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Paolo Branchini* on behalf of the KLOE collaboration * Università and INFN ROMA III.

Results from KLOE. Paolo Branchini* on behalf of the KLOE collaboration * Università and INFN ROMA III. 5th International Conference on Hyperons, Charm and Beauty hadrons. Talk outlook:. DA F NE & KLOE K s properties. Results on F decays. DEAR. DA F NE : the Frascati F - factory.

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Paolo Branchini* on behalf of the KLOE collaboration * Università and INFN ROMA III.

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  1. Results from KLOE Paolo Branchini* on behalf of the KLOE collaboration *Università and INFN ROMA III. 5th International Conference on Hyperons, Charm and Beauty hadrons.

  2. Talk outlook: • DAFNE & KLOE • Ks properties. • Results on F decays.

  3. DEAR DAFNE : the Frascati F - factory • DAFNE parameters: now design • number of bunches : 45120 • Bunch spacing : 5.42.7 ns • Bunch current : 20 40 mA • Single bunch luminosity : 10304·1030 cm2 s1 • Daily delivered luminosity : 3pb1

  4. DAFNE performance Data taken from april 1999 to december 2001~ at f peak + 1 energy scan Analysis status: 2000 data ~completed (25 pb-1  7.5 x 107f) Results in publication 2001 data in progress (190 pb-1  5.7 x 108f) Present day performance: peak average L(cm2 s1) 5·1031 3.5·1031 day L dt (pb1)3 1.8

  5. The KLOE detector 4 m diameter × 3.3 m length 90% helium, 10% isobutane 12582/52140 sense/total wires All-stereo geometry Lead/scintillating fiber 4880 PMTs 98% coverage of solid angle sE/E = 5.7% /Sqrt(E(GeV)) st = 54 ps /Sqrt(E(GeV)) 50 ps sp/p = 0.4 % srf= 150 mm sz = 2 mm

  6. p0 gg h  gg KLOE detector performance • s from the b of KL interacting in the EmC • s from Bhabha electrons momenta measurement At current luminosity Dafne energy at 0.01% within 1 minute of data taking using KLb, Bhabha and KS energy mpp = 497.7 MeV/c2 sm= 1 MeV/c2 KSp+p-

  7. e’/e to via double ratio Semileptonic asymmetry (CPT test) KLKS Interferometry First results 2 fb-1 KL form factors, rare KS decays, KL2p, KLgg, K ± decays s(e+e-p+p-) to < 1 % (stat) 200 pb-1 2000 2001 20 pb-1 • KS physics • BR(KS p+p-)/BR(KS p0p0) • BR(KSpen) f radiative decays f f0g, a0g fh’g, hg 2 pb-1 On tape KLOE physics program 1999

  8. K0 mass from f  KSKL, KS  p+p- 1.0 0.8 0.6 0.4 0.2 0.0 Method: f  KSKL , KS  p+p- M2K=W2/4 - P2K W from e+e- invariant mass spectrum; absolute calibration from f - scan (normalizing to CMD-2 Mf value) PKfrom KS  p+p- Result: single event kaon mass resolution ~ 430 keV MK = 497.574 ± 0.005stat± 0.020syst MeV s(e+e- KSKL )(mb) 0.10 0.05 0.00 -0.05 -0.10 Ds (mb) 497.9 497.7 497.5 1015 1020 1025 1030 W (MeV) KLOE NOTE 181 CMD-2 NA48 KLOE

  9. Results on Ks physics tagging of a pure KS beam (unique opportunity of a f-factory). • KL interaction in the calorimeter (ToF signature) •  s measurement • KS “tagging” Analysis of about 20 pb-1 data concentrated on: semileptonic KS decay G(KSp+p-(g)) / G(KSp0p0) • Measurement of KS decays

  10. G(KSp+p- (g)) / G(KSp0p0) Motivations:  First part of double ratio Notice: experiments measure double ratio at 0.1% and the single ratio at 1% KLOE aims to measure each single ratio (KL and KS)at 0.1%  Extractions of Isospin Amplitudes and Phases A0 A2and d0-d2 consistent treatment of soft g in KS p+p- (g) [Cirigliano, Donoghue, Golowich 2000] Selection procedure: 1. KS tagging 2. KS p+p-(g) two tracks from I.P + acceptance cuts: fully inclusive measurement: no request on g in calorimeter e pp(g) eppg(Eg*) from MC  folded to theoretical g spectrum 3.KS p0p0 neutral prompt cluster (Eg>20 MeV and (T-R/c) < 5st ) at least 3 neutral prompt clusters (p0 e+e-g included)

