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

DAFNE: the Frascati F factory electron positron collider at the f mass energy (ECM= 1020 MeV) separate rings to minimize beam-beam interaction two interaction points (KLOE – DEAR/FINUDA) Machine parameters Design 2002 Total length (m) 98 Max. bunches 120 51 Bunch spacing (ns) 2.7 5.4 Lifetime (min) 40 Bunch current (mA) 20 L single bunch (cm-2 s-1) 4.4 1030 1.5 1030 L peak (cm-2 s-1) 5.3 1032 0.75 1032 f per year (109) 15 0.9 E. Santovetti HEP2003 Aachen, 17-23 July 2003

KLOE data taking history Year pb-1/day average peak 2000 25 pb-1 0.1 0.4 First published results 2001 170 pb-1 0.7 1.8 Luminosity improved but high background Further analyses published 2002 280 pb-1 2.0 4.5 Higher luminosity and background reduced Analysis in progress in 2002 An upgrade of the machine has been done. An increase in luminosity ( > x2 ) is expected in the next data taking. E. Santovetti HEP2003 Aachen, 17-23 July 2003

Kaon physics at DAFNE The kaons are produced in pairs (K+ K- and KS KL ) 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 KS KL system F decay % #/pb-1 K+ K- 49.2 1.5x106 KS KL 33.7 106 r p / p+ p- p0 15.5 5x105 h g 1.3 4x104 p (MeV/c) l (cm) K+ K- 127 95 KS 110 0.6 KL 343 f e- e+ KL KS all KS decay close to the IP reasonable acceptance for KL E. Santovetti HEP2003 Aachen, 17-23 July 2003

The KLOE detector Electromagnetic calorimeter lead/scintillating fibers structure 15 X0 thickness 4880 PMT's Drift chamber (4m Ø x 3.3m) 90% He – 10% IsoB mixture (X0 ~ 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 E. Santovetti HEP2003 Aachen, 17-23 July 2003

Detector performances calorimeter Drift chamber High efficiency for low energy photons E. Santovetti HEP2003 Aachen, 17-23 July 2003

KLOE physics program 500 pb-1 now on tape 2 fb–1 2002 200 pb–1 20 pb–1 Discrete symmetries Re(e/e) via double ratio (CP direct) KLKS Semileptonic asymmetry (CPT) KLKS interferometry 2 pb–1 20 pb–1 200 pb–1 2 fb–1 2002 KS  gg , KS  3p, KS  ppg KL  2p, KL  gg Vus from K± and KL decays K± branching ratios s(e+e–  p+p–) to 1% 2000 f radiative decays f  f0g , a0g scalar f  h’g , hg pseudoscalar KS decays BR(KS  p+p–)/BR(KS  p0p0) BR(KS  pen) first published results 1999 500 pb-1 now on tape E. Santovetti HEP2003 Aachen, 17-23 July 2003

(Mass is calibrated with the CMD-2 value) f mass and width + corrections (phase space + contributions from w r ) f line shape has been fitted for the main f decays K+K– KSKL rp hg In the case of  a fit with several points has been used to find the correct line shape form (interference between direct,  and w) K+K– 49.2% KLKS 33.7%  15.5%  1.3% f parameters: mass, total width, peak cross sections With a combined fit, we measure the f width: Gf=4.19±0.04 MeV (preliminary) (Mass is calibrated with the CMD-2 value) W(MeV) E. Santovetti HEP2003 Aachen, 17-23 July 2003

Neutral kaon mass W (MeV) KLOE can study masses of particles with high accuracy thanks to excellent drift chamber momentum resolution Neutral kaon mass can be measured using KSgp+p- Energy scale from CMD-2 f mass value fgKSKL KSgp+p- s(e+e- g KSKL) (mb) MKs=497.583±0.005stat±0.020syst MeV* PDG: 497.648±0.022 MeV *KLOE Note 181 (http://www.lnf.infn.it/kloe/) 2001 Energy scan W (MeV) E. Santovetti HEP2003 Aachen, 17-23 July 2003

KS/KL tagging KS is tagged by identification of KL in the calorimeter (KL crash): a neutral cluster in a fixed time window efficiency ~ 30% ( largely geometrical) angular resolution on tagged KS ~ 1° momentum resolution ~ 2 MeV KL is tagged by identification of the KS g p+ p- decay: a vertex near the interaction point with the kaon inv. mass efficiency ~ 70% angular resolution on tagged KL ~ 1° momentum resolution ~ 2 MeV E. Santovetti HEP2003 Aachen, 17-23 July 2003

G(KSgp+p-(g))/G(KSgp0p0) Can be used to extract d0-d2 phase shifts and Kgpp amplitudes Provides information on isospin symmetry breaking from EM terms Chiral pert. theory First part of the double ratio From the K g pp decays (KS, K+), in the exact isospin symmetry hypothesis, we have: considering the EM correction: Kgpp decays measure c0-c2 To extract d0-d2, we need a theoretical input dEM. Important to know the effective Eg cutoff in p+ p- g decay E. Santovetti HEP2003 Aachen, 17-23 July 2003

