Overview of the KOPIO Detector

2005 RHIC & AGS Users’ MeetingBrookhaven National Laboratory

June 20, 2005David E. Jaffe

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 2

• Poor kinematic signature: 3-body decay

• Neutral initial and final states

• Only outgoing 0 is observable

• SM prediction Br(KL0) = 3x10-11

• Main background is KL0 0 with

Br=9.3x10-4 which implies a need for suppression of >7x107

Observing KL0

“Experimentally, the problems are perhaps best represented by the statement that nobody has shown that a measurement of this decay is absolutely impossible” F.J.Gilman, “CP violation in Rare K Decays”, Blois CP Violations 1989:481-496

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 3

Experimental Search for KL0

E391a using same technique and

is the first dedicated experiment

to search for KL0

KTeV Results using ‘pencil’ beam

PL B447(1999)240.

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 4

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 5

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 6

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 7

Microbunch Width

93 MHz cavity at 22 kV gave= 240 ps

Microbunch time, in ns

93 MHz cavity at 22 kV gave217 ps

Microbunch time, in ns

Data Simulation

SimulationData

Simulations predict = 180ps utilizing

new 25 and 100MHz cavities

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 8

Interbunch ExtinctionInterbunch Extinction

4.5 MHz cavity at 130 kV gave= 8 (+/- 6) x 10-6

Microbunch time, in ns Microbunch time, in ns

Data Simulation

4.5 MHz cavity at 130 kV gave= 1.7 (+/- 0.9) x 10-3.

Data Simulation

Interbunch events

Interbunch events

Extinction performance at high AGS intensities last

remaining issue to be verified

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 9

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 10

ExtrudedScintillator &WLS fibers

Cathode strip drift chambers

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e+

e-

Preradiator – convert & measure properties

64 Layers (4% X0/layer, 2.7 X0) 256 Chambers 288 Scintillator Plates (1200 m2) 150,000 Channels Readout

4m

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 11

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 12

Shashlyk Photon Calorimeter

APD

Shashlyk modules prototyped and tested in beams. Requiredspecs have all been met

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 13

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 14

Every detector is a photon veto!

Fine-sampling lead/scintillator-basedshower counters of shashlyk & bar geometry. All thick enough so punch-through not an issue.

KOPIO PV estimates and simulations based on

BNL E949 measurements supplemented by FLUKA

calculations

1 MeV Visible Energy Threshold

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 15

Catcher: Hadron Blind Beam Veto

beam

420 modules ofPb-Aerogel counter

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 16

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 17

Plastic Scintillator – backed up by vetoes!

185 290

10-5

10-4

10-3

Data

MC

Charged Particle Veto Performance

10-6

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 18

KOPIO technique: work in KL CMS

Measure everything possible

Microbunched KL beam

Measure directions in PR

Measure energy in CAL

Reconstruct 0 from Measure KL velocity from TOF

Photon Veto (PV)

Charged Particle Veto (CPV)

Kinematic veto

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 19

Kinematic Separation of Signal &Backgrounds

Signal BackgroundsPion kinetic energy squared (T*2) vs Ln(Missing Energy)

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 20

Discovering/Constraining New Physics

1st yr2nd yr

3rd yr

KOPIO Proposal

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 21

• Only approved experiment sensitive enough reach the SM level

• Uses a robust innovative technique to suppress background

• Only experiment that measures the area of the unitarity triangle

• Excellent discovery potential for non-SM physics

KOPIO is Unique

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 22

Extras

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 23

BNL scientists and KOPIO

BNL physics dept scientists currently participating on KOPIOD.Beavis: Integration SSM,Vacuum,CDRJ.Frank : CPV STL, CPV constructionD.Jaffe : Sim. SSM, Parameters STL, CDR, 2 students/2004,1

student/2005S.Kettell: Trig/DAQ/Offline/FEE STL, TriggerL.Littenberg: Spokesman,CDR,1student/2004,1student/2005G.Redlinger: DAQ SSM,CDR,PV ineff’y,1student/2004C.Scarlett:CDR,1student/2004,2students/2005M.Sivertz:AGS SSM,CAL/PV STL, CDR, CPVconstruction,

microbunch testbeam,2students/2004,1student/2005STL=Scrub Team Leader for Apr05 NSF reviewCDR=author of chapter(s) in KOPIO Conceptual Design Report for

