Recent Charm Semileptonic Decay Results

1. Recent Charm Semileptonic Decay Results Content I: Charm Semileptonic decay motivation II: Semileptonic BF results from CLEO-c III: Fully leptonic results from BaBar/CLEO-c IV: Form Factors for PseudoScalar l n from FOCUS, BaBar &CLEO-c V: Vector l n Form Factors from CLEO-c VI: Summary. Jim WissUniversity of IllinoisFPCP06April 11,2006 Representing:

2. Charm semileptonic decay as tests of LQCD The hadronic complications are contained in the form factors, which can be calculated via non-perturbative Lattice QCD, BF provides a measurement of |VCq|2 Charm SL decays provide a high quality lattice calibration, which is crucial in reducing systematic errors in the Unitarity Triangle. The techniques validated by charm decays can be applied to beauty decays.  Improvement of CKM @ beauty sector.

3. Semileptonic reconstruction in Cleo-c  K- K+ - e+ (~117 events) Events / 10 MeV U ( = Emiss – |Pmiss| ) CLEO BFRelative to PDG

4. Inclusive Semileptonic BF. Inclusive BF vs sum of exclusive BF CLEO-c 281 pb-1 Consistent with the known exclusive modes saturating the inclusive B . Some room for new modes? Consistent w/ SL isospin symmetry:

5. Fully leptonic decays: D+  m+n and DS m+n n Tag D m+ Signal D 50 signal candidates

6. D Pseudoscalar ln form factors Rate  P3 This process can give a clean measurement of CKM angles and powerful tests of LQCD Unfortunately the rate vanishes at highest q2 where sensitivity to the form of f+(q2)is greatest.This is also the zero recoil limit where theory calculations are cleanest. What do we know about f+(q2) ?

7. Pole Dominance in K*ln Cauchy Theorem (2004) <Mpole> is 5.1 s lower than Ds* Ds* Integral term is important BK expression is a good fit to recent lattice calculations

8. FOCUS D0 Km+n analysis 12,840 Km+n Dm cut RS-WS MC WS Lab frame • A good muon candidate. • Cerenkov ID for K/p candidates. • L/s > 5 between two good vertices. • D* tag required, and wrong sign soft p subtraction. Km frame • Fixed Target Neutrino closure • Jump to Km rest frame • The D and D* mass constraints the neutrino lies on a cone around the soft pion. • Pick the f that points the D closest to the primary vertex. q2 reconst q2 actual

9. Correcting for charm backgrounds inD0 Km+n After subtracting known charm backgrounds,f+(q2) is an excellent match to a pole form withmpole= 1.91  0.04  0.05 GeV/c2 or = 0.32 (CL 87%, 82%). The background only affects the highest q2 bins.

10. Comparing to Lattice Gauge & prelim BaBar ~100K 13K Nearly identical q2 resolution!

11. Preliminary untagged DK/p e n from CLEO-c CKM info Modified pole Dq2 resolution still about 10x better than FOCUS/BaBar Neutrinos are closed by energy-momentum balance but no recoil D tag Slightly lower than previous measurements Dq2

12. DVector l n Decay S-wave interfere asymmetry cosV Korner+Schuler form from 1990 Present in K* l nu H0(q2), H+(q2), H-(q2) are helicity-basis form factors computable by LQCD A new factor h0 (q2) is needed to describe s-wave interference piece.

13. KS / GS model for H and H0 Spectroscopic pole dominance Versus B&K style “effective” poles This is traditional method • V(q2) essentially same as B&K with one physical and one effective 1- poles. • A1(q2) forced to one effective 1+ pole • A2(q2) has two effective 1+ poles But S-pole dominance should work poorly at low q2  Need for alternative…

14. Spectroscopic pole dominance DVln fits theory RV RV Ds fmn D+  K*mn theory R2 R2 The latest (FOCUS) data on Dsfmnis consistent with D+ K*mn

15. A non-parametric approach D: M+M- M0 Disentangle helicity form factors based on their different angular bin populations. cosL cosV

16. Preliminary CLEO D+  Kpen from 281/pb CL = 40% CL = 24% CL = 0.2% CL = 59% FOCUS model Low q2 peaking of Ho and ho is very apparent. Apart from interference term the CL are rather good.

