Recent Results from KLOE experiment at DAFNE e+e- collider Marco Incagli - INFN Pisa Apr 2004

Marco Incagli - INFN Pisa Greek mythology Daphne ® DAFNE (Greek dafnis, 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 not to be confused with Daphnis son of Hermes (Mercurius) and a Sicilian nymph later a common name of herdsmen Chloe ® KLOE the greening, is a surname of Demeter (Ceres), later on a common name of sheperdness Daphnis and Chloe couple of lovers in the hononymous novel of Logos (~300 BC) made famous by Ravel symphonic poem Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa DAFNE DEAR DAFNE : e+ e - high luminosity collider (Ldesign= 5x1032cm-2s-1) set at the F peak: s = MF = 1.02 GeV s(F)  3.3 mb a f-factory is mostly a kaon factory kaons are produced back to back in the CoM with |p|~110 MeV e+e- in two separate rings with crossing angle 25mrad at IP (small F momentum pF13MeV) Decay BR(%) f  K+ K- 49.1 f  KS KL 33.8 f  r p / p+p-p0 15.6 f  h g 1.26 Marco Incagli - INFN Pisa

Characteristics of a F factory Tagging: observation of KS,L signals presence of KL,S (same is true for K) precision measurement of absolute BR’s pL,S = 110 MeV lS = 0.6 cm Ks decays near interaction point bL,S = 0.22 lL = 3.4 m Large detector to keep reasonable acceptance for KLdecays (~0.5 lL) The KK pairs in the final state have the same F quantum numbers i.e. are produced in a pure JPC = 1– – state F KS (K+) KL (K-) purity 10-10 Interferometry measurements of KSKL system Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa DAFNE performances  L(pb-1) DAFNE Parameters Design 2002 (KLOE) N bunches 120+120 51+51 Lifetime (mins) 120 40 Bunch current(mA) 20 Lbunch (cm-2s-1) 4.4 · 1030 1.5 · 1030 Lpeak (cm-2s-1) 5.3 · 1032 0.8 · 1032 Standard analysis sample: 450 pb-1 from 2001-2002 Beam trajectory length ~ 98 m Beam crossing frequency 368.25 MHz Bunch spacing : 2.7 ns Bunch sizes @ I.P.: sx sy sz 2mm 20 mm 3 cm Lpeak = 2 · 1032 cm-2s-1 L int / day = 10 pb-1 L int / year = 2 fb-1 (2109KSKL) 2004 goal Marco Incagli - INFN Pisa

Physics reach vs Integrated luminosity Interferometry e/e to O(10-4) via double ratio rare KS,L decays, CPT tests 5 fb-1 KS semileptonic asymmetry, KS  3p0, KL  2p, KL gg, K  mn,pp,ppp,pen,ppen, s(e+e-  hadrons) to 1% Today 500 pb-1 2001 50 pb-1 2000 KS physics BR(KS  p+p-)/BR(KS  p0p0) BR(KS pen) f radiative decays f  f0g, a0g f  hg, hg 5 pb-1 1999 Marco Incagli - INFN Pisa

KLOE detector d=4m Lead, Scint.Fibers ECAL Helium, all stereo wires Drift Chamber Marco Incagli - INFN Pisa

Electromagnetic calorimeter Pb - Sc.Fibres - Matrix <r> = 5 g/cm3 ; <X0> = 1.6 cm sampl. frac.~15% (m.i.p.) Measured performances : sE /E = 5.7% /E(GeV) s t= 54 ps /E (GeV)  50 ps 1.2 mm Lead 1.35 mm 1.0 mm 52.5 cm 15X0 450 cm Efficient Detection of Photons  20 MeV 98% Hermetic Coverage Discriminate KL p0p0 vs KL p0p0 p0 Excellent timing to reconstruct KL p0 p0 decay vertex with a precision < 1 cm Serve as a 1st level Trigger Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Drift Chamber High and uniform track reconstruction efficiency Determine the KL,S vertex with an accuracy  1mm Good momentum resolution (dpt/pt0.4% ) Transparent to low energy g (down to 20 MeV) and KL,S regeneration ~52000 stereo wires cell structure: 3:1 field:sense ratio 3 × 3 cm2 in the 46 outer layers 2 × 2 cm2 in the 12 inner layers [90% He, 10% iC4H10 ( X0=900m ) mechanical structure in C-Fibre (<0.1 X0)] Marco Incagli - INFN Pisa

