April 12, 2006FPCP -- Vancouver1 Review –KLOE (Frascati) Absolute Branching Ratios Kaon Lifetime Form-Factors –NA48/2 (CERN) Search Direct CP-Violation

April 12, 2006 FPCP -- Vancouver 1

• Review– KLOE (Frascati)

• Absolute Branching Ratios• Kaon Lifetime• Form-Factors

– NA48/2 (CERN)• Search Direct CP-Violation

in K±

• Measurement of scattering length

• RK=(K e ) /(K – E391a (KEK)

• K0→ – KTeV (Fermilab)

• Radiative decays

• Outlook – DANAE– JPARC

• K0L→

– CERN-P-326 (NA48/3)• K→

Review & Outlook, KaonsAugusto Ceccucci/CERN

'

'

'

ub

cb

td

ud us

cd cs

ts tb

V

V

V V

d d

s s

b b

V

V

V

V V

Vus


KLOE@DANE Frascati

e e- K K(K0S K0

L)

• Advantages:– K0

S and K0L tagging

• Measure of absolute BR

– Kaons have definite momentum

• Study of K0S and K0

L semileptonic decays without ambiguities

– Low K momentum• K0

L and K+ lifetimes measurements can be done precisely


KLOE K0L Measurements

BR(K0L) =1 K

L)= (50.72 0.140.33ns

BR(KLe) = 0.4007 0.0006stat 0.0014syst

BR(KL) = 0.2698 0.0006stat 0.0014syst

BR(KL 3) = 0.1997 0.0005stat 0.0019syst

BR(KL) = 0.1263 0.0005stat 0.0011syst

L/c (ns)

6 - 24.8 ns40-165 cm

0.37 L

× 102Events/0.3 nsPK = 110

MeV

Quadratic fit: 1 t/m t/m2

= (25.5 1.5 1.0) 103

= ( 1.4 0.7 0.4) 103

Correlation: (, ) = 0.95Pole model fit: MV = 870(7) MeV

hep

-ex/

0601

038

L = 50.92 0.17 0.25 ns

PLB626 (2005) 15

KL

PLB608(2005) 199

K0L(e3)

Vosburgh et al. ’72:

L = 51.54 ± 0.44 ns


|Vus|f+(0)

0 3

2 5( ) 192

| | (0)(1 )

Lus e

L F K EW K

BR K eV f

G M S IK

Blucher & MarcianoPDG 05 f+(0)=0.961+/-0.008

Leutwyler & Roos

Only KLOE providesBR,L & f.f. (for Ie

K)


NA48/2 (CERN-SPS)

Beam pipe

20032003 run: ~ 50 daysrun: ~ 50 days

20042004 run: ~ 60 daysrun: ~ 60 days

Total statistics in 2 years:Total statistics in 2 years:

• KK + + : ~4: ~4·10·1099

• KK 00 0 0 : ~2: ~2·10·1088

~ ~ 200 TB of data recorded200 TB of data recorded

•400 GeV/c SPS protons•60 GeV/c secondary hadron beams•Simultaneous collection of K+ and K- decays


Direct CP-violation in KK

|M(u,v)|2 ~ 1 + gu + hu2 + kv2

Centre of mass frame

u = 2mK∙(mK/3-Eodd)/m2;

v = 2mK∙(E1-E2)/m2.

• Measured quantity sensitive to direct CP violation:

Slope asymmetry:

Ag = (g+-g-)/(g++g-)≠0

Lorentz-invariantsu = (s3-s0)/m

2;

v = (s2-s1)/m2;

si = (PK-Pi)2, i=1,2,3 (3=odd );

s0 = (s1+s2+s3)/3.