Apr05 NSF review

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 24

The Challenge of KOPIO

• B(KL0) ~ 310-11, need huge flux of K’s– rates inevitably rather high

• Kinematic signature weak (2 particles undetectable)• Backgrounds with 0 up to 1010 times larger• Veto inefficiency on extra particles must be 10-4

• Huge flux of neutrons in beam– can make 0 off residual gas – require high vacuum

– halo must be very small

– hermeticity requires photon veto in this beam

• Need convincing measurement of background

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June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 25

KOPIO Technique

• High intensity micro-bunched beam from the AGS• Measure everything! (energy, position, angle, time)• Eliminate extra charged particles or photons

– KOPIO: 0 inefficiency < 10-8

• Suppress backgrounds– Predict backgrounds from data:dual cuts– Use “blind” analysis techniques– Test predictions “outside the box”

• Weight candidate events with S/N likelihood function

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 26

• Proton Beam

• 100TP/spill (upgraded from present 70TP)• ~5s spill, 2.3s interspill• Microbunching

• Extract debunched beam resonantly between empty buckets• 25MHz frequency• 200ps bunch width• 10-3 interbunch extinction

• Kaon Beam• 42.5o take-off angle• Soft momentum spectrum

• 0.5-1.5 GeV/c

• 3108 KL/spill• 8% decay

• 10 GHz neutrons

Need AGS to provide

40 ns between microbunches=200 ps

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 27

ExtrudedScintillator &WLS fibers

Cathode strip drift chambers

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

e+

e-

Preradiator – convert & measure properties

64 Layers (4% X0/layer, 2.7 X0) 256 Chambers 288 Scintillator Plates (1200 m2) 150,000 Channels Readout

4m

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 28

Preradiator Angular resolution: 25 mr at 250 MeV/c

Simulations agree with measurements.

KOPIO Prototype Measurements – BNL LEGS Tagged Photon Beams

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 29

Shashlyk Photon Calorimeter

APD

Shashlyk modules prototyped and tested in beams. Requiredspecs have all been met

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 30

Beam test of Calorimeter modulesBeam test of Calorimeter modules

Simulation: Combined PR +CAL Energy Resolution

2.7%

( )E GeV

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 31

Charged Particle Veto in vacuum

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 32

Plastic Scintillator – backed up by vetoes!

185 290

10-5

10-4

10-3

Data

MC

Charged Particle Veto Performance

10-6

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 33

Every detector is a photon veto!

US Wall

Barrel veto

Preradiator

Prerad outer veto

Calorimeter

vetoes in D4 sweeping magnet

vetoes in DS vacuum pipe

Fine-sampling lead/scintillator-based shower counters of shashlyk & bar geometry. All thick enough so punch-through not an issue. All with sufficient efficiency

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 34

E949 Single Ineff’y Measurement

+

2

1

K2 Decay

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 35

KOPIO PV Estimates and Simulations based on improved BNL E949 Measurements supplemented by FLUKA calculations

1 MeV Visible Energy Threshold

Photon Veto Inefficiency

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 36

Catcher: Hadron Blind Beam Veto

Aerogel Counterbeam

420 modules ofPb-Aerogel counter

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 37

Catcher R&D results

Modules prototyped and tested in beams.

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 38

KL modes simulated for bkgnd studies

Largest back-grounds

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 39

Other Backgrounds

• K+ contamination of beam: <0.001 of signal rate

• KLK+e-, K-e+: ~ 0.001 of signal rate

• nN N: negligible production from residual gas in decay volume if pressure<10-6 Torr. Requirements on reconstructed ZV(KL) suppress rate from US wall to <0.01 of signal rate

• n: far smaller than neutron background

• Hyperons: <10-5 of signal rate

• Fake photons < 0.05 of signal rate assuming ~10-3 10-3 suppression from (vetoing) (/n discrimination)

• Two KL giving single candidate: negligible due to vetoes

• (KL X) (e ): ~0.01 of signal rate

• KS 10-4 of KL background rate

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June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 40

Kinematic Separation of Signal &Backgrounds

Signal Backgrounds

Pion kinetic energy squared (T*2) vs Ln(Missing Energy)

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 41

*

ew physics could be revealed K .

