1. V.Patera CERN seminar 28 March 2006 1  [nb]  s [MeV] Recent results of KLOE at DA  NE V.Patera Rome I University & Laboratori Nazionali di Frascati (INFN) 

2. V.Patera CERN seminar 28 March 2006  Daphne  Daphne  DA  NE (Greek , English laurel, Italian alloro) daughter of the river god Peneios and Gaea (goddess of the earth) flew the courting of Apoll and was metamorphosed into laurel by her mother; later on the name of this plant was attributed to Apoll Daphnis  not to be confused with Daphnis –son of Hermes (Mercurius) and a Sicilian nymph  Chloe  Chloe  KLOE –the greening, is a surname of Demeter (Ceres)  Daphnis and Chloe –couple of lovers in the hononymous novel of Logos (~300 a.C.) –made famous by Ravel symphonic poem DA  NE & KLOE : the origin

3. V.Patera CERN seminar 28 March 2006 3 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions Recent results → 2005-2006

4. V.Patera CERN seminar 28 March 2006 Physics at a  -factory (I) Not only KAON physics V us, Medium-Rare K S, L decays, CPT with K s, K L charge asymmetries, Quantum Interferometry, But also: hadronic cross section, radiative  decays. “Natural” luminosity unit: fb -1 A  factory is a collider e + e - running at  s = M  = 1.02 GeV  (1020)   a 0 (980) f 0 (980)   '     KK  0-0- 0-0- 1-1- 1-1- 0+0+ 0+0+   BR 83% BR 15% BR 1.3%   decay Produced ev/fb -1 K+K-K+K- 1.5x10 9 KLKSKLKS 1.0x10 9  5x10 7 ’’2x10 5

5. V.Patera CERN seminar 28 March 2006 5 K S K L and K + K - pairs are produced in a pure quantum state (J PC =1 -- ) :  decay ~at rest. Detection of a K S (K L ) guarantees the presence of a K L (K S ) with known momentum and direction (the same for K + K  ) Extensively study all the possible decay channels with a multipurpose detector Physics at the  -factory (II) Kaon physics # precision measurement of absolute BR’s # interference measurements in K S K L system # unique feature is the production of pure and quasi monochromatic K S, K L, K + and K - beams quasi monochromatic K S, K L, K + and K - beams BR(   K + K  ) = 49.2% BR(  K 0 K 0 ) = 33.8%

6. V.Patera CERN seminar 28 March 2006 6 Physics at the  -factory (III) Radiative  decays ( )   M  to probe the quark structure of the meson M  Hadronic cross-section measurement using the Initial State Radiation to vary the energy: e + e         a0f0a0f0 s’ ISR ’’ mixing angle Non-kaon physics a  hadr down to the threshold energy for  production For the theoretical estimate of the hadronic contribution (a  hadr ) to the anomalous magnetic moment of the muon (a  ) down to the threshold energy for  production

7. V.Patera CERN seminar 28 March 2006 7 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions

8. V.Patera CERN seminar 28 March 2006 DA  NE: the Frascati  -factory e  e  collider @  s = M   = 1019.4 MeV 2 interaction regions (KLOE – DEAR/FINUDA) Separate e , e  rings to minimize beam-beam interactions Crossing angle: 12.5 mrad ( p x  12.5 MeV )

9. V.Patera CERN seminar 28 March 2006 DA  NE: the Frascati  -factory 105+105 bunches 2.7 ns bunch spacing I - peak ~ 2.4 A I + peak ~ 1.5 A Injection during data taking

10. V.Patera CERN seminar 28 March 2006 10 DA  NE 24h Performance (Dec. 05) 1.2e -32 8 pb -1 e-e- e+ 1 A 2 A

11. V.Patera CERN seminar 28 March 2006 11  s monitored to within 70 keV Some variations in 2004 Stable (1019.3-1019.6) in 2005 DA  NE: energy stability 2004 2005  s (MeV) Run number IP position, spot size and  s monitored on line by bhabha and KK events

12. V.Patera CERN seminar 28 March 2006 KLOE@DA  NE: the data sample Data taking finished march 2006 L peak = 1.3 × 10 32 cm  s  Integrated L  2.5 fb -1 200 pb -1 off-peak 2001 170 pb -1 2002 280 pb -1 Analysis nearly complete 2004 734 pb -1 2005 1256 pb -1 analysis ongoing

13. V.Patera CERN seminar 28 March 2006 13 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions

14. V.Patera CERN seminar 28 March 2006  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% C 4 H 10  12582 stereo–stereo sense wires  almost squared cells  Electromagnetic calorimeter  lead/scintillating fibers (1 mm  ), 15 X 0  4880 PMT’s  98% solid angle coverage  Superconducting coil (B = 0.52 T) The KLOE design was driven by the measurement of direct CP through the double ratio: R =  (K L  +   )  (K S  0  0 ) /  (K S  +   )  (K L  0  0 ) KLOE experiment

15. V.Patera CERN seminar 28 March 2006 The KLOE Calorimeter: 9 σ(E)/E = 5.7%/  E(GeV) σ(t) = 54 ps/  E(GeV)  50 ps   95% for 20 MeV photons  vtx (  ) ~ 1.5 cm (  from K L  ) Lead Pb-scintillating fibers matrix: ~ 5 g/cm 3, ~ 1.6 cm 4880 PMTs 98% hermetic coverage

16. V.Patera CERN seminar 28 March 2006 The KLOE Drift Chamber:  p /p = 0.4 % (tracks with  > 45°)  x hit = 150  m (xy), 2 mm (z)  x vertex ~ 1 mm  (M  ) ~1 MeV (from K S →     ) Drift Chamber 90% He, 10% iC 4 H 10 ( X 0 =900m ) 12582 stereo sense wires structure in C-Fibre (<0.1 X 0 ) Non saturated drift velocity 2x2 (inner) & 3x3 (outer) cm 2 squared cell size

17. V.Patera CERN seminar 28 March 2006 17 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions

18. V.Patera CERN seminar 28 March 2006 18 K physics at KLOE - tagging Tagging: observation of K S,L signals presence of K L,S ; K + signals K  pure J PC = 1  state  K S, K  K L, K  BR  decay mode 34.1%KSKLKSKL 49.1%KKKK  absolute branching ratio measurement: BR=(N sig /N tag )(1/  sig ) K + K   = 0.245 p* = 127 MeV/c  ± = 95 cm K L K S  = 0.22 p* = 110 MeV/c S = 6 mm; L = 3.4 m The  decay at rest provides monochromatic and pure beam of kaons  Clean, normalized K +,K -,K L and K S beams (K S unique!!)  Kaon momentum is measured with 1 MeV resolution (e.g. p(K L ) = p(  )- p(K S ))

