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Dominant K L Branching Ratios, K L Lifetime and V us at KLOE

Dominant K L Branching Ratios, K L Lifetime and V us at KLOE. Introduction - CKM and V us - DA F NE and KLOE K L physics - Branching Ratios - Lifetime - Form Factor - V us  f + (0) Conclusions. Paolo Beltrame IEKP University of Karlsruhe. V ud.

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Dominant K L Branching Ratios, K L Lifetime and V us at KLOE

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  1. Dominant KL Branching Ratios, KL Lifetime and Vus at KLOE • Introduction - CKM and Vus - DAFNE and KLOE • KLphysics - Branching Ratios - Lifetime - Form Factor - Vus  f+(0) • Conclusions Paolo Beltrame IEKP University of Karlsruhe DPG - Dortmund 31.03.2006

  2. Vud Vus Vub 95% 5% 0.00001% ve • e- Vus • s u p + K0 d d CKM Matrix and Vus Couplings parameters between quarks in Weak Interactions, mixing Mass and Weak Eigenstates. Wolfenstein parametrization: four free parameters (, A,, ). Standard Model does not predict the value of any of them. CKM matrix unitarity: first row |Vud|2 + |Vus|2 + |Vub|2~ |Vud|2 + |Vus|2 1 –  Determination of Vus K0 e,(Kl3)semileptonic decays DPG - Dortmund 31.03.2006

  3. KL K- KS K+ f Thef – Factory f(1020) – Factory: electron-positron-collider at s = Mf= 1019.4 MeV BR(  K+K-) = 49.1% BR(  KSKL) = 34.1% f – Factory K – Factory • The fdecay at rest provides monochromatic and pure beams of kaons • Tagging: observation of KL(KS)signals presence of KS(KL) • -precision measurements of absolute BR’s • KLandKSare well separated: - ct (KS) = 6 mm, KS decays near to the interaction point - ct (KL) = 3.4 m, large detector to keep reasonable acceptance for KL decays DPG - Dortmund 31.03.2006

  4. The DAFNEf – Factory s = Mf= 1019.4 MeV Ldesign =5 1032 cm-2 s-1 2001 170 pb-1 2002 280 pb-1 Analysis nearly complete 2004 750 pb-1 2005 1250 pb-1 • Data taking at peak finished in 2005 • Lpeak= 1.3 × 1032 cms • Ltot 2.4 fb-1 • Off-peak run s = 1 GeV finished in March • Ltot 250 pb-1 DPG - Dortmund 31.03.2006

  5. The KLOE detector Superconducting coil Drift chamber Magnetic Field of 0.52 T Track momentum resolution sp/p 0.4% (q > 45°) Vertex resolution sxy 150 mm, sz 2 mm 12582 sense wires 52140 wires in total 90% He + 10% C4H10 Electromagnetic calorimeter Energy resolution sE/E = 5.7%/E(GeV) Time resolution sT = 54 ps/E(GeV)  50 ps Lead/Scint fibres 4880 PM DPG - Dortmund 31.03.2006

  6. KS KL 2 The Tagging method Tagging of KS, KL and K beams allows absolute Branching Ratios measurement: • Relies on capability of selecting a tagging kaon independently on the decay mode of the other kaon in the other hemisphere • In fact some dependence on signal mode exists: tag bias aTB • Tag bias: carefully measured using MC, and data control samples, typically O(1%) KL tagged byKSvertex at IP Efficiency ~70% (mainly geometrical) KL angular resolution: ~1° KL momentum resolution: ~2 MeV DPG - Dortmund 31.03.2006

  7. Data e    (MeV) (Pmiss- Emiss) in  or  hyp Dominant KL Branching Ratios High momentum resolution of KLOE DC Ke3, Kµ3, p+p-p0 vertex • Tag KL by decay KSp+p- • Charged decays selected by closing the kinematics at the vertex: lesser of Pmiss- Emiss • Fit data with linear combination of three MC shapes • Radiative corrections included in MC 2001-2002 Data: 328 pb-1 From PDG‘04 Rare KLdecays: 0.0036 KL Lifetime: 51.50 ns BR(e +  +  + 3KLOE + BR(+ ) PDG’04 = 1.0104 0.0076 Imposing S(BR  x) = 1 tKL= (50.72  0.14stat 0.36syst) ns DPG - Dortmund 31.03.2006

  8. Dominant KL Branching Ratios results (328 pb-1) BR(KL e()) = 0.4007  0.0006stat 0.0014syst BR(KL ()) = 0.2698  0.0006stat 0.0014syst BR(KL 3) = 0.1997  0.0005stat 0.0019syst BR(KL ()) = 0.1263  0.0005stat 0.0011syst Phys. Lett. B632 (2006) 43 • Reasonable agreement with KTeV and NA48 • The new results go in the same direction respect to the PDG older values DPG - Dortmund 31.03.2006

  9. Measure the mean decay path L Lg  000 I.P. LK  +- KL Lifetime: direct measurement Time resolution of KLOE EmC KL  p0p0p0 × 102 Events/0.3 ns PK = 110 MeV Excellent lever arm for lifetime measurement 6 - 24.8 ns 40-165 cm 0.37 lL • KL  p0p0p0tagged by KS  p+p- • Lg and LK obtained from tcl • At least three g’s required • e(LK) ~99% uniform in L • 1.3% residual background • sL(KL) ~2 cm L/bgc (ns) KL= (50.92 0.17stat 0.17syst) ns Phys. Lett. B626 (2005) 15 Average with result from KLBR’s: KL= (50.84 0.23) ns DPG - Dortmund 31.03.2006

