Heavy quarks and leptons ‘02 KLOE results on Kaon decays and F radiative decays E. De Lucia (INFN Roma) for the KLOE Collaboration Heavy Quarks and Leptons 2002, Vietri 27/5-1/6 E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 DAFNE parameters Design parameters Beam energy : 510 MeV Max number of bunches : 120 Bunch spacing : 2.7 ns Bunch current : 40 mA Single bunch luminosity : 4·1030 cm2 s1 DEAR 50 m L = 5 ·1032 cm2 s1 E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 DAFNE Performance KLOE Integrated Luminosity april ’99  december ‘01 pb-1 1999 (25 pb-1  7.5 x 107 f) analysis completed 2000 (190 pb-1  5.7 x 108 f) analysis in progress 2001 1.0 0.8 0.6 0.4 0.2 0.0 s(e+e-  KSKL )(mb) F resonance s (MeV) 1015 1020 1025 1030 2001 day performance: peak average L(cm2 s1) 5 · 10 31 3.5 · 10 31 day L dt (pb1) 3 1.8 MAY ’02 new data taking started L(cm2 s1) 4.6 · 10 31 3.2 · 10 31 day L dt (pb1) 2.5 2 machine background reduction of a factor 23 E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 The KLOE detector detection of a KS (KL) guarantees the presence of a KL(KS) with known momentum and direction TAGGING Neutral kaons are produced in a pure quantum state (JPC=1--) : (contamination from KSKS,KLKL < 10-9) EMC pK  110 MeV/c S = 6 mm L= 3.4 m 4 m diameter × 3.3 m length 90% helium, 10% isobutane 12582/52140 sense/tot wires All-stereo geometry 7 m 20 < Eg < 500 MeV DC 6 m Lead/scintillating fiber 98% coverage of solid angle 88 modules (barrel + end-caps) 4880 PMTs (two side read-out) 155 < pp < 265 E. De Lucia Heavy quarks and leptons ‘02

The KLOE detector performances mpp = 497.7 MeV/c2 sm = 1 MeV/c2 KS  p+p- sr f (mm) sp/p = 0.4 % sr f = 150 mm sz = 2 mm sV = 3 mm p0  gg h  gg sE /E = 5.4% / st = 54 ps / s(t-r/c) (ps) 50 ps(cal) 120 ps (coll.time) E. De Lucia Heavy quarks and leptons ‘02

DAFNE energy and bunch-crossing time  s from the b of KL interacting in the EmC s from KS pions and Bhabha electrons momenta measurement Energy s (MeV) At current luminosity Dafne energy at 0.01% within 1 minute of data taking using KL b, KS energy and Bhabha scattering events Bunch-crossing time e+e- large spread of the trigger time with respect to the crossing time but the signal is synchronized with machine RF/4 (10.8 ns) at 50 ps level Off-line determination of the bunch-crossing time T0 10.8 ns hp: the fastest cluster with time tCLUS in EMC is due to a prompt  from I.P. with time of flight tTOF = RCLUS/c : (ECLUS > 50 MeV and CLUS > 60 cm to avoid selection of “accidental” clusters) E. De Lucia Heavy quarks and leptons ‘02

The KLOE physics program KS physics : BR(KS  p+p-(g))/BR(KS  p0p0) BR(KS  pen) f radiative decays f  f0g, a0g f  h’g, hg 2000 statistics:  first publications O( 20 pb-1 ) rare KS decays KL form factors, KL  2p, KL  gg K ± decays s(e+e- p+p-) via ISR h decays 2001 statistics: on tape analysis in progress O( 200 pb-1 ) e’/e via double ratio Semileptonic asymmetry (CPT test) KLKS Interferometry E. De Lucia Heavy quarks and leptons ‘02

