us-japan and the ktev research program at fermilab
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US-Japan and the KTeV Research Program at
Fermilab
R. TschirhartUS-Japan 30th Anniversary Symposium
Kona, HawaiiOctober 20th 2010
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Kaons at the TeVatron• The KTeV experiment was primarily
a comprehensive study of neutral kaon decays, data collected 1996-2000.
• The research program yielded 32 PhD theses and 50 physics publications, most notably the establishment of matter/antimatter asymmetry in particle decay amplitudes.
• This rich research program was largely driven by intense beams of in-flight neutral kaon decays reconstructed with a high-speed , high-resolution spectrometer.
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Context and Prejudice: Flavor Physics in the early
1990’s • Neutrino mixing out of reach??
• What is CP violation? Why is it so small? A new super-weak force??
• The top quark is elusive…..very high mass; does it even exist?
• If the top quark exists and is heavy…new high mass particles can compete in virtual loops in flavor changing neutral currents.
• But…B meson’s are reconstructed only by the handful.
• K mesons can be produced in large numbers, but how can we possibly measure the rare KLgp0p0 neutral mode decay with sufficient precision to search for direct matter anti-matter asymmetries??
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Fast forward…Highlights of KTeV
Science…• Re(e’/e) = (1.66 ± 0.26)×10-3*
• KLg p0ee, p0mm
G(K0→p+p-) - G(K0→p+p-) G(K0→p+p-) + G(K0→p+p-)
= (5.04 ± 0.22) ×10-6 **
Matter/Antimatter asymmetry in a decay amplitude established, Superweak model excluded.Large component of this asymmetry might arise from New Physics.
KTeV limited these rates to x8 and x25 the Standard model rates (10-11 level) for the ee and mm modes….fertile hunting ground for new physics models. * PDG, **J Imazoto
Insert piee/pimumu plot here
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Serendipity: Resolution of the Vud/Vus/Vub non-Unitarity tension by precision measurement of KLgpen
decays.
Enrico Lunghi, LME-2010, Fermilab
2010: KTeV,BNL-865,NA48,KLOE
New Physics models squeezed out beyond the 5 TeV scale
2004: |Vud|2+|Vus|2+|Vub|2 < 1 ??
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
…Our competitors and colleagues…
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Emergence of the “Flavor Problem”
Why don’t we see the Terascale Physics we expect affecting the flavor physics we study today??
4
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
KTeV was the culimanation of the high-energy in-flight program at
Fermilab
University of Chicago Group
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Enabling Collaboration!
1996 KTeV Collaboration meeting at the University of Arizona.
75 collaborators, 32 PhD students, 50 science publications.
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
US-Japan Contributions to KTeV: Unprecedented
photon calorimetry and Trigger & DAQ
Beam view of K0gp0p0 in CsI calorimeter
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
KTeV Pure CsI Calorimeter
• 3100 crystals, 1.9mx1.9m
• 27 X0 deep (50cm)
• 90% of light has 20-nsec component
• Osaka group and US-J developed “collar” veto systems that cleanly defined acceptance.
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Calorimeter Readout
• 5-6 Stage low-gain (x3000) PMTs critical to preserve large dynamic range. Developed by Osaka, Fermilab, and UCLA (Arisaka-san) working closely with Hamamatsu.
• PMTs funded by US-Japan.
• QIE: 16-bit range-
compressed charge integrating pipelined readout (9-bit resolution) operating at 53 MHz local to PMT base, developed by FNAL.
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Delivered EM-calorimetry performance better than 1%
resolution over full physics energy range: Best in the field
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
KTeV CsI Crystals and PMTs continuing great science in the
JPARC E14 KLgp0nn adventureJPARC PAC tour of E14 calorimeter
E14 Calorimeter assembly
KTeV Calorimeter assembly
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
US-Japan largely funded the visionary DAQ that was first in the field to filter
out most events based on full reconstruction
Great science needs great throughput!
Visionary effort led by Yamanaka-san and Nakaya-san
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
The US-Japan@KTeV Legacy
• Established decay-amplitude matter-antimatter asymmetries together with our CERN colleagues.
• Probed many, many rare-decays that have cranked up the tension on the “flavor problem”.
• Substantially advanced the state of the art in precision calorimetry and data acquisition in High Energy Physics.
• Developed next generation leaders in flavor physics and elsewhere.
Ichiro Suzuki, Seattle Mariners: ( 鈴木 一朗 )
Best player in the league-Achieved through systematic high quality team-work and
leadership on the field
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Spares
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
Osaka Unviersity PhDs
• “Study of the Decay KL->pi+-e-+nu e+e- to Probe the Semileptonic K-pi Structure” by Katsushige Kotera, Osaka University, September, 2006.
• "CP Asymmetry in the Decay KL-> pi+pi-e+e-" by Katsumi Senyo, Osaka University, December, 1999.
• "Search for the Decay KL ->pi0 mu+ mu-" by Masayoshi Sadamoto, Osaka University, February 1999.
• "Search for the Decay KL->pi0 nu nu-bar" by Kazunori Hanagaki, Osaka University, August 1998.
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
US-Japan 30th Anniversary Symposium October 20th 2010 R. Tschirhart - Fermilab
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