Latest Charm Semileptonic Decay Results from CLEO-c

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1 Latest Charm Semileptonic ecay Results from CLEO-c OUTLINE CLEO-c in the context of testing the Standard Model with precision quark flavor physics. ecay constants Form Factors CKM matrix elements K - ν π - e K Ian Shipsey, Purdue University CLEO-c Collaboration ψ (377) PF Jul 3 9 Charm Semileptonic Ian Shipsey 1 K π, K e ν

2 ynamics of flavor? Big Questions in Flavor Physics Why generations? Why a hierarchy of masses & mixings? Origin of Baryogenesis? Sakharov s criteria: Baryon number violation CP violation Non-equilibrium 3 examples: Universe, kaons, beauty but Standard Model CP violation too small, need additional sources of CP violation Connection between flavor physics & electroweak symmetry breaking? Extensions of the Standard Model (ex: SUSY) contain flavor & CP violating couplings that should show up at some level in flavor physics, but precision measurements and precision theory are required to detect the new physics PF Jul 3 9 Charm Semileptonic Ian Shipsey

3 η ~ V ub Precision Quark Flavor Physics (ρ, η) Δm d,s The discovery potential of B physics is limited by systematic errors from QC: l ν B π B π f ( q) V ub B l ν π ρ B d B d π f ( q) V cd ν f V Bd td [ ] f V cd measurements of absolute rates for semileptonic & leptonic decays yield decay constants & form factors to test and hone QC techniques into a precision theory which can be applied to the B system enabling improved determination of the apex (ρ,η) Br(B )~1% absolute hadronic rates normalize B physics important for V cb (scale of triangle) - also normalize physics PF Jul 3 9 Charm Semileptonic Ian Shipsey 3

4 η ~ V ub Precision Quark Flavor Physics (ρ, η) Δm d,s The discovery potential of B physics is limited by systematic errors from QC: l ν B π B π f ( q) V ub system- CKM elements known to <1% by unitarity l ν B measurements of absolute rates for semileptonic & leptonic decays yield decay constants & form factors to test and hone QC techniques into a precision theory which can be applied to the B system enabling improved determination of the apex (ρ,η) Br(B )~1% absolute hadronic rates normalize B physics important for V cb (scale of triangle) - also normalize physics PF Jul 3 9 Charm Semileptonic Ian Shipsey 4 B d ρ f π π f ( q) V cd ν B d Bd Vtd [ ] f V cd

5 Precision theory charm = large impact Now η ~ V ub (ρ, η) Δm d,s Theoretical errors dominate width of bands ρ Plot uses all CKM inputs PF Jul 3 9 Charm Semileptonic Ian Shipsey 5

6 Precision theory charm = large impact Now η ~ V ub (ρ, η) Δm d,s Theoretical errors dominate width of bands η ρ Plot uses all CKM inputs Few % precision QC Calculations tested with few % precision charm data theory errors of a few % on B system decay constants & semileptonic form factors ρ Plot uses Vub Vcb from exclusive decays PF Jul 3 9 Charm Semileptonic Ian Shipsey no gamma or alpha constraints 6

7 Precision theory? Lattice QC BEFORE Quenched 1-15% precision theory-expt. expt Aspen Feb 1 9 CLEO-c Results Ian Shipsey 7

8 Precision theory? In 3 a breakthrough in Lattice QC Recent revolutionary progress in algorithms allows inclusion of QC vacuum polarization. LQC demonstrated it can reproduce a wide range of mass differences & decay constants. These were postdictions BEFORE Quenched 1-15% precision This dramatic improvement needs validation of predictions. m(bc) successful. Charm decay constants f & f s Charm semileptonic form factors theory-expt. expt theory-expt. expt Understanding strongly coupled systems is important beyond flavor physics. LHC might discover new strongly interacting physics PF Jul 3 9 Charm Semileptonic Ian Shipsey 8