Recent results in publication Using a sample of 5 x 107 f decays (2000 data): (KS  p+p-() )/ (KS  p0p0) hep-ex/0204024 , accepted by Phys.Lett.B BR(KS  pen) Phys.Lett. B 535 37 (2002) BR(f  h p0 g )  BR(f  a0 g  h p0 g ) Phys.Lett. B 536 209 (2002) BR (f  p0 p0 g)  BR(f  f0 g  p0 p0 g ) Phys.Lett.B 537 21 (2002) BR(f  h’g) /BR( f  hg) to be submitted to Phys.Lett. B E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 KS analysis at KLOE b* after correction for different pion velocities and trigger latency KS tagging using time of flight identification of KL interacting in the EmC (“KL-crash”) selected as a calorimeter cluster with: Eclus > 200 MeV | cos(qclus)| < 0.7 0.195  b*  0.2475 (b* = KL velocity in the f rest frame) =0.004  WDANE= 1 MeV b* ~ 0.218 KL-crash KS  p+ p -  KS momentum from KL cluster position  easier determination of trigger efficiency 40% of times , KL-crash triggers by itself  relies on the measurement of b* slightly dependent on KS decay 2000 data analysis = 5.4x106 KL crash 2001 data on tape ~ 6 x107 KL crash E. De Lucia Heavy quarks and leptons ‘02

(KS  p+p - ())/(KS  p0p0) Motivations first step towards Re(e) extraction of Isospin 0 and 2 amplitudes and phases from consistent treatment of soft  in KS  p+p -() KL-crash .and.  3 neutral “prompt” clusters: |tCLUS-RCLUS/c| < 5st .and. ECLUS > 20 MeV .and. cos <0.9 KS  p0p0 selection acceptance and E cuts correction from MC KS   +  - () selection KL-crash.and.2 tracks from IP reaching EMC(*) 120 < Ptrack < 300 MeV/c .and. 30o <  < 150o fully inclusive measurement  no  required in EMC Eg cosqg (*) acceptance depending on the photon energy E* epp(g)(E* ) from MC folded to theoretical  spectrum Ptrack (MeV/c) MC- signal DATA E. De Lucia Heavy quarks and leptons ‘02

Efficiency evaluation KS   +  - () KS  p0p0 single-track reconstruction efficiency from KS  p + p - data, used to scale MC e+ - (sel and rec) = (57.6 ± 0.2) % photon detection efficiency from data using f  p+ p- p0 events. The overall selection efficiency (mostly acceptance): e00 = (90.1 ± 0.2)% single-particle t0 and trigger efficiencies using data: KS  p+p - from KL  p +p -p0 –tagged sample (t0-independent), f  p +p -p0 and KS  p+p - with 2 trigger sectors fired by KL-crash plugged into MC e + - (t0 and trig) = (97.9 ± 0.03) % Cluster cuts: Prompt means t-R/c < min(5sig, 3ns), E > 20 MeV, cos theta < 0.9 (theta > 26 deg) Photon efficiency not parameterized by single cluster as in Ke3 analysis, but parameterization put in MC via EmCFakeThresh module T0 efficiency is actually from MC t0 and trigger efficiency using data: KS  p0 p0 from KL  p +p -p0 –tagged sample (t0-independent), KS  p0p0 with 2 trigger sectors fired by KL-crash e00 (t0 and trig) = (99.86 ± 0.04)% E. De Lucia Heavy quarks and leptons ‘02

(KS  p+p - ())/(KS  p0p0) Result Statistical error (%) 0.14 0.20 photon counting 0.23 trigger and t0 0.26 tracking 0.68 Overall systematic error 0.55 KS  p0p0/KS  p+p- tag % Contribution to systematic error Nev (KS  p+p- ) = 1.098 x 106 Nev (KS  p0p0 ) = 0.788 x 106 KLOE 2000 data 2.239  0.003stat  0.015syst PDG 2000 average 2.197  0.026 (without clear indication of E* ) With 2001 data (180 pb-1) improvement s on: absolute scale  tagging efficiency bias statistics of control sub-samples Eg* spectrum Cluster efficiency biggest error because EmCFakeThresh used to evaluate. Accidental clusters and splitting also discrepant Tag bias may go down when data with wider cuts analyzed Syst error on inclusive measurement due to contribution to KL -> p+p-g must be insignificant: Eff vs. Eg is 15% lower at 20 MeV than at 0 MeV, and falls off slowly. Meanwhile, Eg spectrum falls off sharply (1/Eg). So vast majority of p+p-g decays are detected. E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 BR( KS  p e  n) Motivations if (CPT).and.(DS.eq. DQ) then BR( KS  p e  n) = BR( KL  p e  n)x GL/ GS from PDG values = (6.704  0.071)x10-4 only one measurement (CMD-2 1999): (7.2  1.4)x10-4 KL-crash.and.charged vertex at IP (r<8cm , |z|<10cm) .and.2 tracks with associated EmC clusters invariant mass of the tracks in p hp Mpp < 490 MeV/c2 (against background from KS  p+p-) p/e identification using time-of-flight Emiss - |pmiss| Selection b  0.8 t  9 ns b = 1 t  7 ns e p Ddt (p,e) =[t1CLU - t2CLU] – [L1 /c (p) –L2 /c (e)] |Ddt (p, p)| > 1.5 ns to reject KS  p+p- Cuts on Ddt (p, e) and Ddt(e, p) p/e identification using time-of-flight Vertex cuts: dxy < 8 cm, |z| < 10 cm. Preselection in P* vs Mpp: Neither is peaked since nu carries away momentum, anticorrelation since small Mpp = smaller mass of track system, larger momentum for same energy ? TCA cut: dtTCA < 30 cm Purity of Klpen sample: contmination < 0.3% E. De Lucia Heavy quarks and leptons ‘02

