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Hadronic physics at KLOE Salvatore Fiore (on behalf of the KLOE collaboration) Università di Roma “La Sapienza” and sez. INFN Roma. Talk outline. DA F NE and KLOE Scalar Mesons f  f 0 (980) g  p + p - g f  f 0 (980) g  p 0 p 0 g   a 0 (980) g   0   5 

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  1. Hadronic physics at KLOESalvatore Fiore(on behalf of the KLOE collaboration)Università di Roma “La Sapienza” and sez. INFN Roma

  2. Talk outline • DAFNE and KLOE • Scalar Mesons • ff0(980)gp+p-g • f f0(980)gp0p0g •   a0(980)g  0  5  • f (f0+a0)g K0K0g (KsKsgp+p-p+p-g sensitivity evaluation). • Pseudoscalar Mesons • h-h’ mixing angle and h’ gluonic content • h  p+p-0 (dalitz plot fit) • h mass • e+e-p+p- cross-Section below 1 GeV • Kaon physics • B.R. determination and • fit to the pp, hp spectra.

  3. Physics at a f – factory: a window on the lowest mass mesons 0-+ 1-- 0++ (1020) KK  a0(980)  f0(980)  '   r(770)   Direct decay Radiative decay p-emission  f decays give access to light mesons (scalar, pseudoscalar, vector) These processes allow to study the structure of these mesons, in particular their s-quark content via couplings with the f (ss) #events in KLOE data = Br.F. × 8 × 109  ~108h; ~105h’, pp, hp

  4. The DAFNE e+eF-factory f-factory : an e+e- collider with center of mass energy s=m(f)=1019.4MeV • s(e+e f)~3 mb • Separate e+e- rings to reduce beam-beam interactions • crossing angle: 25 mrad • Bunch crossing every 2.7 ns • injection during acquisition integrated Luminosity 2001-5:  L dt = 2.5 fb-1 L peak=1.5×1032 cm-2s-1

  5. The KLOE experiment • Be beam pipe(spherical, 10 cm , 0.5 mm thick)+instrumented permanent magnet quadrupoles(32 PMT’s) • Drift chamber(4 m   3.75 m, CF frame) •  Gas mixture: 90% He + 10% iso-C4H10 •  12582 stereo sense wires •  almost squared cells • Calorimeter •  lead/scintillating fibers (1 mm ), 15 X0 •  4880 PMT’s •  98% solid angle coverage • Superconducting coil(B = 0.52 T)

  6. KLOE detector specifications sE/E = 5.7% /E(GeV) st= 54 ps /E(GeV)  50 ps svtx(gg) ~ 1.5 cm (neutral vertex resolution) sp/p = 0.4 % (tracks with q > 45°) sxhit = 150 mm (xy), 2 mm (z) sxvertex ~1 mm s(Mpp) ~1 MeV

  7. Scalar mesons

  8. Scalar Mesons Mass (GeV/c2) • Scalar Mesons Spectroscopy: • f0(980),s(500) and a0(980) are accessible • through f  Sg (knot accessible) • Questions: • 1. Is s(500) needed to describe • the mass spectra ? • 2. “couplings”of f0(980) and • a0(980) to f  |ss> and to KK, • pp and hp. • allows to investigate the inner structure: 4-quarkvs.2-quarkvs. KK molecule f(1020) 1. a0(980) f0(980) k(800) s(500) 0. I=0 I=1/2 I=1

  9.  +-0  2(1) e+   1(2) e- Previous results f a0(980)g  hp0g KLOE already published f0 and a0 results based on a sample 20 times smaller (20pb-1) than the statistics of the analyses presented in the following (~400pb-1): Old ff0(980)g analysis w background: subtracted assuming no interference with f0 BR fp0p0g= (1.08±0.03stat±0.03syst±0.04norm)x10−4 BR fhp0g : h  gg = (8.51±0.51stat±0.57syst)x10−5 +-0=(7.96±0.60stat±0.40syst)x10−5 Physics Letters B 537 (2002) 21–27 Physics Letters B 536 (2002) 209–216 Old analysis Physics Letters B 536 (2002) 209–216

  10. p g Kaon Loop No Structure p p K+ K- g K- p f0,a0 f0,a0 f f Definition of the relevant couplings (Achasov - Ivanchenko Nucl.Phys.B315(1989)465, Achasov - Gubin Phys.Rev.D63(2001)094007, Achasov - Kiselev Phys.Rev.D68(2003)014006 ) (G.Isidori et al., JHEP0605(2006)049) S to fgfSg (GeV-1) S to kaons gSKK=gSK+K-=gSK0K0 (GeV) f0 to pp (I=0) gf0pp=√3/2 gf0p+p-=√3 gf0p0p0(GeV) a0 to hp (I=1) ga0hp(GeV) Coupling ratio Rf0=(gf0K+K-/ gf0p+p-)2 (S=f0 or a0) Ra0=(ga0K+K-/ ga0hp)2