19. V.Patera CERN seminar 28 March 2006 19 Neutral Kaons K S semileptonic decays K S →       decay K L dominant BR’s K L lifetime K Le3 form factor slopes K L →  -  + and   K L,K S and Bell-Steinberger K L,K S Quantun Interferometry

20. V.Patera CERN seminar 28 March 2006 20 Tagging of K S K L beams  ~ 70% (mainly geometrical) K L angular resolution: ~ 1° K L momentum resolution: ~ 1 MeV KS  KS  KS  KS   KL  2KL  2KL  2KL  2  ~ 30% (largely geometrical) K S angular resolution: ~ 1° (0.3  in  ) K S momentum resolution: ~ 1 MeV K L “crash”  =0.22 (TOF) K S    e  K S    e  K L tagged by K S      vertex at IP by K S      vertex at IP K S tagged by K L interaction in EmC by K L interaction in EmC

21. V.Patera CERN seminar 28 March 2006 21 Analysis of K S →  e decays ee  Data  MC fit  e     bad   bad  other  50 500 0 100 200 300 400 500 600 700 E miss (  e)  p miss (MeV)  100  150 Events/MeV Fit distributions of 5 variables in data with various MC sources including  e  and  processes ee Event selection (410 pb -1 ) Obtain number of signal events from a constrained likelihood fit of multiple data distributions Normalize using K S       events in same data set K S tagged by K L crash 2 tracks from IP to EMC Kinematic cuts to reject background from K S →  Track-cluster association e/  ID from TOF Identify the charge of final state

22. V.Patera CERN seminar 28 March 2006 22 K S   e decay – Results BR(K S    e + ) = (3.529  0.057  0.027)  10 -4 BR(K S    e - ) = (3.518  0.051  0.029)  10 -4 BR(  e ) BR(  e ) [KLOE ’02, Phys.Lett.B535, 17 pb  1 ] :( 6.91  0.34 stat  0.15 syst ) 10 -4 BR(K S   e ) = (7.048  0.076 stat  0.050 syst )  10 -4 Accepted by PLB Charge asymmetry With 2.5 fb  1 :  A S  3  10  3  2 Re  Linear form factor slope Linear form factor slope + = (33.8  4.1)  10 -3 In good agreement with linear fit from K L semileptonic form factor [ ( 28.6  0.6)×10    A S =A L if CPT and  S=  Q  A S  A L signals CPT in mixing and/or decay with  S  Q  A S -A L =4Re(  )  if CPT holds in decays with  S  Q A S e = (1.5  9.6  2.9)  10 -3  →      →       →      →      A=  →      →      A=

23. V.Patera CERN seminar 28 March 2006 23 K S   e : CPT test A S = 2(Re    Re   Re y  Re x  ) A L = 2(Re    Re   Re y  Re x  ) CPT in decay CPT in mixing CP  S   Q and CPT Sensitivity to CPT violating effects through charge asymmetry  M 11  M 22  i      m S  m L  i  S  L  1 2  (K S,L   - e + )  (K S,L   + e - )  (K S,L   - e + )  (K S,L   + e - ) A S,L = A S  A L  0 violates CPT A L = (3.322  0.058  0.047) 10 -3, KTeV 2002

24. V.Patera CERN seminar 28 March 2006 24 K S →  e : results Test of  S =  Q rule  (x + ) = ( 0.4  3.1  1.8) × 10  Factor 2 improvement w.r.t. current most precise measurement (CPLEAR,   )  (K S ) PDG  (K L ) PDG + KLOE ’05 (avg.) BR(K L →  e ) KLOE Test of CPT and  S   Q:  (x  ) = (  0.2  2.4  0.7) × 10  Factor 5 improvement w.r.t. current most precise measurement (CPLEAR,   ) A L KTeV  (  ) CPLEAR Test of  S =  Q rule  (K S ) = 89.58  0.06 ps PDG  (K L ) = 51.01  0.20 ns PDG + KLOE ’05 (avg.) BR(K Le3 ) 0.40 0.39 KTeV ’04 KLOE ’05 PDG ’04 KLOE K S assuming  S =  Q Accepted by PLB

25. V.Patera CERN seminar 28 March 2006 25 K S   : first observation E miss  P miss (MeV) 40-40020-20  2002 Data K S      +  +  Measurement never done before More difficult than K Se3 : 1) Lower BR: expect   2) Background events from K S    : same PIDs of the signal Event counting from the fit to E miss (  )  P miss distribution:  3% stat error Efficiency estimate from K L  early decays and from MC + data control samples.

26. V.Patera CERN seminar 28 March 2006 K S   0  0  0 – test of CP and CPT K S  3  0 is purely CP violating If CPT conserved,  S =  L |  ’ 000 | 2 BR SM (K S  3  0 ) = 1.9 × 10  9 Best previous result from direct search: BR < 1.4 × 10  5 90% CL [SND ’99] BR< 7.4  10  7 [interference, NA48, ‘04] Signature (  presel ~ 14%): K L crash + 6  ’s, no tracks from IP Background rejection: K S      + 2  split/accidental clusters       MC 3  (BR 10  5 ) MC 2  Define signal box in  2 3  vs.  2 2  plane:    3 cluster pairs with best  0 mass estimates    2 best cluster pairs -  0 masses, E(K S ), p(K S ), angle between  0 ’s

27. V.Patera CERN seminar 28 March 2006 N bkg (MC) = 3.13 ± 0.82 ± 0.37 N obs = 2 KLOE 450 pb  1 ’01+’02 data BR < 1.2 × 10  7 90% CL Prospects for 2.5 fb  1 : 6.5  increase in statistics ( L  efficiency) 1.5  decrease in background Potential to reduce limit ~10              MC Eff. Stat. = 5.3  data 450 pb  1 ’01+’02 data K S   0  0  0 (II) PLB 619 (2005) 350 pb -1

28. V.Patera CERN seminar 28 March 2006 28 Dominant K L branching ratios Absolute BR measurements to 0.5-1% from 328 pb -1 data sample K L tagged by K S      : 13  10 6 for the measurement 4  10 6 used to evaluate efficiencies BR’s to  e, , and  +  -  0 : K L vertex reconstructed in DC PID using decay kinematics Fit with MC spectra including radiative processes and optimized EmC response to  /  /K L BR to  0  0  0 : Photon vertex reconstructed by TOF using EmC (3 clusters)  rec = 99%, background < 1% Lesser of p miss  E miss in  or  hyp. (MeV)

