(Episodio II)

Signal/BackgroundReaction: 0

ee0

ee0

X-section [b]:2.04 10-3

9.87 10-3

0.30 10-3

0. 460.14 10-3

• Most frequent charged decays:BR() = (22.73±0.28) 10-2

BR(0) = (4.60±0.16) 10-2

BR(ee) = (6.8±0. 8) 10-3

09/04/28 2

Analysis versus EVCL

ALLRADRPIKPM

09/04/28 3

• Stream correlation for MC charged RAD investigated: run RAD, RPI & RAD, KPM & RAD & RPI

Selection Criteria (see Marek J. talk)

Event Signature: 2 PNC: |tcl-lcl/c|<5t

Recoil photon: most energetic cluster with E250 MeV 2 tracks closest to IP (using PCA, no vertex requirement)

Kinematical Constraints: Two body decay kinematics to calculate E recoil kinematics to calculate : |Et-Pt|<10 MeV (EtPt) Best Photon: we choose one PNC with <0.2 rad to the calculated

(OPAN)

Main background is 0 (B:S=200:1): M(M

Background hypothesys: in the 0 rest frame cos>-0.98

in the plane versus Egood S/B separation09/04/28 4

509/04/28E(MeV)

Background rejection

Main background is 0 (B:S=200:1): M(M

Background hypothesys: in the 0 rest frame cos in the plane versus Egood S/B separation

calcX

SignalBkg

cos(sys)

SignalBkg

E(MeV)

E(MeV)

: BestPhoton

09/04/28 6

RAD RPI

Black: Pre-SelectedBlue: EtPt +OPAN Green: (PI0) cosRed: (Inside) plane versus E

MeV MeV

MeV

RAD&RPI

: BestPhoton, PI0

09/04/28 7

Black: cos(RAD & RPI)/Selected(RAD & RPI)Red: cos(RAD)/Selected(RAD&RPI)Blue: cos(RPI)/Selected(RAD&RPI)

MeV

: BestPhoton, Inside

09/04/28 8

Black: Inside Cut (RAD & RPI)/ cos(RAD & RPI)Red: Inside Cut (RAD)/cos(RAD&RPI)Blue: Inside Cut(RPI)/ cos(RAD&RPI)

MeV

09/04/28 9

RAD RPI

MMeV) MMeV)

Black: Pre-SelectedBlue: EtPt +OPAN Green: (PI0) cosRed: (Inside) plane versus E

Cossys)

09/04/28 10

RAD RPI

)(cosd

dN

CosCos

Black: Pre-SelectedBlue: EtPt +OPAN Green: (PI0) cosRed: (Inside) plane versus E

RAD+RPI Event Signature Full Selection

Signal : Bkg 1:100 17:1

Signal 58% 42%

Background 53% 2.5 10-4

L (run 2005) = 130 pb-1 N() 105

09/04/28 11

Efficiency study: going on…

Signal/Background

Reaction: () 0

ee0

ee0

X-section [b]:6.04 10-5

8.80 10-5

2.04 10-3

9.87 10-3

0.30 10-3

0. 460.14 10-3

09/04/28 13

Selection Criteria

Event Signature:2 PNC: |tcl-lcl/c|<5t

Recoil photon: less energetic cluster with E>20 MeV (89%)2 tracks closest to IP (using PCA, no vertex requirement)

Kinematical Constraints or Kinematic Fit ?:Two body decay kinematics to calculate E recoilBest Photon: we choose one PNC with <0.2 rad to the

calculated

……..

09/04/28 14

MC Simulation

• V00: official MC only with -contribution

• V01: PMCC using the matrix element as from Gormley et al. [PRD2(1970)]

• V02: PMCC Pure phase space

E(MeV)

09/04/28 15

V00

Comparison with

Background investigation: from we learn how to reject 0 ;

Stream versus two photon invariant mass

M(MeV)

09/04/28 16

V00

E and E

E(MeV)

E(MeV)09/04/28 17

After Pre-Selection

Outlooks…• Work on selection efficiency is going on• Data-MC looks promising

Preliminary investigation on • Selection to be optimize

• Improve MC Simulation? QCD AnomalyPunitary effects via final state interactions:– WZW in the context of HLS

– Chiral unitarity approach Bethe-Salpeter-equation– Omnes function

09/04/28 18

SPARE

09/04/28 19

kinematics to calculate

cos2

22

PE

mmE recoil

().Mcalc

recoilcalc

From 2-body decay E recoil:

From decay we disentangle our control sample: 0

09/04/28 20

Control Sample: 0

0McalcX

recoilcalcX

95.0

clu

i

recoil

Frac

E

EEE

cal

09/04/28 21

MeVMMcalc 15|().| 0

Physics Motivations

Gormley et al. Phys. Rev. D2 (1970) 501

Angular distribution expected

QCD Anomalyunitary effects via final state interactions:

– WZW in the context of HLS

– Chiral unitarity approach Bethe-Salpeter-equation– Omnes function

3

022222

222;sin

q

q

mmmq

mkM

2sin)(cosn

d

dN

09/04/28 22

Past Results: +-

1970-BNL: Gormley et. Al Phys. Rev. D2, 501 (1970)

7250 events spectra agree with simple -dominant model

1973: Layter et. al Phys. Rev. D7, 2565 (1973)

18150 events spectra agree with -dominance of the +- final state

Gormley Layter

09/04/28 23

Past Results: +-1975: A.Grigorian et. al Nucl. Phys. B91, 232 (1975) 474 events1984-TASSO: 130 events 1987-ARGUS: 795 (1990: 2626) events1987-TPC-: 321 events1984-PLUTO: 195 events1990-CELLO: 586 events1992-WA76: 401 events1991-Serpukhov: 2491 events

1997-Crystal Barrel: 7392 events Box Anomaly evidence (independent of any assumption on )

1998-L3: 2123 events well described by resonant contribution (published spectra no background subtracted)

CB

09/04/28 24

Conclusions and Outlooks

KLOEKLOE2: unique opportunity to search for Box Anomaly : analysis with full KLOE data set, good results from

background suppression and promising MC-Data comparison : very very preliminary work on MonteCarlo (toy!),

insert element matrix in GEANFI; analysis with KLOE2 data set • KLOE2 data set ….

09/04/28 25

L =2.5 fb-1 L =2.5 fb-1 L =5 fb-1 L =5 fb-1

P 108 5·105 2x108 106

P + - 5·106 15·104 107 3·105

Efficiency 40%

2·105 6·104 4·105 1.2·105

Efficiency 20%

3·104 6·104