Future rare kaon decays experiments

Paolo Valente – INFN Roma – Paolo Valente – INFN Roma – 11 BEACH 2006, Lancaster UniversityBEACH 2006, Lancaster University

Future rare kaon decays experimentsFuture rare kaon decays experiments

How will the UT look like in years >2010?…


Why study rare K decays in the LHC era?Why study rare K decays in the LHC era?

Are K rare decays still interesting? Are K rare decays still interesting? More importantly, will it be worth to study them in the years of LHC? More importantly, will it be worth to study them in the years of LHC?

Theory tells us: yes, a few K rare decays are – and will be – still very Theory tells us: yes, a few K rare decays are – and will be – still very interestinginteresting

because:because: There could be more degrees of freedom near the electroweak scale, i.e. There could be more degrees of freedom near the electroweak scale, i.e.

New Physics beyond the SMNew Physics beyond the SM We know very well the flavour mixing, but we still do not understand the We know very well the flavour mixing, but we still do not understand the

underlying mechanismunderlying mechanism

Rare K decays are the ideal toolsRare K decays are the ideal tools


Why study rare K decays in the LHC era?Why study rare K decays in the LHC era?

Rare K decays are the ideal tools:Rare K decays are the ideal tools: Mediated by Mediated by Flavour Changing Neutral CurrentsFlavour Changing Neutral Currents Strongly Strongly suppressedsuppressed by the by the hierarchyhierarchy in the CKM matrix in the CKM matrix Theoretically Theoretically cleanclean since dominated by since dominated by short-distanceshort-distance contributions contributions

In other words, from K rare decays we can extract information on the flavour In other words, from K rare decays we can extract information on the flavour structure of New Physicsstructure of New Physics

ss ddVVtdtdVVtsts**


Flavour mixingFlavour mixing

'

'

'

ub

cb

td

ud us

cd cs

ts tb

V

V

V V

d d

s s

b b

V

V

V

V V

- 3 generations (implying CP violation is possible)3 generations (implying CP violation is possible)- hierarchyhierarchy

Quark mixing is described by the Cabibbo-Kobayashi-Maskawa (CKM) matrixQuark mixing is described by the Cabibbo-Kobayashi-Maskawa (CKM) matrix

Success of the Standard Model: Direct CP violation in the K system: ’ 0 [NA48, KTeV] CP violation in the B sector: ACP(J/ Ks), [BaBar, Belle]

Now we need precise determinations of the CKM parameters: Use observables with small theoretical errors

Im Im tt= Im V= Im Vtsts*V*Vtd td ≠ 0≠ 0


UT fitsUT fits

Constraints from |VConstraints from |Vubub| / |V| / |Vcbcb|, Δm|, ΔmBdBd and Δm and ΔmBsBs compared with constraints from CP violating compared with constraints from CP violating quantities in the K (εquantities in the K (εKK) and in the B (sin2β) ) and in the B (sin2β) sectorssectors

ρ = 0.181 ± 0.060 ρ = 0.181 ± 0.060 η = 0.404 ± 0.035 η = 0.404 ± 0.035

95% confidence regions extracted using 95% confidence regions extracted using |V|Vubub| / | V| / | Vcbcb|, ε|, εKK, Δm, ΔmBdBd, Δm, ΔmBsBs and sin2β and sin2β

ρ = 0.214 ± 0.047 ρ = 0.214 ± 0.047 η = 0.343 ± 0.028 η = 0.343 ± 0.028


KL eeKL vv

UT and rare K decaysUT and rare K decays

KL

K vv

Already strong bounds on the unitarity triangle come from K and B Already strong bounds on the unitarity triangle come from K and B F=2 and tree level transitionsF=2 and tree level transitions FCNC transitions can tell us more…FCNC transitions can tell us more…

Im t = A2 5 Re t = A2 5

Enhanced sensitivity to SM Enhanced sensitivity to SM violations because of strong violations because of strong CKM suppression ~CKM suppression ~5


