Sandra Malvezzi - Charm Meson Results in Focus 1 Sandra Malvezzi I.N.F.N. Milano Meson Lifetimes, Decays, Mixing and CPV in FOCUS

Sandra Malvezzi - Charm Meson Results in Focus 2 A new charm-physics era The high statistics and excellent quality of data allow for unprecedented sensitivity & sophisticated studies Investigation of decay dynamics both in the hadronic and semileptonic sector Phases and Quantum Mechanics interference FSI role & CP studies Lifetime better than 1% non-spectator processes Mixing possible window on physics beyond SM

Sandra Malvezzi - Charm Meson Results in Focus 3 Outline Hadronic decays Amplitude Analysis of three pseudoscalar channels Semileptonic decays Anomaly in decay New BR of and Lifetimes Precise measurements for and preliminary for First clear evidence (DSCD) First evidence (SCSD) First Dalitz analysis New method for CPV s-wave interference Mixing Prelimary results from and

Sandra Malvezzi - Charm Meson Results in Focus 4 Over 1 million reconstructed!! Successor to E687. Designed to study charm particles produced by ~200 GeV photons using a fixed target spectrometer with upgraded Vertexing, Cerenkov, E+M Calorimetry, and Muon id capabilities. Includes groups from USA, Italy, Brazil, Mexico, Korea 1 million charm particles reconstructed into D  K , K2 , K3  FOCUS Spectrometer

Sandra Malvezzi - Charm Meson Results in Focus 5 First observation First clear observation Yield = 65.5  15.0 Yield = 31.4  7.4 hep-ex / R W c d s s s u d Intervention of resonances coupling both to  and KK or annihilation

Sandra Malvezzi - Charm Meson Results in Focus 6 Spin 0 Spin 1 Spin 2 and Where Dalitz plot analysis of K

Sandra Malvezzi - Charm Meson Results in Focus 7 Yield D + = 190  24 S/N D + = 1.0 DCS  D +  K +  +  - Decay fractions and phases NR = 9  5 % (-6  16) ° K*(892) = 43  7 % (208  16)  ° K*(1410) = 12  8 % (133  23)  ° K 2 (1430) = 6  3 % (48  27) ° K*(1680) = 22  10 % (2  20)  °  (770) = 51  10 % (0 fixed) f 0 (980) = 9  5 % (73  31) °  (1450) = 10  5 % (-113  15) ° K +   projection  +   projection Preliminary

Sandra Malvezzi - Charm Meson Results in Focus 8 Decay fractions and phases NR = 18  4 % (34  7)° K*(892) = 22  3 % (163  7) ° K*(1410) = 14  5 % (-10  7) ° K* 0 (1430) = 14  6 % (68  7) °  (770) = 40  4 % (0 fixed) f 2 (1270) = 2  1 % (33  21) °  (1450) = 8  2 % (219  14) ° SCS Yield D s + = 468  29 S/N D s + = 2.4 Ds+K++-Ds+K++- First Dalitz analysis Preliminary K +   projection  +   projection

Sandra Malvezzi - Charm Meson Results in Focus 9 D s, D +  KK  D s +  K + K   + D +  K + K   +

Sandra Malvezzi - Charm Meson Results in Focus 10 Interference term

Sandra Malvezzi - Charm Meson Results in Focus 11 K + K   projectionK    projection Yield D + = 7106  92 S/N D + = 8.62 Decay Fraction and phases K*(892) = 20.7  1.0 % (0 fixed)  (1020) = 27.8  0.7 % (243.1  5.2)° K*(1410) = 10.7  1.9 % (-47.4  4.9)  ° K * (1430) = 66.5  6.0 % (61.8  3.8)° f 0 (1370) = 7.0  1.1 % (60.0  5.3) ° a 0 (980) = 27.0  4.8 % (145.6  4.3)° f 2 (1270) = 0.8  0.2 % (11.6  7.0) °  (1680) = 1.6  0.4 % (-74.3  7.5) ° Preliminary

Sandra Malvezzi - Charm Meson Results in Focus 12 CP violation For a two amplitude decay  i  i = strong phase CP asymmetry: 2 different amplitudes strong phase-shift A tot A tot = g 1 M 1 e i  1 + g 2 M 2 e i  2 CP conjugate A tot A tot = g 1 M 1 e i  1 + g 2 M 2 e i  2 ** a CP = 2Im(g 2 g 1 *) sin(  1 -  2 )M 1 M 2 |g 1 | 2 M 1 2 +|g 2 | 2 M Re(g 2 g 1 *)cos(  1 -  2 )M 1 M 2 |A tot | 2 - |A tot | 2 |A tot | 2 + |A tot | 2 =

Sandra Malvezzi - Charm Meson Results in Focus 13 FULL OBSERVATION Dalitz plot = FULL OBSERVATION of the decay COEFFICIENTS and PHASES for each amplitude Measured phase :  =  +  CP conserving CP violating CP conjugate  =   =  -   =  -  E831 a CP =0.006±0.011±0.005 Measure of direct CP violation: D   K  K   asymmetrys in decay rates of D   K  K    CP violation:Dalitz analysis

