1. 1 BESIII-Cleo-c workshop J. Wiss Fully leptonic and semileptonic decay CLEO-c and BESIII Joint workshop on charm, QCD and tau physics Jan. 13-15, 2004 in Beijing, China Acknowledgements and Full Disclosure 1.This talk is from the perspective of a brand new CLEO-c member 2.It borrows very heavily from an excellent longer talk of Ian Shipsey 3.I have worked on semileptonic decays from the Fermilab FOCUS (fixed target) experiment with vastly different systematics and very complementary techniques. Allowed transition Jim Wiss University of Illinois

2. 2 BESIII-Cleo-c workshop J. Wiss Hi impact leptonic and semileptonic physics The most uncertain CKM elements are |V td |and |V ub |. Both uncertainties are dominated by systematics on calculating hadronic effects that can be significantly reduced by calibrating LQCD on related charm decays. D+   D0   l An impressive check of the unitarity triangle.

3. 3 BESIII-Cleo-c workshop J. Wiss B(D +  l )/  D+ : f D+ |Vcd| B(D S  l )/  Ds : f Ds |Vcs| * Charm meson lifetimes known 0.3-2% * 3 generation unitarity Vcs, (Vcd) known to 0.1% (1.1%)  f D+ f Ds D meson Decay Constants In a pseudoscalar D meson decay: c and q annihilate |f D | 2 |V CKM | 2 Helicity suppression

4. 4 BESIII-Cleo-c workshop J. Wiss Improving knowledge Vtd using D+   Lattice predicts f B /f D with small errors  precision measurement of f D  precision estimates of f B  precision determination of Vtd 1.2% ~15% (LQCD) (ICHEP02)

5. 5 BESIII-Cleo-c workshop J. Wiss D meson Decay Constants Current Status Common systematic error from B(D s   ) Estimated BR using fDs=260 fD=220 fB=200 MeV 14% relative error f D s Values from D s  f D+ < 290 MeV @ 90% CL (Mark III)  B(  D+ 4.2  10 -4 1.1  10 -3 DS+DS+ 5.7  10 -3 5.5  10 -2 B+B+ 3.2  10 -7 7.1  10 -5

6. 6 BESIII-Cleo-c workshop J. Wiss D+ D+  MC Huge improvement over existing knowledge! UL 33% 17% PDG  f D+  f Ds  f Ds 2.3% 1.6% 1.9% 3fb -1 f D+ from Absolute Br(D+     Fully reconstruct one D (tag) Require one additional charged track and no additional photons

7. 7 BESIII-Cleo-c workshop J. Wiss Probing the hadronic current

8. 8 BESIII-Cleo-c workshop J. Wiss D 0 Modes  (%) Detection “efficiency” N Detected Xe tagging fraction N Detected Xe + Tag CKM K - e + 3.4746%559,500  14% 77,670 V cs K *- e + 2.0212%28,2003,900 V cs  - e + 0.3763%81,00011,190 V cd  - e + 0.2023%15,6002,190 V cd D + Modes K 0 S e + 3.4037%219,000  7.5% 16,560 V cs K *0 e + 4.6519%151,50011,250* V cs  0 e + 0.3144%34,5002,580 V cd  0 e + 0.2538%24,0001,770 V cd yields with 3 fb -1 Exclusive Charm Semileptonic Signal Yields in 3 fb -1 yellow book The BESIII yields are likely to be 5 to 10 times larger! *  Focus K*  FF sample

9. 9 BESIII-Cleo-c workshop J. Wiss List of Modes PDG(2000)  (%) PDG(2000)  /  (%) (3fb -1 )  /  (%) D 0  K - e + 3.47  0.17 4.90.36 D 0  K *- e + 2.02  0.33 16.31.60 D 0  - e + 0.37  0.06 16.20.95 D 0  - e + --2.14 D +  K 0 e + 6.7  0.9 13.40.63 D +  K *0 e + 4.7  0.4 9.40.94 D +  0 e + 0.31  0.15 48.41.97 D +  0 e + 0.22  0.08 36.42.38 Improvements in charm semileptonic branching ratios from 3 fb -1 Threshold running can dramatically improve on the PDG value of dB/B for every D + and D 0 semileptonic branching ratio.

