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DPG - Dortmund 31.03.20061 Dominant K L Branching Ratios, K L Lifetime and V us at KLOE Introduction - CKM and V us - DA NE and KLOE K L physics - Branching Ratios - Lifetime - Form Factor - V us f + (0) Conclusions Paolo Beltrame IEKP University of Karlsruhe
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DPG - Dortmund 31.03.20062 CKM Matrix and V us 95%5%0.00001% V ub V us V ud 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 |V ud | 2 + |V us | 2 + |V ub | 2 ~ |V ud | 2 + |V us | 2 1 – Determination of V us K 0 e , K l3 ) semileptonic decays K0K0 s + u veve ee V us dd
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DPG - Dortmund 31.03.20063 The – Factory (1020) – Factory: electron-positron-collider at s = M = 1019.4 MeV BR( K + K ) = 49.1% BR( K S K L ) = 34.1% – Factory K – Factory KSK+KSK+ KLK-KLK- The decay at rest provides monochromatic and pure beams of kaons Tagging: observation of K L (K S ) signals presence of K S (K L ) - precision measurements of absolute BR’s K L and K S are well separated: - c (K S ) = 6 mm, K S decays near to the interaction point - c (K L ) = 3.4 m, large detector to keep reasonable acceptance for K L decays
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DPG - Dortmund 31.03.20064 The DA NE – Factory s = M = 1019.4 MeV L design = 5 10 32 cm -2 s -1 2004 750 pb -1 2005 1250 pb -1 2001 170 pb -1 2002 280 pb -1 Analysis nearly complete Data taking at peak finished in 2005 L peak = 1.3 × 10 32 cm s L tot 2.4 fb -1 Off-peak run s = 1 GeV finished in March L tot 250 pb -1
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DPG - Dortmund 31.03.20065 The KLOE detector Magnetic Field of 0.52 T Superconducting coil Track momentum resolution p / p 0.4% ( > 45 ° ) Vertex resolution xy 150 m, z 2 mm Drift chamber 12582 sense wires 52140 wires in total 90% He + 10% C 4 H 10 Energy resolution E / E = 5.7% / E(GeV) Time resolution T = 54 ps / E(GeV) 50 ps Electromagnetic calorimeter Electromagnetic calorimeter Lead/Scint fibres 4880 PM
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DPG - Dortmund 31.03.20066 The Tagging method KS KS KS KS KL 2KL 2KL 2KL 2 K L tagged by K S vertex at IP Efficiency ~70% (mainly geometrical) K L angular resolution: ~1° K L momentum resolution: ~2 MeV Tagging of K S, K L 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 TB Tag bias: carefully measured using MC, and data control samples, typically O(1%)
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DPG - Dortmund 31.03.20067 Dominant K L Branching Ratios High momentum resolution of KLOE DC Ke3, Kµ3, vertex Tag K L by decay K S Charged decays selected by closing the kinematics at the vertex: lesser of P miss - E miss Fit data with linear combination of three MC shapes Radiative corrections included in MC 2001-2002 Data: 328 pb -1 From PDG‘04 Rare K L decays: 0.0036 K L Lifetime: 51.50 ns BR( e + + + 3 KLOE + BR( + ) PDG’04 = 1.0104 0.0076 Imposing (BR x) = 1 K L = (50.72 0.14 stat 0.36 syst ns (P miss E miss ) in or hyp Data e (MeV)
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DPG - Dortmund 31.03.20068 BR(K L e ) = 0.4007 0.0006 stat 0.0014 syst BR(K L ) = 0.2698 0.0006 stat 0.0014 syst BR(K L 3 ) = 0.1997 0.0005 stat 0.0019 syst BR(K L ) = 0.1263 0.0005 stat 0.0011 syst Dominant K L Branching Ratios results (328 pb -1 ) Reasonable agreement with KTeV and NA48 The new results go in the same direction respect to the PDG older values Phys. Lett. B632 (2006) 43
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DPG - Dortmund 31.03.20069 K L Lifetime: direct measurement + + I.P. 0 0 L LL LKLK Measure the mean decay path L/ c (ns) 6 - 24.8 ns 40-165 cm 0.37 L × 10 2 Events/0.3 ns P K = 110 MeV Excellent lever arm for lifetime measurement K L tagged by K S L and L K obtained from t cl At least three ’s required (L K ) ~99% uniform in L 1.3% residual background L (K L ) ~2 cm Average with result from K L BR’s: L = (50.84 0.23) ns Time resolution of KLOE EmC K L Phys. Lett. B626 (2005) 15 L = (50.92 0.17 stat 0.17 syst ) ns
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DPG - Dortmund 31.03.200610 K e3 Form Factor slopes Parametrizations: f (t) = f (0) [1 t] or f (0) [1 t t 2 / 2] t = (p K - p ) 2 / m 2 + Signal selection: - K L e decays tagged by K S - Two tracks in fiducial volume forming vertex - Kinematic cuts + ToF PID to reduce background Fit t distribution + 10 3 10 -3 KTeV ISTRA NA48 KLOE 1 contours Linear fit ( 2 /dof ~ 330/363): + = (28.6 0.5 0.4) 10 -3 Quadratic fit ( 2 /dof ~ 325/362): + = (25.5 1.5 1.0) 10 -3 + = (1.4 0.7 0.4) 10 -3 hep-ex/0601038 Submitted to Phys. Lett. B
