recent results from cleo-c

Recent CLEO-c Results Alex Smith – University of Minnesota La Thuile ’05 1

Recent Results From CLEO-cRecent Results From CLEO-c

Les Rencontres de Physique de la Vallee D’AosteFebruary 27 – March 5, 2005

Alex SmithUniversity of Minnesota

Motivation Leptonic D decays Semileptonic D decays

Exclusive Inclusive

D hadronic BR, (DD) Conclusions


CLEO-c Detector/CESR-c Accelerator CLEO-c Detector/CESR-c Accelerator

SVX

CLEO III • Ability to run at cms energies from J/ up to (5S)

Beam Energy (GeV)

CLEO-III

SVXMini DriftChamber

CLEO-c

(3770)

’

• Addition of superconducting wigglers to CESR required for low energy running– Additional damping to

compensate for lower synchrotron radiation

• Simple conversion of detector from (4S) to (3770) running


Running at the Running at the (3770)(3770)

• No extra energy for fragmentation particles– Known/coherent initial state – Clean neutrino reconstruction– Simple combinatorics

• Large cross section• Good kinematic particle ID

Ecm ~ (3770) Ecm ~ (4S)

CLEO III CLEO-c


Impact of CLEO-c MeasurementsImpact of CLEO-c Measurements

• Calibration and validation of Lattice QCD• Test theoretical form factor calculations and models

– Impacts prediction of form factors for B meson decays

• Measurements of |Vcs| and |Vcd|• Improved decay constants fB possible from CLEO-c fD

measurement + LQCD• Improved measurement of many important

normalization modes

e+

W+

ElectroweakPhysics

StrongPhysics


CLEO-c + Lattice QCD +B factories + ppbar

CLEO-c + Lattice QCD +B factories

CLEO-c

The Future of Precision Flavor PhysicsThe Future of Precision Flavor Physics

Vub/Vub 15%lB

l

D

Vcd/Vcd 7%lD

Vcs/Vcs =16%l

B D

Vcb/Vcb 5%

Bd Bd

Vtd/Vtd =36%

Bs Bs

Vts/Vts 39% Vtb/Vtb 29%

Vus/Vus =1%

l Vud/Vud 0.1%

e

pn

t

b

W

The Goal: Measure all CKM matrix elements and associated phases in order to over-constrain the unitary triangles


DD Leptonic Decays: Leptonic Decays: DD++++

• Many large BR tag modes– ~25% Efficiency for

reconstructing a tag• Signal is very pure after

tagging– 28651 +/-207 tag cand.

Getting the ABSOLUTE branching fractions... “Other side D” tag

e+ e-

Signal D+

Tag D

• Tag D decay modes:–

00

0

0

0

S

S

S

KD

KD

KD

KD

KD

22beam

2MM ppEED

• Fit for (“missing mass”)2:

• Additional charged track presumed to be +


DD Leptonic Decays: Leptonic Decays: DD++++

MeV 1741202

106.04.15.3 4

Df

DB

Published in PRDPhys. Rev. D, 70, 112004 (2004)

Will also measure Ds++ in run above DsDs threshold

Monte Carlo (1 fb-1)Data (60 pb-1)

First Observation!

0LK

8 candidate events

1 background event in signal region

4X statistics by end of April


Exclusive Semileptonic D Meson DecaysExclusive Semileptonic D Meson Decays

)()(

)()( 0

00

DNeK

eKNeKDB

• Reconstruct one D meson in hadronic tagging channel– –

• Reconstruct the remaining observable tracks

• Use the missing energy (Emiss) and missing momentum (|Pmiss|) in the event to form kinematic fit variable for the neutrino

Technique:

22candidatebeambc PEM

candidatebeam EEE

missPEU

miss

From fit of Mbc

and E for number of tags

Signal componentfrom fit to variable U

From MonteCarlo/Data

))()(()(

)()(0

00

DNDNeK

eKNeKNB

Both flavors combined:


Exclusive Semileptonic DExclusive Semileptonic D00 Meson Decays Meson Decays

U = Emiss– Pmiss(GeV)




Events

/ (

10

MeV

)Events

/ (

10

MeV

)

Events

/ (

10

MeV

)Events

/ (

10

MeV

) eD0

eD0

eKD0

0*

*0

KK

eKD

(~110 events)

(~30 events)

(~1400 events)

(~90 events)

Cabibbo suppressed modes Cabibbo favored modes

First Observation!

Preliminary


Exclusive Semileptonic DExclusive Semileptonic D++ Meson Decays Meson Decays

Preliminary





Events

/ (

10

MeV

)Events

/ (

10

MeV

)

Events

/ (

10

MeV

)Events

/ (

10

MeV

) eD 0

eD 0

eKD 0

KK

eKD*0

*0 ,

(~60 events)

(~30 events)

(~500 events)

(~400 events)

Cabibbo suppressed modes: Cabibbo favored modes:


Exclusive Semileptonic DExclusive Semileptonic D++ Meson Decays Meson Decays

Preliminary


Events

/ (

10

MeV

)

eD

(8 events)

First Observation!