29. V.Patera CERN seminar 28 March 2006 29 Dominant K L BR’s and K L lifetime Using the constraint  BR(K L ) = 1 we get: BR(K L  e  ) = 0.4007  0.0006 stat  0.0014 syst BR(K L  ) = 0.2698  0.0006 stat  0.0014 syst BR(K L  3   ) = 0.1997  0.0005 stat  0.0019 syst BR(K L        ) = 0.1263  0.0005 stat  0.0011 syst Lifetime indirect measurement:  L = 50.72  0.17  0.33  ns  L = 50.72  0.17  0.33  ns L/  c (ns) 6 - 24.8 ns 40-165 cm 0.37 L x10 2 Events/0.3 ns P K = 110 MeV Excellent lever arm for lifetime measurement Lifetime direct measurement [PLB 626 (2005)] :  L = 50.92  0.17  0.25 ns K L lifetime, KLOE average  L = 50.84  0.23 ns K L lifetime, KLOE average :  L = 50.84  0.23 ns Vosburg, ’72:  L = 51.54 ± 0.44 ns  L direct measurement from K L         400 pb  1 ) Require  3  ’s  (L K ) ~ 99%, uniform in L  L (  ) ~ 2.5 cm Background ~ 1.3% Use K L  π + π - π 0 for: EmC time scale Photon vertex efficiency [PLB 632 (2006)]

30. V.Patera CERN seminar 28 March 2006 30 K Le3 form factor slopes (*) ISTRA+ m  /m  0 correction Phase space integral Pole model versus Quadratic parameterization: KLOE: 0.5 per mil difference KTeV: 6 per mil difference.   10 3    10 3  2 /dof e    24.6  2.1 1.9  1.0152/180   e  26.4  2.1 1.0  1.0173/180 All 25.5  1.5 1.4  0.7325/362  = (25.5  1.5  1.0)  10  3   = ( 1.4  0.7  0.4)  10  3 Correlation:  ( ,   ) =  0.95 Quadratic fit Pole model M V = 870(7) MeV 328 pb  1, 2  10 6 K e3 decays Kinematic cuts + TOF PID to reduce background ( ~ 0.7% final contamination ) Separate measurement for each charge state (e   ,   e  ) to check systematics t measured from  and K L momenta:  t /m  2  0.3   10 3  2 /dof e    28.7  0.7156/181   e  28.5  0.6174/181 All 28.6  0.5330/363  = (28.6  0.5  0.4)  10  3 Linear fit Accepted by PLB

31. V.Patera CERN seminar 28 March 2006 BR K L     Decay CP violating Related to  K K L beam tagged by K S →     328 pb -1 ’01+’02 data Selection K L vertex reconstructed in DC PID using decays kinematics Fit with MC spectra including radiative processes Normalize using K L   events BR(K L      )= (1.963  0.012  0.017)  10 -3 Submitted to PLB

32. V.Patera CERN seminar 28 March 2006 KLOE in agreement with KTeV [PRD70 (2004),092006] BR=(1.975  0.012)   confirm the discrepancy (4 standard deviations) with PDG04 PDG2004 KTeV KLOE preliminary BR(K L      )  10 -3 agreement with prediction from Unitarity Triangle (1.5  ) Using BR(K S   ) and  L from KLOE and  S from PDG04  | = (2.216  0.013)  10 -3 |  | PDG04 = (2.280  0.013)  10 -3 BR K L     and l  l

33. V.Patera CERN seminar 28 March 2006 33 Measurements of K S K L observables can be used for the CPT test from unitarity : ff (1 + i tan  SW ) [Re  i Im  ]  A*(K S  f ) A(K L  f ) SS 1   f  f      K S       00    K S            K S       kl3  S  L B(K L l3)  Re  Re y  i( Im  Im x  )   S  L B(K L l3)  (A S +A L )/4  i( Im  Im x  )     S  L     K L           S  L     K L        CPT test: Bell-Steinberger relation  f = A(K L → f)/A(K S → f)

34. V.Patera CERN seminar 28 March 2006 34  K S      K S       K S        K L        K L  l   K S          K L         K S          SW  = (0.759±0.001)         CPT test: inputs to the Bell-Steinberger relation  S  0.08958 ± 0.00006 ns  L = 50.84 ± 0.23ns A L   A S    K L        K L         =0.757 ± 0.012   = 0.763 ± 0.014 Im x + = (0.8 ± 0.7)  10 -2 KLOE measurements Im x  from a combined fit of KLOE + CPLEAR data

35. V.Patera CERN seminar 28 March 2006 35 Re    Im   Re    Im   CPLEAR: Re    Im   KLOE preliminary: Re  Im  CPT and Bell-Steinberger: result Im  - Uncertainty on Im  is now dominated by   and   - Semileptonic sector contributes by ~ 10%

36. V.Patera CERN seminar 28 March 2006 no simultaneous decays (  t=0) in the same final state due to the destructive quantum interference  t/  S I(  t) (a.u)  m  from here Kaon interferometry:   K S K L              t2t2 t1t1  t=t 1 -t 2 Perfect vertex reolution

37. V.Patera CERN seminar 28 March 2006   K S K L         Analysed data: L=380 pb  Fit including  t resolution and efficiency effects + regeneration  S,  L fixed from PDG K L regeneration on beam pipe Data Fit result KLOE PRELIMINARY  m = (5.34  0.34)  10 9 s  1 At 2.5 fb -1  m  0.14  10 9 s  1 PDG ’04: (5.290  0.016)  10  s  1 Best (Ktev’03)(5.288  0.043)  10  s  1

38. V.Patera CERN seminar 28 March 2006 Fit including  t resolution and efficiency effects + regeneration  S,  L  m fixed from PDG From CPLEAR data, Bertlmann et al. (PR D60 (1999) 114032) obtain: KLOE preliminary result: with 2.5 fb -1 :   K S K L         : test of quantum coherence as CP viol. O(        high sensitivity to  Decoherence parameter:

39. V.Patera CERN seminar 28 March 2006 39 Charged Kaons K ± lifetime BR(K +  2 ) K ± semileptonic decays

40. V.Patera CERN seminar 28 March 2006 40 Tagging K + K - Measurement of absolute BR’s: K  beam tagged from K         Measurement of absolute BR’s: K  beam tagged from K         p *  (MeV) Kinem. ID 180200220240 1000 3000 2000 10 2 Ev/0.5MeV  Data — fit: 6x10 8 tags/fb -1  Two-body decays identified as peaks in the momentum spectrum of secondary tracks in the kaon rest frame: 6x10 8 tags/fb -1  Given the tag a dedicated reconstruction of K  tracks is performed, correcting for dE/dx losses of charged kaons in the DC    K +   +  K –   –  0 – – + +

41. V.Patera CERN seminar 28 March 2006 41   region MC includes radiative process P * [MeV] BR(K +   + (  )) = 0.6366  0.0009 stat.  0.0015 syst. [PLB 632 (2006)]  (K  (  ))/  (  (  ))  |V us | 2 /|V ud | 2 f K 2 /f  2 From lattice calculations: f K /f  =1.198(3)( +16  5 ) (MILC Coll. PoS (LAT 2005) 025,2005) |V us | / |V ud | =0.2294  0.0026 Measurement of BR(K    (  )) Tag from K -  -. 175 pb -1 : 1/3 used for signal selection, 2/3 used as efficiency sample Subtraction of  0 identified background. Count events in (225,400) MeV window of the momentum distribution in K rest frame (  hypothesis) Signal selection Selection efficiency measured on data Radiated  acceptance measured on MC

42. V.Patera CERN seminar 28 March 2006 42 Measurement of the K  lifetime Tag events with K  2 decay Kaon decay vertex in the fiducial volume Measure from PDG not in agreement Measure the kaon decay length taking into account the energy loss:  K =  i L i /(  i  i c) Tracking efficiency and resolution functions measured on data by means of neutral vertex identification. Fit of the  K distribution.   = 12.367  0.044 Stat  0.065 Syst ns KLOE preliminary  K (ns) 16-30 ns  PDG = (12.385±0.024)ns 200 pb -1

43. V.Patera CERN seminar 28 March 2006 43 BR(K  e3 ) = (5.047  0.019 Stat  0.039 Syst-Stat  0.004 SysTag )×10 -2 (5.047  0.019 Stat  0.039 Syst-Stat  0.004 SysTag )×10 -2 BR(K   3 ) = (3.310  0.016 Stat  0.045 Syst-Stat  0.003 SysTag )×10 -2 (3.310  0.016 Stat  0.045 Syst-Stat  0.003 SysTag )×10 -2 BR(K  e3 ) = (5.047  0.019 Stat  0.039 Syst-Stat  0.004 SysTag )×10 -2 (5.047  0.019 Stat  0.039 Syst-Stat  0.004 SysTag )×10 -2 BR(K   3 ) = (3.310  0.016 Stat  0.045 Syst-Stat  0.003 SysTag )×10 -2 (3.310  0.016 Stat  0.045 Syst-Stat  0.003 SysTag )×10 -2 Measurement of BR(K  ℓ 3)  4 independent-tag samples: K +  2, K +  2, K   2, and K   2 keep under control the systematic effects due to the tag selection  Kinematical cuts to reject non-semileptonic decays, residual background is about 1.5% of the selected K  l3 sample  Constrained likelihood fit of m 2 data distributions from ToF measurements count the number of signal events  Selection efficiency from MC and correct for Data/MC differences. KLOE preliminary Perform the BR measurement on each tag sample, separately normalizing to tag counts in the same data set, and average accounting for correlations: K nuc.int K  0  0 K  0 Ev/(14MeV) 2 K  e3 K3K3

44. V.Patera CERN seminar 28 March 2006 44 All Kaons together! Test of CKM unitarity: the first row

45. V.Patera CERN seminar 28 March 2006 45 Unitarity test of CKM matrix – V us & V us / V ud Most precise test of unitarity possible at present comes from 1 st row: Can test if  = 0 at 10 -3 level: from super-allowed nuclear  -decays: 2|V ud |  V ud = 0.0005 from semileptonic kaon decays: 2|V us |  V us = 0.0009 |V ud | 2 + |V us | 2 + |V ub | 2 ~ |V ud | 2 + |V us | 2  1 –  Extract |V us | from K l3 decays. EM effects must be included:  (K   ℓ  )  |V us f + K0  - (0) | 2 I( t ) S EW (1 +   +  SU(2) )   |V us | |V us |   t )  t )  f + K0  - (0) f + K0  - (0) = 0.5  0.5  Relative uncertainty: Extract |V us |/ |V ud | from  (K   (  ))/  (    (  )) ratio. Dominated by the theoretical uncertainity on the f K /f  evaluation from lattice QCD KLOE can measure almost all experimental inputs for neutral and charged kaons: branching ratios, lifetimes, and form factors (but  S ).

46. V.Patera CERN seminar 28 March 2006 46 V us from KLOE results (BR’s and  L ) 12.384(24) ns89.58(6) ps50.84(23) ns  0.03310(40)0.05047(46)7.046(91)×10 -4 0.2698(15)0.4007(15) BR K   3K  e3K S e3K L  3K L e3  2 /dof = 1.9/4 f + (0)=0.961(8) Leutwyler and Roos Z. [Phys. C25, 91, 1984] V ud =0.97377(27) Marciano and Sirlin [Phys.Rev.Lett.96 032002,2006] From unitarity V us ×f + (0) = 0.2187(22)      (Pole model: KLOE, KTeV, and NA48 ave.)   (KTeV and Istra+ ave.) Slopes

47. V.Patera CERN seminar 28 March 2006 47 V us around the world and Unitarity V us f + (0) plot: F.Mescia courtesy WORLD AV. = 0.2164(4) WORLD AV. = 0.2164(4)  L = 50.99(20) ns, average KLOE-PDG Including all new measurements for semileptonic kaon decays (KTeV, NA48, E865, and KLOE) f + (0)=0.961(8) Leutwyler and Roos [Z.Phys. C25, 91, 1984] V ud =0.97377(27) Marciano and Sirlin [Phys.Rev.Lett.96 032002,2006] From unitarity V us ×f + (0) = 0.2187(22) PDG04