New Physics potentialNew Physics potential

SecondSecond order weak interactions order weak interactions sensitive to NPsensitive to NP

A A deviationdeviation from the predicted rates of SM would be a from the predicted rates of SM would be a clear clear indicationindication of of NPNP

Complementary program to the highComplementary program to the high--energy frontier:energy frontier:

If [If [WhenWhen!]!] new physics will appear at the new physics will appear at the LHCLHC, rare decays may help , rare decays may help to understand the nature of it to understand the nature of it


New Physics scenarioNew Physics scenario

VVttddVVttss**

ss dd

ss dd

•Is flavour mixing completely Is flavour mixing completely governed by universal CKM matrix?governed by universal CKM matrix?

No extra complex phasesNo extra complex phases

Same operators as in Standard Same operators as in Standard Model, but with different coefficientsModel, but with different coefficients

High correlation between K and B High correlation between K and B rare decaysrare decays

yesyes

Minimal flavour violation (MFV)Minimal flavour violation (MFV)

Extra phases Extra phases

- can lead to large deviations from - can lead to large deviations from SM prediction (especially for the SM prediction (especially for the CP-violating modes)CP-violating modes)

nono

New flavour simmetry breaking, New flavour simmetry breaking, ~ 1 TeV natural scale ~ 1 TeV natural scale


Expected improvements NNLO calculation + reduction parametric CKM Expected improvements NNLO calculation + reduction parametric CKM uncertainties uncertainties 2 % error expected in the next few years 2 % error expected in the next few years

KK++→→++ : SM prediction : SM prediction

The hadronic matrix element can be extracted from theThe hadronic matrix element can be extracted from the well measured Kwell measured K++→→ee++ Small theoretical uncertainty, no long distance contributionsSmall theoretical uncertainty, no long distance contributions

QCD NLOBuchalla,Buras 1999

= C+ A4 [] = (8.0±1.0) 10-11

BRSM(K)


Expect to be completely dominated by parametric CKM uncertainties [VExpect to be completely dominated by parametric CKM uncertainties [V tdtd and and

mmtt] in the next few years] in the next few years

The cleanest mode!The cleanest mode!

KKLL→→00 : SM prediction : SM prediction

BRSM(KL) = C0 [Im(Vts* Vtd)/10-4]2 = (3.0±0.6) 10-11

Already at the level of 2 % Already at the level of 2 %


So, why study rare K decays in the LHC era?So, why study rare K decays in the LHC era?1.1. Search for Search for explicit violation of Standard Modelexplicit violation of Standard Model

Lepton Flavour ViolationLepton Flavour Violation2.2. Study the Study the strong interactions at low energystrong interactions at low energy

Chiral Perturbation Theory, Form FactorsChiral Perturbation Theory, Form Factors3.3. Test fundamental Test fundamental symmetriessymmetries

CP,CPT CP,CPT 4.4. Probe the Probe the flavour sectorflavour sector of the Standard Model of the Standard Model

FCNCFCNC

11stst ingredient: ingredient:

Physics!Physics!

KKLL→→llllKKLL→→KK++→→are the golden modes…are the golden modes…

BR ~ 10BR ~ 10-10-10 or below or belowfew % precision desirable to match the theoretical errorfew % precision desirable to match the theoretical error

Need very intense kaon beamsNeed very intense kaon beams Need dedicated detectors with exceptional background rejectionNeed dedicated detectors with exceptional background rejection

……more more

needed!needed!