17. Intensity contributions  q2 H2(q2) H- contribution vanishes at 0. H+ contribution vanishes at 0. Subtle deviation of H0 from pure 1/q . Confirms KS expected forms

18. Pole mass sensitivity MV=2.1 MA=2.5 MV=MA=  Data fits spectroscopic poles and constant form factors equally well

19. Confirming the s-wave phase Focus For d40 the high mass BW is nearly  to s-wave amp and interference nearly vanishes. Our interference “Ho (q2)ho (q2)” should also vanish above pole if d40 and it does! CLEO-c

20. Search for D-wave Kp Add a D-wave projector Guard against “phase cancellation” by showing above and below the K* q2 GeV2

21. Summary • New result on BF D+mnand fDfrom CLEO-c 281/pb and preliminary fDsfrom BaBar • Exclusive BF of semileptonic decays from CLEO-c. • With just 56 pb-1, many CLEO SL BF are already the world best. Results on 281 pb-1 coming soon!. • Inclusive BF of D Xen preliminary from 281/pb. Consistent with SL(D0)/ SL(D+) = 1. The sum of exclusive BF almost saturates the inclusive BF • Non-parametric form factor measurement from FOCUSfor D K l n, in comparison with the latest unquenched light-flavor LQCD results and preliminary BaBar results

22. Summary Continues… • (4) Preliminary non-parametric Form Factor measurements for D V l n from CLEO-c 281/pb • H+, H-, H0 appear very consistent with expected K&S shapes. • Data fits constant A1(q2), A2 (q2), V (q2) as well as it fits spectroscopic pole dominance  no sensitivity to q2 dependence • Statistically significant Ho (q2)ho (q2)interference term ho (q2)1/q confirming s-wave interference effect. • The effective “Ho (q2)ho (q2)” vanishes above the K* pole, suggesting an s-wave amplitude phase near 40 which is consistent with the Focus phase. • No evidence for a Kp non-resonant d-wave or f-wave contribution.

23. Question slides

24. More semileptonic signals The first 56pb-1 (~1311 events) (~545 events) Events / 10 MeV (~422 events) (~8 events) First Observ. U ( = Emiss – |Pmiss| ) plots

25. fD from Absolute Br(D+  m+n) |fD|2 |VCKM|2 Vcd (1.1%) from 3 generation unitarity tD+ (0.3%)well-measured • Based on 281 pb–1,158,354 tags and 50 signal events. • Background ~ three events. 2+1 flavorPRL 95, 122002

26. Summary of CLEO-c (56 pb-1) Exclusive BF Phys. Lett. B 597, 39 (2004) Phys. Lett. B 608, 24 (2005) References: PRL 95 181801 and PRL 95 181802 (2005)

27. Expected q2 Dependence of Helicity FF Only 0 helicity components can survive at q2  0because of V-A helicity laws.

28. q2 dependence: Deconvolution A deconvolution matrix is constructed from the number of events generated in thei-th q2 bin that end up reconstructed in the j-th q2 bin. This matrix is then used to correct data for resolution and efficiency. We actually use a 10  10 matrix

29. Information on vector-axial pole masses V  H--H+ A1 and V are very consistent with spectroscopic pole forms and measured rV. But the slopes are only a few sigma from 0, so no useful pole mass information can be obtained with present statistics. A1  H++H- q2 q2 Difference and sum of non-parametric H+ and H- data

30. Comparing CLEO-c & FOCUS Results Data 2472 PreliminaryCLEO D+ Kpen FOCUS D+ Kpmn Data 11397 q2 res q2 res

31. IV. c. Isospin Conjugation Test. From CLEO-c (56pb-1) measurements,