48. V.Patera CERN seminar 28 March 2006 48 The V us  V ud plane unitarity V us = 0.2254  0.0020 K l3 KLOE, using f + (0)=0.961(8) V ud = 0.97377  0.00027 Marciano and Sirlin Phys.Rev.Lett.96 032002,2006 V us /V ud = 0.2294  0.0026 K  2 KLOE  (K  (  ))/  (  (  ))  |V us | 2 /|V ud | 2 f K 2 /f  2Inputs: Fit results Fit results, P(  2 ) = 0.66: V us = 0.2246  0.0016 V ud = 0.97377  0.00027 Fit result assuming unitarity, P(  2 ) = 0.23: V us = 0.2264  0.0009

49. V.Patera CERN seminar 28 March 2006 49 Non Kaons physics (my personal selection)  mass  (e + e  →     ) off peak physics @ 1 GeV off peak physics @ 1 GeV

50. V.Patera CERN seminar 28 March 2006  After the kinematic fit (p,E tot,cluster times) the mass measurement is almost independent from the energy of the clusters, it is dominated by the cluster positions.  The  momentum and the vertex position are precisely determined from Bhabha scattering at large angle e+e- → e+e. Absolute scale buy  - line shape and  mass   measurement:     cross checking:   measurement @ KLOE GEM: M  = (547.311 ± 0.028 ± 0.032) MeV/c 2 PLB 619 (2005) 281 NA48: M  = (547.843 ± 0.030 ± 0.041) MeV/c 2 PLB 533 (2002) 196 Large discrepancy between the two most precise measurements E2E2 E1E1 E3E3  measurement method

51. V.Patera CERN seminar 28 March 2006 51   measurement @ KLOE Kinematic fit applied on  →  events   and  0 selected by looking at different Dalitz plot regions M  (MeV) = ( 547.708  0.014 ) MeV  = ( 2.143  0.012 ) MeV <m   = ( 134.956  0.018 ) MeV  = ( 1.66  0.005 ) MeV  2 /ndf = 304/257 00  2 /ndf = 146/161 E 1 <E 2 <E 3 M  (MeV)  00 

52. V.Patera CERN seminar 28 March 2006 52   measurement @ KLOE Data set divided in 8 periods M(  0 ) = ( 134990  6 stat  30 syst ) keV M(  0 ) PDG = ( 134976.6  0.6 ) keV  Systematics mainly from √ s and vertex position  EMC linearity in progress  NA48 compatibility: 0.24  547.95 547.90 547.85 547.80 547.75 547.70 M  (MeV) M  (MeV) M(  ) = ( 547822  5 stat  69 syst ) keV KLOE preliminary NA48

53. V.Patera CERN seminar 28 March 2006  μ and  (e + e  →     ) @ KLOE Process e + e -   +  - @  s < 1 GeV contributes as much as 66% to a  had So far, estimates of a  had from: 2) using the spectral function from        (LEP, CESR data) Dispersion integral relates   had (vac-pol) to s(e + e -  hadrons) 1) measuring  (e + e      ) vs  s at an e + e - collider, varying the beam energy

54. V.Patera CERN seminar 28 March 2006 54  (e + e  →     ) @ KLOE (s’ = s – 2 E  s)  Luminosity from e + e  (  ) counts, 55  <  e < 125 ,  at 0.5% (th) 0.3%(exp)  Radiator function H(M   ), defined as: d  M    dM    M    M    with inclusion of radiative effects, as FSR, from QED MC calculation ( PHOKHARA, Karlsuhe Theory Group, Kühn et al.) At the  mass it is possible to measure  e + e        with high accuracy: Exploit ISR to extract  (e + e    +   ) for  s´ from 2m    s M  2 FSR

55. V.Patera CERN seminar 28 March 2006 55  (e + e  →     ) : data samples for      events Photons at small angles  (   165 ° )  Photon NOT DETECTED High Statistics for ISR Photons Low relative contribution of FSR <0.5% in entire M   – range Small amount of other background Photons at large angle  ( 50 o <   < 130 ° )  Photon detection required High amount of FSR and background Allows measurement at threshold Allows measurement of charge asymmetry  Test of FSR

56. V.Patera CERN seminar 28 March 2006 56  (  e + e -      )  nb  0.40.50.60.70.80.90.3 200 40 0 600 800 1000 1200 1400 M  2 (GeV 2 ) KLOE 2001 Data 140pb -1 Phys. Lett. B606 (2005) 12  (e + e  →     ) : small angle results a   [10 -10 ] KLOE (‘05) SND (‘05),    CMD-2 EPS (‘05) preliminary CMD-2 (‘04) fair agreement btw all 4 data sets CMD-2 and KLOE agree within 0.5  disagreement btw KLOE and SND ca.1.5 2  contribution to a  hadr [0.37-0.93 GeV 2 ]

57. V.Patera CERN seminar 28 March 2006 Changes of online and offline reconstruction The goals for the analysis of 2002 data:  considerable reduction of errors Total theoretical error 0.9% *Goal : Error < 1% 0.5%Radiator Function 0.3%FSR Corrections 0.2%Vacuum Polarization <<0.6%Luminosity * Total experimental error 0.9% 0.2%Unfolding Effects 0.3%Background 0.2%Trackmass Cut 0.1%Particle ID << 0.6%Reconstruction Filter * <0.3%Vertex 0.3%Tracking <0.3%Trigger * 0.3%Acceptance New version of BABAYAGA with full NLO  dN/dM 2 (events/GeV 2 ) 2002 Data Normalisation to Muons M 2 (GeV 2 )  (e + e  →     ) : improvement at small angle

58. V.Patera CERN seminar 28 March 2006 the threshold region is accessible photon tagging is possible (4-momentum constraints) lower signal statistics large FSR contributions large       background irreducible bkg. from  decays PRO & CONTRA 50 o <   <130 o 50 o <   <130 o L = 240 pb -1 preliminary       MC      MC< By means of dedicated selection cuts it is possible to fight the dominant       background Analysis in very advanced state Threshold region non-trivial due to irreducible FSR-effects, which have to be cut from MC using phenomenol. Models (interference effects unknown)     ffff          FSR f0f0  M  2 (GeV 2 )  (e + e  →     ) : large angle

59. V.Patera CERN seminar 28 March 2006 59  (e + e  →     ) :  (e + e  →     ) :Forward-backward asymmetry Using the f 0 amplitude from Kaon Loop model, good agreement data-MC* both around the f 0 mass and at low masses. M  (MeV) data  MC: ISR+FSR  MC: ISR+FSR+f 0 (KL) Phys.Lett.B634 (06), 148 * G. Pancheri, O. Shekhovtsova, G. Venanzoni, hep-ph/0506332  +  - system: A(ISR)  C-odd while A(FSR) & A(scalar)  C-even  asymmetry in the variable: Pion polar angle [ o ] 90 o MC

