22ndnd Kloe Physics Workshop Kloe Physics WorkshopJune 10June 10thth-12-12thth, 2002 Otranto (LE), 2002 Otranto (LE) Status report on Status report on

physicsphysics

F. Ambrosino, T. Capussela,C. Di Donato, F.Perfetto

Status report on Status report on physicsphysics

• Correction factor to the observed cross sections (- paper)

• Dalitz plot

• Study of

• Correction factor to the observed cross sections (- paper)

• Dalitz plot

• Study of

ee++ee-- PP

The correction factor to the observedcross sections due to the interference between the amplitudes A() and A() at s = m

The correction factor to the observedcross sections due to the interference between the amplitudes A() and A() at s = m

R.R.Akhmetshin et al., Phys. Lett. B 434 426 (1998)

ee++ee-- PP

P(s)=

(0)

P(s)=

(0)

VV

FFP(s) s3/2 3

BBPP + + AAVV

22

V

mm33VV mmVV VV e eiiVV

FFP(mm22VV) mm22

VV-s-is VV(s) ••AV=

The Born cross section of the process:

ee++ee-- PP

(0)V = m2

V

12BVe+e-BVP

m2V

(0)V = m2

V

12BVe+e-BVP

m2V

==

e+e-VP

For meson see Gounaris-Sakurai model (Phys. Rev. Lett. 21 (1968) 244)

ee++ee-- PP

P(s)=C•|A+A|2 with P=

P(s)=C•|A+A|2 with P=

= K K=0,95

meas

meas

BR() = (6.100.610.43)•10-5 ++- - 33

(6.700.58 )•10-5 ++- - 77

BR() = (6.100.610.43)•10-5 ++- - 33

(6.700.58 )•10-5 ++- - 77+0.89

-0.92

Dalitz plot Dalitz plot

•

• Topological selection• Kinematic fit

• Fit to dalitz plot: efficiency and resolution study

•

• Topological selection• Kinematic fit

• Fit to dalitz plot: efficiency and resolution study

already done(- paper)

Dalitz variableDalitz variable

X=3(T+-T-)/Q

Y=(3T0/Q)-1

Q = T++T-+T0

X=3(T+-T-)/Q

Y=(3T0/Q)-1

Q = T++T-+T0

X

|M(x,y)|2= N0f(x,y)

Nij=N0ij|M(xi,yj)|2dxidyj

|M(x,y)|2= N0f(x,y)

Nij=N0ij|M(xi,yj)|2dxidyj

Study on resolutionStudy on resolution

X

Study on resolutionStudy on resolution

Y

Relevant for the box anomaly: /decays are dominated by the meson; chiral theory expects an anomalous contribution

Relevant for the box anomaly: /decays are dominated by the meson; chiral theory expects an anomalous contribution

Careful spectral shape measurement

in order to study the anomalous

contribution (Holstein hep-ph/0112150)

BR = 6.16•10-4

• PDG’00: 18K events (’73) L = 200 pb-1 means ~385K events

Careful spectral shape measurement

in order to study the anomalous

contribution (Holstein hep-ph/0112150)

BR = 6.16•10-4

• PDG’00: 18K events (’73) L = 200 pb-1 means ~385K events

Topological selectionTopological selection

• One charged vertex r<4 cm and |z|<8 cm • two prompt neutral clusters

• One charged vertex r<4 cm and |z|<8 cm • two prompt neutral clusters

EE (MeV) (MeV)

=56%=56%

MM (MeV)(MeV)

Main backgroundMain background

EE (MeV) (MeV)

• BR = 15.31%• = 63% S/B = 3.5x10-3

• BR = 15.31%• = 63% S/B = 3.5x10-3

MM (MeV)(MeV)

S/B comparison S/B comparison

EE (MeV) (MeV)

EE (MeV) (MeV)

MM (MeV)(MeV)

MM (MeV)(MeV)

prompt prompt

MM (MeV)(MeV)

cos

cos

coscos

coscos

Background rejectionBackground rejection

M> 500 MeV cos < 0.20

M> 500 MeV cos < 0.20

M M tracks tracks

MM (MeV)(MeV)

= 45%S/B=0.14

= 45%S/B=0.14

Ncut/Ntop

MM (MeV)(MeV)

Background rejectionBackground rejection

MM (MeV) (MeV)

MM (MeV) (MeV)

MM (MeV) (MeV)

M > 200 MeV M < 560 MeV M > 200 MeV M < 560 MeV

MM

(M

eV

) (

MeV

)

M M tracks tracks

MM (MeV)(MeV)

= 45%S/B=2

= 45%S/B=2

Ncut/Ntop

MM (MeV)(MeV)

•A first look at the final statefinal state•Kinematic fit•likelihood to improve S/B without deforme the shape of the distributions

•A first look at the final statefinal state•Kinematic fit•likelihood to improve S/B without deforme the shape of the distributions

ConclusionsConclusions

• - paper submitted

• first look at dalitz plot

• likelihood function either to

improve S/B either to have distribution with shape not biased

• - paper submitted

• first look at dalitz plot

• likelihood function either to

improve S/B either to have distribution with shape not biased

M M tracks tracks

MM (MeV)(MeV)

= 45%S/B=2

= 45%S/B=2