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Over 1 million reconstructed!!

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

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Over 1 million reconstructed!!

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  1. 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 first results <Jim Wiss>

  2. Ds+ Do  (Ds+) =0.506  0.008  sys (ps) Preliminary measurement of the Ds+ lifetime Ds+ and Do have unique CF non-spectator decays WA WX Theory  (Ds+) / (Do) =1.07 1.20 We use 5668 Ds+ decays in ~50% of FOCUS to suppresseslong-lived backgnd fromD+K- ++K+ Also allows us to enhance S/N with cos cut cos K Using E791 (Ds+) =0.518  0.014  0.007 ps We project:WA is  (Ds+) / (Do) = 1.214 0.017See talk of Harry Cheung

  3. PRELIMINARY D*D Mass Splittings ~50% FOCUS We are seeing very strong D*o Dosignals in FOCUSwith our new & improved E&M calorimeters.Project a final sample of25000 D*o Dodecays . CLEO92 has provided the best past data on D0* mass, widths, and branching ratios from ~1200 D*o Do decays D*o - Do D*+ - D+ IE-IE 0’sonly FOCUS first results <Jim Wiss>

  4. PRELIMINARY Mass splittings Isosplittings depend on same physics as the D decay constant PDG98 24% of FOCUS PDG98 S/N • Both °samples consistent with PDG98 already w/ smaller errors! HQ98 LGT FOCUS first results <Jim Wiss>

  5. We are even getting our first glimpse at Ds*+ Ds*+ Ds+ Preliminary ~20% FOCUS IE  only FOCUS first results <Jim Wiss>

  6. K K2 K2 K Y=2150 Y=3545 Y=12713 Y=996 K3 K3 Y=303 Y=1396 “Golden” signals with pi0’s # per 5 MeV Signals based on 20% of FOCUS No optimization of  cuts! • Can study a rich new set of charm decay • Many are required to complete isospin amplitude triangles FOCUS first results <Jim Wiss>

  7. Beyond the D* • HQET predicts a rich L=1 spectrum • 2 broad states with s-wave  decays (CLEO has evidence for 1) • 2 narrow states with d-wave  decays (seen in e+ e- &  N) • Predictions are made for masses, widths, and angular distributions and the relationship to B** splitting. • FOCUS has PRELIMINARY signals for • D01D* D0*2D* • D0*2D D+*2D • D*s?K D The low multiplicity of primary vertex gives photoproduction an advantage for D** study. FOCUS first results <Jim Wiss>

  8. PRELIMINARY D** signals ~27% FOCUS reflection • We observe • 2 peaks in D*+- • 1 real peak in D+- • 1 real peak in D0+ • 1? peak in D0K+ • Also see reflections at M-m from D*°D with missing ° • Angular distributions can often be used to disentangle states and confirm HQET predictions. D1(2420) D2*0 (2460) D2*0(2460) D1(2420) absent by parity unresolved in E687 except by angular cuts WS Do1 , D*o2  D*-+(D)+ Ds+*D0K Ds** (D)K+ DsJ(2573)+? D2*+ (2460) WS WS FOCUS first results <Jim Wiss>

  9. Dalitz Amplitude Analyses • Dalitz analyses are a traditional strength of E687 which has published on: • K- + +K- +o Ks- +K-K+- ++- • Dalitz analysis provides powerful probes on charm hadronic decay • Underscores the importance of quasi-two body decay and extends tests of factorization models to vector-pseudoscalar decay • Often highly unusual resonances dominate charm Dalitz plots. • Allows one to directly investigate non-spectator effects such as W-annihilation • Provides new handles on charm CP violation by comparing the phases and amplitudes that one gets for particles versus antiparticle decay. Best in Cabibbo suppressed decays. • Provides a preview of the FSI complication for beauty • Studies on many Dalitz plots studied by E687 are already underway. I will discuss two interesting Dalitz plots featuring decays with an unusual number of final state kaons. FOCUS first results <Jim Wiss>

  10. Favored D decays with “unusual “ numbers of kaons Conventional spectatorbut withweird resonances? Too few kaons! An example is Ds BR is large ~1.4% suggesting a Cabibbo favored decay Cabibbo favored would produce a s s u d as final quarks and no kaons appear in the final state. How are they lost? NR Weak Annihilation ? Resonant Weak Annihilation? FOCUS first results <Jim Wiss>

