1. Hadronic results from KLOE E. Santovetti (INFN – Roma II) for the KLOE Collaboration European Physical Society International Europhysics Conference on High Energy Physics EPS (July 17th-23rd 2003) in Aachen, Germany

2. E. Santovetti DA  NE: the Frascati  factory HEP2003 Aachen, 17-23 July 2003  electron positron collider at the  mass energy (E CM = 1020 MeV)  separate rings to minimize beam-beam interaction  two interaction points (KLOE – DEAR/FINUDA) Machine parametersDesign2002 Total length (m)98 Max. bunches12051 Bunch spacing (ns)2.75.4 Lifetime (min)12040 Bunch current (mA)4020 L single bunch (cm -2 s -1 )4.4 10 30 1.5 10 30 L peak (cm -2 s -1 )5.3 10 32 0.75 10 32  per year (10 9 ) 150.9

3. E. SantovettiHEP2003 Aachen, 17-23 July 2003 KLOE data taking history Year pb -1 /day averagepeak 200025 pb -1 0.10.4 First published results 2001170 pb -1 0.71.8 Luminosity improved but high background Further analyses published 2002280 pb -1 2.04.5 Higher luminosity and background reduced Analysis in progress An upgrade of the machine has been done. An increase in luminosity ( > x2 ) is expected in the next data taking. in 2002

4. E. Santovetti Kaon physics at DA  NE HEP2003 Aachen, 17-23 July 2003 The kaons are produced in pairs (K + K - and K S K L ) with opposite momentum. The detection of a kaon on one side can be used to tag the other kaon in the opposite side Measure of absolute branching ratios Interferometry studies on K S K L system  e-e- e+e+ KLKL KSKS p (MeV/c)l (cm) K + K - 12795 KSKS 1100.6 KLKL 110 343 all K S decay close to the IP reasonable acceptance for K L F decay%#/pb -1 K + K - 49.21.5x10 6 K S K L 33.710 6       15.55x10 5  1.34x10 4

5. E. SantovettiHEP2003 Aachen, 17-23 July 2003 The KLOE detector Electromagnetic calorimeter  lead/scintillating fibers structure  15 X 0 thickness  4880 PMT's Drift chamber (4m Ø x 3.3m)  90% He – 10% IsoB mixture (X 0 ~ 500m)  12582/52140 sense/total wires  stereo geometry for z measurement Quadrupole calorimeter  lead/sc. tiles calorimeter surrounding the permanent quadrupoles (32 PMT's) Superconducting coil (5m Ø)  B = 0.52 T

6. E. SantovettiHEP2003 Aachen, 17-23 July 2003 Detector performances calorimeter Drift chamber High efficiency for low energy photons

7. E. SantovettiHEP2003 Aachen, 17-23 July 2003 KLOE physics program 1999 2000 2 pb –1 20 pb –1 200 pb –1 2 fb –1 2002  K S  , K S  3 , K S    K L  2 , K L    V us from K ± and K L decays  K ± branching ratios   (e + e –     – ) to 1%   radiative decays   f 0 , a 0  scalar    ’ ,  pseudoscalar  K S decays BR(K S     – )/BR(K S      ) BR(K S   e ) first published results 500 pb -1 now on tape Discrete symmetries  Re(  ) via double ratio (CP direct)  K L K S Semileptonic asymmetry (CPT)  K L K S interferometry

8. E. SantovettiHEP2003 Aachen, 17-23 July 2003  mass and width  line shape has been fitted for the main  decays W(MeV) + corrections (phase space + contributions from  ) K + K – 49.2% K L K S 33.7%  15.5%  1.3%  parameters: mass, total width, peak cross sections K+K–K+K– KSKLKSKL   In the case of  a fit with several points has been used to find the correct line shape form (interference between direct,  and  ) With a combined fit, we measure the  width:    4.19±0.04 MeV (preliminary) (Mass is calibrated with the CMD-2 value)