SM estimates vary within an order of magnitude (few 10few 10-6-6…8x10…8x10-5-5). Models beyond SM predict substantial enhancement


Selected Statistics 2003

U

|V|

even pionin beam pipe

Data-taking 2003: 1.61x101.61x1099 events selected

KK+ + : 1.03x10: 1.03x109 9 eventsevents

KK : 0.58x10: 0.58x109 9 eventsevents

odd pionin beam pipe

MM=1.7 MeV/c=1.7 MeV/c22

Events


Stability and Systematics Systematic uncertainties

Effect on Δx104

Acceptance and beam geometry

0.3

Spectrometer alignment 0.1

Analyzing magnet field 0.1

π± decay 0.4

U calculation and fitting 0.2

Pile-up 0.2

Total systematics 0.6

Trigger efficiency: L2 0.5

Trigger efficiency: L1 0.4

Control of Detectorasymmetry

Control of Beamlineasymmetry

Jura Jura (Left)(Left)

A+A+

A- A- SalèveSalève(Right)(Right)

ZZ

XXYY

Achromats: KAchromats: K+ + UpUp

Achromats: KAchromats: K++ DownDown

B+B+

B-B-


NA48/2 (2003 data)K Slope difference:Δg = (-0.7±0.9stat.±0.6stat.(trig.)±0.6syst.)x10-4 = (-0.7±1.0)x10-4

Charge asymmetry:Ag = (1.7±2.1stat.±1.4stat.(trig.)±1.4syst.)x10-4 = (1.7±2.9)x10-4

KSlope difference:Δg = (2.3 ± 2.8stat. ± 1.3trig.(stat.) ± 1.0syst. ± 0.3ext.)x10-4 = (2.2 ± 3.1)x10-4

Charge asymmetry: Charge asymmetry: [using g0=0.638 ]

A0g = (1.8 ± 2.2stat. ± 1.0trig.(stat.) ± 0.8syst. ± 0.2ext.)x10-4 =

(1.8 ± 2.6)x10-4

hep-ex/0602014; PLB 634 (2006)

Order of magnitude improvement


Observation of scattering effect in K→3 decays

1 bin = 0.00015 GeV2

K±±00

4mπ+2

30M events

4mπ+2

NA48/2 has made the first observation the of the charge exchange process +00 in the K00 decay.

M2(00) (GeV/c 2)2

NA48/2PLB 633 (2006) hep-ex/0511056

N. Cabibbo, hep-ph/0405001 PRL 93121801 (2004)

N. Cabibbo and G. Isidori, hep-ph/0502130 JHEP 503 (2005)

~|M0+M1|2


Difference between scattering length in I=0 and I=2 states

(a0 – a2)m+ = 0.268 ± 0.010(stat) ± 0.004(syst) ± 0.013(theor)

In agreement with theory (a0 – a2)m+ = 0.265 ± 0.004 (Colangelo 2001)

NA48/2PLB 633 (2006)

hep-ex/0511056


hep-ph/0511289

NA48/2EPS05

RK=(K e ) /(K


CKM Unitarity and Rare Kaon Decays The unitarity of the CKM matrix can be expressed by triangles in a complex plane. There are six triangles but one is more “triangular”:

VudVub*+VcdVcb*+VtdVtb*=0

Wolfenstein parameterization: Vus ~ Vcb ~ Vub ~ iVtd ~ i

Sensitive to |Vtd|

Im t = 2 5 Re t = 2 5

SM: BR(KSM: BR(K++++) ) (1.6×10(1.6×10-5-5)|V)|Vcbcb||44[[22+(+(cc--))22] ] (8.0 ± 1.1)×10 (8.0 ± 1.1)×10-11-11

BR(KBR(KLL00) ) (7.6×10 (7.6×10-5-5)|V)|Vcbcb||442 2 ± 0.6± 0.6×10×10-11-11


Reminder: K+→+

BR(K+ → + ) = 1.47+1.30-0.89 × 10-10

hep-ex/0403036 PRL93 (2004)

Stopped K+

~0.1 % acceptance

AGS


K0L E391a Upper Limit

BR(K0L )<2.8610-7 90%CL

Preliminary (KAON2005)6 improvement over KTeV one day special run2 improvement over published limit (KTeV Dalitz technique)