Efficiency evaluation 2000 Fit to Emiss-Pmiss spectrum using MC spectra for signal and p+p- background Normalization to KS  p+p- decays Vertex reconstruction, fiducial cuts and Mpp efficiency from MC but also from data KL  pen near I.P. (high-purity sample (> 99.7 %), by kinematic cuts) and KS  popo to scale MC Tracking efficiency for MC and data from KS  p+p- Single-particle t0 , track-cluster, and trigger efficiencies from data using KL  pe n near origin and KS  p+p- but also fp+p-p0 . MC efficiency scaled accordingly Time of flight ID efficiency from KL  pen decays near origin and KS  p+p Overall selection efficiency: (20.8 0.4)%  Single particle efficiencies: KL used for all e and for low-p pions, pi-pi used for most of p range, pi+pi-pi0 for high-p Separate overall t0-TCA-trig measurement possible from KL decays alone Fit takes into account finite statistics in MC background Normalization sample same as in BR(+-)/BR(00) analysis Standard t0/trig unbiasing and isolation cuts when obtaining single-particle efficiencies from pi+pi- and pi+pi-pi0 E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 BR( KS  p e  n ) CPT and DS=DQ predicts: G(KS  p e n ) = G(KL  p e n ) and then: BR(KS  p e n ) = BR(KL  p e n ) x (GL/GS) Using PDG: BR(KS  p e n ) = ( 6.704 ± 0.071 ) x 10-4 KLOE 2000 data, (6.79  0.33stat  0.16syst)x10-4 627  30 evts CMD-2 1999, (7.2  1.4)x10-4 75  13 evts Result Main contributions to the total error % Statistics 4.9 Tracking + vertex efficiency 2.0 Cluster, t0 , trigger 0.9 TOF selection eff 0.8 Tag eff 0.6 Total 5.9 lower with the 2001 data !! 600 lb systematic gorilla is track and vertex efficiency E. De Lucia Heavy quarks and leptons ‘02

F Radiative decays: f  (f0g) p0p0g; f  (a0g) hp0g Motivations various models for f0 and a0 mesons : qqqq state, KK molecule, ordinary qq meson. f  f0g , a0g BR and mass spectra sensitive to f0 ,a0 nature [Achasov, Ivanchenko 1989]: phenomenological framework (kaon loop model) coupling constants g(fKK) from G(fK+K-) g(f0KK) g(a0KK) f0 , a0 model g(f0pp) g(a0hp) M(p0p0) M(hp) spectra f0, a0 Kaon loop final state f radiative g a0 analysis : uses f  a0g  (hp0 ) g gg 2tracks + 5g final state p+p-p0 5g final state  first observation 0.2 nb taken for indicative CS into f0g and a0g for background est. f0 analysis : uses f  f0g  (p0p0) g 5g final state Overlap = structure dependent function k = f0 momentum E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 F Radiative decays: f  f0g , a0 g  5 g final state Selection 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| conservation ) 1 0 000 00 |M(1) - M (2) | (MeV) M (MeV/c2) e+e  wp0 w  p0g f  00 f  hp0g h  gg f  hg h  gg 3g final state Background sources 5g final states h  p0p0p0 7g final state in hp 1. 0.2 nb taken for indicative CS into f0g and a0g for background est. Photon pairing in the hypothesis kinematic fit with mass constraint 00 0 000 (M(0)=M()) 3 (rejecting events  and  with E  =363 MeV) for (2)  e 0 mass for (1) e (3) two 0 2 cut E. De Lucia Heavy quarks and leptons ‘02