Exclusive Semileptonic DExclusive Semileptonic D00 Decays Decays

Preliminary

eD

eKD

eKD

eD

eD

eKD

eKD

eD

eD

eKD

eKD

s

s

s

:11

:10

:9

:8

:7

:6

:5

:4

:3

:2

:1

0*

0

0

0

*0

0

0

0

*0

0

Now (60 pb-1):

CLEO-c goal:


Extracting Decay Constants, FF, |Extracting Decay Constants, FF, |VVcscs| and || and |VVcdcd||

c

du or

e+

W+

ds or

du or

|Vcs| or |Vcd|Use ratio of semileptonic to leptonic branching ratios to eliminate CKM element and isolate hadronic terms:

2

22

31

22

0

02

22

13

DKm

m

D

edqd

f

qfpmm

D

eKD

D

Theory is calibrated/tested with this data

Assuming a precision of ~3% for the SL form factors and ~1% for the decay constants is achieved by the theory:

•Error on |Vcd| of ~1.4% (presently 7%) from D++ and De•Error on |Vcs| of ~1.1% (presently 16%) from Ds

++, Ds

++ and DKl


Inclusive Semileptonic D Meson DecaysInclusive Semileptonic D Meson Decays

• Tag opposite side D meson

• Identify electron– Select correct e charge

using opposite side D meson:

• Charge of K for D0

• D meson charge for D+/-

• Correct for electron efficiency and backgrounds– Efficiency from reweighted

radiative Bhabhas– Fake rates

Technique:



Preliminary

CLEO-c (in D rest frame)



%3.0~sysstat:PDG

%2.0~stat:c-CLEO : 0

BR

BRXeD

%9.1~sysstat:PDG

%3.0~stat:c-CLEO :

BR

BRXeD

tag m

ode

tag m

ode

Combiningtag modes:

PreliminaryResults---No BR yet


DD Hadronic BR’s and Production Cross Sections Hadronic BR’s and Production Cross Sections

e+ e-

DX

ijjiDDij BBNN iiDDi BNN

Single tagged Double tagged

e+ e-

DXj

DXi DXi

ij

j

j

iji

ji

ij

ij

jiDD

N

NB

N

NNN

Independent ofintegrated luminosity!



Fitting technique• A simultaneous fit for all BR and cross sections is

performed– Charged and neutral modes fit simultaneously

– All correlations taken into account• These systematic errors are included in the fit

• Efficiencies– Denominator of efficiency may be determined using

missing mass in data and MC (all particles measured)• Uncertainty on charged track efficiencies will go down by

factor of four• Improvements to uncertainties on 0 and KS

0 efficiencies nearing completion

0

00

,

, ,

SKKD

KKKD



22PPEM Kbeambc

beamK EEEE

Key Variables for extracting yields:

Preliminary

Double Tag Yields

~2500 Double Tagged D0

~500 Double Tagged D+



KD0

Single Tag Yields00 KD KD0

KD 0SKDPreliminar

y



Preliminary

NDD (1.98 ± 0.04 ± 0.03) x 105

K+ 0.0392 ± 0.0008 ± 0.0023

K+ 0.143 ± 0.003 ± 0.010

K++ 0.081 ± 0.002 ± 0.009

ND+D- (1.48 ± 0.06 ± 0.04) x 105

K++ 0.098 ± 0.004 ± 0.008

KS+ 0.0161 ± 0.0008 ± 0.0015

(e+e DD) 3.47 ± 0.07 ± 0.15 nb

(e+e D+D) 2.59 ± 0.11 ± 0.11 nb

(e+e DD) 6.06 ± 0.13 ± 0.22 nb

ND+D- / NDD 0.75 ± 0.04 ± 0.02

Cross sections:

Neutral Modes:

Charged Modes:

Stat. Errors ~ 2.0%

Stat. Errors ~ 4.5%

%4.91C.L.

160.9

:ResultsFit Global dof

2

N

K+0/ K+ 3.64 ± 0.05 ± 0.17

K+ + -/ K+ 2.05 ± 0.03 ± 0.14

KS+ / K+ + 0.164 ± 0.004 ± 0.006

Ratios:



• PDG global fit includes ratios to D0K-+ and D+K- ++ – Charged and neutral modes are correlated in that fit

• Our results higher than PDG– Final state radiation (FSR) included in our results and not in PDG results

• 1-2% increase depending on mode

Results shown normalized to PDG valuesPreliminary


DD Hadronic BR’s and Production Cross Sections Hadronic BR’s and Production Cross SectionsB(D0 K-+)

B(D+ K- ++)

• Branching fractions and cross sections are competitive with world averages with only ~60 pb-1

• Results are presently systematics limited but improving– Dominant per track

systematic error recently improved by factor of 4!

– Most systematic errors will improve with luminosity, however

• Four more D+ modes being added (3X DT statistics)

• These measurements will impact the determination of |Vcb| (from BD*l)

(Bands are PDG average, NOT global fit)

Preliminary


CLEO-c Impact on the Unitarity TriangleCLEO-c Impact on the Unitarity Triangle

Now: Theory uncertainties dominate

With few % theory errors

made possible by CLEO-c and 500

fb-1 each from the B factories:


Other CLEO-c Physics Not Covered in This TalkOther CLEO-c Physics Not Covered in This Talk

• (3770)– Data still coming in, luminosity improving

• ’ – Large sample collected... lots of results

– Observation of hc

• Ecm ~ 4140 MeV (just above Ds pair threshold)

– fDs from Ds++

– Ds semileptonic decays

• J/ – Sample of 109 J/’s anticipated– Radiative J/ decays– Glueball candidates, hybrids, ...


SummarySummary

• CLEO-c is producing results that will have a broad impact on the field– These measurements are essential for other

measurements at the B Factories and Tevatron to realize their full potential

• With only 60 pb-1 of (3770) data analyzed many measurements are already the best

• Exciting results on the horizon– More data on (3770)

– Data at Ecm above 2MDs threshold

– J/ radiative decays

recent results from cleo-c

Documents

mev events

emiss pmissgevu

emiss pmissgevevents

ntag d decay modes

missing energy emiss

d0d meson charge

cleoc goal

cleoc measurementscalibration