9. E. SantovettiHEP2003 Aachen, 17-23 July 2003 Neutral kaon mass KLOE can study masses of particles with high accuracy thanks to excellent drift chamber momentum resolution Neutral kaon mass can be measured using K S      W (MeV)  (e + e -   K S K L ) (  b) KSKLKSKSKLKS Energy scale from CMD-2  mass value M Ks =497.583±0.005 stat ±0.020 syst MeV* PDG: 497.648±0.022 MeV * KLOE Note 181 (http://www.lnf.infn.it/kloe/) 2001 Energy scan

10. K S is tagged by identification of K L in the calorimeter (K L crash): a neutral cluster in a fixed time window efficiency ~ 30% ( largely geometrical) angular resolution on tagged K S ~ 1° momentum resolution ~ 2 MeV E. SantovettiHEP2003 Aachen, 17-23 July 2003 K S /K L tagging K L is tagged by identification of the K S     - decay: a vertex near the interaction point with the kaon inv. mass efficiency ~ 70% angular resolution on tagged K L ~ 1° momentum resolution ~ 2 MeV

11.  (K S       )/  (K S      ) Can be used to extract     phase shifts and K   amplitudes Provides information on isospin symmetry breaking from EM terms Chiral pert. theory First part of the double ratio From the K   decays (K S, K + ), in the exact isospin symmetry hypothesis, we have: E. Santovetti HEP2003 Aachen, 17-23 July 2003 considering the EM correction: K   decays measure     To extract    , we need a theoretical input  EM. Important to know the effective E  cutoff in      decay

12.  (K S       )/  (K S      ) E. SantovettiHEP2003 Aachen, 17-23 July 2003 K S      at least 3 neutral clusters in time E cl > 20 MeV, |cos  | < 0.9 to reduce machine Bkg Efficiency ~ 90% K S      2 tracks from IP extrapolated to the EmC (120 MeV <p TRK < 300 MeV) Efficiency ~ 60% The measurement is fully inclusive in the radiated photon energy (no cut in the      invariant mass) Efficiency is corrected for the radiated photon in the final state by folding the MC distribution (linear interpolation) with the photon spectrum theoretically predicted 0.3% effect MC  MC 

13.  (K S       )/  (K S      ) E. SantovettiHEP2003 Aachen, 17-23 July 2003 KLOE ‘02 KLOE '022.236  0.003  0.015 17 pb -1 2000 data PDG ’022.197  0.026World average         KLOE  (K S       )/  (K S      ) 47.8±2.8 47.7±1.5** PDG '02  (K S       )/  (K S      ) 56.7±8.0* Physics Letters B538 (2002) *Cirigliano et al. (2000) **G. Colangelo et al. (2001)

14. Cut on time of flight: The mass hypothesis m=m e and m=m  on both tracks allows to discriminate a large part of background E. SantovettiHEP2003 Aachen, 17-23 July 2003 K S    e +,   e - Together with the K L   e  can be used to strictly test CPT and the  S=  Q Provides information about V us Difficoult to isolate K s   e respect to the more abundant (x1000) K s   best measurement CMD-2: BR(K s   e ) = (7.2 ± 1.4) x 10 -4 (75 events)

15. E. SantovettiHEP2003 Aachen, 17-23 July 2003 K S    e +,   e - Use of variable E miss -cp miss For  e decays this is the neutrino mass, while for the     decays a value larger than zero is expected. A fit of the data to the sum of the signal and background spectra simulated by MonteCarlo allows to extract the number of events. KLOE preliminary (170 pb -1 '01 data) BR(   e + )3.46 ± 0.09 stat ± 0.06 syst BR(   e - )3.33 ± 0.08 stat ± 0.05 syst BR(  e )6.81 ± 0.12 stat ± 0.10 syst 6 7 8 ×10 -4 CMD-2 ’99 PDG eval. from K L KLOE ’02* (17 pb -1 2000 data) KLOE ’03 preliminary * Physics Letters B535 (2002)