  11. The p+p-g final state is dominated by: Initial State Radiation Final State Radiation ISR FSR The p+p-ganalysis • Event selection: • 2 tracks with qt>45o; missing momentum qpp>45o (large angle) • pion identification through tracking, Time of Flight and Shower shape • 1 photon matching the missing momentum •  6.7 ×105 events / 350 pb-1 Afb f0(980) signal Events data MC no f0 MC with f0 m(pp) (MeV) m(pp) (MeV)

  12. Fit of the mass spectrum We use 2 different models for the scalar amplitude: Kaon-loop (KL) No-Structure (NS) An acceptable fit is obtained with both models: P(c2)(KL)=4.2% P(c2)(NS)=4.4% P.L.B634 ,148 (2006)  Mass values ok gf0K+K-> gf0p+p- “Large” coupling to the f B.R.(f f0(980)g  p+p-g) = 2.1  2.4 × 10-4 (from integral of |Amplitude|2)

  13. The p0p0ganalysis • Event selection: • 5 photons with qg>21o ; no tracks; • Kinematic fit  energy-momentum conservation; • Kinematic fit p0 masses: choice of the photon pairing to p0’s •  4 ×105 events / 450 pb-1  analysis of Dalitz-plot 2 components in the Dalitz-plot Non resonant Resonant

  14. Dalitz plot fit Models: Improved Kaon-Loop (introducing the fs(500)g) “No Structure” A good fit is obtained with both models: P(c2)(KL)=14% P(c2)(NS)= 4% Comments: • s(500) is neededin KL fit[p(c2) ~ 10-4  14% !] (best s parameters are: M=462 MeV, G=300 MeV – Imposed to the fit); • f0(980) parameters agree with p+p-g analysis KL R > 1 (gf0KK > gf0p+p-) • NS fit gives large gff0g but R<1 (??); • BR extracted:  integral of |scalar amplitude|2 Accepted by EPJC (hep-ex/0609009) With BR( p0p0g) ~ 1/2 × BR(p+p-g) and neglecting KK:  BR(f  f0(980)g) = (3.1 ÷ 3.5) × 10-4 , G(f  f0(980)g) = 1.2 ÷ 1.6 keV

  15. recoil g gKK ga0KK ga0  K+ f a0 K 0 0 ga0 ga0 e+ a0   e- g The hp0ganalysis To extract the relevant a0(980) parameters we fit the M spectrum Two different models exploited: • Kaon loop (5 parameters) Ma0, ga0KK2/(4), ga0π/ga0KK, Br(  π0  π0),  (phase between scalar and vector ampl.) • No structure (8 parameters) Ma0, ga0π,ga0, ga0KK, c0 and c1 (complex) (Achasov - Ivanchenko Nucl.Phys.B315(1989)465, Achasov - Gubin Phys.Rev.D63(2001)094007, Achasov - Kiselev Phys.Rev.D68(2003)014006 ) IN PROGRESS [a0 = (m; ga0π , ga0KK)] (G.Isidori et al., JHEP0605(2006)049)

  16. Analysis scheme • dominant scalar contribution from a0(980) with a0(980)0 (exp. Br  7-8  10-5 – KLOE 2000 data) • vector contribution VP; VP' (V = , P,P' = ,0) (exp. Br  0.3-0.5  10-5 - VDM calculations) •     5  final state • Analyzed sample: Ldt = 424 pb-1 • Pre-selection of 5 photon events • kinematic fit lost or merged photons accidental or split clusters

  17. 7 rejection 20(2nd fit)<24 Signal (a0) 7π0 f0 c2  0 0        |M|-d1 (MeV) 3 event rejection E1+E2+E3 < 980 MeV E1+E2+E3 (MeV) 3 a0 mhp(MeV) d2 d1 ω07 f03 a0 |M(1)- M(2)|=|M| (MeV) 0 rejection M(MeV) Cut: |M|< d1 .OR. |M|> d2 .OR. (ω0)<30° .OR. (ω0)>60°

  18. Background evaluation • We rely on MC simulation for the description of the background shape • and determine the several background components directly on data • A weight (Nfit / Nexpected(MC)) for each process has been determined • from data • data • ω07 • f0 3 Background subtracted 1+cos2