  11. Result (from 17 pb-1): Nev (KS p+p- ) = 1.098 x 106 Nev (KS p0p0 ) = 0.788 x 106 R = 2.239 ± 0.003stat ± 0.015syst  stat. uncertainty at 0.14% level  contributions to “systematic”: tagging eff. Ratio 0.55% photon counting 0.20% tracking 0.26% Trigger 0.23% -------------------------------------- Total syst. uncertainty 0.68% PDG 2001 average is 2.197 ± 0.026 ( without clear indication of Eg*cut ) Notice: efficiencies by data control samples (statistically limited) Goal = reach 0.1% systematic uncertainty [< 2 x 10-4 on Re(e’/e)]. Physics letters B 538 pag 21.

  12. Analysis of KS  pe n decays • Motivation: •  If (CPT ok) .AND. (DS=DQ at work): • G(KS p en) = G(KL p en) BR(KS p en) = BR(KL p en) x (GL/GS) • = ( 6.704 ± 0.071 ) x 10-4 • (using all PDG information). • Only one measurement 75events (CMD-2 1999): • = ( 7.2 ± 1.4 ) x 10-4 b= 1 t 7 ns Preselection onMpe and KS momentum Acceptance and selection efficiency from MC e p/e identification using time-of-flight • Cuts on Ddt(p, e), (e, p), (p, p), e.g.: • Ddt(p,e) =[t1-t2] – [T1(p)exp – T2(e)exp] b 0.8 t 9 ns dedicated to the memory of L. Paoluzi

  13. 2000 After ToF cuts  assignment of electron and pion  Emiss –Pmiss distribution  a clear signal peaked at 0 Result from 17 pb-1 Physics Letter B 535 pag 37 may 2002 BR(KS p en) BR(KS p en) = (6.91 ± 0.34stat ± 0.15syst) x 10-4

  14. Results on f radiative decays: Rad. Decay BR (PDG) hg 1.26% p0g 1.3 x10-3 h’g ~10-4 ppg ~10-4 hp0g ~10-4 f P (0-+) g f  S (0++) g S  pp / hp • Analysis of 2000 data on: • f h’g / hg • f  p0p0g • f  hp0g

  15. f Pseudoscalar + g  hg  h’g According to quark model:  assuming: no other contents (e.g. gluon)) p0 = (uu-dd)/2 h = cosaP(uu+dd)/2 + sinaPss h’ = -sinaP(uu+dd)/2 + cosaPss  assuming: f = ss state (aV=0) (F slowly varying function; model dependent) G(f  h’g) Kh’ R = = cotg2aP ( )3 x F(aP, aV) G(f  hg) Kh • Decay chains used: (same topology 2T + 3 photons / final states different kinematics) • (a) f  hg  p+p-p0g  p+p- 3g • (b) f  h’g  h p+p-g  p+p- 3g

  16. 3 “prompt” g with Eg > 7 MeV and q > 21o.and.2 tracks vertex in IP • Preliminary kinematic fit: conservation of total E, p and b = 1 for eachg • Simple kinematic cuts to eliminate background: • fp+p-p0with extrag fKSKLp+p- p0 p0withglost • negligible background but N(a)N(b)/100 f radiative decays:f  h’g, hg Motivations: Measurement of BR(f h’g)/BR(f hg) gives an accurate determination of pseudoscalar mixing angle. The BR(f h’g) allows to estimate the gluon content of h’. Selection: Used decay chains: a) f  h’g  p+p-hg  p+p-3g b) f  hg  p+p-p0g  p+p-3g the topology is the same: 2 tracks 3 g

  17. f radiative decays:f  h’g, hg KLOE 2000 data BR(f h’g)/BR(f hg) = (5.3  0.5stat 0.3syst) ·10-3 using PDG value for BR(f h g) we obtain: BR(f h’g) = (6.8 0.6stat  0.5syst) ·10-5 (flavor basis) (octet-singlet basis)

  18. 10 8 6 4 2 0 2000 data BR (f  h’g ) x 10-5 CMD-2 SND KLOE Gluonium: comparison of KLOE results on BR (f  h’g ) with previous results (from VEPP-2M) Los Alamos Archive HEPX 0206010 h’ = X h’(uu+dd)/2 + Y h’ ss + Z h’ gluonium Assume Z h’ =0  evaluate X h’ from other channels  evaluate Y h’ from f  h’g Result