60. V.Patera CERN seminar 28 March 2006      @ large angle: looking for f  The f 0 signal is a deviation of M      spectrum from the expected ISR + FSR shape. Scalar amplitude from models: M(  ) (MeV ) f 0 (980) region M(  ) (MeV ) Events/1.2 MeV 676000 events 1.Kaon-loop KL ( Achasov-Ivanchenko, NPB315 1989 ): for each scalar meson S there are three free parameters of the fit: g S , g SKK, M S 2.No-Structure NS ( by G.Isidori and L.Maiani ): a modified BW + a polynomial continuum : g  S , g S , g SKK, M S + pol. cont. parameters S g  KK g SKK g SPP  KK KK  S V  g V S  g S   e+e+ e-e-

61. V.Patera CERN seminar 28 March 2006 Fit to the m(  ) spectrum: ( 491 bins, 1.2 MeV wide, m(  ) = 420 to 1009 MeV) Fit : ISR + FSR +  + scalar ± interf( SCAL+ FSR ) Kaon-Loop and No-Structure fits:  Good description in both cases of signal and background  “negative” interference;  The introduction of a  (600) doesn’t improve the fit. KL fitNS fit f 0 signal [PLB634 (2006) 148]

62. V.Patera CERN seminar 28 March 2006 KLOE Integrated 200pb -1 at  s = 1.00 GeV In addition has been performed a  -scan of 4 points, 10pb -1 each background-free Radiative Return 200pb -1 allow to be statistically com- petitive with VEPP-2000 at threshold a  -scan allows to study the model- dependence in desciption of f 0 (980) background-free  - program  s ( MeV )   s = 1023  s = 1030  s = 1018  s = 1010  s = 1000 Run-Nr. Trackmass [MeV] Number of Events / MeV 10pb -1 ONPEAK OFFPEAK   First look into off-peak-data very promising..... ! - Large photon angle acceptance cuts - PID: both tracks identified as pions Off resonance run @ 1 GeV

63. V.Patera CERN seminar 28 March 2006 K S   PLB 538, 21 (02) K L   PLB 566, 61 (03) K +   +  0  0 PLB 597, 49 (04) K S   e PLB 535, 37 (02) K S   0  0  0 PLB 619, 61 (05) K L  main PLB 632, 43 (06) K L lifetime PLB 626, 15 (05) KLOE physics papers published to date K +   + (  ) PLB 632, 76 (06)    0  0  PLB 537, 21 (02)    0  PLB 536, 203 (02)    +    0 PLB 561, 55 (03)    '  PLB 541, 45 (02)   l + l  PLB 608, 199 (05)    +    PLB 606, 12 (05)    PLB 591, 49 (04)    +   PLB 606, 12 (05)    +    PLB 634, 148 (06)

64. V.Patera CERN seminar 28 March 2006 64 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions

65. V.Patera CERN seminar 28 March 2006 65 DA  NE & KLOE future DA  NE upgrades physics program KLOE upgrades KLOE upgrades

66. V.Patera CERN seminar 28 March 2006 DA  NE : near term future 2006 – Final KLOE run (up to 2 fb -1 ) -shutdown for FINUDA installation -FINUDA run 2007 – FINUDA run (up to 1 fb -1 ) -shutdown for SIDDHARTA installation -SIDDHARTA run 2008 – SIDDHARTA run (up to 1 fb -1 ) -shutdown for FINUDA installation -Final FINUDA run (up to 2 fb -1 ) DAFNE scientific program scheduled up to 2008. Upgrades have been proposed and submitted to INFN. Explicitely mentioned in the 3-years “ROAD-MAP” of INFN Only e + e - collider in Europe

67. V.Patera CERN seminar 28 March 2006 DA  NE Upgrade – short term (3 years) Starting from 1.5x10 32, 2fb -1 /year:  Reduction of e - ring beam impedance (by a factor  2) :  Removal and shielding of the broken Ion-Cleaning-Electrodes  Higher positron current (up to 2 A), so far limited to 1.3 A:  New injection kickers  Ti-Coating against electron cloud  Feedback upgrades  Wigglers modifications to increase Lifetime (by a factor  2):  New interaction region  Transfer lines upgrade (continuous injection) To be discussed:  Crab cavities, waist modulation (RF quads) Expected a factor > 3 in Luminosity

68. V.Patera CERN seminar 28 March 2006 DA  NE-2: Long term upgrade (2010  ) Change of machine layout, insertion of: Superconducting cavities Superconducting wigglers Ramping Dipoles New vacuum chamber Energy (GeV) 1.022.4 Integrated Luminosity per year (fbarn -1 ) >10 Total integrated luminosity (5 years, fbarn -1 ) >50>3 Peak luminosity (cm -1 sec -2 ) >8 10 32 >10 32 Machine can go higher in energy (up to 2.4 GeV) in energy (up to 2.4 GeV) TDR in preparation: necessary to submit the project

69. V.Patera CERN seminar 28 March 2006 The KLOE future: KLOE-2 An Espression of Interest for the continuation of the KLOE has been presented. The physics program is focused on K S physics,  ’ physics and quantum interferometry studies. Time schedule and luminosity foreseen are 30fb -1 on tape within 2014 11 institution x 7 nations involved

70. V.Patera CERN seminar 28 March 2006 KLOE2: perspectives for Kaon physics K S   0  0  0 CP,CPT < 1.2 10 -7 < 5  10 -9 seen K S  e CPT,  S=  Q (7.09  0.10)  10 -4  0.2  10 -5  0.1  10 -5 A s CPT (1.5  11)  10 -3  2  10 -3  1  10 -3 K S   +  -  0  pt (3  1)  10 -7  0.4  10 -7  0.3  10 -7 K S  e + e - < 1.4  10 -7 < 2  10 -8 < 9  10 -9 K S   0 e + e - K L CP (6  3)  10 -9 seen  2  10 -9 K S   pt (2.78  0.07)  10 -6  0.03  10 -6  0.02  10 -6 Assuming/extrapolating present KLOE efficiencies/systematics Present @20fb -1 @50 fb -1 Competitive on rare K S decays, CPT and  S=  Q violating parameters, interesting for CHPT L int = 20-50 fb -1 BR(K ± e2 )/BR(K ±  2 ) SM test (2.416  0.053)  10 -5 <% rel. err few ‰ rel err