Sandra Malvezzi - Charm Meson Results in Focus 14, D +, D - Coefficients: D ±, D +, D - D ±, D +, D - Phases: D ±, D +, D - D + /D - split sample analysis Preliminary! No evidence of CPV K-matrix approach to improve the quality of the analysis

Sandra Malvezzi - Charm Meson Results in Focus 15 New results on Our K  spectrum looks like 100% K*(892) This has been known for about 20 years...but a funny thing happened when we tried to measure the form factor ratios by fitting the angular distributions

Sandra Malvezzi - Charm Meson Results in Focus 16 An unexpected asymmetry in the K* decay forward-backward asymmetry in cos below the K* pole but almost none above the pole Sounds like QM interference A 4-body decays requires 5 kinematics variables: 3 angles and 2 masses

Sandra Malvezzi - Charm Meson Results in Focus 17 Try an interfering spin-0 amplitude will produce 3 interference terms (plus mass terms) We simply add a constant amplitude in the place where the K* couples to an m=0 W+ with amplitude Phys.Lett.B535,43, 2002

Sandra Malvezzi - Charm Meson Results in Focus 18 Studies of the acoplanarity-averaged interference Extract this interference term by weighting data by Since all other  averaged terms in the decay intensity are constant or We begin with the mass dependence: A constant 45º phase works great but the solution is not unique.

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Sandra Malvezzi - Charm Meson Results in Focus 20 New FOCUS semileptonic BRs & Form Factors All values consistent with their average value with a CL of 19% Our number is 1.59 standard deviation below CLEO and 2.1 standard deviation above E691

Sandra Malvezzi - Charm Meson Results in Focus 21 Form Factors The vector and axial form factors are generally parametrized by a pole dominance form Nominal spectroscopic pole masses Decay intensity (including s-wave amplitude) parametrized by hep-ex / New FOCUS results

Sandra Malvezzi - Charm Meson Results in Focus 22 Form Factor Ratios Our analysis is the first to include the effects on the acceptance due to changes in the angular distribution brought about the s-wave interference rad

Sandra Malvezzi - Charm Meson Results in Focus 23 Baseline cuts a) 2682 evts b) 4695 evts Baseline, out-of-material. isolation cuts c) 793 evts d) 2192 evts hep-ex /

Sandra Malvezzi - Charm Meson Results in Focus 24 Charm Meson Lifetimes Lifetime fits Signal  520 evts  360 evts  385 evts

Sandra Malvezzi - Charm Meson Results in Focus 25 PDG difference in the hadronic sector Phys.Lett.B537,192, 2002 FOCUS fs

Sandra Malvezzi - Charm Meson Results in Focus 26 Lifetime 506  8 fs 5668  95 events (50% FOCUS data) signal PDG  9 fs Theoretical prediction (Bigi Uraltsev) (no WA/WX) (different process interference ) 4 x statistics including Preliminary

Sandra Malvezzi - Charm Meson Results in Focus 27 Mixing Direct comparison of CP final state lifetime Phys.Lett.B485,62,2000

Sandra Malvezzi - Charm Meson Results in Focus 28  is the relative strong phase only statistical error ! FOCUS K+  - New Mixing Results Preliminary.... towards CLEO & a big relative 95% C.L.

Sandra Malvezzi - Charm Meson Results in Focus 29 Conclusion Charm physics is revealing itself a rich source of new results FOCUS is playing a crucial role in understanding the charm phenomenology new suppressed decay modes decay dynamics of three-body hadronic channels via quasi two-body decays semileptonic sector very precise lifetime measurements (will dominate PDG) mixing

Sandra Malvezzi - Charm Meson Results in Focus 30 R W c d s s s u d Intervention of resonances coupling both to   and KK Not obvious evidence of QUESTION SLIDES

Sandra Malvezzi - Charm Meson Results in Focus 31 Five observables are studied A 4-body decays requires 5 kinematics variables: 3 angles and 2 masses Left-handed  Two amplitude sums over W polarization Right-handed  Wigner D-matrices (“mass terms”) are helicity-basis form factors

Sandra Malvezzi - Charm Meson Results in Focus 32 Since  interference will dominate.....  here will be only three terms as If we average over acoplanarity we only get the first term  his is the term creating forward-backward asymmetry! If our model is right: The asymmetry will have a particular mass dependence The asymmetry should be proportional to The asymmetry should have a dependence from q given by

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Sandra Malvezzi - Charm Meson Results in Focus 38 All values consistent with an average of 0.54  0.04 Groupelectronmuon This work 0.54   CLEO  0.05  0.04 E  0.17  0.07 ARGUS 0.57  0.15  0.15 CLEO 0.49  0.10  0.12

Sandra Malvezzi - Charm Meson Results in Focus picture 2002 new measurements: BELLE BaBar preliminary E791: CLEO: BELLE: (preliminary) Very preliminry FOCUS result on from semileptonic 3 times better than E791 The comparison with CLEO is valid only if there is a small strong phase difference 

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Sandra Malvezzi - Charm Meson Results in Focus 41 Inner muon preliminary

Sandra Malvezzi - Charm Meson Results in Focus 42 outer muon preliminary

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