Search for T-violation in stopped kaon decays at J-Parc - PowerPoint

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					   OLYMPUS Collaboration Meeting, DESY, April 6-7, 2009

The Time Reversal Experiment
with Kaons (TREK) at J-PARC
    Michael Kohl <>
      Hampton University, Hampton, VA, USA
      Jefferson Lab, Newport News, VA, USA
        Time Reversal violation Experiment with Kaons:
     Search for New Physics beyond the Standard Model by
                  Measurement of T-violating
      Transverse Muon Polarization in K+  μ+π0 νμ Decays

  New official website:

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

      90%CL.   90%CL.

  Transverse muon polarization
                                              ● K+ ➙π0μ+ν
                                               Decay at rest
                                               T-odd correlation

PT≠0 ⇒ T violation
(CPT theorem) ⇒ CP violation

KEK-E246:                                  M. Abe et al., PRL83 (1999) 4253
PT = - 0.0017 ± 0.0023(stat) ± 0.0011(sys) M. Abe et al., PRL93 (2004) 131601
( |PT | < 0.0050 : 90% C.L. )              M. Abe et al., PRD72 (2006) 072005
KEK-PS E246 experiment: K+→π0μ+ν (Kμ3)

   Stopped K+ decay at K5
   Superconducting Toroidal Spectrometer   6
E246: Superconducting toroidal magnet

E246: Active target and CsI calorimeter
                         • 768 CsI crystals, 75%4 sr
                         • 12 muon gaps

           • 20 cm active length
           • 6 mm ring counters

                      • 25 cm length
                      • PIN diode readout

         • 9 cm diameter
         • 256 fibers 5x5 mm2
New proposal of PT (K3) at J-PARC

Time Reversal Experiment with Kaons
   TREK/E06: Upgrade of E246 setup

   Reduce systematic errors by factor ~>10
       - alignment with data
       - correction of systematics              10-4
   Decrease statistical error by factor ~>20
       - 20x higher K+ intensity at J-PARC
       - 10x larger polarimeter acceptance
       - >1.6x higher polarimeter sensitivity
 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

• π0 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
  Active fiber target: Baseline design
                                                   c.f. E246 Ring counters
One element                                             PSI FAST target
                              70 – 150

Cross section                      Light guide :
                 3 x 3 mm                lBicron 692 WLS or
                 492 fibers              lKuraray Y11 WLS or
                                         lClear optical fiber
                                   Readout:
                                         SiPMT (HPK MPPC) or
                                   Estimated hits in the photon
                                     ~ 7 x107 particles/year         11
   Timing counters
Active Muon Polarimeter

 10 times more acceptance
 Full angular acceptance for positrons
 Improved field alignment
TREK/E06 Tracking Upgrade
                                 GEM technology:
                                 In collaboration with
                                 Hampton U., MIT, and
                                 Jefferson Lab

                                      70 µm
                                       140 µm

  Planar GEMs (C1)
   between CsI and C2
  Cylindrical GEM (C0)
   in replacement of former C1
C0 Cylindrical GEM for TREK

                                   300 mm
   160 mm

            140 mm

 Vertex tracking near target, δ < 0.1 mm
 Very high rate capability 25 kHz/mm2 (COMPASS)
 Radiation-hardness 4 x1010 MIPs/mm2 (COMPASS)

 TREK:                                                              14
  Rates <250 Hz/mm2 (halo <5 Hz/mm2), total dose: 7 x107 particles
 Tracking upgrade: Geant4
Geant4 studies initiated   GOALS:
                            Realistic geometry of upgraded TREK apparatus
  in summer 2008
                            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


Location of J-PARC



  February 22, 2008
Bird’s eye photo in Nov. 2006
                                Shin'ya Sawada @ TREK
                                      Meeting, KEK
                                                        Hd   17
Hadron Experimental Hall



               target (T1)                      K1.1
 30~50 GeV                   T1 target K0.8
primary beam                           C-type

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

2007-2009: R&D and experiment design phase
               J-PARC PS and HF start operating
2010-2011: Kaon 0.8 beamline, experiment upgrade and
2011-2012: Start of experiment (1 year)
2012-2013: Analysis and results