Quadrupole Calorimeter (QCAL) 45 cm 0.5 mm Al-Be 9° permanent magnet quadrupoles 10 cm Spherical Beam Pipe QCal Acceptance increased thanks to Quadrupole Instrumentation: Lead-Scintillator Tile Sampling Calorimeter QCAL Marco Incagli - INFN Pisa

A first glance at interference KSKL  p+p-p+p-: KLOE preliminary 340 pb-1 ’01 + ’02 data Fit with PDG values for GS, GL c2/d.o.f. = 43.7/47 Dm = (5.64  0.37)×109  s-1 PDG ’02: (5.301  0.016)×109  s-1 First observation of quantum interference in relative decay- time distribution of KS, KL No simultaneous decays to same final state ; antisymmetric initial state Peak position sensitive to Dm Coherent KL regeneration on beam pipe |t1 - t2|/t(KS) Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa KAON physics at KLOE This talk (KS KL interference in progress) KSp0en Phys. Lett. B537(2002)21, update KSp0p0p0 preliminary results Other topics Kpp0p0 hep-ex/0307054 KSp+p-(g)/p0p0 Phys. Lett. B538(2002)21 KS mass KLOE note 181 (www.lnf.infn.it/kloe) KLgg/p0p0p0 Phys. Lett. B566(2003)61 KL semileptonic decays in progress K semileptonic decays in progress Kp0en in progress Kpp0/mn in progress Marco Incagli - INFN Pisa

KL on ECAL as a tag of KS “beam” KS tagged by KL interaction in EmC Efficiency ~ 30% (largely geometrical) KS angular resolution: ~ 1° (0.3 in f) KS momentum resolution: ~ 1 MeV b* = velocity of KL in rest frame of f Nominal b* 0.218 KL “crash” = 0.22 (TOF) KS  p-e+n To get the particle TOF, the global event t0 must be fixed Tag efficiency is slightly dependent on the KS decay due to the different global t0 estimation Marco Incagli - INFN Pisa

KS  p+p- as a tag of KL “beam” sM ~ 1 MeV/c2 KS  p+p- KL tagged by KS  p+p- vertex at IP Efficiency ~ 70% (mainly geometrical) KL angular resolution: ~ 1° KL momentum resolution: ~ 1 MeV KL  2p0 Marco Incagli - INFN Pisa

KS pen decays – Physics issues Can be studied in e+e- machines only! Sensitivity to CP violation in K0-K0 mixing: AS = 2Re e (CPT symmetry assumed) - never measured before _ G(KS,L  p-e+n) - G(KS,L  p+e-n) G(KS,L  p-e+n) + G(KS,L  p+e-n) _ AS,L = If CPT holds, AS=AL ASAL signals CPT in mixing, with possible contribution from DSDQ DS=DQ rule can be probed through the measurement of: SM predictions: GammaS = GammaL, As = AL = 2Re epsilon Can extract |Vus| via measurement of BR(KS  pen) - in progress Marco Incagli - INFN Pisa

KS pen decays – Analysis outline Main background from KS pp(g) Kinematic rejection: Mpp < 490 MeV TOF identification: compare p-e expected flight times, reject pp,pm bkg Data MC pen e-p+ 5 5 4 4 3 3 dt(p-e+) (ns) 2 2 e+p- Pipi rejection: Invariant mass, Signal TOF selection, Kinematic closure. 1 1 -1 -1 -1 1 2 3 4 5 -1 1 2 3 4 5 dt(e-p+) (ns) Marco Incagli - INFN Pisa

