1

HADRONIC BRANCHING FRACTIONS OF D0 AND D+ AND THE PRODUCTION CROSS SECTION AT

THE (3770) RESONANCE

Outline Introduction and Motivation Method Event Selection Fitting Yield Extractions Systematics Results Conclusion and Summary

Batbold Sanghi, Purdue Universityfor the CLEO collaboration

DD

2

Introduction

CLEO-c, in a pilot run, has accumulated 57.2 pb-1. with this data, we present a preliminary measurement of absolute branching fractions and cross section. We use double tagging technique pioneered by MARK III.

branching fractions: and are reference branching fractions. Determine other branching fractions Reduce systematics when extracting CKM matrix elements

cross section

Precise measurement since many systematic errors canceled.

DD

RESULTS ARE PRELIMINARY

KDB 0 KDB

DD

3

Using double tags to measure and

ijjiDDij BBND

2

2

42 i

ii

ii

iDD

ji

ij

ij

jiDD D

SNor

D

SSN

e+ e

0D

0D

K+

+

K-

iiDDi BNS 2

XSingle tagged D

Double tagged D

e+ e

0D

0D

K+

DD B

ii

i

i

iii

ij

j

j

iji S

DBor

S

DB

2

Single and double tags give and

Use 3 modes : , ,

Use 2 modes : ,

DDNB0DD

KD0 00 KD KD0

KsD KD

4

Using double tags to measure and DD B

and yields fitted separately.

10 single tag yields and 13 double tag yields.

Perform fits

Parameters: 5 branching ratio and and

Yields corrected by backgrounds and crossfeeds

The fit includes statistical and systematic uncertainties. Statistical errors for efficiencies, yields, and background subtractions Correlated and uncorrelated systematic errors

Some systematic errors for and completely cancelled

and in this approximation,

D D

2

DDN

00DDN

1/ jiij ijjiDD DSSN /~

00DDN DD

N

5

Selection criteria Two key variables(D0K-+ as an example)

22PPEM Kbeambc

EEEE Kbeam

0

3.0 σ mass cut for 0 mass Shower energy > 30MeV

Track selection criteria: Track quality criteria Hadronic PID criteria are based on

the dE/dX information the RICH information

0

3.0 σ mass cut for 0 mass Shower energy > 30MeV

Ks 3.0 σ mass cut for Ks mass

Additional cuts Mode dependent cuts Lepton veto to reject cosmics, radiative bhabhas and pairs when an event

has two tracks.

Best candidate selection for single tag modes Choose the entry with the smallest

Best candidate selection for double tag modes Choose the entry with the smallest

E

E

Dbcbc mDmDm 2

6

Single tag fitting

Mbc(GeV)

Signal MC without ISR: fit with Argus+Gaus+wide bif. Gaus

Ratio between widths of Gaus and wide bif. Gauss

Ratio between areas of Gaus and wide bif. Gaus

Generic MC(no ISR) fit with Argus+Gau+wide bif. Gaus

Fix the above parameters

Signal MC with ISR: fit with Argus+Crys.Ball+ wide bif.

Gau Data

fit with Argus+Crys.Ball+ wide bif. Gau

Mbc(GeV)

Signal MC with ISR

Signal MC without ISR

DD bar MC

Data

DD

KD0

7

Double tag fitting Double tag sample

. Signal components

A a diagonal Crys.BallGau : a wide Gaussian

Background components A diagonal Argus function two Argus functions.

00 KD 00 KD

M2(

GeV

)

M1(GeV)

M2(

GeV

)

M1(GeV)

M1(GeV)

8

Single and Double tag efficiency

within statistical uncertainty

Eff(%)

single tag 62.5 32.0 40.4

61.4 37.8 20.6 24.8

31.7 20.0 10.7 12.7

40.1 24.8 13.0 16.4

Eff(%)

single tag 47.5 42.0

47.8 22.4 19.8

41.7 20.0 17.3

K 0 K K

Ks

K

0D

0D

K0 K

K

D K

Ks

D

jiij

PRELIMINARY

9

Generic MC Yields

All *1000

singletag 47.5±0.2 87.9±0.3 65.0 ±0.3

47.1±0.2 1.12±0.03 2.06±0.05 1.53±0.04

87.0±0.3 2.19±0.05 4.11±0.07 2.86±0.05

64.0±0.2 1.55±0.04 2.90±0.05 2.10±0.05

All *1000

singletag 65.0 ±0.3 9.42 ±0.10

64.7 ±0.3 2.82±0.05 0.38 ±0.02

9.33 ±0.1 0.41 ±0.02 0.07 ±0.01

0D K 0 K K

K

0D

0 K K

D K KsD

KKs

Check the technique for yield extraction and branching ratio fit Samples : (10data),CONT and RR MC.

