No Slide Title

Extract the partial rates

We can make fits to the partial decay rates

to extract (1) normalization f+ (0)|Vcx|(2) Form factor shape parameters r1 and r2 (or just r1) for series

Mpole for simple pole

for modified pole

r for ISGWII

Assuming |Vcd |= 0.22560.0010 (CKM unitarity)1 bands (stat and syst) by FNAL-MILC-HPQCD

IntroductionFits to the U DistributionsD Tagging at 3770 MeVSummaryForm factors as a stringent test of LQCD|Vcs | and |Vcd | Results Bo Xin, Ian Shipsey, Purdue University, CLEO Collaboration

Improved measurements of D meson semileptonic decays to and K mesons

Goals of CLEO-c semileptonic decay analysis program To provide validation and calibration data for LQCD and other theoretical approaches thereby enabling theory (especially LQCD) to be applied to B physics (|Vub|). To measure |Vcs| and |Vcd| with a validated theory We have perform an analysis using CLEO-cs final data set to meet these goalsMost precise branching fraction determinations for D Ke+ and D e+ Stringent test of LQCD calculations of semileptonic form factors. D Ke+, D e+ form factors are found to be in general agreement with LQCD.Best direct measurement of |Vcs|, measured to 1.1%(experimental) 10%(theory). |Vcd| is measured to 3.1%(experimental) 10%(theory). DK/e+ Branching fractions Standard D Tags (Tag): One D in the event is fully reconstructed in a hadronic decay mode, the second D decays semileptonically

The three charge +2/3 quarks and three charge -1/3 quarks change identity via the weak interaction with a probability proportional to the elements of the 3x3 unitary Cabibbo-Kobayashi-Maskawa matrix. These nine elements are related to four fundamental parameters of the standard model of particle physics and must be determined by experiment. Semileptonic decays are the principal process for measuring the CKM matrix elementsStrong interaction effects are confined to the hadronic current and are parameterized by form factors in massless lepton limitFor P to P transitionsThe theory must predict the absolute normalization of the form factors:

As |Vcd| and |Vcs| are tightly constrained by the unitarity of the CKM matrix. Measurements of charm semileptonic decay rates and form factors rigorously test the theory (e.g. LQCD)Validated theory can then be applied to B decays to determine |Vub|, which is the one of the most poorly known CKM matrix elements

from fits to Mbc

from fits to U

Pure DD,zero additional particles, ~5-6 charged particles per event

~6.6x 105 D0 and~4.8 x 105 D+ tagsreconstructed from~5.4 x 106 DD events

We tag ~20% of the events, compared to ~0.1% of Bs at the Y(4S)

818 pb-1 @3770 (full data set)Worlds largest data set at 3.770 GeV

(, )~|Vub|md,slnBp

lnp(K)D

HQSSuffer from large theory uncertaintyMoriond 09We perform binned likelihood fits to U distributions in each q2 bin and tag modeSignal shapes are taken from signal MC, smeared with double GaussiansBackground shapes are taken from MC with all DD and non-DD decays

4 of 27 U fits

S/N~300/1Signal events~14000U resolution~10 MeVq2 resolution~0.008 GeV2/c4

4 of 54 U fits

4 of 42 U fits4 of 21 U fitsS/N~40/1Signal events~1400U resolution~10 MeVq2 resolution~0.008 GeV2/c4

For semileptonic D : U peaks at zero for real semileptonic decaysAn absolute measurement, independent of the integrated luminosity and number of D mesons in the data sample

Precision measurements from BABAR/Belle/CLEO-c. CLEO-c most precise. Theoretical precision lags experiment.

1 bands (stat and syst) by FNAL-MILC-HPQCD

Modified pole model used to compare with LQCD

Form factor measures probability hadron will be formed

Assuming |Vcs |=0.973340.00023 (CKM unitarity) : CLEO-c prefers smaller value for shape parameter than other experimentsf+ (0): experiments (1.2%) consistent with LQCD (10%) CLEO-c is most precise. Theoretical precision lags.

: CLEO-c measurements are compatible with LQCDf+ (0): experiments (2.9%) consistent with LQCD (10%). CLEO-c is most precise. Theoretical precision lags.

arXiv:0906.2983 (accepted PRD Jul 22 2009)arXiv:0906.2983 (accepted PRD Jul 22 2009)

CLEO-c: the most precise direct determination of |Vcs |

*

CLEO-c: N remains most precise determination

* PDG2002The data determine |Vcs(d)|f+(0). To extract |Vcs(d)|, we combine the measured |Vcs(d)|f+(0) values using the Becher-Hill parameterization with (FNAL-MILC-HPQCD) for f+(0)

*

* PDG2002THEORY UNCERTAINITY REMOVED* PDG2002*The uncertainties on our results are dominated by uncertainties from LQCD Theoretical precision lags. In particular,CLEO-c measures form factor normalizations for D Ke+, D e+ to 1% and 3%, respectively, while LQCD predicts them at 10% level.

We are eagerly awaiting more precise LQCD calculations of semileptonic form factors

CLEO-c NowCLEO-c full dataset + 3-4% theoryuncertaintiesPlots by Sebastien Descortes-Genon & Ian ShipseySee also talk by Descotres-Genon at joint BABAR-Belle-BESIII-CLEO-c Workshop 11/07, Beijing