71. V.Patera CERN seminar 28 March 2006    ChPT, study of  spectrum expected 3000 events  ’   l + l -,lll (‘) l (‘) (Dalitz & double dalitz decays) with high statistics       e + e test of CP violation beyond SM  ’      sensitive to   expected 200.000 events KLOE-2: perspectives for  & scalars physics With 20 fb-1  f 0 , f   K + K - (KK) ( expected BR ~ 10 -6(-8) ) well measured (10 5 K + K - and 10 3 KK), direct measure of the g fKK coupling  -factory =  ed  ’ factory BR(    ) = 1.3 × 10 -2  N  (20 fb -1 ) ~ 9 × 10 8 BR(    ’  ) = 6.2 × 10 -5  N  ’ (20 fb -1 ) ~ 5 × 10 6 Monochromatic prompt photon: clear signature

72. V.Patera CERN seminar 28 March 2006 KLOE2: Kaon interferometry: main observables measured quantity parametersmode

73. V.Patera CERN seminar 28 March 2006  Use of a lower magnetic field. This can increase acceptance for several of the above mentioned channels and ease pattern recognition (.5T →.3T → x 2 gain in acceptance on K Sl3 )  Insertion of a vertex chamber. At present, first tracking layer is at 30 cm (i.e. 50  S ) from the I.P. Increase the K S, K ± geometrical acceptance  Increase calorimeter’s readout granularity. Can improve photon counting, as well as particle identification (e/  /  ).  A small angle tagger for  physics KLOE2: detector upgrades The KLOE efficiency/systematics can be improved, increasing quadratically the collected events both via the tag and via the signal emisphere. The KLOE experience suggest as upgrades of the detector

74. V.Patera CERN seminar 28 March 2006 74 Outline  Physics @  peak  DA  NE, the frascati  factory  The KLOE detector  KLOE recent results: Kaon physics (mostly) Non Kaon physics  Future of KLOE & DA  NE  Summary and conclusions

75. V.Patera CERN seminar 28 March 2006 Conclusions  KLOE has integrated 2.5fb -1 during its data taken at DA  NE  During 2005-2006 published results leading to substantial improvement to V US, TCPV,   hadr  Analysis of approx. 2/3 of the data set on-going  An EoI for the continuation of the KLOE physics program at an improved DA  NE has been presented

76. V.Patera CERN seminar 28 March 2006 76 SPARES

77. V.Patera CERN seminar 28 March 2006 Magnetic field value dramatically affects signal acceptance. Can improve up to a factor ~ 2 Proper balancing with consequent loss in momentum resolution yet to be studied B (kG)  (K L Crash + Ks DC selection) Present analysis, MC with detailed field map 400 pb  MC with LSF=0.5, with uniform axial B field 0.1 0.2 35 4 0 0.15 0.05 T. Spadaro Bfield & reconstruction eff: K S   e decays Bfield & reconstruction eff: K S   e decays

78. V.Patera CERN seminar 28 March 2006 K S  3  0 decays Background mostly due to photon clusters double splittings Preliminary studies show that there is room for “algorithmic” improvements in background rejection without big losses in signal efficiency Study of the entire KLOE data set crucial for a better assessment of the real potentialities of the analysis Ideally, with 20 fb  1 one can reach a limit ~ 5x10  9 With 50 fb  1 one could hope to observe a few events!

79. V.Patera CERN seminar 28 March 2006 K S   +    0 : a test for ChPT ChPT predicts B(K s   +    0 ) = (2.4 ± 0.7)x10  7 The present experimental value (3.3 +1.1  0.9 ) x10  7 is the average of three different measurement each individually precise at ~ 40% A preliminary KLOE analysis obtains  sig ~ 1.3%, S/B ~ 2 Assuming Error on BR @ 2 fb  1 (%) Error on BR @ 20 fb  1 (%) Error on BR @ 50 fb  1 (%) No further effort made to reduce background ~ 60% ~ 20% ~ 12% Further efforts completely remove background ~ 40% ~ 12% ~ 8%

80. V.Patera CERN seminar 28 March 2006 K S   +    0 as a pedagogical example This is the typical case where analysis would greatly benefit from simple detector upgrades lost only due to acceptance At least one of the two tracks has low momentum: 65% of signal lost only due to acceptance lower B field a vertex chamber Acceptance can be increased by the use of a lower B field. Also the use of a vertex chamber could definitely help Both can be useful also for the rejection of the background due to patological charged kaon events

81. V.Patera CERN seminar 28 March 2006 K S   0 e + e  decays Fundamental to assess indirect CPV contribution to parent K L decay Measured by NA48 on the basis of 7 events (plus 6  +   ) Theoreticians’ dream: measurement at 15% accuracy BR = (5.8 ± 3) x 10 -9 What efficiency can reasonably be expected for KLOE?

82. V.Patera CERN seminar 28 March 2006 K S   0 e + e  decays Further selection based on cuts on 5 independent variables e + e  inv. mass  2 kinem. fit MC DATA 400 pb  1 signal

83. V.Patera CERN seminar 28 March 2006 K S   0 e + e  decays Cuts tuned on MC: 0 events retained  < 4.8 ev / fb  1 @ 90% CL Detailed studies of problematic topologies: single dalitz : 880 pb  1 : 0 events  < 2.6 ev / fb  1 double dalitz: 4200 pb  1 : 0 events  < 0.55 ev / fb  1 K + K  : 880 pb  1 : 0 events  < 2.6 ev / fb  1 Overall efficiency on signal: 4.3% Check on data (~ 400 pb  1 ) : 0 observed (0.12 expected) Optimistically (no further bkg) ~ 5 events observed in 20 fb  1

84. V.Patera CERN seminar 28 March 2006 ModeParameter Best measurement or PDG-04 fit KLOE-2 L=100 fb -1          mm 5.288 ± 0.043  10 9  s -1 ± 0.02 STAT  10 9  s -1          Re  ’  (1.67 ± 0.26)  10 -3 ± 0.2 STAT  10 -3          Im  ’  0.0012 ± 0.0023 ± 0.0022 STAT       e ALAL (3322 ± 58 ± 47 )  10 -6 ± 18 STAT  10 -6  e    e Re(   ) (0.29 ± 0.27)  10 - 3 ± 0.2 STAT  10 -3  e    e Im(   )(0.24 ± 0.50)  10 - 4 ± 20 STAT  10 -4 Prospectives for Interferometry

