DPG - Dortmund 31.03.20061 Dominant K L Branching Ratios, K L Lifetime and V us at KLOE ...

DPG - Dortmund 31.03.2006 1

Dominant Dominant KKL L Branching Ratios,Branching Ratios,

KKL L Lifetime and Lifetime and VVus us at KLOEat KLOE

Introduction - CKM and Vus

- DANE and KLOE KL physics - Branching Ratios - Lifetime - Form Factor - Vus f+(0) Conclusions

Paolo BeltrameIEKP University of Karlsruhe


CKMCKM Matrix and Matrix and VVusus

95% 5% 0.00001%

VubVusVud

1)1(

2/1

)(2/1

23

22

32

AiA

A

iA

VVV

VVV

VVV

tbtstd

cbcscd

ubusud

Couplings parameters between quarks in Weak Interactions, mixing Mass and Weak Eigenstates. Wolfenstein parametrization: four free parameters (, A, , ). Standard Model does not predict the value of any of them.

CKM matrix unitarity: first row |Vud|2 + |Vus|2 + |Vub|2 ~ |Vud|2 + |Vus|2 1 –

Determination of Vus

K0 e,Kl3)semileptonic decays

)1()()0(192

22

3

52

3 EMIKl

usEWK

Kl IfVSMG

F

)1()()0(

192

22

3

52

3 EMIKl

usEWK

Kl IfVSMG

F

•

K0s +u

ve

eVus•

dd


TheThe– Factory– Factory

(1020) – Factory: electron-positron-collider at s = M= 1019.4 MeV

BR( K+K) = 49.1%BR( KSKL) = 34.1%

– Factory K – Factory

KS

K+

KL

K-

The decay at rest provides monochromatic and pure beams of kaons

Tagging: observation of KL(KS) signals presence of KS(KL)-precision measurements of absolute BR’s

KL and KS are well separated: - c (KS) = 6 mm, KS decays near to the interaction point

- c (KL) = 3.4 m, large detector to keep reasonable acceptance for KL decays


The DAThe DANENE– Factory– Factorys = M= 1019.4 MeVLdesign = 5 1032 cm-2 s-1 2004 750 pb-1

2005 1250 pb-1

2001 170 pb-1

2002 280 pb-1

Analysis nearly complete

Data taking at peak finished in 2005 Lpeak= 1.3 × 1032 cms

Ltot 2.4 fb-1

Off-peak run s = 1 GeV finished in March Ltot 250 pb-1


The KLOE detectorThe KLOE detector

Magnetic Field of 0.52 T

Superconducting coil Superconducting coil

Track momentum resolutionp/p 0.4% ( > 45°)Vertex resolutionxy 150 m, z 2 mm

Drift chamber Drift chamber

12582 sense wires52140 wires in total90% He + 10% C4H10

Energy resolution E/E = 5.7%/E(GeV)Time resolution T = 54 ps/E(GeV) 50 ps

Electromagnetic calorimeter

Electromagnetic calorimeter

Lead/Scint fibres 4880 PM


The Tagging methodThe Tagging method

KKSS

KKLL 2 2

KL tagged by KS vertex at IPEfficiency ~70% (mainly geometrical)KL angular resolution: ~1°KL momentum resolution: ~2 MeV

Tagging of KS, KL and K beams allows absolute Branching Ratios measurement:

TBFVseltag

sig α)(

1

N

NBR

LKTB

FVseltag

sig α)(

1

N

NBR

LK

Relies on capability of selecting a tagging kaon independently on the decay mode of the other kaon in the other hemisphere

In fact some dependence on signal mode exists: tag bias TB

Tag bias: carefully measured using MC, and data control samples, typically O(1%)


Dominant Dominant KKLL Branching Ratios Branching RatiosHigh momentum resolution of KLOE DC Ke3, Kµ3, vertex

Tag KL by decay KS Charged decays selected by closing the kinematics at the vertex:

lesser of Pmiss- Emiss

Fit data with linear combination of three MC shapes Radiative corrections included in MC

2001-2002 Data: 328 pb-1 From PDG‘04 Rare KL decays: 0.0036 KL Lifetime: 51.50 nsBR(e+ + + 3KLOE