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DPG - Dortmund 31.03.200611 V us f + (0) at KLOE Quadratic Form Factor parametrization: KTeV + ISTRA + = 0.0221 0.0011 + 0.0023 0.0004 0 = 0.0154 0.0008 K L Lifetime: from KLOE Average between K L BR’s and direct measurement L = 50.84(23) ns Kaon Semileptonic Branching Ratios: all of them from KLOE KLe3KLe3 KL3KL3 KSe3KSe3Ke3Ke3 K3K3 BR0.40070.26980.007090.05050.0331 BR 0.00180.00120.000090.00040.0005
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DPG - Dortmund 31.03.200612 Conclusions KLOE can determine the absolute K L Branching Ratios tagging the K L pure beam by means of K S → decaying in the other detector hemisphere Using 328 pb -1 of 2001 and 2002 data, KLOE has measured the main K L Branching Ratios with relative errors of 0.5% - 1% Using 400 pb -1 of data collected in 2001 and 2002, ~10 6 K L → events, KLOE has performed a direct measurement of K L Lifetime at the level of 0.5% KLOE has measured the K – vector current parameters using 328 pb -1 of data collected in 2001 and 2002, corresponding to ~2 10 6 of K L → e events Using Form Factor parameters from KTeV and ISTRA, K L Lifetime determined by KLOE (average between direct and K L BR’s measurements), main K L Branching Ratios (K L e3, K L 3, K S e3, K e3, K 3): KLOE has extracted V us f + (0) value with a relative error, on the average, of 0.2%
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DPG - Dortmund 31.03.200613 Backup slides... In jeden Quark begäbt er seine Nase
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DPG - Dortmund 31.03.200614 Ademollo Gatto theorem The Ademollo 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.” More theory Electromagnetic correction Virtual corrections Real Bremsstrahlung changes (in addition) significantly the accpetance Acceptance 100% KLOE MC
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DPG - Dortmund 31.03.200615 K L physics at KLOE: determination of V us Kl3 Partial Decay width – Experiment Kl3 = BR(K L → l ) / K L S EW Short ElectroWeak Radiative corrections – Theory Included in Monte Carlo EM Electromagnetic corrections and SU(2) corrections – Theory Included in Monte Carlo f + (0) Form Factor at t=0 – Theory f + (0) theoretical calculations I Kl ( ) Integral over the momentum dependence of the Form Factor – Experiment I Kl ( ) determined by KLOE and other experiments 0.5%0.4% experimental 0.8% theoretical
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DPG - Dortmund 31.03.200616 Form Factor parameterizations Linear Quadratic Pole Fit on t spectrum A ij Smearing matrix (MC) j Reconstruction efficiency j “Bare” K e3 decay density F j FSR FSR correction KTeV K e3 - phase space Ed Blucher t dN/dt phase space + FF
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DPG - Dortmund 31.03.200617 Shapes Lesser of P miss E miss in or hypotesis (MeV)
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DPG - Dortmund 31.03.200618 V us compared with unitarity and V ud The value considered for V ud is 0.9740 0.0005 taken from A. Czarnecki, W. J. Marciano, A. Sirlin, Phys. Rev. D70 (2004) 093006 Unitarity Band (1-|V ud | 2 )·f + (0) Leutwyler-Roos FF conf. by Lattice New V ud value from 0 + 0 + 0.9738 ±0.0003 Unitarity Band (1-|V ud | 2 )·f + (0) Bijnens-Talavera FF New V ud value from 0 + 0 + 0.9738 ±0.0003 |V us | f + Kπ (0) PDG02
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DPG - Dortmund 31.03.200619 PT Leutwyler-Roos (1984) f + (0) = 0.961 0.008 PT + Quark Model (Bijnens-Talavera, 2003) f + (0) = 1 + f p4 + f p6 loop + f p6 LR = 0.976 ± 0.010 PT + Dispersion Relations (Jamin-Oller-Pich, 2004) f + (0) = 0.974 0.011 PT + Large N C (Cirigliano-Eidemuller-Kaiser-Pich-Portoles, 2005) f + (0) = 0.984 0.012Lattice-QCD (Becirevic-Isidori-Lubicz-Martinelli-Simula-Tarantino-Villadoro) f + (0) = 1 + f p4 + f p6 q = 0.960 ± 0.005 stat ± 0.007 syst Kaon Form Factor at zero momentum transferred
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DPG - Dortmund 31.03.200620 Perspectives with 2.5 fb of collected data: Limit on K S 0 0 0 at 10 –8 level Competitive measurement of K S + - 0 K s semileptonic asymmetry to 4 10 -3 Fractional accuracy of < 1% on the BR for K S e and for K ℓ3 Form factors of K L and K semileptonic decays First direct measurement of BR(K S ), accuracy < 2% Studies of K S K L system with interference: exploit KLOE’s capability to CP,CPT mmts Future
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