  11. Preliminary FOCUS Ds Dalitz plots (~40%) • Observe: • f0(980) • f2(1270) • f0 (1500) • Clearer in FOCUS • No evidence for WA • (770) • NR f2 f2 • Dominated byweirdresonances with simultaneous KK and  couplings • No evidence for non-spectator decays such as NR or  FOCUS first results <Jim Wiss>

  12. PRELIMINARY D0Ks K+ K- Dalitz plot a0(980) f0(980) f(1020)? ~50% FOCUS Y=395S/N=17 Too many kaons Here we have only an s u d quarks in the final state yet three kaons appear! 2 spectator diagrams with resonances which couple to ’s and K’s m²K+K- a0(980)? f0(980)? f(1020) We use D* tagging to determine strangeness of K°s m²K+Ko FOCUS first results <Jim Wiss>

  13. Studies of Cabibbo Suppressed decays • FOCUS’s powerful Cerenkov ID and very large data sample gives it unique opportunities to study Cabibbo Suppressed Decays • Will present evidence for five DCS Decays ( 2.50.5 decays are new!) • See talk of Jon Link • Historically the pattern of Cabibbo suppression has been full of surprises and has yielded unique insight into hadronic decay mechanisms to challenge models • The rate for DCSD is often very different than tan4C • D° DCSD interferes with hadronic decay mixing. This is good news / bad news since small amplitudes are best measured through interference • Differences in DCSD/CF Dalitz plots can probe Do mixing (T. Liu) FOCUS first results <Jim Wiss>

  14. 5913 E791 DCSD : D+ K++- ~40% of FOCUS Data Y(D+)=17228Y(Ds+)=22421 K++-)/K-+ +=(0.68  0.15)% PDG98 Our results already much better than PDG98 (  3  E791) Preliminary FOCUS CL1<0.1 CL1<110-8 (K++-)/ (K-+ +)=(0.650.11)%  3tan4Cabbibo  (+/0)tan4C M(K++-)

  15. Y=7221.6±87.80 + K+ M=0.1455 W=0.91 D0 D0 rmix PRELIMINARY (~40%) D° DCSD Here we look for WS D° decays where the kaon has the same sign as the D+* decay pion. This is also a classic way to search for mixing and could interfere with mixing. BR(DCSD) WS/RS K rs mixed CF D*+ Y=60.337±21.40 - WS mass &  fixed by RS + K+ DCSD D0 K ws D*+ - FOCUS first results <Jim Wiss>

  16. PDG error Kp PDG Relative WS/RS ratio versus CITADL Cuts Cut variations on 19/155 with K candidates. ws/rs Miss-id yield MC study W -WK W -WK Slight variation in BR as pid cuts are tightened. Would expect exponential decrease if double mis-id. The signal level is consistent with existing world’s average but higher than CLEO’s recent measurement at APS FOCUS first results <Jim Wiss>

  17. PRELIMINARY D +sK+K+- This is the first observation of D+s DCSD The rate relative to K-K++ is1.5% (~6  tan4Cabbibo) ~50% PRELIMINARY FOCUS first results <Jim Wiss>

  18. PRELIMINARY D+K+K-K+~40% FOCUS • Ds+K+K-K+is a SCSD • D+K+K-K+ is aC = -S DCSD which cannot occur via a spectator diagram. • (D +K+K-K+)/( D +) = (1.450.39)10-4 • Just below PDG 98 limit from E687 of Br < 1.410-4 CL=90% • Our rarest DCSD BR yet : (D +K+K-K+) / (K-++)  tan4C/2 • No evidence for D+  K • A KKK Dalitz analysis may shed light on the KKK decay mechanism. Y(D+ ) = 27±7 Y(Ds+ ) = 28±7 FOCUS first results <Jim Wiss>