  10. 1 contours + 10-3 KTeV ISTRA KLOE NA48 + 103 Ke3 Form Factor slopes • Parametrizations: f(t) = f(0) [1 t] or f(0) [1 t +t2 / 2] t = (pK - pp)2/m2p+ • Signal selection: - KLedecays tagged by KS - Two tracks in fiducial volume forming vertex - Kinematic cuts + ToF PID to reduce background • Fit t distribution Quadratic fit (2/dof ~ 325/362): Linear fit (2/dof ~ 330/363): l+ = (25.5  1.5  1.0)  10-3 l+ = (1.4  0.7  0.4)  10-3 l+ = (28.6  0.5  0.4)  10-3 hep-ex/0601038 Submitted to Phys. Lett. B DPG - Dortmund 31.03.2006

  11. Vus  f+(0) at KLOE • Quadratic Form Factor • parametrization: KTeV + ISTRA • l+= 0.0221 0.0011 • l+= 0.0023 0.0004 • l0= 0.0154 0.0008 KL Lifetime: from KLOE Average between KL BR’s and direct measurement tKL = 50.84(23) ns Kaon SemileptonicBranching Ratios: all of them from KLOE DPG - Dortmund 31.03.2006

  12. Conclusions • KLOE can determine the absolute KL Branching Ratios tagging the KL pure beam by means of KS →p+p- decaying in the other detector hemisphere • Using 328 pb-1 of 2001 and 2002 data, KLOE has measured the main KL Branching Ratios with relative errors of 0.5% - 1% • Using 400 pb-1 of data collected in 2001 and 2002 , ~106KL →p0p0p0 events, KLOE has performed a direct measurement of KL Lifetime at the level of 0.5% • KLOE has measured the K – p vector current parametersusing 328 pb-1 of data collected in 2001 and 2002, corresponding to ~2106 of KL →pen events • Using Form Factor parameters from KTeV and ISTRA, KL Lifetime determined by KLOE (average between direct and KL BR’s measurements), main KL Branching Ratios (KLe3, KLm3, KSe3, K e3, Km3): KLOE has extracted Vus  f+(0) value with a relative error, on the average, of 0.2% DPG - Dortmund 31.03.2006

  13. Backup slides ... In jeden Quark begäbt er seine Nase DPG - Dortmund 31.03.2006

  14. Acceptance 100% KLOE MC More theory TheAdemollo Gatto theorem: “for strangeness-violating leptonic decays of baryons and mesons: the vector coupling constants (i.e., the limit of the vector amplitudes for vanishing momentum transfer) are uniquely predicted up to first order in symmetry breaking.” Electromagnetic correction • Virtual corrections • Real Bremsstrahlung changes (in addition) significantly the accpetance DPG - Dortmund 31.03.2006

  15. 0.5% 0.4% 0.4% 0.8% experimental theoretical KL physics at KLOE: determination of Vus GKl3Partial Decay width – Experiment GKl3 = BR(KL→pln)/tKL SEW Short ElectroWeak Radiative corrections – Theory Included in Monte Carlo dEM Electromagnetic corrections and SU(2) corrections – Theory Included in Monte Carlo f+(0) Form Factor at t=0 – Theory f+(0) theoretical calculations IKl(lI) Integral over the momentum dependence of the Form Factor – Experiment IKl(lI)determined by KLOE and other experiments DPG - Dortmund 31.03.2006

  16. Ke3 - phase space Ed Blucher dN/dt KTeV • phase space + FF t Form Factor parameterizations Linear Quadratic Pole Fit on t spectrum Aij Smearing matrix (MC) j Reconstruction efficiency j “Bare” Ke3 decay density FjFSR FSR correction DPG - Dortmund 31.03.2006

  17. Shapes Lesser of Pmiss  Emiss in  or  hypotesis (MeV) DPG - Dortmund 31.03.2006

  18. Unitarity Band (1-|Vud|2)·f+(0) Bijnens-Talavera FF New Vud value from 0+0+ 0.9738 ±0.0003 Unitarity Band (1-|Vud|2)·f+(0) Leutwyler-Roos FF conf. by Lattice New Vud value from 0+ 0+ 0.9738 ±0.0003 Vus compared with unitarity and Vud The value considered for Vud is 0.9740  0.0005 taken from A. Czarnecki, W. J. Marciano, A. Sirlin, Phys. Rev. D70 (2004) 093006 |Vus|  f+Kπ(0) PDG02 PDG02 DPG - Dortmund 31.03.2006

  19. Kaon Form Factor at zero momentum transferred • cPT • Leutwyler-Roos (1984) f+(0) = 0.961  0.008 • cPT + Quark Model (Bijnens-Talavera, 2003) f+(0) = 1 + fp4 + fp6loop + fp6LR = 0.976 ± 0.010 • cPT + Dispersion Relations (Jamin-Oller-Pich, 2004) f+(0) = 0.974  0.011 • cPT + Large NC (Cirigliano-Eidemuller-Kaiser-Pich-Portoles, 2005) • f+(0) = 0.984  0.012 • Lattice-QCD • (Becirevic-Isidori-Lubicz-Martinelli-Simula-Tarantino-Villadoro) f+(0) = 1 + fp4+ fp6q = 0.960 ± 0.005stat ± 0.007syst DPG - Dortmund 31.03.2006

  20. Future Perspectives with 2.5 fb of collected data: • Limit onKS000 at 10 –8 level • Competitive measurement of KS+-0 • Ks semileptonic asymmetry to 4  10-3 • Fractional accuracy of < 1% on the BR for KSe and for Kℓ3 • Form factors of KL and K semileptonic decays • First direct measurement of BR(KS), accuracy < 2% • Studies of KSKL system with interference: exploit KLOE’s capability to CP,CPT mmts DPG - Dortmund 31.03.2006

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