Rare K decays panoramaRare K decays panorama

KAMI @FNALpK=10 GeV38M/s

CKM @FNALseparated, pK=22 GeV9 M/s

P940 @FNALunseparated, pK=45 GeV 3.5 M/s

KOPIO @BNLpK=0.7 GeV33 M/s

P326 @CERNunseparated, pK=75 GeV9 M/s

E391a @KEKpK=2 GeV0.6 M/s

E391a @JPARCpK=2 GeV 320 M/s

K

K

E787 @BNLstopped K

E949 @BNL

OKA @Protvinoseparated, pK=15 GeV 0.4 M/s

E949 @JPARCpK=0.6 GeV2.3 M/s

KLOD @Protvino7 M/s

JPARC is coming …JPARC is coming … you’ve heard from Tadashi Nomurayou’ve heard from Tadashi Nomura

I will concentrate on I will concentrate on P326 in the followingP326 in the following


P326: KP326: K→→ at the CERN SPS… at the CERN SPS…

400 GeV protons from the SPS, producing an 400 GeV protons from the SPS, producing an high intensityhigh intensity kaon beam kaon beam

22ndnd ingredient: ingredient:

The beamThe beam


……using part of the NA48 setup…using part of the NA48 setup…

Some pieces [and many physicists] from previous [successful] kaon experimentsSome pieces [and many physicists] from previous [successful] kaon experiments

33rdrd ingredient: ingredient:

A community A community

of physicistsof physicists

44thth ingredient: ingredient:

A suitable detector!

A suitable detector!


……but P326 is also much more!but P326 is also much more!

The P326 project wants to exploit aThe P326 project wants to exploit a combination of opportunitiescombination of opportunities::

1.1. A strongA strong physics casephysics case eagerly waited from theoristseagerly waited from theorists fully complementary to the high-energy frontierfully complementary to the high-energy frontier

2.2. The possibility of having an high intensity kaon beam at the CERN SPS, The possibility of having an high intensity kaon beam at the CERN SPS, using anusing an existing infrastructureexisting infrastructure

3.3. A A communitycommunity of of (enthusiast) (enthusiast) physicists coming from successful kaon physicists coming from successful kaon physics experiments (NA48, KLOE, and more)physics experiments (NA48, KLOE, and more)

4.4. The possibility of using The possibility of using part ofpart of anan high-performance and highly-high-performance and highly-specializedspecialized detectordetector as NA48 [in particular very valuable parts as the as NA48 [in particular very valuable parts as the Liquid Kr, the vacuum tank, the hodoscope, the magnet, the muon Liquid Kr, the vacuum tank, the hodoscope, the magnet, the muon detector, …]detector, …]

… … but it is also a playground for further improving experimental but it is also a playground for further improving experimental techniques for rare kaon decays studies by dedicated R&D studiestechniques for rare kaon decays studies by dedicated R&D studies


Measurement technique: decay in flightMeasurement technique: decay in flight

K

p (GeV/c)

ppK K = 75 GeV/c= 75 GeV/c

At least 10% acceptanceAt least 10% acceptance Signal to background Signal to background 10:1 10:1 80 events in 2 years80 events in 2 years 10101212 rejection power needed rejection power needed Define kinematical cuts ...Define kinematical cuts ...

K

K

2 2 2 2( cos )miss K K K Km EE pm m p


Background rejectionBackground rejection

92% of total background92% of total background

Define a Define a signal regionsignal region Due to KDue to K++ , , split signal region in 2 split signal region in 2

Span across the signal regionSpan across the signal region

Kinematically constrainedKinematically constrained Not kinematically constrainedNot kinematically constrained

8% of total background8% of total background

2 2 2 2( cos )miss K K K Km EE pm m p


Background rejectionBackground rejection

Kinematical cuts Kinematical cuts are not sufficient to are not sufficient to bring down bring down backgrounds by a backgrounds by a factor ~10factor ~101212

Need Need veto veto detectordetectors!s!

RejectionRejection

0.05e

0.03

0.02

0.06

0.21

0.63

BRBRDecayDecay

kin

emat

ics

kin

emat

ics

charged charged

vetoveto

E/pE/p

vetoveto

vetoveto

vetoveto

vetoveto

vetoveto

vetoveto


An experimental challenge!An experimental challenge!