  19. Rounding out the all kaon final states... 45% Focus These two are difficult for us to study because charm in FOCUS is brought out through vertexing and the Ks in FOCUS generally verticize downstream of the SSD. Y=208 Y=491 Y=556 50% Focus KsK D +KsKsK+ Altogether we show SIX all kaon charm decays D0  K+K-D + KsK Ds+ KsK D0 Ks K+ K- D + KsKsK+ D+ K+K-K+ FOCUS first results <Jim Wiss>

  20. c &*c Spectroscopy  cpK 80% FOCUS c specta *c specta We can study all of this spectroscopy! FOCUS first results <Jim Wiss>

  21. Preliminary c -c mass differences c0 - c+ M=167.170.260.27 MeV Theoretically one expects M(c0) > M(c++) But world’s data including our measurement has M(c0) < M(c++) by about 1.5 c++ - c+ M= 167.450.170.36 MeV c++ -  c0 M= 0.280.310.15 MeV See talk of Eric Vaandering FOCUS first results <Jim Wiss>

  22. Kinky decays of the c+ c+-K++ ~75% FOCUS Y=607 in ~22% FOCUS Y=253 in ~22% FOCUS E687 saw 56 events CLEO saw 487 events • We have unique abilities to reconstruct the - n  - • Will study (1385)  since only contributions are internal W and WX FOCUS first results <Jim Wiss>

  23. A Gallery of +c decays +K-+ K-++ - + + ~75% Focus ~30% Focus ~20% Focus Using the 3 favored decay modes, we project a sample of 860 +cdecays ~30 times the E687 lifetime sample which provides the best c lifetimes ~70% Focus pK-+ SCSD 1st reported by Selex HQ98

  24. Search for CP violating SCSD decays E791 Look for (DK+K-)  (DK+K-) Tag D charm through D* D DK We normalize to DK-+ to eliminate 4% production asymmetry. FOCUS (26%) Much less DK Reflection World’s best data using 26% of Focus! FOCUS first results <Jim Wiss>

  25. + RS K-  D0 + WS + K+  D0 D0 rmix - Semileptonic Mixing Searches D*+ D*+  from another event Limit follows from fitting time evolution of WS and RS signal. No DCSD interference. FOCUS first results <Jim Wiss>

  26. Mixing sensitivity • FOCUS projected sensitivity is rmix ~ 0.15% • Including electrons we project rmix ~ 0.1% • Present E791 limit rmix < 0.50% (90% CL) We have unique advantages in searching for direct  differences between CP-even eigenstates such as D°K+ K-and states of mixed CP such as D° K- +or CP odd states such as Ks or Ks We expect a yield of from 5000-10000 D°K+ K- decays. This should give us a lifetime measurement for CP even states of better than ()/ < 1.5% FOCUS first results <Jim Wiss>

  27. K*l from 80% Focus RS-WS = 64244 M(K) FOCUS Semileptonic Physics • We improved all aspects of our lepton id system including an entirely rebuilt inner muon system, a new outer muon system, a rebuilt inner E&M calorimeter and an enhanced outer E&M calorimeter. • We project a ~50 fold increase over E687 which published form factors for each of these states Our projected Kl yield should make us very competitive with other charm experiments! Our vertex tagging gives us the ability to study Kl without D* tagging  Enormous yield

  28. p - ~ K + p + p - D 0 _ _ D (recoil) D* + p - p + Soft pion tagging as means to absolute BF Can tag the presence of a D° by observing a right sign  which balances Pt with a reconstructed D . You then count the number of D° decays into a particular final state, correct by efficiency and ratio to find an absolute branching fraction. Low primary vertex multiplicity is a big advantage. Proof of Principle 1: Is there an excess of RS over WS events at low Pt ? Proof 2: Can we reconstruct both D’s in an event? Already have a copious sample of very clean events with both reconstructed D’s Expect 7500 30% FOCUS

  29. What I left out • Production dynamics => Unique tests of QCD • Xf , PT and Egdependence compared to NLO -g fusion • Charm/Anticharm asymmetry as probes of fragmentation • Kinematic correlations in D D events as probes of NLO QCD • Amplitude analyses for 4 body and 5 body final states • Semileptonic decays • Semileptonic Form factor measurement. • Cabibbo suppressed semileptonic decay • Rare or forbidden decays • Many of these studies are already underway or will start shortly! FOCUS first results <Jim Wiss>

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