9 Precision theory? In 3 a breakthrough in Lattice QC Recent revolutionary progress in algorithms allows inclusion of QC vacuum polarization. LQC demonstrated it can reproduce a wide range of mass differences & decay constants. These were postdictions BEFORE Quenched 1-15% precision More Quantities added 7 This dramatic improvement needs validation of predictions. m(bc) successful. Charm decay constants f & f s Charm semileptonic form factors theory-expt. expt theory-expt. expt Understanding strongly coupled systems is important beyond flavor physics. LHC might discover new strongly interacting physics PF Jul 3 9 Charm Semileptonic Ian Shipsey 9

10 Precision Experiment for charm? Circa 4 (pre-cleo-c) Poorly known Experiment : Theory Br τ = Γ Key leptonic, semileptonic & hadronic modes: 1 8 Br % error Measured very precisely.4-.8% 4 δ B ( e π υ) = 45% B δ B ( μυ) = 1% B Before CLEO-c precise measurements of charm decay constants and form factors did not exist, because at Tevatron/FT/ B factories: Br( X ) = #X Observed efficiency x #'s produced Backgrounds are large. # s produced is usually not well known. PF Jul 3 9 Charm Semileptonic Ian Shipsey 1

11 CLEO-c: World s largest data sets at charm threshold CLEO-c: Oct. 3 March 8, CESR (1GeV) CESR-c at 4GeV CLEO III detector CLEO-c ψ ( S) * s s PG-8 s -1 (MeV) Ldt (pb ) N( ψ ( S)) 7M ψ (377) (*) (*) 5 * ( s) ( s) s s 6 X86 MARK III X5 BES II E (GeV) First sample at this energy PF Jul 3 9 Charm Semileptonic Ian Shipsey 11

12 sig e ψ(377) Analysis Strategy e e - ψ(377) e tag ψ(377) is to charm what Y(4S) is to beauty π K Pure, no additional particles (E = E beam ). σ () = 6.4 nb (Y(4S)->BB ~ 1 nb) Low multiplicity ~ 5-6 charged particles/event high tag efficiency: ~% of events Compared to ~.1% of B s at the Y(4S) A little luminosity goes a long way: Tagging ability: # tags in 8 pb charm factory ~ # B tags in 13 fb Y(4S) π π π ψ (377) PF Jul 3 9 Charm Semileptonic Ian Shipsey 1 K π π, K K CLEO-c ATA π π

13 Absolute Charm Branching Ratios at Threshold 81/pb E E beam : Δ E = E E beam M = E p BC beam 1 reconstructed (a tag) 1 & 1 - reconstructed in same event K K π π π, π 151±18 Independent of L and cross section candidate mass (GeV) M BC B ( Kππ) = candidate mass (GeV) # ( K ππ)observed in tagged events detection efficiency for ( K ππ ) # tags PF Jul 3 9 Charm Semileptonic Ian Shipsey 13 M BC

14 B( o K - π ) Sets scale of bd triangle BABAR B( Κ - π π ) Previous best: CLEO-c Phys. Rev. Lett. 1, 518 (8) CLEO-c measure: B ( π ) * B ( π ) * B ( B ( K π ) B ( Kπ π ) Kπ π ) dependent on Wrong sign B( K π ) B (%) Error(%) Source 3.8 ±.9.4 PG ±.35 ± ±.37 ±.7.. CLEO-c BABAR Syst. limited: % CLEO-c & BABAR agree vastly superior S/N at CLEO-c 81/pb B (%) Error(%) Source 9.3±.6± CLEO 9.1±1.3± MKIII 9.1± PG ±.1± CLEO-c now : B ( Kππ ) independentlymeasured CLEO-c x 3.5 More precise than PG charm hadronic scale is finally on a SECURE FOUNATION 81/pb PF Jul 3 9 Charm Semileptonic Ian Shipsey Phys. Rev. 76, 111 (7) 14

