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OKA Experiment for Studying Rare Kaon Decays. Status and Prospects. Viacheslav Duk , INR Moscow for collaboration. IHEP, Protvino. OKA collaboration: IHEP, Protvino INR, Moscow JINR, Dubna. Experiments with charged kaons Separated kaon beam at IHEP OKA physics program - PowerPoint PPT Presentation
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V.Duk, INR Moscow Quarks-2008, May 23-29
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OKA ExperimentOKA Experimentfor Studying Rare Kaon Decaysfor Studying Rare Kaon Decays
Viacheslav Duk, INR Moscow
for collaboration
V.Duk, INR Moscow Quarks-2008, May 23-29
2
IHEP, Protvino
OKA collaboration:IHEP, ProtvinoINR, MoscowJINR, Dubna
V.Duk, INR Moscow Quarks-2008, May 23-29
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1. Experiments with charged kaons
2. Separated kaon beam at IHEP
3. OKA physics program
4. Current status of the experiment
5. Conclusions
Contents
V.Duk, INR Moscow Quarks-2008, May 23-29
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Current and future experiments with kaons
In-flight decays Stopped kaons
E06 – J-PARC,K+→μνπ0
E09 – J-PARC, K+ →π+νν
NA62 – CERN, K+
(talk by Augusto Ceccucci)
OKA - IHEP, Protvino, K±
(this talk)
E14(KOTO) – J-PARC, K0
(talk by Mikhail Doroshenko)
V.Duk, INR Moscow Quarks-2008, May 23-29
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Experiments with charged kaons
Studying more rare decays Inreasing presicion
High intensity beams Separated (“Clean”) beams
NA62 OKA
how
experiment
2 strategiesin kaon experiments
Strategies are complementary
V.Duk, INR Moscow Quarks-2008, May 23-29
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Separated beams
Low background from inelastic scattering
Absence of trigger effects
Possibility of fixed target program
Complicated channel
Relatively low intensity
+ –
V.Duk, INR Moscow Quarks-2008, May 23-29
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separated and unseparated beams:complementarity
NA62 OKA
beam
Intensity
~109 5*106
Beam rate 800 MHz 1.1 MHz
Kaons in the beam
~5% ~70%
Duty cycle 30% 22%
% of kaons decaying in decay pipe
13% 9%
Kaon decay rate
520 x 104 7 x 104
V.Duk, INR Moscow Quarks-2008, May 23-29
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RF separated beam at IHEP
Panofsky scheme • Deflectors: largest possible distance• Synchronized em field (3GHz) in deflectors• (-1) optics: pions are deflected in opposite directions• Beam stopper: absorbe pions• Choose momentum: maximal deflection of kaons• Protons also absorbed (mp)2 /(mπ)2 ~ 4
kaon deflection
proton deflection
Nd deflectors are cooled by liquid He, T=1.8K
V.Duk, INR Moscow Quarks-2008, May 23-29
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Physics program at OKA
Baseline: ISTRA+ program
on a larger statistics
The program is being tuned
by latest results from NA48/2, NA62, KLOEMain directions method
ChPT tests, deviations from SM
BR and/or dalits-plot in Kl2,Kl2gamma, Kl3 decays
T-odd effects T-odd asymmetries in 4-body decays
Sgoldstino search K->π π0 P decay: peak in (PK-Pπ-Pπ0)2 distribution
exotica Fixed target program
ISTRA+: 3%(kaons)*2*106=6*104
OKA: 70%(kaons)*5*106=350*104
OKA / ISTRA+ ~60
V.Duk, INR Moscow Quarks-2008, May 23-29
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Physics: ChPT tests, deviations from SM
Search for tensor and scalar terms
K→μνπ0 (Kμ3) and K→eνπ0 (Ke3) decays
aa
ISTRA+: ~500K Kμ3
OKA: ~20M Kμ3
Formafactors in Ke3, Kμ3, Fv and FA in K→μνγ, K→eνγ
V.Duk, INR Moscow Quarks-2008, May 23-29
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Status of the experiment: separated beam
Beamline with RF deflector
RF deflector
V.Duk, INR Moscow Quarks-2008, May 23-29
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Status of the experiment: separated beam
1%
7%
Kaons in the beam
No separator
with separator
Separator status:• commissioned• Worked during 2007 test run• Cleaning in progress
V.Duk, INR Moscow Quarks-2008, May 23-29
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OKA status: beam spectrometer
Beam profile
efficiency
•Beam proportional chambers: 1mm step 20cm X 20cm •Threshold Cherenkov counters
•Beam magnet
σP/P ~ 1%
V.Duk, INR Moscow Quarks-2008, May 23-29
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OKA status: active decay volume
• 11m long• Filled with He• sandwich veto counters with fiber readout (~300 channels)
V.Duk, INR Moscow Quarks-2008, May 23-29
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OKA status: spectrometer
Straw tubes:9mm tubes2 layers140cm x 140cm
Drift tubes:4cm tubes3 layers200cm x 200cm
V.Duk, INR Moscow Quarks-2008, May 23-29
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OKA status: electromagnetic calorimeter
• 3.8cm x 3.8cm cells• Resolution 5%/√E• ~20 X0
• ~4000 channels
V.Duk, INR Moscow Quarks-2008, May 23-29
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RF separated high energy kaon beam at IHEP, Protvino has been constructed and is being commissioned
First stage of OKA setup has been commissioned
First statistics – November 2008
Conclusions