Track and identify kaons in the beamTrack and identify kaons in the beamatat 0.8 GHz0.8 GHz rateratewithwith 0.5%0.5% momentum resolutionmomentum resolutionwithwith 150 ps150 ps time resolutiontime resolutionwith a tight material budgetwith a tight material budget

Track decay productsTrack decay productsin ain a 1010-6-6 mbar mbar vacuumvacuumwithwith 0.5%0.5% momentum resolutionmomentum resolutionwithwith 150 ps150 ps time resolutiontime resolutionwith a tight material budgetwith a tight material budget

Reject Reject and veto additional and veto additional with awith a 1010-5-5 single single detection detection inefficiency inefficiency EE > 1 GeV > 1 GeV

Reject Reject background atbackground at 1010-6-6 levellevel1010 separation at high pseparation at high p

GigaTracker

GigaTracker

+ Cherenkov

+ Cherenkov

Liquid Krypton

Liquid Krypton

+ + vetoes vetoes

Straw tra

cker

Straw tra

cker

+ hodoscope

+ hodoscope

Magnetized

Magnetized

Iron + RICH

Iron + RICH


What is already available: NA48 What is already available: NA48

1996Total: 5.3M KL00

Magnetic spectrometerMagnetic spectrometer

90 m vacuum tank90 m vacuum tank

beambeam

Liquid krypton Liquid krypton EM calorimeterEM calorimeter

HodoscopeHodoscopeMagnetizedMagnetizedIronIron


Experiment layoutExperiment layout

*

*

**m

agn

et

mag

net

*

* Already available

1 m

200 m0 m 100 m

Gigatracker

Notice the ~30:1 aspect ratioNotice the ~30:1 aspect ratio


P326 beamP326 beam

K12 NA48/2

K12

P326

SPS protons/pulse on T10 1×1012 3×1012

Duty cycle (s./s.) 4.8 / 16.8

Solid angle (msterad) 0.40 16

K+ momentum <pK> [band] (GeV/c)

60 [4%] 75 [1%]

Area at Gigatracker (cm2) 7.0 20

Total beam/pulse (107) 5.5 250

[per eff. spill length MHz] 18 800

MHz/cm2 (at Gigatracker) 2.5 40

Eff. run time / year (pulses)

3×105 3.1×105

K+ decays per year

(60 m fiducial region)1.01011 4.8×1012

QuadrupolesQuadrupolesQuadrupolesQuadrupoles

Dipoles Dipoles (1(1stst achromat) achromat)

Muon Muon sweepsweep C

ED

AR

CE

DA

R

Dipoles Dipoles (2(2ndnd achromat) achromat)

GigatrackerGigatracker

ScraperScraper

Col

limat

orC

ollim

ator

Col

limat

orC

ollim

ator

From From T10 targetT10 target

Col

limat

orC

ollim

ator

Almost 50Almost 50×× more kaons with more kaons with presentpresent SPS SPS


Challenge #1Challenge #1

Track and identify kaons in the beamTrack and identify kaons in the beamatat 0.8 GHz0.8 GHz rateratewithwith 0.5%0.5% momentum resolutionmomentum resolutionwithwith 150 ps150 ps time resolutiontime resolutionwith a tight material budgetwith a tight material budget

GigaTracker

GigaTracker

+ Cherenkov

+ Cherenkov

Beam Cherenkov counter already available (CEDAR) Beam Cherenkov counter already available (CEDAR) New photo-detectorsNew photo-detectors Will be tested at SPS North Area in OctoberWill be tested at SPS North Area in October


GigatrackerGigatracker

Specifications: Specifications: Momentum resolution Momentum resolution ~ 0.5 % ~ 0.5 % Angular resolution Angular resolution ~ 10 ~ 10 radrad Time resolution Time resolution ~ 100 ps~ 100 ps Minimal material budgetMinimal material budget Perform all of the above in Perform all of the above in 800 MHz800 MHz hadron beam, hadron beam,