16. E. SantovettiHEP2003 Aachen, 17-23 July 2003 K 0   e, CPT and  S=  Q KLOE preliminary A S = (19 ± 17 stat ± 6 syst ) x 10 -3 First measurment of A S ! A S = A L if CPT conserved ALAL PDG '02(3.33 ± 0.14) x 10 -3 KTeV '02(3.322 ± 0.058 ± 0.047) x 10 -3 Re(x) (x 10 -3 ) KLOE preliminary3.3 ± 5.2 ± 3.5 CPLEAR '98-1.8 ± 4.1 ± 4.5 CPT:  b = d = 0  S   Q transitions are forbidden at lowest order in the SM  S=  Q: c = d = Re(x) = 0

17. E. SantovettiHEP2003 Aachen, 17-23 July 2003  (K L   )/  (K L        ) Provide information about the absortive contribution (A abs ) to the K L   decay (long-distance term) – Prediction on K s   Very sensitive to the calorimeter performance in reconstructing the neutral vertex very clean signals: low background (K L      ) K L        inclusive measure: at least four neutral clusters in time with E  > 20 MeV Efficiency > 99% Background ~ 0.4% (K L      ) K L   Close kynematics: cuts on - E * tot, Collinearity, Invariant mass Efficiency ~ 80% Background negligible  (K L   )/  (K L        ) (x10 -3 ) KLOE '03 * 2.793 ± 0.022 stat ± 0.024 syst NA48 '022.81 ± 0.01 stat ± 0.02 syst PDG '022.82 ± 0.08 * Physics Letters B? (2003)  invariant mass plot after the cut on collinearity and total energy 362 pb -1 of data analysed ('01+'02 data) Preliminary 1/10 of 362 pb -1  L (ns) 51.7 ± 0.4PDG '02 51.5 ± 0.4KLOE KLKL

18. E. SantovettiHEP2003 Aachen, 17-23 July 2003 K L  charged (very preliminary) Very preliminary 78 pb -1 ’02 data *Errors are statistical only! (including MC statistics) Systematic errors also ~1-2% but not yet fully evaluated P miss - E miss in  or  hyp. (MeV)  e    KLOE*PDG ‘02 KLKL 0.132  0.0020.1257  0.0019 K L   0.271  0.0020.2717  0.0025 K L   e 0.384  0.0020.3878  0.0027 KLKL (2.02  0.19)·10 -3 (2.081  0.026)·10 -3

19. E. SantovettiHEP2003 Aachen, 17-23 July 2003 K ±        (  ') Direct CP violation in the charge asimmetry (from theory 10 -6 ÷ 10 -4 ) Dalitz plot parameters (CP) Extract isospin amplitudes and phase shifts for K   decay (  PT) (  ') best value (PDG '02) has ~2% error and concerns only K + 00 00 –– K–K– K+K+ ++ 00       Selection   /  0 – tagging and self-triggering  2-tracks vtx in DC volume  p * < 135 MeV/c   4 clusters ontime @ vtx (  t<4  )  E tot < 450 MeV Background: main K ± decays, K e4 ’ Efficiencies evaluated from data by using control samples (ex.  cl from K ±      )

20. E. SantovettiHEP2003 Aachen, 17-23 July 2003 K ±        (  ') BR(K ±  ±  0  0 ) (%) KLOE '03*1.781±0.013 stat ±0.016 syst PDG '021.73±0.04 187 pb -1 event counting (~80000 ev.) 250 pb -1 efficiency estimate s i =( P K –P i ) 2 s 0 =  i s i / 3 ; X =(s 1 –s 2 ) / m  2 Y =(s 3 –s 0 ) / m  2 KLOE* (6.3 pb -1 )PDG '02 g0.586±0.010 ±0.0120.652±0.031 h0.030±0.010 ±0.0130.057±0.018 k0.0055±0.0026 ±0.00180.0197±0.0054 * KLOE Note 187 Preliminary Dalitz plot analysis: F(X,Y) = 1+gY+hY 2 +kX 2 Charge asimmetry analysis in progress