+ BR(+ ) PDG’04 = 1.0104 0.0076

Imposing (BR x) = 1

KL= (50.72 0.14stat0.36systns

(PmissEmiss) in or hyp

Data

e

(MeV)


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

Dominant KL Branching Ratios results (328 pb-1)

Reasonable agreement with KTeV and NA48 The new results go in the same direction respect to the PDG older values

Phys. Lett. B632 (2006) 43


KKLL Lifetime: direct measurement Lifetime: direct measurement

+

clcl t,x

I.P. 0

L L

LK

Measure the meandecay path

L/c (ns)

6 - 24.8 ns40-165 cm

0.37 L

× 102 Events/0.3 nsPK = 110 MeVExcellent lever

arm for lifetime measurement

KL tagged by KS L and LK obtained from tcl At least three ’s required (LK) ~99% uniform in L 1.3% residual background L(KL) ~2 cm

Average with result from KL BR’s:L

= (50.840.23) ns

Time resolution of KLOE EmC KL

Phys. Lett. B626 (2005) 15

L= (50.920.17stat 0.17syst) ns

DPG - Dortmund 31.03.2006 10

KKe3e3 Form Factor slopes Form Factor slopes

Parametrizations:f(t) = f(0) [1 t]

or f(0) [1 t t2 / 2]

t = (pK - p)2 / m2+

Signal selection: - KLedecays tagged by KS

- Two tracks in fiducial volume forming vertex - Kinematic cuts + ToF PID to reduce background

Fit t distribution + 103

10-3

KTeVISTRA

NA48

KLOE

1 contours

20

10 ),(

j

FSRjjjiji FANN

Linear fit (2/dof ~ 330/363):

+ = (28.6 0.5 0.4) 10-3

Quadratic fit (2/dof ~ 325/362):

+ = (25.5 1.5 1.0) 10-3+ = (1.4 0.7 0.4) 10-3

hep-ex/0601038Submitted to Phys. Lett. B

DPG - Dortmund 31.03.2006 11

VVus us ff++(0) at KLOE(0) at KLOE

Quadratic Form Factor parametrization: KTeV + ISTRA+ = 0.0221 0.0011

+ 0.0023 0.0004

0 = 0.0154 0.0008

KL Lifetime: from KLOEAverage between KL BR’s and direct measurementL

= 50.84(23) ns

Kaon Semileptonic Branching Ratios: all of them from KLOEKLe3 KL3 KSe3 Ke3 K3

BR 0.4007 0.2698 0.00709 0.0505 0.0331

BR 0.0018 0.0012 0.00009 0.0004 0.0005

DPG - Dortmund 31.03.2006 12

ConclusionsConclusions

KLOE can determine the absolute KL Branching Ratios tagging the KL pure beam by means of KS →decaying in the other detector hemisphere

Using 328 pb-1 of 2001 and 2002 data, KLOE has measured the main KL Branching Ratios with relative errors of 0.5% - 1%

Using 400 pb-1 of data collected in 2001 and 2002 , ~106 KL → events, KLOE has performed a direct measurement of KL Lifetime at the level of 0.5%

KLOE has measured the K – vector current parameters using 328 pb-1 of data collected in 2001 and 2002, corresponding to ~2106 of KL →e events

Using Form Factor parameters from KTeV and ISTRA, KL Lifetime determined by KLOE (average between direct and KL BR’s measurements), main KL Branching Ratios (KLe3, KL3, KSe3, K e3, K3): KLOE has extracted Vus f+(0) value with a relative error, on the average, of 0.2%

DPG - Dortmund 31.03.2006 13

Backup slidesBackup slides ... In jeden Quark begäbt er seine Nase

DPG - Dortmund 31.03.2006 14

The Ademollo Gatto theoremAdemollo Gatto theorem: “for strangeness-violating leptonic decays of baryons and mesons: the vector coupling constants (i.e., the limit of the vector amplitudes for vanishing momentum transfer) are uniquely predicted up to first order in symmetry breaking.”