10% of RUN I

•Pencil beam •Expected background from K0

L decays: 0.02

•Acceptance: 0.73%

M=M

Require missingPt


Kaon Radiative Decays (KTeV, preliminary)

• K0L

– gM1 = 1.198 +/- 0.035 (stat) +/- 0.086 (syst)

– a1/a2 = -0.738 +/- 0.007 (stat) +/- 0.018 (syst)

– gE1 < 0.21 (90% CL)

• BR(K0L ) < 2.52 10-7 90%CL

• BR(K0L eee,Mee>5 MeV/c2) =

1.606 +/- 0.012(stat)+0.026-0.016(syst)+/-0.045(ext.) 10-5

• BR( ee,X>0.95)=6.56+/-0.26(stat) +/- 0.23(syst) 10-8

• K0L ee

– BR(K0L ee) = 9.25 +/- 0.03(stat) +/- 0.07(syst) +/- 0.26 (ext) 10-6

– CK* = -0.517 +/- 0.030 (fit) +/- 0.022 (syst)

– DIP= -1.729 +/- 0.043(fit) +/- 0.028(syst)

• BR(K0L ) = 1.70 +/- 0.03(stat)+/- 0.04(syst)) +/- 0.03(norm) 10-4

• BR(K0L ee,Eee>20 MeV/c2) = 1.60 +/- 0.18(stat) 10-7


OUTLOOK


DANE Luminosity and plans

• Last KLOE run: 2006• DANE runs until 2008

for other experiments: FINUDA +SIDDHARTA

• Plans for Luminosity and Energy upgrades (DANAE)

CM Energy

(GeV)

1.02 2.4

Peak Luminosity

(cm-2s-1)

1033 1032

DANAE Motivation:•Kaon interferometry•Nuclear Physics•N N form factor•Synchrotron rad.•R&D


Outlook: K0L

• KOPIO @ BNL stopped• In Japan a step by step approach is followed:• KEK:

– E391a has completed data taking (three runs)– They aim to reach the Grossman-Nir bound from the

accumulated data• J-PARC

– A proposal is being prepared for the new J-PARC hadron facility

– Step I: move the E391a detector at J-PARC– Step II: build a new detector and a dedicated beamline to be

able reach ~ 100 SM events


1.0E- 09

1.0E- 08

1.0E- 07

1.0E- 06

E391a Expected sensitivity

1-day 1-week Run-I Run-II Run-III

Sin

gle

Eve

nt S

ensi

tivi

ty

G-N Limit

KTeV Limit (Current Exp. Limit)

From: T. Inagaki


From Taku YamanakaOutlook: K0

L→0From Taku Yamanaka


Proposal to Measure the Rare Decay K at the CERN SPS

CERN, Dubna, Ferrara,Florence, Frascati, Mainz,Merced, Moscow, Naples,Perugia, Protvino, Pisa,Rome, Saclay, San Luis Potosi, Sofia, Turin

CERN-SPSC-2005-013 SPSC-P-326


Setting the bar for the next generation of K+→+ experiments

100 eventsMean=SM

100 eventsMean=E787/949

Current constraint on plane

?

E787/E949: BR(K+ → + ) = 1.47+1.30-0.89 × 10-10


P-326 Detector Layout

75 GeV/c800 MHz beam/K/p

K+

+

~11 MHz

Gigatracker

(KABES)

K


Background rejection

1) Kinematical Rejection

2) Photon vetoes and PID ()

Basic idea to reject K++0 :P(K) = 75 GeV/c

Require P() < 35 GeV/c

P() > 40GeV/c It can be

hardly missed in the calorimeters

2222 ||||||

||1

||

||1 KK

K

KKmiss PP

P

Pm

P

Pmm

Region I: 0 < m2miss < 0.01 GeV2/c

Region II: 0.026 < m2miss < 0.068 GeV2/c4


Gigatracker

26

X/X0 << 1%

Pixel size ~ 300 x 300 m(p)/p ~ 0.4% excellent time resolution

to select the right kaon track

Provide very good time resolution Minimise mass (multiple scattering and beam interactions)Sustain high, non-uniform rate ( 800 MHz total)