10. 10 BESIII-Cleo-c workshop J. Wiss |f(q 2 )| 2 |V CKM | 2 I. Absolute magnitude & shape of form factors are a stringent test of theory. II. Absolute charm semileptonic rate gives direct measurements of V cd and V cs. III Key input to precise Vub vital CKM cross check of sin2  b c u d l l 1) Measure D  form factor in D  l. Calibrate LQCD uncertainties. 2) Extract V ub at BaBar/Belle using calibrated LQCD calc. of B  form factor. 3) But: need absolute Br(D  l ) and high quality f(q 2 ) data and neither exist   B D. Importance of absolute charm semileptonic decay rates.

11. 11 BESIII-Cleo-c workshop J. Wiss f(q 2 ) models of the past cleanest theory highest rate ISGW A major disconnect between experiment and theory afflicts published data An incisive test of LQCD requires one to measure f(q 2 ) where there is still rate and compare in a theoretically controlled q 2 region Previous data had low rates and terrible q 2 resolution which required a parametric form for meaningful measurement is easiest for LQCD

12. 12 BESIII-Cleo-c workshop J. Wiss Measuring q 2 evolution At present, K*l data fits to the pole form return poles slightly lower than D s *. But past studies were compromised by poor q 2 resolution and control of backgrounds at low visible mass and K*l is not an optimal state...  l probe q 2 dependence nearly up to the spectroscopic pole! D  K*l “yellow book” 1 fb -1 MC Signals at the  (3770) will be clean, copious, and well resolved in q 2

13. 13 BESIII-Cleo-c workshop J. Wiss Pole versus ISGW form in D  e yellow book 1 fb -1 MC The lattice can now calculate f+ as a function of q 2. D  e provides a powerful test of the lattice predictions. Once validated, the lattice can be used with confidence in the extraction of CKM matrix. for both B’s and D’s Lattice hep-ph/0101023 better sys

14. 14 BESIII-Cleo-c workshop J. Wiss D  vector l decays M K  M W 2  q 2 A 4-body decay requires 5 kinematic variables: Three angles and two masses. H 0 (q 2 ), H + (q 2 ), H - (q 2 ) are helicity-basis form factors computable by LQCD These evolve according to vector and axial pole forms right-handed  + left-handed  + (“mass terms”) Wigner D-matrices Two amplitude sums over W polarization

15. 15 BESIII-Cleo-c workshop J. Wiss Form Factor Ratios The H+, H-, and H0 form factors are various combinations of vector and axial pole forms which are parameterized as spectroscopic poles. Nominal spectroscopic pole masses The intensity is then described by just 2 numbers  r v / r v = 4.6%  r 2 / r 2 = 9.2% YB 1 fb -1 stat Focus sys+stat r2r2 rVrV Latest LGT: Becirevic (ICHEP02) R V = 1.55  0.11 Although ratios of form factors are known precisely, A1(0), A2(0) and V(0) measurement requires knowledge of (1) absolute BR (2) charm lifetimes (3) reliance on q 2 model

16. 16 BESIII-Cleo-c workshop J. Wiss Hadronic complications in K*l Yield 31,254 Data MC constant s-wave The K  l process consists of both K* l and an interfering, s-wave component which creates a forward- backward asymmetry in the K* decay angle with a distinctive mass variation.