  19. Preliminary results (I) • N - iBi = 13099  172 events •  = 37.9 % • L = (424.0  2.5) pb-1 (0.6 % uncertainty – EPJC47) •  = 3090 nb from () = (40.2  1.0) nb • Br() = (39.38  0.26) % Preliminary Br(0) = (6.70  0.09stat  0.24syst)  10-5

  20. Preliminary results (II) Br(0) Achasov-Ivanchenko Nucl.Phys.B315(1987),465 Achasov-Gubin Phys.Rev.D56(1997),4084 Close-Isgur-Kumano Nucl.Phys.B389(1993),513 Kalashnikova et al., Eur.Phys.J.A24(2005),437 Br(0) = (6.70  0.09stat  0.24syst)  10-5 To extract the relevant a0(980) parameters we have to fit the M spectrum

  21. Kaon loop fit Combined fit: charged and neutral channel () (π+ππ0) Preliminary

  22. Couplings: ga0/ga0KK andf0/a0 ga0/ga0KK  = mixing angle of s and non-s quarks in f0 and  KL – combined gf0KK/ga0KK Kaon loop (f0+) (f000) Achasov-Ivanchenko Nucl.Phys.B315(1987),465 Achasov-Gubin Phys.Rev.D56(1997),4084 Bugg Eur.Phys.J.C47(2006),45 Eur.Phys.J.C47(2006),57 Close-Isgur-Kumano Nucl.Phys.B389(1993),513 Kalashnikova et al., Eur.Phys.J.A24(2005),437

  23. g K+ gKK gf0(a0)KK K0 f0(a0) f K0 K- In progress: • Kaon Loop model:f meson couples to f0(a0) through a charged kaon loop (Achasov,Gubin Phys.Rev.D64:094016,2001) • Linear sigma model:same graph as kaon loop, • different coupling evaluations for gKK and gf0(a0)KK (Escribano, hep-ph/0607325) • Analysis scheme • We look for KSKSg events, with both KS decaying in p+p- • Triggerrequirement • Two Vertices close to IP (regeneration rejection) • # of tracks: two tracks attached to each vertex are required • Cut on KS reconstructed invariant mass and momenta • Cut on E2miss-P2miss

  24. B.R. (10-8) Escribano Achasov Preliminary: efficiency and sensitivity • The preliminary selection efficiency we obtained is 24.2% • The expected number of background events is 7 B.R. sensitivity: 7.5·10-8 @ 90%C.L with 420 pb-1 MC sample Evaluated according to: G. J. Feldman and R. D. Cousins, Phys. Rev. D57 (1998) 3873 Preliminary

  25. Pseudoscalar mesons

  26. BR(fhg)/BR(fhg):Motivations of this analysis • BR(fhg) can probe the ss and gluonium content of h • The ratio R= BR(fhg)/BR(fhg) can be related to the h-h mixing parameters and determine the mixing angle in the flavor basis P, the best parameter for a description of the mixing • The two mixing parameter, has emerged from EcPT and phenomenological analyses, in the flavor basis are equal apart from terms which violate OZI-rule Method: measurement of using similar h and h’ decay chains: p+p-7g for the h’, 7g for the h

  27. Br()/Br() with PDG BR() 427 pb-1 (’01-’02 data) N(hg) = 1665000  1300 (no bck) N(p+p-7g’s) = 375060 (Nbckg= 345) N(h´g) = 3405 ± 61stat±28syst h signal (no bck) h’ signal (~10% bck) Submitted to PLB (hep-ex/0612029) Systematics are dominated by knowledge of h,h’ branching ratios Previous KLOE results Phys. Lett. B541 (2002)

  28. Y‘ P X‘  gluonium content • Using the approach by Bramon et al. [Eur. Phys. J. C7, 271(1999)] • and introducing a possible gluonium content via cos2G • one can extract the -’ mixing angle P : • Combined analysis to evaluate • possible gluonium content of ’ • (4 constraints in X-Y-plane) Submitted to PLB (hep-ex/0612029) Black line: imposing Z=0 (sinfg)2=Z2=0.14 ± 0.04

  29. + - 0 analysis The 3decay issensitive to isospin symmetry breaking due to light quark mass difference mu md. The amplitude decay A(X,Y) is expanded around the center of the Dalitz-plot as: A(X,Y)2 ≈ 1 + aY + bY2 + cX+ dX2+eXY + fY3 with:

  30. Preliminary + - 0results Nevents = 1.377 Mevts (450 pb-1) a b d f a 1 -0.226 -0.405 -0.795 b 1 0.358 0.261 d 1 0.113 f 1 correlation matrix Fitting with the C-violating parametersc and e left free we obtain: • From our preliminary results (hep-ex/0410072) (B. V. Martemyanov and V. S. Sopov, Phys. Rev. D 71 (2005) 017501) Q2h = 22.8  0.4 • Using Dashen rule J. Kambor, C. Wisendanger and D.Wyler, Nucl. Phys. B 465 (1996) 215 Q2D= 24.2 • Large NC evaluation confirms deviation from Dashen rule: Q2LNC= 22.0 ± 0.6

  31. 3g Dalitz-plot p0 h Measurement of theh(andp0) masses • Two recent measurements done with different techniques: • GEM (COSY) p+d  3He+h  M(h)=(547311 ± 28 ± 32) keV/c2 (missing mass technique) • NA48 (CERN) p-+p n+h  M(h)=(547843 ± 30 ± 41) keV/c2 (h 3p0 reconstruction) • 8 s discrepancy: dM(h)=(532 ± 41 ± 52) keV/c2 (errors added in quadrature) KLOE: ;  check with 0; 0 Technique: kinematic fit mostly based on photon positions and timing;  energy-momentum and vertex positionfrom large angle Bhabha scattering The p0 and the h peak are well defined Mass (MeV)

  32. KLOE NA48 GEM h mass (MeV) Preliminary results • The statistical uncertainty is ~negligible • Systematic uncertainties from knowledge of s and vertex position • (work in progress to reduce it) The h mass is in agreement with NA48 and in disagreement with GEM M(h) = ( 547822  5stat  69syst ) keV Preliminary The p0 mass is well in agreement with PDG value M(p0)KLOE = ( 134990  6stat 30syst ) keV M(p0)PDG = ( 134976.6  0.6 ) keV

  33. e+e-p+p- cross-Section below 1 GeV

  34. Motivation fors (e+e- p+p-) • Hadronic contribution aµhadr is limiting the standard model prediction for (g-2)µ ! aµhad is estimated by means of a dispersion relation (intrinsically ~1/s2): • Experimental input into dispersion integral at low energies where • pQCD is not applicable • Dominant channel below 1 GeV is e+e- r p+p-, which • contributes with ca. 70% to the total value of aµhad • s(e+e- p+p-) needed with  1% precision!

  35. gISR r0 ds(e+ e- hadrons + gISR) dMhadr Mhadr s(e+ e- hadrons) H(Mhadr) (e+e-+-) with ISR: Modern particle factories, such as DAFNE are designed for a fixed center-of-mass energy: s = mf = 1.02 GeVin the case of DAFNE Energy-scan not possible! Complementary approach: Consider events with Initial State Radiation (ISR) S. Binner, J.H. Kühn, K. Melnikov, Phys.Lett. B459 (1999) 279 • Requires precise calculations of the radiator H • Requires precise understanding of effects from Final State radiation (FSR) H. Czyz, A. Grzelinska, J.H. Kühn, G. Rodrigo, Eur. Phys. J. C33 (2004), 333 Pancheri, Shekhotsova, Venanzoni, Phys. Lett. B642, (2006) 342

  36. s (e+e- p+p- ) nb 1400 1200 1000 800 600 400 200 Mpp2 (GeV2) 0.3 0.4 0.5 0.6 0.7 0.8 0.9 First published result: Contrib. to syst. error on ahad: Published Result: Phys. Lett. B606 (2005) 12 KLOE 2001 Data 140pb-1 Statistical error negligible (1.5 Million events)

  37. Work in progress on d /dM2: • A new analysis is carried out at small photon angles using 2002 data (240pb-1) • with improved machine background and calibration conditions. This alone should allow for a reduction of the total systematic error on to <1%. • In addition, one can extract (e+e-+-) by performing a normalization with muon events: • many effects cancel in the ratio: • Vacuum Polarisation • Luminosity • Radiator function • Analysis with photons detected at large angle allows us to access the 2-pion-threshold region. Main limitation is caused by the contribution from model dependent effects of decays (f0 , ) and Final State Radiation from pions. - Interference •  Estimate these effects from MC: • PHOKHARA • [EPJ C47(2006) 617] • Pancheri/Shekhovtsova/Venanzoni • [PLB 642 (2006) 342]