G(KSgp+p-(g))/G(KSgp0p0) at least 3 neutral clusters in time Ecl> 20 MeV, |cosq| < 0.9 to reduce machine Bkg Efficiency ~ 90% KSgp+p- 2 tracks from IP extrapolated to the EmC (120 MeV <pTRK < 300 MeV) Efficiency ~ 60% MC  MC  The measurement is fully inclusive in the radiated photon energy (no cut in the p+p- 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 E. Santovetti HEP2003 Aachen, 17-23 July 2003

G(KSgp+p-(g))/G(KSgp0p0) KLOE '02 2.236  0.003  0.015 17 pb-1 2000 data PDG ’02 2.197  0.026 World average Physics Letters B538 (2002) KLOE ‘02 c0-c2 d0-d2 KLOE G(KSgp+p-(g))/G(KSgp0p0) 47.8±2.8 47.7±1.5** PDG '02 56.7±8.0* *Cirigliano et al. (2000) **G. Colangelo et al. (2001) E. Santovetti HEP2003 Aachen, 17-23 July 2003

KSgp-e+n, p+e-n Together with the KLgpen, can be used to strictly test CPT and the DS=DQ Provides information about Vus Cut on time of flight: The mass hypothesis m=me and m=mp on both tracks allows to discriminate a large part of background Difficoult to isolate Ksgpen respect to the more abundant (x1000) Ksgpp best measurement CMD-2: BR(Ksgpen) = (7.2 ± 1.4) x 10-4 (75 events) E. Santovetti HEP2003 Aachen, 17-23 July 2003

KSgp-e+n, p+e-n Use of variable Emiss-cpmiss For pen decays this is the neutrino mass, while for the p+p- 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. 6 7 8 ×10-4 CMD-2 ’99 PDG eval. from KL KLOE ’02* (17 pb-1 2000 data) KLOE ’03 preliminary *Physics Letters B535 (2002) KLOE preliminary (170 pb-1 '01 data) BR(p-e+n) 3.46 ± 0.09stat ± 0.06syst BR(p+e-n) 3.33 ± 0.08stat ± 0.05syst BR(pen) 6.81 ± 0.12stat ± 0.10syst E. Santovetti HEP2003 Aachen, 17-23 July 2003

K0gpen, CPT and DS=DQ AS = (19 ± 17stat ± 6syst) x 10-3 CPT: b = d = 0 AS = AL if CPT conserved KLOE preliminary AS = (19 ± 17stat ± 6syst) x 10-3 First measurment of AS ! AL PDG '02 (3.33 ± 0.14) x 10-3 KTeV '02 (3.322 ± 0.058 ± 0.047) x 10-3 DSDQ transitions are forbidden at lowest order in the SM DS=DQ: c = d = Re(x) = 0 Re(x) (x 10-3) KLOE preliminary 3.3 ± 5.2 ± 3.5 CPLEAR '98 -1.8 ± 4.1 ± 4.5 E. Santovetti HEP2003 Aachen, 17-23 July 2003

G(KLggg)/G(KLgp0p0p0) Provide information about the absortive contribution (Aabs) to the KLgmm decay (long-distance term) – Prediction on Ksggg Very sensitive to the calorimeter performance in reconstructing the neutral vertex very clean signals: low background (KLgp0p0) KLgp0p0p0 inclusive measure: at least four neutral clusters in time with Eg > 20 MeV Efficiency > 99% Background ~ 0.4% (KLgp0p0) KLggg Close kynematics: cuts on - E*tot, Collinearity, Invariant mass Efficiency ~ 80% Background negligible gg 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 tL (ns) 51.7 ± 0.4 PDG '02 51.5 ± 0.4 KLOE KLgp0p0p0 G(KLggg)/G(KLgp0p0p0) (x10-3) KLOE '03* 2.793 ± 0.022stat ± 0.024syst NA48 '02 2.81 ± 0.01stat ± 0.02syst PDG '02 2.82 ± 0.08 *Physics Letters B? (2003) E. Santovetti HEP2003 Aachen, 17-23 July 2003

Pmiss - Emiss in pm or mp hyp. (MeV) KLg charged (very preliminary) KLOE* PDG ‘02 KLgp+p-p0 0.1320.002 0.12570.0019 KLgpmn 0.2710.002 0.27170.0025 KLgpen 0.3840.002 0.38780.0027 KLgp+p- (2.020.19)·10-3 (2.0810.026)·10-3 Pmiss - Emiss in pm or mp hyp. (MeV) pen pmn p+p-p0 p+p- *Errors are statistical only! (including MC statistics) Systematic errors also ~1-2% but not yet fully evaluated Very preliminary 78 pb-1 ’02 data E. Santovetti HEP2003 Aachen, 17-23 July 2003