15 Tag fully reconstructed f from Absolute Br( μ ν) at ψ(377) MM = ( E E ) ( P P ) where E = E, P = P μ μ beam tag 1 additional track (consistent with a muon) Zero additional photons Compute missing mass : peaks at for signal B f MkIII < 7. < 9 4 ( μν ) 1 MeV BESII 1. ± ± f V cd Mark III PRL 6, 1375 (1988) ~9pb tags S=3 B=.33 Phys.Lett.B61:183(5) ~33pb tags PF Jul 3 9 Charm Semileptonic Ian Shipsey 15 p μ ν MKIII BESII MM MM

16 f from μ ν f from μ ν & τ ( π ν) ν 818 pb -1 at ψ(377) 6 pb -1 at 417 MeV s s π K μ ν MM (GeV ) PR 78,53 (8) Background 3 π / K π / ηπ PR 79,51(9) s f Method : τ ντ, e νν s Aspen Feb 1 9 CLEO-c Results Ian Shipsey PR 79:5,9 16 s

17 Comparison to LQC CLEO f consistent with calculations (4% test of lattice) CLEO f s (and Belle & BABAR) higher than most theoretical expectations PR 79,51(9) PR 79:5,9 CLEO f s is ~.3σ above the most recent & precise LQC calculations s leptonic decay width could be modified by new physics example: obrescu and Kronfeld arxiv:83.51 The difference between experiment HPQCUKQC could be due to new physics, unlikely statistical fluctuations in experiment or lattice calculations or systematic uncertainties which are not understood in the lattice calculation or experiment. BES III measurements are eagerly awaited. PF Jul 3 9 Charm Semileptonic Ian Shipsey 17

18 1 Importance of Charm Semileptonic ecays V CKM f(q ) Assuming theoretical form factors V cs and V cd dγ V f (q ) dq ( K) π cs(d) Assuming V cs and V cd known, we can check theoretical calculations of the form factors 3 Potentially useful input to Vub from exclusive B semileptonic decays Br( B πlν )~6% precision BABAR/Belle/CLEO(HFAG) (summer 8) Expt. 5% q > 16GeV V ub = (3.6 ±. ± ) 1 ± exp ± LQC V ub 11-17% e.g. HPQC &FNAL β HQS B B l ν π l ν π B π f ( q) V ub π f ( q) V cd Related at same invariant 4 velocity PF Jul 3 9 Charm Semileptonic Ian Shipsey 18

19 Absolute Semileptonic Branching Fractions K - ν π - e K The neutrino direction is determined to 1 o no kinematics ambiguity U E p = S/N ~3/1 miss miss arxiv: (accepted PR Jul 9) (~14, events) ψ (377) K π, Tagging creates a single beam of known 4-momentum K e ν B( Keν ) = U = E miss P miss (GeV) N( Keν ) Efficiency N PF Jul 3 9 Charm Semileptonic Ian Shipsey tags 19

20 CLEOIII 1 GeV π ν K ν π e ν CLEO-c arxiv: (accepted PR Jul 9) π e ν Δm Tag with Compare to: obse state of the art measurement at 1 GeV (CLEO III) PRL 94, 118 (4) S/N ~1/3 * π ν rvable : Δ m= m( π π ν) m( π ν) s π s S/N ~4/1 (~1,4 events) U = E miss P miss (GeV) Only other high statistics measurement is from Belle 8/fb (x35 CLEO-c) ± 17 events S/N 4/1 Note: kinematic separation. PF Jul 3 9 Charm Semileptonic Ian Shipsey K e ν