:

*

New flavor physics in the sector may be very different from that in the secto b r:

s-d

If B - physics is consistent with the SM

I

N

K would add crucial additional information;

the complexity of the flavor sector beyond the SM

:

is

f deviations from the SM are indicated

foreseen in many models.

Roles of K Measurements in Flavor Physics

Results from will be needed to interpret

non-SM physics discoveries at BABAR, BELLE,

CDF/D0, and the

K

LHC.

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 42

• KTeV (FNAL): B(KL0) < 5.910-7 (90% CL)• KEK E391a >10-9 ?? J-PARC LOI • KOPIO (BNL): single event sensitivity <10-12

– Discovery (5) for B(KL0)>510-11 or <1.8 10-11

– If nothing new, ~300 SM events• Rule out BRs outside of (10.17)BRSM @ 95%CL• Bound operators, B-system can’t access

[ , ] 9Limit based on via iso 1.4 10spin : Grossman NirK x

0 0Experiments Seeking LK 0 0 11LSM: B(K ) (3.0 0.6) 10x

_

_

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 43

KOPIO Parameters

bunch width (extinction) 200ps (10-3)• Beam halo 10-4

• Vacuum 10-7 Torr resolution @ 250MeV 25 mr

• E resolution 2.7%/ E(GeV)

• t resolution 90ps/ E(GeV)

veto inefficiency(outside beam) E949 or better veto efficiency(inside beam) >99% at 300 MeV• n efficiency (inside beam) <0.3% at 800 MeV• Charged particle inefficiency 210-5(+), 1.210-4(-)

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 44

Preradiator

64 Layers (4% X0/layer, 2.7 X0)256 Chambers288 Scintillator Plates (1200 m2)

150,000 Channels Readout

4m

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 45

Primary detection mode: Secondary mode:2 photons covert in preradiator 1 photon in preradiator, 1 in BV

Reconstruct 1st e+e- in “Preradiator”,

Point to K decay vertex in vacuum

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 46

Simulation: Combined PR+ CAL Energy Resolution

2.7%

( )E GeV

Shashlyk Beam Measurements

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 47

Barrel Veto/Calorimeter

• Cylindrical array of 840 modules with 2.5m ID

• Both signal detection and vetoing functions– 1 in prerad + 1 in BV/C

• Modified version of calorimeter shashlyk technology, pmt readout– Energy resolution calculated

to be almost as good as calorimeter

– Time resolution should be comparable

• B V/C lined with thin, high-efficiency, charged particle veto scintillators

US end of barrel sealed by wall of plate shower-counter vetoes

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 48

D4 & downstream vetoes

• Charged & vetoes in D4 sweeping magnet– Field sweeps vertically

• DS vetoes detect ’s emerging from the beam

• Lead/scintillator plate sandwich counters

• Hermeticity completed by catcher veto at the back

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 49

Primary Backgrounds

K * PV2

K * C2 * PV

K * C2

K * PV4

Rejections0 0 0 3L

0 2L

0 0L

0 0 0 0L

10

10

0.93

0.36

0.1255

10Background suppression factor needed: 10

Mode Branching Ratio

K

K

K

K

0 0

Primary Backgrounds

Measurement

x

xe

LK

0.2105

Others

Worst backgrounds are from KL decay

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 50

Simulation Tools

• GEANT3– FLUKA, GCALOR, GHEISHA hadronic packages

• GEANT4

• FLUKA

• MCNPX

• MARS

• KOPTICs – custom optics simulator

• FastMC– uses input from detailed simulators + input from experiments

• Critical parameters directly measured – Either in prototype tests or experiments

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 51

Alternative Display of Results

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 52

KOPIO Operations Plan

• 2010 Test Run – partial detector

• 2011 Engineering Run

“Discovery phase”: Sensitivity goal:~10-10

• 2012-16 Data Acquisition

June 20, 2005 David E. Jaffe 2005 RHIC & AGS Users’ meeting 53

Branching Ratio Measurement Precision

• Precision at B(KL0) = 310-11 Using probability likelihood method employing all observed events (approximately 300) 10%

• (Statistical) Precision on Im t: 5%