40 MHz/cm40 MHz/cm22

36 mm36 mm

48 m

m48

mm

Station 1Station 1

Station Station 22

Station Station 33

Hybrid Detector:Hybrid Detector: SPIBES (Fast Si micro-pixels)SPIBES (Fast Si micro-pixels)

Momentum measurement Momentum measurement Facilitate pattern recognition in subsequent FTPCFacilitate pattern recognition in subsequent FTPC Timing to select the right trackTiming to select the right track

FTPC (NA48/2 KABES micro-megas with FADC readout)FTPC (NA48/2 KABES micro-megas with FADC readout) Track directionTrack direction


Gigatracker: Si micro-pixelGigatracker: Si micro-pixel

Timing resolution (ps)Timing resolution (ps)

Sig

nal

/Bac

kgro

un

d ra

tio

Sig

nal

/Bac

kgro

un

d ra

tio

size: 36 mm (X) × 48 mm (Y)size: 36 mm (X) × 48 mm (Y) pixel size: 300 pixel size: 300 m × 300 m × 300 mm chip thickness 100 chip thickness 100 mm X/XX/X << 1% << 1% momentum resolution 0.4%momentum resolution 0.4%

Objective: Objective: (t) ~ 200 ps (per station):(t) ~ 200 ps (per station):

Complex readout chip bump-bonded on Complex readout chip bump-bonded on the sensor 0.13 the sensor 0.13 m CMOS technology m CMOS technology (now under development, CERN+INFN)(now under development, CERN+INFN)


Gigatracker: FTPCGigatracker: FTPC

driftE

driftE

Tdrift1

Tdrift2

mmicroicro-m-megasegas

ggap 25 ap 25 mm

Gas TPC + micro-megasGas TPC + micro-megas Coming from NA48/2Coming from NA48/2 R&D on new, fast, readout electronics R&D on new, fast, readout electronics

to improve time resolutionto improve time resolution



Track decay productsTrack decay productsin ain a 1010-6-6 mbar mbar vacuumvacuumwithwith 0.5%0.5% momentum resolutionmomentum resolutionwithwith 150 ps150 ps time resolutiontime resolutionwith a tight material budgetwith a tight material budget

Straw tra

cker

Straw tra

cker

+ hodoscope

+ hodoscopeUncorrelated Non-Gaussian Uncorrelated Non-Gaussian tails due to Non-Gaussian ptails due to Non-Gaussian p

resolutionresolution

MMmissmiss22 (GeV/c (GeV/c22))22

Region IRegion I Region IIRegion II


Straw tracker in vacuumStraw tracker in vacuum 6 chambers with 4 double layers of 6 chambers with 4 double layers of straw tubesstraw tubes 9.6 mm diameter 9.6 mm diameter Rate: ~45 KHz per tube (max 0.5 MHz) (Rate: ~45 KHz per tube (max 0.5 MHz) ())

130 130 m/hit m/hit

(p)/p = 0.23% (p)/p = 0.23% 0.005% p 0.005% p(() ~ 50 ) ~ 50 20 mrad 20 mrad

2 magnets2 magnets270 and 360 MeV P270 and 360 MeV Pt t kickkick

5 cm radius beam holes 5 cm radius beam holes displaced in the bending plane displaced in the bending plane according to the beam path according to the beam path

Redundant Redundant p measurementp measurement

Good resolutionGood resolution

Low massLow mass Operate in high vacuumOperate in high vacuum

X/XX/X00 ~ 0.1% per view ~ 0.1% per view

Veto for charged Veto for charged particles particles up to 60 GeV/cup to 60 GeV/c

8.8

m

7.2

m

7.2

m

5.4

m

2.3

m


TRT ATLAS TRT ATLAS

Straw diameter – 4 mm, length – 40 and 150 cmStraw diameter – 4 mm, length – 40 and 150 cm

17 end-cap wheels are built in JINR (105 kpc of straws)