Statistical errors (3 times smaller than for data) crossfeed and background contributions

DD

PRELIMINARY

10

Generic Monte Carlo Fit Result

The yields corrected by crossfeed and background contributions. Statistical errors for yields(3 times smaller than for data) Systematic errors (substantially smaller than for data) Fitted values reproduced input variables.

Fitted 2.08106 0.0377 0.1373 0.0786 1.55106 0.0901 0.0147

Input 2.04106 0.0383 0.1390 0.0790 1.52106 0.0900 0.0145

Error 0.02106

1.1%

0.0004

1.1%

0.0013

1.0%

0.0008

1.0%

0.03106

2.1%

0.0017

1.9%

0.0003

2.3%

Input +1.6 -1.4 -1.3 -0.5 +1.1 +0.1 +0.6

00DDN K 0 K K DD

N K Ks

PRELIMINARY

11

Data Yields

All *1000

single 5.16±0.08 9.58±0.12 7.39 ±0.10

5.14±0.07 0.11±0.01 0.25±0.02 0.21±0.01

9.62±0.12 0.26±0.02 0.48±0.02 0.36±0.02

7.39±0.10 0.20±0.01 0.34±0.02 0.28±0.02

All *1000

single 7.57 ±0.09 1.12 ±0.04

7.58 ±0.09 0.38±0.02 0.06 ±0.01

1.09 ±0.04 0.41 ±0.02 0.009±0.003

K0D 0 K K0D

K0 K K

D K KsD

KKs

PRELIMINARY

Single tag 44260 neutral single tags and 17360 charged single tags

Double tag Poor statistics for some double tag modes 2480 neutral double tags and 502 charged double tags

12

Systematics

Source Systematic Uncertainty(%)

Data processing 0.3

Yield fit functions 0.1-2.9

Background bias 2.5

Double DCSD interference 0.8

Tracking efficiency 3.0

Ks efficiency 3.0

0 efficiency 4.4

PID 0.3

K PID 1.0

Trigger efficiency 0.3

FSR 0.5

E cut 1.0

Resonant substructure 1.5 in K3

PRELIMINARY

Currently dominated by tracking efficiency systematics. Most systematics will improve with further study.

13

Data Fit Result

All branching fractions consistent with PDG averages(higher than) Better agreement for ratio of branching fractions. Statistical errors for branching fractions : 20-40% of total error(systematics limited) Precise measurement for and (some systematic errors cancelled)

*Our branching fractions are corrected by FSR. PDG values are not

Parameter Fitted Value PDG2004*

(1.980.04 0.03) 105

0.0392 0.0008 0.0023 0.0380 0.0009

0.143 0.003 0.010

0.0810.0020.009

(1.480.060.04) 105

0.098 0.004 0.008 0.092 0.006

0.01610.0008 0.0015

00DDN

KB

0 KB

KB

DDN

KB

KsB

3.64 0.05 0.17 3.42 0.22

2.05 0.03 0.14 1.96 0.06

0.164 0.004 0.006 0.1530.003

KBKB /0

KBKB /

KBKsB /

00DDN DD

N

14

Cross Sections Luminosity collected on : 57.2pb-1

Cross section :

nb

nb

nb

3770

PRELIMINARY

LN DD /

15.007.047.300 DDee

11.011.059.2 DDee

22.013.006.6 DDee

02.004.075.0/ 00 DDeeDDee

reference

MARK III 2.10.3 2.9 0.4 5.0 0.5 PRL 60,89(1988)

BES 3.260.090.25

2.520.070.24

5.71 0.110.11

Hep-ex/0604027

00DD DD DD

15

Summary Cross sections :

nb

nb

nb

PRELIMINARY

The preliminary results for reference branching fractions :

Many systematic uncertainties will be improved with further study. more results from CLEO-c in the near future

15.007.047.300 DDee

11.011.059.2 DDee

22.013.006.6 DDee

02.004.075.0/ 00 DDeeDDee

%23.008.092.30 KDB

%8.04.08.9 KDB