KS pen decays – Analysis outline 6000 Kinematic closure: use KL to obtain KS momentum PK and test for presence of neutrino: Emiss = MK2 + PK2 – Ep – Ee Pmiss = |PK – Pp – Pe | Determine number of signal counts by fitting data to a linear combination of MC spectra for signal and background  Data — MC sig + bkg 5000 4000 3000 2000 Pipi rejection: Invariant mass, Signal TOF selection, Kinematic closure. 1000 -60 -40 -20 20 40 60 80 Emiss–cPmiss(MeV) Marco Incagli - INFN Pisa

KS pen decays – Analysis outline 400 1200 1600 2000 800 Signal spectrum clearly sensitive to the presence of a photon in the final state  Data — MC sig + bkg Include radiative effects through an IR-finite treatment in MC (no energy cutoff) Normalize signal counts to KS pp(g) counts in the same data set Use BR(KSpp(g)) from previous KLOE measurement Pipi rejection: Invariant mass, Signal TOF selection, Kinematic closure. Emiss–cPmiss(MeV) 10 -10 -20 20 30 Marco Incagli - INFN Pisa

KS pen decays – Preliminary results Correct for charge-dependent efficiencies, mostly extracted from data (data control sample of KL  pen) e  20% given the tag BR(KS  p-e+n) = (3.54  0.05stat  0.05syst) 10-4 BR(KS  p+e-n) = (3.54  0.05stat  0.04syst) 10-4 KLOE preliminary Evaluation of the systematics near completion AS = (-2  9stat  6syst) 10-3 BR(KS  pen) = (7.09  0.07stat  0.08syst) 10-4 Published results: BR(KS  pen) = (6.91  0.34stat  0.15syst) 10-4, KLOE ’02 AL = (3.322  0.058  0.047) 10-3 [KTeV 2002] AL = (3.317  0.070  0.072) 10-3 [NA48 2003] Branching ratio, Rex, As Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Check of DS=DQ rule The quantity Rex+ can be different from zero only if the DS=DQ rule is violated The Standard Model predicts a value Rex+ ~10-6 Using 2001 data only: Rex+ =(2.25.3stat3.5syst)10-3 In agreement with the validity of the rule DS=DQ and with the published CPLEAR result Marco Incagli - INFN Pisa

KS p0p0p0 – test of CP and CPT Observation of KS  3p0 signals CP violation in mixing and/or in decay: SM prediction: GS = GL|h|2, giving BR(KS  3p0) = 1.910-9 Present published limit: BR(KS  3p0) < 1.410-5 Uncertainty on KS  3p0 amplitude limits precision of CPT test: from unitarity Sf A*(KSf) A(KLf)/GS = (1 + i tanfSW)Re e+ (i - tanfSW) Im d (eS,L = e  d) SM prediction Dominating contribution in real part of Bell-Steinberger relation, allow estimate of M11-M22 (ReDelta) A limit on BR(KS  3p0) at 10-7 level translates into an improvement on the accuracy of Im d, i.e. d(MK0 - MK0) d(MK0 - MK0) _ _  210-18   810-19 (MK/MPlanck = 410-20) MK MK Marco Incagli - INFN Pisa

Search for KS p0p0p0 – 2p0 vs 3p0 Data MC KS  3p0 c22p Compare 3p vs 2p hypotheses: 80 c23p - pairing of 6g clusters with better p0 mass estimates c22p - best pairing of 4g’s out of 6: p0 mass, p(KS), CoM angle between p0’s 60 40 Signal selection: 6 prompt clusters, test of energy-momentum conservation, test of 2pi vs 3 pi hypotheses normalize to Ks->pi0pi0 Definition of the signal box obtained from analysis of 6-pb-1-equivalent MC subsample 20 c23p 10 20 30 40 Marco Incagli - INFN Pisa

Search for KS p0p0p0 - sidebands c22p  Data  MC KS  2p0  BR(KS  3p0) = 10-5 Data MC KS  3p0 80 300 60 40 20 200 c23p 10 20 30 40 KS  3p0 decay switched on during MC production of 450 pb-1 equivalent data, with BR equal to the present upper limit Signal selection: 6 prompt clusters, test of energy-momentum conservation, test of 2pi vs 3 pi hypotheses normalize to Ks->pi0pi0 100 c23p 20 40 60 Marco Incagli - INFN Pisa

