oka experiment for studying rare kaon decays

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


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IHEP, Protvino

OKA collaboration:IHEP, ProtvinoINR, MoscowJINR, Dubna


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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


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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)


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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


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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

+ –


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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


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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


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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


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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


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Physics: T-odd effects


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Status of the experiment


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Status of the experiment: separated beam

Beamline with RF deflector

RF deflector


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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


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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%


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OKA status: active decay volume

• 11m long• Filled with He• sandwich veto counters with fiber readout (~300 channels)


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OKA status: spectrometer

Straw tubes:9mm tubes2 layers140cm x 140cm

Drift tubes:4cm tubes3 layers200cm x 200cm


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OKA status: electromagnetic calorimeter

• 3.8cm x 3.8cm cells• Resolution 5%/√E• ~20 X0

• ~4000 channels


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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


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Spares: separator


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K→


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K→

oka experiment for studying rare kaon decays

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