  19. radiative g g(fKK) from G(fK+K-) g(f0KK) g(a0KK) f0, a0 model g(f0pp) g(a0hp) M(p0p0) M(hp) spectra f f0,a0 Kaon loop final state f Scalar Meson + g[f0(980) I=0, a0(980) I=1] Precise measurements of BR(ff0g) and BR(fa0g) may distinguish between various models for f0 and a0 mesons : qqqq state, KK molecule, ordinary qq meson. f  f0g , a0g  sensitive to f0,a0 nature [Achasov, Ivanchenko 1989]: phenomenological framework (kaon loop model)  coupling constants For the f0 analysis used f  (f0g) p0p0g , a5g final state. The f  (a0g)hp0gdecay chain was analyzed both in the 5g final state (h gg) and in the very clean 2tracks + 5g final state (h  p+p-p0 )

  20. F Radiative decays: f  f0g , a0 g 5 g final state 1 • 0 • 000 • 00 • 5 “prompt” g with Eg > 7 MeV • | cos| < 0.93 (to avoid background from I.P.) • 5Ei > 700 MeV to reject KLKS neutrals • kinematic fit (4-mom. + |t-r/c| ) |M(1)- M (2)| (MeV) Background sources e+ewp0 w  p0g f  00f  hp0g h  gg f  hg h  gg 3g final state 5g final states M (MeV/c2) h  p0p0p0 7g final state • for (2) and 0 mass • for (1) and (3) two 0 kinematic fit with mass constraint Photon pairing in the hypothesis • 00 • 0 • 000 (M(0)=M()) • 3(rejecting events  and  with E  =363 MeV)

  21. f  p0p0g  5g Result (from 17 pb-1): Nev = 2438  61 BR(f  p0p0g )=(1.09  0.03stat  0.05syst)x10-4 CMD-2 (0.920.080.06)x10-4 SND (1.140.100.12)x10-4 Fit to the Mppspectrum (kaon loop): contributions from f  f0g f  sg + “strong” negative interference negligible contribution f  r0p0 p0p0g Fit results: M(f0) = 973  1 MeV g2(f0KK)/4p = 2.79  0.12 GeV2 g(f0pp) /g(f0KK) = 0.50  0.01 g(fsg) = 0.060  0.008 BR(f  f0g  p0p0g ) = (1.49  0.07)x10-4 Physics Letter B537 pag 21 june 2002

  22. f  hp0g Measured in 2 final states: (Sample 1) h  gg (5g) (Sample 2) h  p+p-p0 (2t + 5g) Results (from 17 pb-1): (Sample1) Nev = 916 Nbck = 309  20 BR(f  hp0g) = (8.5  0.5stat 0.6syst)x10-5 (Sample2) Nev = 197 Nbck = 4  4 BR(f  hp0g) = (8.0  0.6stat 0.5syst)x10-5 CMD-2 (9.02.41.0) x 10-5 SND (8.81.40.9) x 10-5 Combined fit to the Mhp spectra: dominated by f a0g negligible f  r0p0 hp0g Fit results: M(a0) = 984.8 MeV (PDG) g2(a0KK)/4p = 0.40  0.04 GeV2 g(a0hp) /g(a0KK) = 1.35  0.09 BR(f  a0g  hp0g) = (7.4  0.7)x10-5 Physics letter B536 pag 209 june 2002

  23. Summary: KLOE Results on Scalars vs. models. KLOE qqqq qq(1) qq(2) g2f0KK/(4) 2.790.12“super-allowed” “OZI-allowed” “OZI-forbidden” (GeV2) (~2 GeV2) g2a0KK/(4) 0.400.04“super-allowed” “OZI-forbidden” “OZI-forbidden” (GeV2) (~2 GeV2) gf0 /gf0KK 0.500.010.3—0.5 0.5 2 ga0/ga0KK 1.350.090.9 1.5 1.5 • f0parameters compatible with 4q model • a0parameters not well described by the 4q model • (2001 data  more accurate study of a0)

  24. Conclusions: KLOE side: We have a very good detector and we are fully exploiting its main characteristic in the analysis we are doing. We still need an improvement in DAFNE luminosity. DAFNE side: A dramatic improvement in delivered luminosity has been reached since 1999. We believe the latest forseen upgrades will allow DAFNE to reach the ambitious goal of 5*1032 cm-2s-1 Therefore: Stay tuned!!!!

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