21 CLEO-c semileptonic tagging analysis technique: big impact 1 st Observations: Precision Measurements: ρ e ν e ηe ν e ωe ν e K π π e ν e Xe ν / e Note: use PG4, as PG6 & PG8 are dominated by CLEO-c measurements * K e ν e form factors PRL. 97, 5181 (6); arxiv:96.983(accepted PR); PRL, 1, 518(8); PR, 77, 115(8); PR. 74, 51(6); PRL, 1, 8181(9); PRL. 99, (7); Normalized to PG * K e ν branching fractions are for 56/pb π K π K e ν / / / branching fractions are for 818/pb CLEO s measurements most precise for ALL modes; 4 modes observed for the first time PF Jul 3 9 Charm Semileptonic Ian Shipsey 1

22 K e ν K, π eν Branching Fractions π e ν (BABAR measures K π relative to ) K e ν B( ) 3.5(3)(4)% 1 (CLEO-c 818 pb ) σ ( BKe ( ν)) / BKe ( ν) ~ 1.4% σ( B( πeν)) / B( πeν) ~ 3.% B( π e ν).88(8)(3)% arxiv: (accepted (CLEO-c PR 818 Jul pb 9) ) Precision measurements from BABAR/Belle/CLEO-c. CLEO-c most precise. Theoretical precision lags experiment. PF Jul 3 9 Charm Semileptonic Ian Shipsey

23 K e ν e Measuring the form factor in K/πeν dγ( Keν ) = dq 4π G F 3 4 of 7 U fits P 3 K f ( q ) Vc s Form factor probability hadron forms as a function of q q = m = ( P P) W e v Kev All tags integrated over q 1411± 11 U = E Pmiss miss S/N ~3/1 Signal events ~14 U resolution ~1 MeV q resolution ~.8 GeV /c 4 We perform binned likelihood fits to U distributions in each q bin and each tag mode Signal shapes are taken from signal MC, smeared with double Gaussians Background shapes are taken from MC with all and non- decays arxiv: (accepted PR Jul 9) PF Jul 3 9 Charm Semileptonic Ian Shipsey 3

24 3 par (a a 1 a ) K/πe ν : Fits to the dγ/dq istributions dγ G = F P dq 4π 3 3 K / π f ( q ) Vc x par (a a 1 ) Fit to Becher-Hill Series 1 k f ( q ) = ak z ( q,) P q k ( ) φ ( q,) Other form factor parameterizations exist, but are only used as functional forms as their physical pictures are not supported by the data Simultaneous fits to isospin conjugate modes are also performed Experimentally measured decay rates measured Γ i χ Theoretically predicted decay rates G V predicted Γ = d Γ = f q p dq i F Qq' 3 ( ) 3 P' 4π i PF Jul 3 9 Charm Semileptonic Ian Shipsey 4 i

25 dγ = dq G 4π F 3 3 P K ( q ) Vcs Form factor measures probability hadron will be formed f Ke ν Form Factor: test of LQC FNAL-MILC-HPQC PRL 94, 1161 (5), and arxiv: [hep-lat]. Shape: α( Keν) Kfast Assuming V cs =.97334(3) (CKM Unitarity) K at rest tag K Normalization: f () α K =.39() my average (Fit to CLEO, Belle & BaBar) Modified pole model used as example f ( q ) = f () ( 1 q mpole )( 1 α q mpole ) Normalization: experiments (1.%) consistent with LQC (1%). Theoretical precision lags. CLEO-c prefers smaller value for shape parameter, α (BABAR measures K π relative to ) PF Jul 3 9 Charm Semileptonic Ian Shipsey 5

26 dγ = dq G 4π F 3 3 P K ( q ) Vcs Form factor measures probability hadron will be formed f Ke ν Form Factor: test of LQC FNAL-MILC-HPQC PRL 94, 1161 (5), and arxiv: [hep-lat]. Shape: α( Keν) Kfast Assuming V cs =.97334(3) (CKM Unitarity) K at rest tag K Normalization: f () α K =.39() my average (Fit to CLEO, Belle & BaBar) Modified pole model used as example f ( q ) = f () ( 1 q mpole )( 1 α q mpole ) CLEO-c prefers smaller value for shape parameter, α Normalization: experiments (1.%) consistent with LQC (1%). Theoretical precision lags. (BABAR measures K π relative to ) PF Jul 3 9 Charm Semileptonic Ian Shipsey 6