Search for KS p0p0p0 - sidebands c22p  Data  MC KS  2p0  BR(KS  3p0) = 10-5 Data MC KS  3p0 80 60 750 40 20 c23p 500 10 20 30 40 Signal selection: 6 prompt clusters, test of energy-momentum conservation, test of 2pi vs 3 pi hypotheses normalize to Ks->pi0pi0 250 c23p 10 20 30 40 50 Marco Incagli - INFN Pisa

Search for KS p0p0p0 – signal region 200 c22p  Data  MC KS  2p0  BR(KS  3p0) = 10-5 Data MC KS  3p0 80 60 150 40 20 100 c23p 10 20 30 40 Signal selection: 6 prompt clusters, test of energy-momentum conservation, test of 2pi vs 3 pi hypotheses normalize to Ks->pi0pi0 50 c23p 10 20 30 40 50 Marco Incagli - INFN Pisa

KS p0p0p0 – Preliminary results Nsel(data) = 4 events selected as signal, with efficiency e3p = 23% Nsel(bkg) = 31.3 0.2 bkg events expected from MC, to estimate the BR upper limit use Nsel(bkg) = 1.6 Can state: N3p < 5.83 with a 90% CL N2p / e2p BR(KS  p0p0p0) = BR(KS  p0p0) < 2.110-7, N3p / e3p Normalize signal counts to KS  p0p0 count in the same data set: Signal selection: 6 prompt clusters, test of energy-momentum conservation, test of 2pi vs 3 pi hypotheses normalize to Ks->pi0pi0 A(KS  p0p0p0) A(KL  p0p0p0) Which translates into a limit on |h000| = < 2.410-2 Marco Incagli - INFN Pisa

Summary & Outlook – Kaon physics Present status - KS: Sensitivity to BR’s at the 10-7 level (preliminary limit for KS  3p0) Measurement of Ke3 mode at the % level, <10-2 accuracy on AS Expect 2 fb-1 of integrated luminosity in 2004, would allow: AS with a total accuracy of 4 10-3, first test of SM prediction AS = 2 Re e Sensitivity to KS  3p0 at 10-8 level A measurement of BR(KS  p+p-p0) with 20% relative uncertainty First direct measurement Test of the cPt prediction, BR(KS  p+p-p0) = (2.4  0.7) 10-7 2fb-1 will allow: As to 1%, Sensitivity to BR(3pi0) at 10-8 level BR(Ks gg) at xx%, BR(Ks pi+pi-pi0) at 20% BR(Ks ppg) In progress: Measurement of BR’s for semileptonic KL and K decays Huge statistics: uncertainty will be limited by systematics Measurement of Vus with d|Vus|2 0.1% accuracy Marco Incagli - INFN Pisa

Non-KAON physics at KLOE This talk s(hadronic) hep-ex/0307051, update Other topics frp, p+p-p0 Phys. Lett. B561(2003)55 ff0g, a0g Phys. Lett. B536(2002)209, B537(2002)21 fh’g, hg Phys. Lett. B541(2002)45 hggg hep-ex/0402011, submitted to PLB h p+p-p0, p0p0p0 in progress Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Hadronic cross section - am Motivation: Determination of Hadronic Vacuum Polarization = High Precision Test of the Standard Model: Anomalous magnetic moment of the muon am = (gm-2)/2 Running fine structure constant at Z0-mass aQED (MZ) Updated measurement from E821@BNL, averaging results for m+ and m-: am = (11 659 208  6) 10-10 am(QED), 11 658 470.4  0.3 Standard Model prediction am(weak), 15.4  0.2 am(hadr), 700 Hadronic Vacuum Polarization 2nd largest contrib., cannot be calculated in pQCD Error of hadronic contribution is dominating total error ! Marco Incagli - INFN Pisa