21. E. SantovettiHEP2003 Aachen, 17-23 July 2003 V us determination For K e3 modes: expth |V us | = 0.2196 ± 0.0019 exp ± 0.0018 th Introduced in 1963, known to 1.5% Experimental inputs to V us from PDG 02 ModeBR(%)10 3  10 3  K+e3K+e3 4.87 ± 0.0628.5 ± 2.1 K0e3K0e3 38.79 ± 0.2729.1 ± 1.8 K+3K+3 3.27 ± 0.063.3 ± 1.04 ± 9 K03K03 27.18 ± 0.253.3 ± 0.527 ± 6  L = (5.17 ± 0.04) · 10 -8 s  S = (8.9598 ± 0.0007) · 10 -11 s  + = (1.2384 ± 0.0024) · 10 -8 s KLOE preliminary BR’s confirm previous values for K 0 e3, K 0  3 KLOE will have BR(K  e3 ) soon KLOE will measure all BR’s to < 1% and can also significantly improve , ,  L preliminary E865

22. E. SantovettiHEP2003 Aachen, 17-23 July 2003         Da  ne produces 5·10 5      0 events/pb -1,allowing a detailed study of the decay dominated by the  intermediate state:  mass measurement (CPT) Selection  2 charged tracks with vtx at I.P.  |M miss – M  ° | < 20 MeV (  0 mass)  2 photons (cos  *  < –0.98) (collinearity)   2 = (E tot - M  ) 2 /  E 2 + (M  -M  ° ) 2 /  M 2 < 8 Efficiency ~ 30% - Negligible background A  : 3 terms : M  +, M  –, M  0 and   (Gounaris Sakurai shape) A  : standard Breit Wigner A dir : constant  a d e i  d : |a d | 2 =  |A dir | 2 /  |A  | 2 Fit of the Dalitz plot considering a direct decay together with  (dominant) and  intermediate staes :

23. E. SantovettiHEP2003 Aachen, 17-23 July 2003         2×10 6 events analyzed (16 pb –1 – 2000 data) X=(E  + – E  – ) /  3 Y=(E  ° – M  ° ) KLOE* (6.3 pb -1 )PDG '02 M  (MeV)775.8  0.5  0.3771.1  0.9   (MeV)143.9  1.3  1.1149.2  0.7 m 0 -m ± (MeV)0.4  0.7  0.60.4 ±0.8 m + -m - (MeV)1.5  0.8  0.7 adad 0.78  0.09  0.13 aa (7.1  0.6  0.8)×10 –3 Relative decay intensities from integration of |A| 2 over Dalitz plot I  = 0.937 I dir = 0.0085 I  = 0.0002 I  + I dir + I   1 (+6%) Interference between  and direct decays * Physics Letters B561 (2003) Very different values depending on the used techniques: e + e -,  decay, hadronproduction

24. E. SantovettiHEP2003 Aachen, 17-23 July 2003    The    decay is a C-violating decay with a branching ratio theoretically predicted extremely low ( < 10 -12 )  production chain: 44 E  = 363 MeV Background: 44 55 33 Analysis strategy: N* prompt-clusters = 4 E min > 50 MeV |cos(  )| < 0.91 + Kinematical fit Constraint: 1) energy momentum conservation 2) t = r/c (photons)  2 min To reject background channels with  0 we cut on m  of any pair of photons. The background shape and normalization is estimated from the data B.R.(    ) C.L. 95% KLOE '03 (preliminary)< 1.4·10 -5 Crystall Ball< 5·10 -5 PDG '02< 5·10 -4

25. E. SantovettiHEP2003 Aachen, 17-23 July 2003 Conclusions and outlook DA  NE luminosity has been continuously improving. KLOE expects to collect at least 1 fb -1 in 2003/2004 Analysis of 2000-2001 data brought to several published results on neutral kaons and  decays Work in progress with 2001/2002 data: - K , K L semileptonic decays (V us ) – Rare kaons decays: K S      , K S  3  , K S      e + e , K S   –  decays (about 2×10 7  produced in 500 pb -1 )