27 dγ G 3 ( ) V = F 3 P π f q cd dq 4π π e ν Form Factor: test of LQC shape: α( πν e ) FNAL-MILC-HPQC π fast Assuming V cd =.56(1) (CKM Unitarity) FNAL-MILC-HPQC PRL 94, 1161 (5), and arxiv: [hep-lat]. π at rest π Normalization: f () tag α π =.(4) my average (Fit to CLEO & Belle) Modified pole model used as example f q ( ) = f () ( 1 q mpole )( 1 α q mpole ) Normalization experiments (%) consistent with LQC (1%). CLEO-c is most precise. Theoretical precision lags. tag PF Jul 3 9 Charm Semileptonic Ian Shipsey 7

28 dγ G 3 ( ) V = F 3 P π f q cd dq 4π π e ν Form Factor: test of LQC shape: α( πν e ) FNAL-MILC-HPQC π fast Assuming V cd =.56(1) (CKM Unitarity) FNAL-MILC-HPQC PRL 94, 1161 (5), and arxiv: [hep-lat]. π at rest π Normalization: f () tag α π =.(4) my average (Fit to CLEO & Belle) Modified pole model used as example f q ( ) = f () ( 1 q mpole )( 1 α q mpole ) Normalization experiments (%) consistent with LQC (1%). CLEO-c is most precise. Theoretical precision lags. The data determines V cd f (q ). To extract V cd we fit to V cd f (q ) using Becher-Hill z -expansion to determine V cd f () & use f () from LQC (FNAL- MILC-HPQC.) Same for V cs PF Jul 3 9 Charm Semileptonic Ian Shipsey 8 tag

29 V cs & V cd Results arxiv: (accepted PR Jul 9) CLEO-c: the most precise direct determination of V cs σ ( V ) / V ~ 1.1%(expt) 1%(theory) cs cs CLEO c V cs 1 (818 pb ) ± ± ±.13 stat syst theory * CLEO-c: σ ( V cd ) / V cd ~ 3.1%(expt) 1%(theory) νn remains most precise determination (for now) CLEO c V cd 1 (818 pb ) ± ± ±.5 stat syst theory ν N * PG Fits use Becher-Hill z-expansion PF Jul 3 9 Charm Semileptonic Ian Shipsey 9

30 V cs & V cd Results arxiv: (accepted PR Jul 9) THEORY UNCERTAINITY REMOVE CLEO-c: the most precise direct determination of V cs σ ( V ) / V ~ 1.1%(expt) 1%(theory) cs cs CLEO c V cs 1 (818 pb ) ± ± ±.13 stat syst theory * CLEO-c: σ ( V cd ) / V cd ~ 3.1%(expt) 1%(theory) νn remains most precise determination (for now) CLEO c V cd 1 (818 pb ) ± ± ±.5 stat syst theory ν N LQC form factors with improved precision are eagerly awaited * PG PF Jul 3 9 Charm Semileptonic Ian Shipsey 3

31 Unitarity Test: Compatibility of charm & beauty sectors of CKM matrix? arxiv: (accepted PR Jul 9) V & V indirect cd V & V direct cd cd cs cs 1)K & nucleon V V & V V ud cs cd us ) Bphysics Indirect= global CKM fit = 1 cs ( semileptonic decays CLEO) CLEO-c full data set σ ( V ) / V ~ 3.1% theory cd σ (V )/V ~1.1% theory cs CLEO-c full data set 3-4% theory uncertainties CLEO-c Now semileptonic decays with comparable theory and experimental uncertainty may lead to interesting competition between direct and indirect constraints We eagerly await new precise lattice calculations Plots by Sebastien escortes-genon & Ian Shipsey See also talk by escotres-genon at joint BABAR-Belle-BESIII-CLEO-c Workshop 11/7, Beijing PF Jul 3 9 Charm Semileptonic Ian Shipsey 31