COMPASS TRACKERCOMPASS TRACKER

Straw diameter – 6 and 10 mm, length up to 3.8 mStraw diameter – 6 and 10 mm, length up to 3.8 m

15 chambers were built in JINR15 chambers were built in JINR

Straw trackers were already operated in vacuum:Straw trackers were already operated in vacuum:

COSY-TOF, Juelich,COSY-TOF, Juelich,

MECO, BNL MECO, BNL

but …but …

Straw tracker in vacuumStraw tracker in vacuum

… … no large straw detector operated in vacuum since nowno large straw detector operated in vacuum since now



Reject Reject and veto additional and veto additional with awith a 1010-5-5 single single detection detection inefficiency inefficiency EE > 1 GeV > 1 GeV

Liquid Krypton

Liquid Krypton

+ + vetoes vetoes


Photon vetoesPhoton vetoes

Large angle vetoes

Large angle vetoes

EE GeV GeV InefficiencyInefficiency

< 0.05< 0.05 11

0.05 ÷ 10.05 ÷ 1 1010-4-4

>1>1 1010-5-5

Liquid K

riptonL

iquid Kripton

EE GeV GeV InefficiencyInefficiency

< 1< 1 11

1 ÷ 31 ÷ 3 1010-4-4

3 ÷ 53 ÷ 5 1010-4-4,10,10-5-5

>5>5 1010-5-5

ANTI: ANTI: Rate ~4 MHz (Rate ~4 MHz ()+ ~0.5 MHz ()+ ~0.5 MHz () (OR of 13 rings)) (OR of 13 rings)

Liquid Kripton: Liquid Kripton: Rate ~7 MHz (Rate ~7 MHz () + ~4 MHz () + ~4 MHz ()+ ~3 MHz ()+ ~3 MHz () )

in vetoin veto

in LKrin LKr

(rad)

(rad)

E (

GeV

)E

(G

eV)


Liquid Kripton calorimeterLiquid Kripton calorimeter

Must achieve inefficiency Must achieve inefficiency < 10< 10-5-5 to detect photons above to detect photons above 1 GeV 1 GeV

Advantages:Advantages: It exists It exists Homogeneous (not sampling) ionization calorimeterHomogeneous (not sampling) ionization calorimeter Very good granularity (~2 Very good granularity (~2 2 cm2 cm22)) Fast read-out (Initial current, FWHM~70 ns)Fast read-out (Initial current, FWHM~70 ns) Very good energy ~1%, Very good energy ~1%, Very good time ~ 300 ps, and position ~1 mm resolutionVery good time ~ 300 ps, and position ~1 mm resolution

Disadvantages:Disadvantages: 0.5 % X0.5 % X00 of passive material in front of active LKr of passive material in front of active LKr

The cryogenic control system needs to be updatedThe cryogenic control system needs to be updated


Veto ringsVeto rings

Set of ring-shaped photon vetoes Set of ring-shaped photon vetoes surrounding the decay tanksurrounding the decay tank

Extensive R&D performed by American and Extensive R&D performed by American and Japanese groups…Japanese groups…… … followed by specialized studies for P326 by followed by specialized studies for P326 by

INFN groupsINFN groups Inefficiency as low asInefficiency as low as 10 10-5-5 challenging but challenging but

possiblepossible Baseline solution: Baseline solution:

Lead/Plastic scintillator sandwich with WLS Lead/Plastic scintillator sandwich with WLS fibers readoutfibers readout

Large contribution to the total cost of the Large contribution to the total cost of the P326 project P326 project

Small angle calorimeters to close the gap of Small angle calorimeters to close the gap of the beam-pipethe beam-pipe

Decay tubeDecay tube



Reject Reject background atbackground at 1010-6-6 levellevel1010 separation at high pseparation at high p

Magnetized

Magnetized

Iron + RICH

Iron + RICH


MAMAgnetized gnetized MUMUon on DDetectoretector

Pole gap is 30Pole gap is 3011 cm11 cm22

Coils cross section 15Coils cross section 1525 cm25 cm22

To provide pion/muon separation and beam sweeping.To provide pion/muon separation and beam sweeping. 150 iron plates, 2 cm thick (260150 iron plates, 2 cm thick (260260 cm260 cm22))