More theoryMore theory

Electromagnetic correction

Virtual corrections Real Bremsstrahlung changes (in addition) significantly the accpetance

Acceptance

100%KLOE MC

%1.0/ radcor

usus VV

DPG - Dortmund 31.03.2006 15

KKLL physics at KLOE: determination of physics at KLOE: determination of VVusus

)1()()0(192

22

3

52

3 EMIKli

usEWK

Kl IfVSMG

F

)1()()0(

192

22

3

52

3 EMIKli

usEWK

Kl IfVSMG

F

Kl3 Partial Decay width – Experiment

Kl3 = BR(KL→l)/KL

SEW Short ElectroWeak Radiative corrections – Theory

Included in Monte CarloEM Electromagnetic corrections and SU(2) corrections – Theory

Included in Monte Carlof+(0) Form Factor at t=0 – Theory

f+(0) theoretical calculationsIKl() Integral over the momentum dependence of the Form Factor – Experiment

IKl() determined by KLOE and other experiments

)0(

)0( 2/1

)(

)( 2/1

2/1

BR 2/1 0

0

K

K

us

us

f

f

I

I

BRV

V

0.5% 0.4% 0.4%

experimental

0.8%

theoretical

DPG - Dortmund 31.03.2006 16

Form Factor parameterizationsForm Factor parameterizations

20,0,0, /1)0()( Mttftf

42''2' 2//1)0()( MtMttftf

200 /1)0()( Mttftf

20,

0, /1

)0()(

Mt

tftf

Linear

Quadratic

Pole

20

10 ),(

j

FSRjjjiji FANN

Fit on t spectrum

Aij Smearing matrix (MC)j Reconstruction efficiencyj “Bare” Ke3 decay densityFj

FSR FSR correction

KTeV

Ke3

- phase space

Ed B

lucher

t

dN/d

tphase space + FF

DPG - Dortmund 31.03.2006 17

Shapes Shapes

Lesser of Pmiss Emiss in or hypotesis (MeV)

DPG - Dortmund 31.03.2006 18

VVus us compared with unitarity and compared with unitarity and VVudud

The value considered for Vud is 0.9740 0.0005 taken from A. Czarnecki, W. J. Marciano, A. Sirlin, Phys. Rev. D70 (2004) 093006

Unitarity Band(1-|Vud|2)·f+(0)

Leutwyler-Roos FFconf. by LatticeNew Vud value

from 0+ 0+

0.9738 ±0.0003

Unitarity Band(1-|Vud|2)·f+(0)

Bijnens-Talavera FF New Vud value

from 0+0+

0.9738 ±0.0003

|Vu

s|

f +K

π(0

)

PDG02 PDG02

DPG - Dortmund 31.03.2006 19

PTPT Leutwyler-Roos (1984) f+(0) = 0.961 0.008 PT + Quark Model (Bijnens-Talavera, 2003) f+(0) = 1 + fp4 + fp6

loop + fp6LR = 0.976 ± 0.010

PT + Dispersion Relations (Jamin-Oller-Pich, 2004) f+(0) = 0.974 0.011 PT + Large NC (Cirigliano-Eidemuller-Kaiser-Pich-Portoles, 2005) f+(0) = 0.984 0.012

Lattice-QCDLattice-QCD (Becirevic-Isidori-Lubicz-Martinelli-Simula-Tarantino-Villadoro)

f+(0) = 1 + fp4+ fp6q = 0.960 ± 0.005stat ± 0.007syst

Kaon Form Factor at zero momentum transferredKaon Form Factor at zero momentum transferred

DPG - Dortmund 31.03.2006 20

Perspectives with 2.5 fb of collected data:• Limit on KS 000 at 10 –8 level

• Competitive measurement of KS +-0

• Ks semileptonic asymmetry to 4 10-3

• Fractional accuracy of < 1% on the BR for KS e and for Kℓ3

• Form factors of KL and K semileptonic decays

• First direct measurement of BR(KS ), accuracy < 2%

• Studies of KSKL system with interference: exploit KLOE’s capability to

CP,CPT mmts

FutureFuture

DPG - Dortmund 31.03.20061 Dominant K L Branching Ratios, K L Lifetime and V us at KLOE ...

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