17. 17 BESIII-Cleo-c workshop J. Wiss Both good news and bad news const amp LASS amp events  CosV M(K  ) Phase (deg) |amp| 2 Adds additional complications such as amplitude and phase variation, an additional helicity form factor etc. But allows additional handles on the relevant hadronic physics such as: 1. Studies of the I=1/2 s-wave phase variation 2. Detailed studies of the K* line shape Estimated errors for a 31 000 event sample A very naive calculation

18. 18 BESIII-Cleo-c workshop J. Wiss Great to extend data to D  l Kinematic projections from 1 fb -1 1 Very clean 2 Great resolution 3 Good efficiency  l K*  l It would very interesting to compare form factors in  l to K*  l and search for s-wave interference in  l MC BESIII could study S-wave interference in  l interference with half the (tagged) statistics as used in the Focus K*  study

19. 19 BESIII-Cleo-c workshop J. Wiss Enigma #1:  (D  K*l   K*l  /  K  muonselectrons 0.62  0.02 A 1 follows from  (K*  ) measured from K*l  K  using the K  BF and D+ lifetime. This can then be compared with LGT prediction The 2002 CLEO result tended to resolve this discrepancy. The 2002 FOCUS result tended to reinstated it. circa 1993 Form factor ratios were well predicted but the scales were not.

20. 20 BESIII-Cleo-c workshop J. Wiss Enigma #2: Ds  l  form factors CL (rV) = 44.3% CL(r2) = 21.5% circa 1999 It was anticipated that the form factor ratios for Ds  l should be within 10% of those for D  K*l Until just recently, it looked like rV values were consistent but r2 for Ds  l was  a factor of two higher than that for D  K*l The new Focus data (hep-ex/0401001) challenges this.

21. 21 BESIII-Cleo-c workshop J. Wiss Determining Vcs and Vcd If theory passes the test….. combine semileptonic and leptonic decays eliminating V CKM  (D +  l  (D +  l  independent of Vcd Test rate predictions at ~4% Test amplitudes at 2% Stringent test of theory!  (D s  l  (D s  l  independent of Vcs Test rate predictions at ~ 4.5% Use CLEO-c validated lattice to calc. B semileptonic form factor, then B factories can use B  lv for precise Vub  Vcs /Vcs = 1.6% (now: 11%)  Vcd /Vcd = 1.7% (now: 7%) I II

22. 22 BESIII-Cleo-c workshop J. Wiss Improving unconstrained CKM elements VcdVcsVcbVubVtdVts 7%11%5%25%36%39% 1.7%1.6%3% 5% B Factory/Tevatron Data & CLEO-c Lattice Validation (Snowmass E2 WG) CLEO-c data and LQCD PDG |Vcd| 2 + |Vcs| 2 + |Vcb| 2 = 1 ?? CLEO –c: test to ~3% (if theory D  K/  l  good to few %) Without invoking powerful unitarity constraints, many CKM elements are relatively poorly known. With lattice validation from threshold e+e- running allows for much better unitarity tests

23. 23 BESIII-Cleo-c workshop J. Wiss Summary Leptonic Decay –Dramatic improvements in fDs and first measurements of fD+ at 2% Plays a crucial role in Vtd when combined with mixing Pseudoscalar semileptonic decay –Unparalleled cleanliness in f+ form factor measurement in D  l Remove reliance of f(q 2 ) models to bridge theory and experiment Pole dominance and ISGW forms can be easily distinguished Provide clean calibration of f+ : Both value and q 2 evolution predicted by LQCD –Provides crucial calibration f+ to use B   l  to measure Vub Vector semileptonic decay –Improvement in rV and r2 parameters –Unique advantages in determining A1(q 2 ), A2(q 2 ), V(q 2 ) q 2 dependence for the first time –Hadronic complications / opportunities due to s-wave interference –Settle two long term experimental enigmas The K*l /Kl problem The Ds   l versus D+  K*l  r2 inconsistency Direct measurements of Vcs, Vcd and incisive unitarity tests

24. 24 BESIII-Cleo-c workshop J. Wiss Crucial Validation of Lattice QCD: Lattice QCD will be able to calculate with accuracies of 1-2%. The CLEO-c decay constant and semileptonic data will provide a “golden,” & timely test. Interplay between semileptonic, leptonic charm and improved beauty data and LQCD Imagine a world Where we have theoretical mastery of non- perturbative QCD at the 2% level B Factories only ~2005 Theory errors = 2%

25. 25 BESIII-Cleo-c workshop J. Wiss Question slides?

