(Episodio II)
Signal/Background Reaction: 0 e e 0 e e 0 X-section [ b]: 2.04 Most frequent charged decays: BR( ) = (22.73±0.28) BR( 0) = (4.60±0.16) BR( e e ) = (6.8±0. 8) /04/282
Analysis versus EVCL ALL RAD RPI KPM 09/04/283 Stream correlation for MC charged RAD investigated: run RAD, RPI & RAD, KPM & RAD & RPI
Selection Criteria (see Marek J. talk) Event Signature: 2 PNC: |t cl -l cl /c|<5 t Recoil photon: most energetic cluster with E 250 MeV 2 tracks closest to IP (using PCA, no vertex requirement) Kinematical Constraints: Two body decay kinematics to calculate E recoil kinematics to calculate : |E t -P t |<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 E good S/B separation 09/04/284
5 E (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 E good S/B separation Signal Bkg cos ( sys) Signal Bkg E (MeV) E (MeV)
: BestPhoton 09/04/286 RADRPI Black: Pre-Selected Blue: EtPt +OPAN Green: (PI0) cos Red: (Inside) plane versus E MeV RAD&RPI
: BestPhoton, PI0 09/04/287 Black: cos (RAD & RPI)/Selected(RAD & RPI) Red: cos (RAD)/Selected(RAD&RPI) Blue: cos (RPI)/Selected(RAD&RPI) MeV
: BestPhoton, Inside 09/04/288 Black: Inside Cut (RAD & RPI)/ cos (RAD & RPI) Red: Inside Cut (RAD)/cos (RAD&RPI) Blue: Inside Cut (RPI)/ cos (RAD&RPI) MeV
09/04/289 RADRPI M MeV) Black: Pre-Selected Blue: EtPt +OPAN Green: (PI0) cos Red: (Inside) plane versus E
Cos sys) 09/04/2810 RAD RPI Cos Black: Pre-Selected Blue: EtPt +OPAN Green: (PI0) cos Red: (Inside) plane versus E
RAD+RPIEvent SignatureFull Selection Signal : Bkg1:10017:1 Signal58%42% Background53% L (run 2005) = 130 pb -1 N( ) /04/2811 Efficiency study: going on…
Signal/Background Reaction: ( ) 0 e e 0 e e 0 X-section [ b]: 6.04 /04/2813
Selection Criteria Event Signature: 2 PNC: |t cl -l cl /c|<5 t 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 recoil Best Photon: we choose one PNC with <0.2 rad to the calculated …….. 09/04/2814
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) 09/04/2815 V00
Comparison with Background investigation: from we learn how to reject 0 ; Stream versus two photon invariant mass M (MeV) 09/04/2816 V00
E and E E (MeV) E (MeV) 09/04/2817 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 Anomaly P unitary effects via final state interactions: –WZW in the context of HLS –Chiral unitarity approach Bethe-Salpeter-equation –Omnes function 09/04/2818
SPARE 09/04/2819
kinematics to calculate From 2-body decay E recoil: From decay we disentangle our control sample: 0 09/04/2820
Control Sample: 0 09/04/2821
Physics Motivations Gormley et al. Phys. Rev. D2 (1970) 501 Angular distribution expected QCD Anomaly unitary effects via final state interactions: –WZW in the context of HLS –Chiral unitarity approach Bethe-Salpeter-equation –Omnes function 09/04/2822
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) events spectra agree with -dominance of the + - final state Gormley Layter 09/04/2823
Past Results: + - 1975: A.Grigorian et. al Nucl. Phys. B91, 232 (1975) 474 events 1984-TASSO: 130 events 1987-ARGUS: 795 (1990: 2626) events 1987-TPC- : 321 events 1984-PLUTO: 195 events 1990-CELLO: 586 events 1992-WA76: 401 events 1991-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 09/04/2824
Conclusions and Outlooks KLOE KLOE2: 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 …. 09/04/2825 L =2.5 fb -1 L =5 fb -1 P ·10 5 2x P + - 5· · ·10 5 Efficiency 40% 2·10 5 6·10 4 4· ·10 5 Efficiency 20% 3·10 4 6·10 4