location of J-PARC

February 22, 2008Shin'ya TREK Meeting, KEK 17 ＭＬＳ Ｆ RCS ＬＩＮ ＡＣ 50GeV-PS Hd Bird’s eye photo in Nov. 2006

18 Beam Dump T1 target K1.8 K1.8BR K1.1 S-type KL K0.8 C-type 30~50 GeV primary beam Production target (T1)‏ Hadron Experimental Hall

19 Feb 2005: New collaboration formed (Japan, Canada, USA, Russia and Vietnam) April 2006:Proposal submission July 2006:Review by PAC → “stage-1” (scientific) approval Feb 2009:First beam in Hadron Facility :R&D and experiment design phase J-PARC PS and HF start operating :Kaon 0.8 beamline, experiment upgrade and commissioning :Start of experiment (1 year)‏ :Analysis and results Timeline