PP

K

•Two Silicon micro-pixel detectors (SPIBES)

•Timing•Pattern Recognition

•Improved KABES (micromegas TPC)•To minimise scattering in the last station

SPIBES:

Dependence of the signal to background (from K+ ) ratioas a function of the gigatracker time resolution


LKr inefficiency measured with data

Cluster not reconstruct

edE = 22

GeV

Pion P=42 GeV/c

Photon E=11 GeV

Expected

position

K+ collected by NA48 in 2004 track and lower energy are use topredict the position of the other

+00

LKr ineff. per photon (E > 10 GeV):

= (2.8 ± 1.1= (2.8 ± 1.1statstat ± 2.3 ± 2.3systsyst) × 10) × 10-5 -5

(prel.)(prel.)


Signal & backgrounds from K decays / year*Total Region I Region II

Signal (SM) 65 16 49

K++0 2.7±0.2 1.7±0.2 1.0±0.1

K2 1.2±0.3 1.1±0.3 <0.1

Ke4 2±2 negligible 2±2

K++ and other 3-tracks

bckg.

1±1 negligible 1±1

2 1.3±0.4 negligible 1.3±0.4

K2 0.4±0.1 0.2±0.1 0.2±0.1

Ke3, K3 ,others negligible

Total bkg 9±3 3.0±0.2 6±3•SPS used as LHC injector (so it will run in the future)•No flagrant time overlap with CNGS•P-326 fully compatible with the rest of CERN fixed target because P-326 needs only ~1/20 of the SPS protons•Beam time estimates based on decennial NA48 experience at SPS

*Before taxes. Proposal quotes 40 evt/year @BR=10-10


Status of P-326 (a.k.a. NA48/3)

• Presented at the CERN SPSC in September 2005

• R&D endorsed by CERN Research Board on December 2005

• Beam Test foreseen in August 2006• Seeking more groups to join• Aims to receive full approval by end of

2006….• …to be able to start data taking some time

in 2009-2010


Action is needed to keep KAONS at the heart of Flavour Physics & CP-Violation

Conclusions• The last two years have been MIXED for kaon physics. On the one side

there have been excellent results:

– Vus Renaissence

– Precise bounds on Direct CP-Violation in charged kaon decays

– Progress on K0L

– Some surprises

• BUT on the other side:

– All US-based future programmes have been stopped !!


SPARE SLIDES


Gigatracker (Hybrid Pixel)

• 200 m Silicon sensor (>11 000 e/h mip)

– Following Alice SPD

– Bump-bonding• Read-out chip

– Pixel 300 m x 300 m

– Thinned down to ~100 m (Alice SPD 150 m)

• Beam surface ~ 14 cm2

– Adapted to the size of the SPIBES

r-o chips • ~125 m Cfibre for cooling & support

y

x2mm/bin

2mm

/bin

Station 1(pixels) 2(pixels) 3(FTPC)

G. Anelli, M. Scarpa, S. Tiuraniemi

Front End and R/O considerations based on the experience of the CERN-PH/MIC and PH/ED Groups with the ALICE SPD

MeV


Example: “hadronic” cluster of a photon

Expected position

Maximum energy ~300 MeVExpected energy: ~29 GeVDeposited energy: ~9 GeV

Measured LKr inefficiency per photon (Eg > 10 GeV): = (2.8 ± 1.1= (2.8 ± 1.1statstat ± 2.3 ± 2.3systsyst) × 10) × 10-5 -5 (preliminary)(preliminary)


Acceptance equalisation for K+ and K-

Detector Left-Right asymmetry cancellation in the 4 K+/K ratios:

SD

N ( , ,u)R (u)

N ( , ,u)

A

B

B

A

+

-

+-- -

=

DJ

N ( , ,u)R (u)

N ( , ,

A

u)

B

BA

+

-

- -+-

=

♦

♦

♦

♦

US

N ( , ,u)R (u)

N ( , ,

A

u)

B

BA

+

-

+ +-+

=

JU

N ( , ,u)R (u)

N ( , ,u)

A

B

B

A

+

-

-++ +

=

R(u) = RUS(u)RUJ(u)RDS(u)RDJ(u) = (1 + 4 Δg u)

Fit of R(u) is sensitive only to the time variation of asymmetries in experimental conditionswith characteristic time smaller than corresponding field alternation periods (beam week,detector day) 2003 data taken in 4 SUPER-SAMPLES of 2 weeks each

Quadruple ratio:

Cancellation of systematic biases: - Detector L-R asymmetries ( K+ Salève / K- Salève and K+ Jura / K- Jura ) - Beam line biases ( K+ beam Up / K- beam Up and K+ beam Down / K- beam Down) - Global time-variable biases (K+ and K- simultaneously recorded)

Jura Jura (Left)(Left)

A+A+

A- A- SalèveSalève(Right)(Right)

ZZ

XXYY

Achromats: KAchromats: K+ + UpUp

Achromats: KAchromats: K++ DownDown

B+B+

B-B-


RICH Layout


Downstream straw tracker 6 chambers with 4 double layers of straw tubes each (

9.6 mm) Rate: ~45 KHz per tube (max 0.5 MHz) (+)Low X/X0

Operate in high vacuum

X/X0 ~ 0.1% per view

Good space resolution

130 m / hit

(P)/P = 0.23% 0.005%P() ~ 50 20 rad

Redundant momentummeasurement

2 magnets:270 and 360 MeV Ptkick

8.8

m

7.2

m

7.2

m

5.4

m

Veto for chargednegative particlesup to 60 GeV/c

5 cm radius beam holes displaced in the bending plane according to the 75 GeV/c beam path

z

x

y

2.3

m


P-326 Detector Layout

75 GeV/c800 MHz beam/K/p

K+

+

~11 MHz

Gigatracker

(KABES)

K


NA48 LKr as Photon VetoEnergy of photonsfrom K hitting LKr: > 1 GeV

GeVConsolidation of thesafety/control system and read-out under way


Backgrounds not kinematically constrained

Decay BRK+0e+

(K(Ke3e3))

0.049

KK33 0.033

KK22 5.5×10-3

K+++00

1.5×1

0-3

KKe4e4 4×10-5

KK44 1×10-58% of K+ decays

They span accross the signal regionsMust rely on Particle ID and veto


Beam:

Present K12

(NA48/2)

New HI K+

> 2006

Factor

wrt 2004

SPS protons per pulse on T10 1 x 1012 3 x 1012 3.0

Duty cycle (s./s.) 4.8 / 16.8 1.0

Solid angle (sterad) 0.40 16 40

Av. K+momentum <pK> (GeV/c) 60 75 K+ ~ 1.5

Mom. band RMS: (p/p in %) 4 1 ~0.25

Area at Gigatracker (cm2) 7.0 14 2.0

Total beam per pulse (x 107)

per Effective spill length MHz

MHz/cm2 (gigatracker)

5.5

18

2.5

250

800

60

~45 (~27)

~45 (~27)

~24(~15)

Eff. running time / yr (pulses)

3 x 105 3 x 105 1.0

K+ decays per year 1.0x1011 4.8x1012 48

New high-intensity K+ beam for P-326 AlreadyAvailable

Documents

April 12, 2006FPCP -- Vancouver1 Review –KLOE (Frascati) Absolute Branching Ratios Kaon Lifetime Form-Factors –NA48/2 (CERN) Search Direct CP-Violation