26. 26 BESIII-Cleo-c workshop J. Wiss Currently  SL of all D mesons are consistent with being equal: Threshold: the best place to measure inclusive semileptonic branching ratios Hadronic tag  30 improvement ! HQE predicts the near equality of  SL for D +, D 0 and D s but large 1/m c corrections and duality violations are a concern. CLEO-c inclusive rate and spectral shape provide precision test of 1/m c expansion Mode  (10 -2 ps -1 )  /  (%) CLEO-c (3fb -1 ) D0e+XD0e+X16.4  0.7 4.41.4 D+e+XD+e+X16.4  1.8 11.01.1 DSe+XDSe+X16.1  10.1 62.72.8 Mode B % PDG2000  B /B % PDG2000  B / B(%) CLEO-c (3fb -1 ) D0e+XD0e+X6.8  0.3 4.40.8 D+e+XD+e+X17.2  1.9 11.00.8 DSe+XDSe+X8  5 631.7 Inclusive Semileptonic Decays

27. 27 BESIII-Cleo-c workshop J. Wiss CLEO-c Yellow Book Run Plan Year 1  (3770) – 3 fb -1 30 million DD events, 6 million tagged D decays (310 times MARK III) Year 2 MeV – 3 fb -1 1.5 million D s D s events, 0.3 million tagged D s decays (480 times MARK III, 130 times BES) Year 3  (3100), 1 fb -1 –1 Billion J/  decays (170 times MARK III, 20 times BES II) CLEO-cCLEO-c A 3 year program …and about to begin the year 1 program with 50 pb -1 @  (3770) X5 Mark III with a state of the art detector that is understood at a precision level, and has proven itself with pioneering measurements of Vub, Vcb, & radiative penguins, discovery of the Y D states and DsJ(2463) and many more.

28. 28 BESIII-Cleo-c workshop J. Wiss Unique Opportunities at Charm Thresholds  (D o D o ) = 5.8 nb  (D + D - ) = 4.2 nb  (D s D s ) = 0.5 nb R (units of  (  +   ))  (  +   )= 5.4 nb at 4 GeV  (3770)  DD  s ~4140  D s D s

29. 29 BESIII-Cleo-c workshop J. Wiss Decay constants are important in many processes

30. 30 BESIII-Cleo-c workshop J. Wiss CKM Facts

31. 31 BESIII-Cleo-c workshop J. Wiss  Vub/Vub 25% l B  l D   Vcd/Vcd 7% l D   Vcs/Vcs =16% l B D  Vcb/Vcb 5% BdBd BdBd  Vtd/Vtd =36% BsBs BsBs  Vts/Vts 39%  Vtb/Vtb 29%  Vus/Vus =1%   l  Vud/Vud 0.1% e p n t b W Goal for the decade: high precision measurements of V ub, V cb, V ts, V td, V cs, V cd, & associated phases. Over-constrain the “Unitarity Triangles” - Inconsistencies  New physics ! Many experiments will contribute. Measurement of absolute charm branching ratios At CLEO-c will enable precise new measurements at Bfactories/Tevatron to be translated into greatly improved CKM precision. Precision Quark Flavor Physics CKM Matrix Current Status: N  c  W  cs

32. 32 BESIII-Cleo-c workshop J. Wiss ExperimentCurrentFull K-+K-+ BABAR91 fb -1 500 fb -1 6.6 x 10 6 Belle46.2 fb –1 500 fb -1 6.6 x 10 6 CDF(Run II-a)65 pb –1 2 fb -1 14 x 10 6 CLEO-c-3 fb -1 5.5 x 10 5 BESIII-30 fb -1 5.5 x 10 6 Super Charm-500 fb -1 9.2 x 10 8 / 10 7 s SuperKEKB-2 ab -1 2.5 x 10 7 / 10 7 s SuperBABAR-10 ab -1 1.3x 10 8 / 10 7 s BTeV-~6 x 10 8 / 10 7 s Charm Facilities Future charm data sets