K±gpp0p0 (t')  + K+ – K– 0 Direct CP violation in the charge asimmetry (from theory 10-6 ÷ 10-4) Dalitz plot parameters (CP) Extract isospin amplitudes and phase shifts for Kgppp decay (cPT) (t') best value (PDG '02) has ~2% error and concerns only K+ 0 – K– K+ +  Selection mn/pp0 – tagging and self-triggering 2-tracks vtx in DC volume p* < 135 MeV/c 4 clusters ontime @ vtx (Dt<4s) Etot < 450 MeV Background: main K± decays, Ke4’ Efficiencies evaluated from data by using control samples (ex. ecl from K±gpp0) E. Santovetti HEP2003 Aachen, 17-23 July 2003

K±gpp0p0 (t') BR(K±±00) (%) KLOE '03* 1.781±0.013stat±0.016syst PDG '02 1.73±0.04 *KLOE Note 187 187 pb-1 event counting (~80000 ev.) 250 pb-1 efficiency estimate Preliminary Dalitz plot analysis: F(X,Y) = 1+gY+hY2+kX2 si=( PK–Pi )2 s0=isi/3 ; X=(s1–s2)/m2 Y=(s3–s0)/m2 KLOE* (6.3 pb-1) PDG '02 g 0.586±0.010 ±0.012 0.652±0.031 h 0.030±0.010 ±0.013 0.057±0.018 k 0.0055±0.0026 ±0.0018 0.0197±0.0054 Charge asimmetry analysis in progress E. Santovetti HEP2003 Aachen, 17-23 July 2003

Experimental inputs to Vus from PDG 02 Vus determination Introduced in 1963, known to 1.5% |Vus| = 0.2196 ± 0.0019exp ± 0.0018th KLOE preliminary BR’s confirm previous values for K0e3, K0m3 KLOE will have BR(K+e3) soon KLOE will measure all BR’s to < 1% and can also significantly improve l+, l0, tL preliminary E865 For Ke3 modes: exp th Experimental inputs to Vus from PDG 02 Mode BR(%) 103 l+ 103 l0 K+e3 4.87 ± 0.06 28.5 ± 2.1 K0e3 38.79 ± 0.27 29.1 ± 1.8 K+m3 3.27 ± 0.06 3.3 ± 1.0 4 ± 9 K0m3 27.18 ± 0.25 3.3 ± 0.5 27 ± 6 tL = (5.17 ± 0.04) · 10-8 s tS = (8.9598 ± 0.0007) · 10-11 s t+ = (1.2384 ± 0.0024) · 10-8 s E. Santovetti HEP2003 Aachen, 17-23 July 2003

f grp,p+p-p0 DaFne produces 5·105 p+p-p0 events/pb-1 ,allowing a detailed study of the decay dominated by the rp intermediate state: r mass measurement (CPT) Selection 2 charged tracks with vtx at I.P. |Mmiss– Mp° | < 20 MeV (p0 mass) 2 photons (cos q*gg < –0.98) (collinearity) c2 = (Etot- Mf )2/sE2 + (Mgg-Mp°)2/sM2 < 8 Efficiency ~ 30% - Negligible background Fit of the Dalitz plot considering a direct decay together with rp (dominant) and wp intermediate staes: Arp : 3 terms : Mr+, Mr–, Mr0 and Gr (Gounaris Sakurai shape) Awp : standard Breit Wigner Adir: constant  ad eifd : |ad|2 =  |Adir|2 /  |Arp|2 E. Santovetti HEP2003 Aachen, 17-23 July 2003

f grp,p+p-p0 X=(E+– E–)/3 Y=(E°– M°) 2×106 events analyzed (16 pb–1 – 2000 data) Very different values depending on the used techniques: e+e-, t decay, hadronproduction KLOE* (6.3 pb-1) PDG '02 Mr (MeV) 775.8  0.5  0.3 771.1  0.9 Gr (MeV) 143.9  1.3  1.1 149.2  0.7 m0-m± (MeV) 0.4  0.7  0.6 0.4 ±0.8 m+-m- (MeV) 1.5  0.8  0.7 ad 0.78  0.09  0.13 aw (7.1  0.6  0.8)×10–3 X=(E+– E–)/3 Y=(E°– M°) *Physics Letters B561 (2003) Relative decay intensities from integration of |A|2 over Dalitz plot Irp = 0.937 Idir = 0.0085 Iwp = 0.0002 Irp + Idir + Iwp  1 (+6%) Interference between rp and direct decays E. Santovetti HEP2003 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 , KL semileptonic decays (Vus) – Rare kaons decays: KS  p+p- g, KS  3p0, KS  p+p- e+e, KS  gg –  decays (about 2×107  produced in 500 pb-1) E. Santovetti HEP2003 Aachen, 17-23 July 2003