Hadronic cross section - am Dispersion integral relates amhad(vac-pol) to s(e+e-  hadrons) Im[ ]  | hadrons |2 amhad = pp (s<0.5GeV) pp (except r) pp (r region) w + ppp f rest (<1.8GeV) rest (1.8-5 GeV) pQCD (>5GeV) s-1 d2(amhad) Process e+e-  p+p- @ s < 1 GeV contributes as much as 66% to amhad Say: disagreement at 2-sigma level For am calculation, Pipi transition is the dominating contribution (60%) CHECK tau data: what kind of extraction, what is really extracted Marco Incagli - INFN Pisa

am – SM prediction vs experiment So far, estimates of amhad from: measuring s(e+e-  p+p-) vs s at an e+e- collider, varying the beam energy (CMD2, 0.9% rel. uncertainty) using the spectral function from t  pp0nt (LEP, CESR data) CMD2 L= 317.3 nb-1 114000  events in  meson region Marco Incagli - INFN Pisa

am – SM prediction vs experiment So far, estimates of amhad from: measuring s(e+e-  p+p-) vs s at an e+e- collider, varying the beam energy (CMD2, 0.9% rel. uncertainty) using the spectral function from t  pp0nt (LEP, CESR data) hadrons   W  e+ e– CVC: I =1 & V W: I =1 & V,A : I =0,1 & V However, amth(e+e-) – amth(t)  (20±10)10-10 Marco Incagli - INFN Pisa

Muon-Anomaly: Theory vs. Experiment Comparison Experimental Value with Theory - Prediction New cross section data have recently lowered theory error: a) CMD-2 (Novosibirsk/VEPP-2M) p+ p- channel with 0.6% precision < 1 GeV b) t-Data from ALEPH /OPAL/CLEO Theoretical values taken from M. Davier, S. Eidelman, A. Höcker, Z. Zhang hep-ex/0308213 THEORY ’20/‘03 e+ e- - Data: 2.7 s - Deviation t – Data: 1.4 s - Deviation Experiment BNL-E821 Values for m+(2002) and m-(2004) in agreement with each other. Precision: 0.5ppm Experiment ’20/‘04 am - 11 659 000 ∙ 10-10 Marco Incagli - INFN Pisa

Hadronic cross section - aW(MZ) The same diagram (vacuum polarization) also affects the value of aW(MZ) In this case there is not the 1/s enhancement, so the relevant part of thespectrum is in the region 1<s<5 GeV not probed by KLOE Rhad=s(had)/s0(mm) contribution to da(MZ) Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Radiative Return Standard method for cross section measurement is the energy scan, i.e. the systematic variation of the c.m.s.-energy of the accelerator DAFNE is a f - factory and therefore designed for a fixed c.m.s.-energy: s = mf = 1.019 MeV; a variation of the energy is not foreseen in near future Complementary approach: Take events with Initial State Radiation (ISR) “Radiative Return” to r-resonance: e+ e- r + g  p+ p- + g r0 Cross section as a function of the 2-Pion invariant mass s’=Mpp MC- Generator PHOKHARA = NLO J. Kühn, H. Czyż, G. Rodrigo Radiator-Function H(s) ISR H(s) s’ ds(e+ e- p + p- g ) dMpp Marco Incagli - INFN Pisa

s(e+e-  p+p-) from ppg events Measure s(e+e-  p+p-g) at fixed s Exploit ISR to extract s(e+e-  p+p-) for s´ from 2mp  s Have to watch out for hard FSR: Rate <ISR due to r resonance FSR causes events with Mg* = s to be assigned to lower s´ values Measure sigma p+p-g at fixed beam energy and exploit ISR to measure s(p*p-) exploring energy range 2mpi,sqrt(s): L measurement at one fixed value of sqrt(s) Have to: 1) take out hard FSR, same order of signal; 2) Include ISR+FSR; 3) Correct vacuum polarization, not to double count.. FSR correction Have to properly include radiative corrections, VP correction Must remove vacuum polarization, Marco Incagli - INFN Pisa

