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

OLYMPUS Collaboration Meeting, DESY, April 6-7, 2009
The Time Reversal Experiment
with Kaons (TREK) at J-PARC
Michael Kohl <[email protected]>
Hampton University, Hampton, VA, USA
&
Jefferson Lab, Newport News, VA, USA
TREK/E06
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:
http://trek.kek.jp
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20 Institutions from 6 Countries
CANADA
JAPAN
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
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
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)
VIETNAM
University of Natural Sciences
THAILAND
Kasetsart University
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TREK/E06
90%CL.
90%CL.
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Transverse muon polarization
● K+ ➙π0μ+ν
 Decay at rest
 T-odd correlation
PT≠0 ⇒ T violation
(CPT theorem) ⇒ CP violation
M. Abe et al., PRL83 (1999) 4253
KEK-E246:
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
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KEK-PS E246 experiment: K+→π0μ+ν (Kμ3)
Stopped K+ decay at K5
 Superconducting Toroidal Spectrometer

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E246: Superconducting toroidal magnet
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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
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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
10-4
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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
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Active fiber target: Baseline design
c.f. E246 Ring counters
PSI FAST target
One element
70 – 150
cm
 Light guide :
Cross section
3 x 3 mm
492 fibers
lBicron 692 WLS or
lKuraray Y11 WLS or
lClear optical fiber
 Readout:
SiPMT (HPK MPPC) or
MA-PMT
 Estimated hits in the photon sensor:
~ 7 x107 particles/year
Timing counters
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Active Muon Polarimeter
 10 times more acceptance
 Full angular acceptance for positrons
 Improved field alignment
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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
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C0 Cylindrical GEM for TREK
140 mm
160 mm
300 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:
Rates <250 Hz/mm2 (halo <5 Hz/mm2), total dose: 7 x107 particles
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Tracking upgrade: Geant4
Geant4 studies initiated
in summer 2008
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
Target/C0
C1
C2
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Location of J-PARC
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RCS
n
ＭＬＳＦ
February 22, 2008
Bird’s eye photo in Nov. 2006
Shin'ya Sawada @ TREK
Meeting, KEK
Hd
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Hadron Experimental Hall
Beam
Dump
K1.8
KL
K1.8BR
Production
target (T1)
30~50 GeV
primary beam
T1 target K0.8
C-type
K1.1
S-type
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Timeline
Feb 2005:
April 2006:
July 2006:
Feb 2009:
New collaboration formed
(Japan, Canada, USA, Russia and Vietnam)
Proposal submission
Review by PAC → “stage-1” (scientific) approval
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
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