32 Observe 6 Exclusive s Semileptonic ecays Similar to s µν analysis: tag; reconstruct visible parts of signal; plot MM First absolute branching fraction measurements for s SL decays Total width of these exclusive modes is 16% lower than the / semileptonic widths. Shed light on η-η -glueball mixing Observation of a semileptonic decay including a scalar meson in the final state. arxiv:93:61 B( f (98) e v) s B( f π π ) 31 pb (Half of full dataset) PF Jul 3 9 Charm Semileptonic Ian Shipsey 3

33 s semileptonic decays provide a very clean environment to study the properties of the f (98) meson s f (98)e ν 6 pb (CLEO-c full dataset) It is suggested that B s J/Ψf can be an alternative to B s J/ΨΦ to measure CP Violation in the B s system Stone & Zhang [PR79, 744] (98) s f e v arxiv: (submitted to PR Jul 18 9) φe v s Many interesting results: Bs f ev f π π B φev = ± ± ( (98), ) = (. ±.3 ±.1)% ( ) ( )% s ππ mass K K mass Γ( f (98) e v, f π π ) Γ s ( s φe v, φ K K ) q = = (4 ± 11)% f e ν form factor fit Γ( Bs J / Ψf(98), f π π ) Predicted to equal Γ( Bs J / Ψφφ, K K ) (Stone & Zhang) 11 3 M f (98) 9 f (98) = (977 ± 1) MeV, Γ = (91 ± 3) MeV Simple pole model M = (1.7 ±.) GeV 4.5 pole.7 φe ν form factor fit PF Jul 3 9 Charm Semileptonic Ian Shipsey 33

34 Inclusive Semileptonic ecays of,, and s NEW PRELIMINARY X e ν X e ν s X e s ν 818 pb 818 pb 6 pb X e ν X e ν s X e ν Inclusive B (%) 6.55±.1± ±.11± ±.4±.18 Sum of exclusive B (%) 6.1±.±. 15.1±.5± ±.6 Use knowledge of semileptonic decay to extrapolate below the momentum cutoff (MeV/c) Any additional exclusive modes will have small branching ratios SL SL Γ / Γ =.99 ±. ±. SL SL Γ / Γ =.81±.5 ±.3 s Isospin symmetry SU(3) is broken PF Jul 3 9 Charm Semileptonic Ian Shipsey 34

35 Summary of CLEO-c CKM physics motivated measurements CLEO-c hadronic, and sbranching fractions more precise than PG averages: (for, % precision is syst.limited) CLEO establishes charm hadronic scale Most precise: f ( ) MeV consistent with LQC 1% ( MeV) full data = ± ± Most precise: fs = (59.5± 6.6 ± 3.1) MeV ~.3 σ higher than LQC. To interpret as "prosaic" or "exciting": requires more data (BES III) Most precise measurement of form factors magnitudes in Most precise =.985 ±.9 ±.6 ±.13 V cs PF Jul 3 9 Charm Semileptonic Ian Shipsey 35 theory K/ π eν V cd =.34 ±.7 ±. ±.5 theory Most precise determination from semileptonic decay 6 exclusive semileptonic decays & measurement of form factor s s in f (98) e ν. SU(3)is broken in Xe ν decays ~9 CLEO-c papers now pubished or submitted, & many more analyses to come. Longer term the charm factory mantle passes to BES III

36 Precision theory charm = large impact Now η ~ V ub (ρ, η) ρ Δm d,s Plot uses all CKM inputs * CLEO-c: a major contribution to the goal the lower plot represents * LQC has been validated at the 4% level (f ) * A triumph for theory & experiment! More precise LQC form factor calculations needed more data BESIII η ρ Few % precision QC Calculations tested with few % precision charm data theory errors of a few % on B system decay constants & semileptonic form factors Plot uses Vub Vcb from exclusive decays PF Jul 3 9 Charm Semileptonic Ian Shipsey no gamma or alpha constraints 36