Measurement of sppg – Analysis scheme Two high-q tracks from a vertex close to IP Compute photon momentum, without explicit g detection: pg = pe++ pe- - pp+- pp- Select signal with a small-q photon, to enhance ISR: dsISR/dW  1/sin2q relative contribution of hard FSR below the % level over entire Mpp spectrum Analysis outline: Select signal with low theta photon, high theta pions, to enhance ISR No events with Mpp< 600 MeV Reduce background Residual background from p+p-p0, e+e-g, m+m-g Marco Incagli - INFN Pisa

Background I - m+m-g, p+p-p0 Kinematical selection based on trackmass (Mtrk) variable: For ppg events Mtrk~mp For ppgg events Mtrk>mp  the cut may reject events with multiphoton emission Estimate and subtract residual background by fitting data to a linear combination of signal and bkg MC distributions rp preselection already applied MTRK (MeV) p+ p- p0 p+p-p0 p+p-gg tail signal region p+ p- g mp mm m+m-g m+ m- g mr2 Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Background II - e+e-g To reduce Bhabha contamination, a -e separation is performed using a particle ID estimator based on: e e  before cutting on particle ID estimator TOF of charged clusters in EMC Shape and energy deposition of the cluster    after cutting on particle ID estimator The event is selected if at least one of the charged tracks is identified to be a pion. p+ p-p0 mp m+ m- g Mtrack Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Luminosity L = NBhabhas / seffMC Experimental precision: Theory precision (radiative corrections): Large Angle Bhabha Events > 55º Excellent agreement Data – MC Background-”free” ( 0.5% p+p- ) Experimental uncertainty 0.3% BABAYAGA event generator (Pavia group) systematic comparison among other generators (Berends, KKMC, VEPP-2M), max. D=0.7% Theoretical uncertainty 0.5% (BABAYAGA) Polar Angle [°] Acoll. [°] Momentum [MeV] Cut 55°<Q<125° p>400MeV Acoll.<9° MC Data Bhabhas Marco Incagli - INFN Pisa

(e+e-  p+p-g) (nb/GeV2) Analysis s( e+e-  p+p-g) ds Efficiencies: - Trigger & Cosmic veto Tracking, Vertex p- e- separation Reconstruction filter Trackmass-cut Unfolding resolution Acceptance — (e+e-  p+p-g) (nb/GeV2) dMpp2 Errors: L = 141pb-1 1.5M events 1.0% Background: e+ e- e+ e- g e+ e-  m+ m- g f  p+ p- po 0.5% obtained from PHOKHARA H(Mpp2) Luminosity: Bhabhas at large angles > 55°, seff = 430 nb, 0.3%exp 0.5%theo Mpp2 (GeV2) Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Extraction s( e+e-  p+p-) Radiator-Function (ISR): s( e+e-  p+p-) ISR-Process calculated at NLO-level Generator PHOKHARA (Kühn et.al) Comparison with KKMC (Jadach et.al.) Precision: 0.5% Radiative Corrections: i) Bare Cross Section divide by Vacuum Polarization ii) FSR - Corrections Cross section spp must be incl. for FSR Vacuum Polarization Cross Section Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa FSR Correction * 10% FSR (nlo) /ISR 8% 6% 4% Before trackmass cut 2% The contribution of FSR is as large as 5% in low M2pp bins The cut in the M2pp -Mtrk plane rejects ISR+FSR events FSR contribution + cut efficiency are evaluated by MC 0% -2% After trackmass cut -4% 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 M2pp Marco Incagli - INFN Pisa