  38. Hadronic physics analyses at KLOE: fp+p-p0 Dalitz plot analysisPLB 561(2003) 65 ff0gp+p-gf0 coupling to f, pp, KKPLB 634(2006) 148 ff0gp0p0g BR(fp0p0g) to 5% PLB 537(2002) 21 PDG06 Dalitz plot analysis, stat/syst improvementsaccepted by EPJ fwp0p0p0g Dependence of svis on √s Preliminary fh p0 g BR(fa0(980) g) to 10% PLB 536(2002) 209 stat/syst improvementsPreliminary fh'g(hg)G(f h'g )/ G (f hg ) to 12%, mixing angle to 5% PLB 541(2002) 45PDG06 stat/syst improvementsPreliminary hggh mass measurementPreliminary hp+p+p0h mass measurement,Dalitz plot analysisPreliminary hp0p0p0Dalitz plot analysisPreliminary hp0 g gBR, mgg spectrum Preliminary hp+p- Upper Limit on BR at 10-5 PLB 606(2005) 276PDG06 hggg Upper Limit on BR at 10-5 PLB 591(2004) 49PDG06 e+e- p+p- gam |had (0.35 < sp< 0.95 GeV2) to ~ 1% PLB 606(2005) 12 am |had down to threshold, m+m-g normalizationPreliminary e+e- e+e- (m+m-) Glept(f) to 1.5% and lepton universality test PLB 608(2005) 199PDG06 etc…

  39. Kaon physics • Of course, the main effort of the KLOE collaboration is on • Kaon physics: • Extraction of the Vus element of the CKM matrix from 5 semi-leptonic decays of neutral and charged kaons  test of CKM Unitarity • CPT tests: first measurement of KS semi-leptonic asymmetry • Kaon interferometry in p+p-p+p- final states:  bounds on quantum coherence + CPT violation • Reduced upper bound on KSp0p0p0CP violating decay • Precision measurement of KS p+p-(g)/ KSp0p0 • Measurement of KL and KSggChPT test • Measurement of KL and K±lifetime • Measurement of KL and K± main B.R.s

  40. Recent Kaon analyses: KS KL  p+p-p+p- Quantum Interference PLB 642 (2006) 315 CP and CPT violation Bell-Steinberger rel. + KLOE data Accepted by JHEP KS p0p0p0UL on BR at 10-7 PLB 619 (2005) 61 PDG06 KS penBR to 1.3%, form factor slope, charge asymmetry PLB 636 (2006) 173PDG06 KS  p+p-, p0p0G(p+p-)/G(p0p0)to ~0.25% Accepted by EPJCPDG06 KL pln, pppAbsolute BR’s to ~ 0.5% PLB 632 (2006) 43PDG06 KL lifetime from S(BR)=1 KL lifetimefrom KLp0p0p0 to ~ 0.5% PLB 626 (2005) 15PDG06 KL penForm factor slopes PLB 636 (2006) 166PDG06 KL pengBR to ~ 2 % Preliminary KL  p+p-BR to 1.1% PLB 638 (2006) 140PDG06 KL  g g G(g g)/G(p0p0 p0) to 1.1% PLB 566 (2003) 61 K+p+p0p0 BR to 1.4% PLB 597 (2004) 139 K+ m+nAbsolute BR to ~ 0.27% PLB 632 (2006) 76PDG06 K± p0l±n Absolute BR’s to ~ 1.5% Preliminary K± lifetime two independent measurements Preliminary etc…

  41. Off-peak data 2 fb-1 What's next? • Measurement of  without resonant background from  • Determination of f0 and FSR parameters • (e+e-0) vs. s • Search for (600) with off-peak data using the reaction  Hadronic physics • Combined fit of both charged and neutral  final states and searches for f0/a0 KK • Single and Double Dalitz  decays,   ,decays • ... • Measurement of BR(KSBR(KSee • Improve on UL(KSUL(KS ee • Improve on semileptonic BRs, lifetimes and form factors • BR(KL) to few 10-3 • (K±e± )/(K± ± ) to few 10-2 • … Kaon physics 2 fb-1

  42. What's next? KLOE2 A new scheme to increase DAFNE luminosity by a factor O(5) has been proposed by P.Raimondi (crab waist collisions) – test in autumn 2007 If successful a new round of measurements with an improved KLOE detector could start in 2009 The KLOE detector has proven to well face the challenge, nevertheless something can be improved: add an inner tracker add a tagging system for e+e-e+e- increase the EMC read-out granularity update / upgradethe data acquisition

  43. What's next? KLOE2 • Time evolution of entangled kaon states, reach the sensitivity to the Planck scale: tests of CPT-symmetry and quantum mechanics • e universality (K e / K  ) and the mass of the muon neutrino • universality of the weak coupling to leptons and quarks, CKM matrix unitarity • rare KS decays (semileptonic charge asymmetry, KS+-0, KS000) • light mesons: structure of scalars (via  interaction), h and h’ physics • (e+e-hadrons), muon anomaly, evolution of em • baryon electromagnetic form factors, e+e-pp, nn,  • … and more a new exciting challenge! who wants to join us is welcome!!!

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