Four coilsFour coils magnetize the iron plates to provide amagnetize the iron plates to provide a 1.3 T dipole field1.3 T dipole field in the beam regionin the beam region Active detector:Active detector:

Strips of extruded polystyrene Strips of extruded polystyrene scintillatorscintillator ( (1144130 cm130 cm33) ) Light is collected by Light is collected by WLS fibers WLS fibers ((1.2 mm diameter1.2 mm diameter)) rejection 10rejection 10-5-5

About 7 MHz of muons and 3 MHz of pionsAbout 7 MHz of muons and 3 MHz of pions


A A RICHRICH for P326 for P326

1 atm Ne gas1 atm Ne gas

18 m18 m

Spherical split mirror, f=17 mSpherical split mirror, f=17 m

PMT’s

PMT’s

PMT’s

PMT’s

18 m long, 1 atm Neon gas18 m long, 1 atm Neon gas 12 GeV threshold for 12 GeV threshold for >3 >3 separation p<35 GeV separation p<35 GeV

beam pipebeam pipe

mirrormirror


P326 collaboration P326 collaboration

Proposal

Proposal S

PS

C-P

-326S

PS

C-P

-326

CERNCERNBeam, CEDAR, Gigatracker (SPiBeS), Beam, CEDAR, Gigatracker (SPiBeS), LKr, Trigger & DAQ, SoftwareLKr, Trigger & DAQ, Software

DubnaDubna Straw trackerStraw tracker

INFN Ferrara, TorinoINFN Ferrara, Torino Gigatracker (SPiBeS)Gigatracker (SPiBeS)

INFN Firenze, PerugiaINFN Firenze, Perugia HodoscopeHodoscope

INFN Frascati, Napoli, Pisa, RomaINFN Frascati, Napoli, Pisa, Roma-veto large angle, Trigger & DAQ, -veto large angle, Trigger & DAQ, SoftwareSoftware

MainzMainz Straw trackerStraw tracker

MoscowMoscow MaMuDMaMuD

ProtvinoProtvino MaMuDMaMuD

SaclaySaclay Gigatracker (KaBeS)Gigatracker (KaBeS)

Saint Luis-PotosiSaint Luis-Potosi RICHRICH

SofiaSofia

-veto small angle-veto small angle


P326 time scheduleP326 time schedule2006-20072006-2007

Refine layout, RICH R&DRefine layout, RICH R&D Gigatracker R&DGigatracker R&D Photon vetoes R&DPhoton vetoes R&D Vacuum testsVacuum tests Straw tracker R&DStraw tracker R&D

Liquid krypton test-beam (Oct. ’06)Liquid krypton test-beam (Oct. ’06)

ApprovalApproval

2008-20092008-2009 Construction, installation and testsConstruction, installation and tests

2010-20112010-2011 Data takingData taking


P326: going on…P326: going on…

We have found a fortunate combination where aWe have found a fortunate combination where a compelling physics casecompelling physics case can be addressed with ancan be addressed with an existing acceleratorexisting accelerator, employing the , employing the infrastructure (i.e. civil engineering, hardware, some sub-systems) of aninfrastructure (i.e. civil engineering, hardware, some sub-systems) of an existing experiment …existing experiment …

… … even though this aeven though this a newnew initiativeinitiative

And with new, challenging detectors to be designed and builtAnd with new, challenging detectors to be designed and built

We are looking for new collaborators!We are looking for new collaborators!


Longer term (more protons needed!)Longer term (more protons needed!)