85. V.Patera CERN seminar 28 March 2006  -factory =  ed  ’ factory BR(    ) = 1.3 × 10 -2  N  (20 fb -1 ) ~ 9 × 10 8 BR(    ’  ) = 6.2 × 10 -5  N  ’ (20 fb -1 ) ~ 5 × 10 6 Monochromatic prompt photon: clear signature Mixing  –  ’: Uncertainty dominated by systematics; improvement can come by measuring main  ’ BR’s  decays :      (test ChPT; major improvements expected with 20 fb -1 ) Dalitz decays:   e + e - ,     , e + e - e + e -  Transition FF       e + e - (Test of CP violation, analogous to K L      e + e - ) Improvements on forbidden/rare decays  ’ decays: Dalitz plot of  ’   +  -  scalar amplitude  ’         first observation / isospin violation Perspectives for  ’ at DA  NE-2

86. V.Patera CERN seminar 28 March 2006 86 K S   e : CPT test A S = 2(Re    Re   Re y  Re x  ) A L = 2(Re    Re   Re y  Re x  ) CPT in decay CPT in mixing CP  S   Q and CPT Sensitivity to CPT violating effects through charge asymmetry   e   H W  K   = a  b   e   H W  K   = a *  b *   e   H W  K   = c  d   e   H W  K   = c *  d * b=d=0 if CPT holds c=d=0 if  S=  Q holds K S   e amplitudes Re y =  Re b/a Re x  =  Re d * /a  M 11  M 22  i      m S  m L  i  S  L  1 2

87. V.Patera CERN seminar 28 March 2006 87  S=  QCPTTCP =0  =0  =0d =0  =0 c =0  =0  =0b  =0 a Semileptonic decay amplitudes: definitions CPT violation:  S=  Q violation: CPT violation &  S=  Q violation :

88. V.Patera CERN seminar 28 March 2006 88 Number of K L       from fit of Number di K L   from fit of K L       CP violation

89. V.Patera CERN seminar 28 March 2006 89 We get the following accuracies on each term of the sum:      K S       00    K S             K S       S  L B(K L l3)  A S +A L )/4  i  Im x      S  L     K L           S  L     K L        10 -4 Im Re CPT test: accuracy on  i

90. V.Patera CERN seminar 28 March 2006 90 CPT test: m(K)-m(K) m(K)-m(K)  (K)-  (K) m(K)-m(K)   GeV  (  m) ~ 2  10  GeV  (  ) ~ 4  10  GeV CPLEAR KLOE  M 11  M 22  i      m S  m L  i  S  L  1 2

91. V.Patera CERN seminar 28 March 2006 91 a   [10 -10 ] KLOE (‘05) SND (‘05),    CMD-2 EPS (‘05) preliminary CMD-2 (‘04) M  2 (GeV 2 )  /  KLOE - 1 CMD-2 (‘04) and KLOE agree @ high M  some disagreement btw. KLOE and CMD-2/SND on the  peak fair agreement btw all 4 data sets CMD-2 and KLOE agree within 0.5  disagreement btw KLOE and SND ca.1.5 interpolation of 60 KLOE data points from 0.35 to 0.95 GeV 2 Comparison with recent e + e  Data Comparison of e+e- experiments 2  contribution to a  hadr [0.37-0.93 GeV 2 ] JETP, Vol. 101, No 6 (2005) 1053 PLB 578 (2004) 285

92. V.Patera CERN seminar 28 March 2006 92  mass measurement : the method   E1E1 E2E2 E3E3 Using the decays: Px,Py,Pz,Etot t-r/c of clusters A kinematic fit is performed imposing: conservation compatible with light velocity As a consequence of the kinematic fit the mass measurement is almost independent from the energy of the clusters, it is dominated by the cluster positions. The  momentum and the vertex position are precisely determined run by run from the study of the Bhabha scattering at large angle e + e -  e + e – (90000 events for each run). Absolute scale determined buy  line shape and  mass     cross checking purpose

93. V.Patera CERN seminar 28 March 2006 93 Prospects for small angle analysis Many systematics cancel out on the theory side: Luminosity, VP, radiator or reduce to small corrections on the experimental side tracking, vtx efficiencies and trigger veto Differently from the old analsyis statistics is an issue, due to the small  cross section in some S bins ′ ′ ′ Analysis of the new data (2 fb  ): take advantage of larger statistics! Change strategy normalizing to      Improvements also on Filter/ECL strategies

94. V.Patera CERN seminar 28 March 2006 Neutral kaons tagging: K S “beam” Kinematic closure of the event (p S =p  -p L ): K S angular resolution: ~ 1° (0.3  in  ) K S momentum resolution: ~ 1 MeV/c **  Clean K S tagging by time-of-flight identification of K L interactions in the calorimeter : tof(K L ) ~30 ns  tof (  ~6 ns)  K L velocity in the  rest frame    0.218  Tagging efficiency  tag,total ~ 30%  1.4 10 8 tagged K S  Clean K S tagging by time-of-flight identification of K L interactions in the calorimeter : tof(K L ) ~30 ns  tof (  ~6 ns)  K L velocity in the  rest frame    0.218  Tagging efficiency  tag,total ~ 30%  1.4 10 8 tagged K S K S      K L  “crash”

95. V.Patera CERN seminar 28 March 2006 95      @ large angle ()      @ large angle ( 50 o 50MeV ) 10 times more statistics on tape! The spectrum extends down to the 2-pions threshold dN/dM  2 Both the particles not identified as electrons Cut on  2  in the        hyp. Cut on TrackMass vs. M  2 Cut on  angle L = 240 pb -1 M  2 [GeV 2 ] KLOE preliminary          – MC       – MC      - MC M  2 [GeV 2 ] M trk [MeV] mm mm mm

96. V.Patera CERN seminar 28 March 2006 Forward-backward asymmetry  +  - system: A(ISR)  C-odd A(FSR)  C-even  an asymmetry is expected in the variable: Pion polar angle [ o ] 90 o MC test of sQED via comparison data/MC Issue: to distinguish the effect of the interference (described in our MC by sQED ) and the effect of f 0 (980). Czyż, Grzelińska, Kühn, Phys.Lett.B 611(116)2006 M  [GeV] 20 o <   <160 o 45 o <   <135 o f 0 kk model f 0 ‘no str’    f 0 ‘no str’    /2 no f 0 A(f 0 )  C-even

97. V.Patera CERN seminar 28 March 2006 The Particle Data Group measures are not in agreement  : experimental picture  = (12.385±0.024)ns