37 Additional Material PF Jul 3 9 Charm Semileptonic Ian Shipsey 37

38 Semileptonic ecay Form Factors Form factors relate to the probability of forming final state at given q. Theoretical predictions for form factors are needed to turn the measured rates into V cx determinations. Theory often calculates this probability at fixed q and uses parameterizations to extrapolate to full q range. Theoretical approaches include phenomenological models, QC sum rules, and LQC. LQC is systematically improvable and aims for several percent precision (we focus on this) Assuming zero lepton mass: dγ G = dq 4π F 3 3 P K f ( q ) Vcs PF Jul 3 9 Charm Semileptonic Ian Shipsey 38

39 In general: Models Model independent Single pole Modified Pole Form Factor Parameterizations Series Expansion f () 1 1 Im( f ( t)) f ( q ) = dt 1 1 P t q i f ( q ) ( q mpole ) ( m m ) λ π ε f ( q ) = = f () ( 1 q mpole ) f () ( 1 q mpole )( 1 α q mpole ) 1 form factors can be written as: f ( q ) [ z( q, t )] accounts for pole K t q t t (, ) = (, ), ± ± K π t q t t zq t t M m * S Measure f () & m pole Measure f () & α m = m( ) pole (Allows for additional poles) = ak ( t) Pq ( ) φ( q ) k = ensure a 's good behaviour z is small and converges quickly, linear or quadratic is sufficient to describe the data * ( s) t : arbitrary q value that maps to z= k Becher & Hill, Phys. Lett. B 633, 61 (6) Measure a, r 1 = a 1 /a, and r =a /a PF Jul 3 9 Charm Semileptonic Ian Shipsey 39

40 Measuring the form factor in K/πeν π e ν 4 of 1 U fits e π e ν S/N ~4/1 Signal events ~14 U resolution ~1 MeV q resolution ~.8 GeV /c 4 e arxiv: (accepted PR Jul 9) π e ν e K e ν e 4 of 4 U fits 4 of 54 U fits PF Jul 3 9 Charm Semileptonic Ian Shipsey 4

41 dγ( B ρν e )/ dq ub * dγ( B K )/ dq Vcb ρeν (tagged, 81/pb) Interest: 1 st measurement of FF in Cabibbo suppressed charm P V decays V U = E c Pmiss miss U = E c Pmiss 81pb -1 81pb -1 * Need Keν, ρν e Fixed background shape and signal tails from MC FF Grinstein & Pirjol [hep-ph/445] Simultaneous fit to ρ eν, ρ - eν R v = 1.4 ±.5 ±.3 R =.57 ±.18 ±.6 PRELIMINARY miss PF Jul 3 9 Charm Semileptonic Ian Shipsey 41 q cos θ e cos θ π Line is projection for fitted R V, R B( ρ - e ν)= (1.56±.16±.9) 1-3 B( ρ e ν)= (.3±.±.1) 1-3 Isospin average: Γ( ρ - e ν) = (.41±.3±.) 1 - ps -1 Update to full data set soon χ

42 s Exclusive Semileptonic ecays Candidate events are selected by reconstructing a s in several hadronic modes The tag is then combined with a well reconstructed γ, The missing mass squared against the γ-tag pair * MM = ( E E E ) ( p p p ) CM ( tag ) γ CM ( tag ) s s γ e e - * s s s 417MeV e e * s s γ η'( ηππ ) π η ρ πη'( ργ) 9 s tag modes: N(tag)= N(tagγ)= reconstructed from ~5.5 x 1 5 s* s events arxiv: (submitted to PR Jul 18 9) 6 pb (CLEO-c full dataset) PF Jul 3 9 Charm Semileptonic Ian Shipsey 4