• KK00LL→→ 00eeeeandand K K00

LL→→ 00

• KK00LL →→ 00

See T. Nomura… E391a and JPARCSee T. Nomura… E391a and JPARC


ConclusionsConclusions Rare K decays Rare K decays areare interesting now, interesting now,

since they are since they are sensitive to New Physicssensitive to New Physics effects effects

They will still be very interesting when results will be coming from the LHC? They will still be very interesting when results will be coming from the LHC? Yes, maybe even more, since they can give unique information on the Yes, maybe even more, since they can give unique information on the flavour structureflavour structure of New Physics of New Physics

Very Very ambitiousambitious experimental programs experimental programs- requiring very requiring very intenseintense hadron hadron beamsbeams - requiring requiring challenging detectorschallenging detectors: hermetic, highly efficient, with PID : hermetic, highly efficient, with PID capabilitiescapabilities

A lively and enthusiastic A lively and enthusiastic communitycommunity- stillstill not tired not tired of many years of success from glorious past kaon of many years of success from glorious past kaon experiments…experiments…- … … even in hard times from the even in hard times from the funding funding point of view! point of view!



KKLL→→00 Purely theoretical error:Purely theoretical error:

2%2% Purely CP-Violating (Littenberg, 1989) Purely CP-Violating (Littenberg, 1989) Totally dominated from t-quarkTotally dominated from t-quark Computed to NLO in QCD ( Buchalla, Buras, 1999)Computed to NLO in QCD ( Buchalla, Buras, 1999) No long distance contribution: No long distance contribution:

SM 3SM 31010-11-11

Experimentally: 2/3 invisible final state !!Experimentally: 2/3 invisible final state !! Best limit from KTeV using Best limit from KTeV using →→eeee decay decay

BR(K0 → ) < 5.9 10-7 90% CL

Still far from the model independent limit: Still far from the model independent limit: BR(KBR(K00 → → ) < 4.4 ) < 4.4 BR(KBR(K++ → → ) ~ 1.4) ~ 1.41010-9-9 Grossman & Nir, PL B407 (1997)Grossman & Nir, PL B407 (1997)


Looking at the far future…Looking at the far future…

A competitive program can start A competitive program can start nownow for charged kaons for charged kaons at the current SPS at the current SPS

For a very competitive neutral kaon decay experiment, For a very competitive neutral kaon decay experiment, ~ 10~ 101313 slowly extracted, high energy protons per second slowly extracted, high energy protons per second would be neededwould be needed


E949E949Stopped K technique ~0.1 % acceptanceStopped K technique ~0.1 % acceptance


2 events E787 + 1 event E9492 events E787 + 1 event E949


E787/E949 resultE787/E949 result

BR(KBR(K→→ = 1.47 = 1.47 +1.30+1.30-0.89 -0.89 1010-10 -10

22 the Standard Model, the Standard Model, but with a large error (3 events…)but with a large error (3 events…)

AGS

hep-ex/0403036 PRL93 (2004)


E391aE391a

CsI calorimeterCsI calorimeter

Front barrelFront barrel Main barrelMain barrel

Vacuum tankVacuum tank

Then going to J-PARC…Then going to J-PARC…


E949 @JPARCE949 @JPARC Stopped KStopped K++

With respect to E787/949:With respect to E787/949: Lower energy Lower energy Separated beamSeparated beam Spectrometer: higher B fieldSpectrometer: higher B field More compactMore compact Better resolutionBetter resolution Finer segmentationFiner segmentation Improved Improved veto detector (crystals) veto detector (crystals)

Objective: Objective: 50 events50 events

Not in J-PARC phase-1Not in J-PARC phase-1 Needs beamline, room, fundingNeeds beamline, room, funding


KLODKLOD

IHEP Protvino 60 GeV proton beamIHEP Protvino 60 GeV proton beam

Off-axis angle=35 mradOff-axis angle=35 mrad

KKLL’s peak momentum = ~6 GeV/c’s peak momentum = ~6 GeV/c

Objective: Objective:

28 events/9 background in 3 years28 events/9 background in 3 years

Run in 2008Run in 2008

Documents

Future rare kaon decays experiments