F Radiative decays: f  p0p0g (f0g) After 2 cut in 00 hp + DMgg cut + background sub. Results 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 (from the fit to the spectrum) The fit to the M0 0 spectrum (kaon loop) contributions from f  f0g and f  sg with “strong” destructive interference (Mpp < 700 MeV) Negligible contribution from f  r0p0 p0p0g 0.2 nb taken for indicative CS into f0g and a0g for background est. 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 E. De Lucia Heavy quarks and leptons ‘02

F Radiative decays: f  hp0g (a0g) Sample (a) from h  gg final state (a) (b) Comb. fit M0 (MeV) Parabolic cut to reject 0 .and. M < 760 MeV to reject f0 .and. 3 cut on M to reject  000 BR(f  hp0g) = (8.5  0.5stat  0.6syst)x10-5 Main background :p0p0g. (Nev = 916 Nbck = 309  20 ) Neutral selection as for (a) .and. 1 vtx in I.P. + 2 tracks .and. Minv(p+p-) < 425 MeV to reject KS  p+p .and.kinematic fit with mass constraint on  and 0 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 Sample (b) from h  p+p-p0 final state Combined fit to the Mhp0 spectra using PDG for a0 mass (984.8 MeV ) g2(a0KK)/4p = 0.40  0.04 GeV2 g(a0hp) /g(a0KK) = 1.35  0.09 0.2 nb taken for indicative CS into f0g and a0g for background est. Negligible background with the same topology . (Nev = 197 Nbck = 4  4) BR(f  a0g  hp0g) = (7.4  0.7)x10-5 E. De Lucia Heavy quarks and leptons ‘02

Summary of the results on f0 and a0 Within the context of the kaon-loop model with point-like coupling of scalars to kaon pairs, we have obtained: KLOE 4q model g2f0KK/(4) 2.790.12 ”super-allowed” (few GeV2) (GeV2) gf0 /gf0KK 0.500.01 0.3-0.5 f0 g2a0KK/(4) 0.40  0.04 ”super-allowed” (few GeV2) ga0/ga0KK 1.35  0.09 0.91 a0 f0 parameters compatible with 4q model a0 parameters not well described by the 4q model (2001 data  more accurate study of a0) E. De Lucia Heavy quarks and leptons ‘02

F Radiative decays: f  h‘ g ,hg Motivations Precise measurements of BR(f  h’g) and BR(f  hg) and the determination of h-h’ mixing angle probe hidden strangeness and gluonium content of h’ 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 each g Simple kinematic cuts to eliminate background: f  p+p-p0 with extra g f  KSKL  p+p- p0 p0 with g lost negligible background but N(a)N(b)/100 Selection Used decay chains: a) f  h’g  p+p-hg  p+p-3g  hg  p+p-p0g  p+p-3g the topology is the same b) E. De Lucia Heavy quarks and leptons ‘02

F Radiative decays: f  h‘ g ,hg Result Invariant mass spectrum of h’g N(b) = 50210  220 N(a) = 120  12stat ±5bck R = BR(f  h’g)/BR(f  hg ) KLOE 2000 data R = (4.70  0.47stat  0.31syst) x 10-3 From R we obtain the pseudoscalar mixing angle: (flavor basis) (octet-singlet basis) p= ( 41.8  1.7)o [ qP = (-12.9  1.7)o ] BR (f  h’g ) x 10-5 10 8 6 4 2 2000 data Using PDG value for BR(f  hg) we obtain: BR(f  h’g ) = (6.10  0.61stat  0.43syst) x 10-5 most precise determination to date CMD-2 SND KLOE consistent with the gluonium contents of the h‘ < 15% E. De Lucia Heavy quarks and leptons ‘02

Heavy quarks and leptons ‘02 Conclusions DAFNE improved continuously during the first two years of KLOE data taking and improvements on the background are already visible in 2002 data taking The KLOE detector is performing well With 2000 data we measured: (KS  p+p- (g))/ (KS  p0p0), BR(KS  pe n) f  f0g  p0p0g, f  a0g  hp0g With 2001 data we will improve the results and expect results from: KL  2p, K ± decays, KL  gg decays Rare KS decays ( BR ~ 10-5) s(e+e-  p+p-) by ISR  decays (6106  tag from f  hg Eg = 363 MeV photon) E. De Lucia Heavy quarks and leptons ‘02