Charge asymmetry at large qg To check FSR evaluation in MC, we measure the charge asymmetry (Aq) induced by ISR-FSR interference The asymmetry is suppressed at small photon angles, so it has been evaluated in the angular region 50o<qg<150o The preliminary difference data-MC is 10-20% which we completely assign to a lack of knowledge of FSR FSR correction is ~2% , so the maximum effect on am is 0.4% 0.9 – 1. GeV2 data D(Aq) ~ 15% MC KLOE preliminary 0.8 – 0.9 GeV2 data D(Aq) ~ 13% MC Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Muon Anomaly We have evaluated the dispersions integrals for the 2-Pion-Channel in the energy range 0.35 <Mpp2<0.95 GeV2 ampp = (389.2  0.8stat  4.7syst  3.7theo) 10-10 Comparison with CMD-2 in energy range 0.37 <Mpp2<0.93 GeV2 KLOE (376.5  0.8stat  5.4syst+theo) 10-10 CMD2 (378.6  2.7stat  2.3syst+theo) 10-10 Discrepancy of ca. 10% between e+e- - Data and t – Data (ALEPH) for Mpp2 > 0.6 GeV2 KLOE – data confirms discrepancy with respect to t – data ! Explanation: m(r0)  m(r) ??? Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Muon Anomaly |Fp|2 We have evaluated the dispersions integrals for the 2-Pion-Channel in the energy range 0.35 <Mpp2<0.95 GeV2 — KLOE 40 ampp = (389.2  0.8stat  4.7syst  3.7theo) 10-10  CMD2 30 Comparison with CMD-2 in energy range 0.37 <Mpp2<0.93 GeV2 20 KLOE* (376.5  0.8stat  5.4syst+theo) 10-10 CMD2 (378.6  2.7stat  2.3syst+theo) 10-10 10 * Error on model dependence FSR and VP not included! Discrepancy of ca. 10% between e+e- - Data and t – Data (ALEPH) for Mpp2 > 0.6 GeV2 0.5 0.7 0.9 KLOE – data confirms discrepancy with respect to t – data ! Explanation: m(r0)  m(r) ??? Marco Incagli - INFN Pisa

Muon-Anomaly: Theory vs. Experiment Comparison Experimental Value with Theory - Prediction Preliminary New cross section data have recently lowered theory error: a) CMD-2 (Novosibirsk/VEPP-2M) p+ p- channel with 0.6% precision < 1 GeV b) t-Data from ALEPH /OPAL/CLEO Theoretical values taken from M. Davier, S. Eidelman, A. Höcker, Z. Zhang hep-ex/0308213 THEORY ’20/‘03 e+ e- - Data: 2.7 s - Deviation t – Data: 1.4 s - Deviation Including KLOE result Experiment BNL-E821 Values for m+(2002) and m-(2004) in agreement with each other. Precision: 0.5ppm Experiment ’20/‘04 am - 11 659 000 ∙ 10-10 Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Summary on s(had) We have proven the feasibility to use the Radiative Return to perform a high-precision measurement of the hadronic cross section at the f-factory DAFNE Statistical Error is negligible In the energy range Mpp2 > 0.6 GeV2 we do reproduce the large deviation seen by t-data with respect to e+e- Our evaluation of the hadronic contribution of the muon anomaly confirms the deviation btw. Theory and Experiment of about 3 sigma A draft for a paper is under collaboration-wide review! and in this sense data has still to be considered as PRELIMINARY Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa am – Prospects 4000 Measure s(pp) in the region close to threshold, Mpp < 600 MeV, responsible for 20% of amhad This region currently excluded by angular selection N(ppg) / MeV 3000 2002 data ISR+FSR MC 2000 1000 Mpp (MeV) N(ppg) / MeV 103 Pion FF vs Mpp, comparison wrt CMD2 Prospects for measurement of the region close to threshold, around xx% of the pipi contribution to am, poorly known Normalize to mumugamma and check ISR,FSR calculated from scalar QED (Kuhn) 102 Mpp (MeV) 10 Mg* (MeV) 300 400 500 600 700 800 900 Marco Incagli - INFN Pisa

Marco Incagli - INFN Pisa Summary and Outlook KLOE experiment has already provided relevant results, in particular in KS physics and s(hadronic) Continue analysis on s(hadronic) in order to cover the region close to threshold (contribution to am  20%) Analysis on KS,L and K decays with current luminosity New data taking just started Expext to collect >2fb-1, with instant luminosity close to the design one, in order to study KS- KL interference pattern Re(e’/e) with double ratio method KS,L rare decays … Marco Incagli - INFN Pisa