Recent Charm Physics

Results at

Alessandro Cerri

Outline• Introduction– CDF– Charm Cross section and yields

• D** properties– D** terminology– Masses and widths of narrow

states– D** in semileptonic B decays

• D0 Cabibbo suppressed decays:– Theory intro– Decay BR– Direct CP– Prospects for DCD mixing

• X(3872)– Covered in other talks

• Near term prospects– D+ BR and CP violation

• Conclusions

Swamped by Charm

Plenty of clean charm!

CD

FII Publis

hed

PR

L 91, 241804 (

2003).

Pt thr.

GeV/c

b

D0 5.5 13.30.20.5

D*+ 6.0 5.20.10.8

D+ 6.0 4.30.10.7

Ds 8.0 0.750.050.22

D**: Introduction

•Plenty of D**: Dj narrow, wide, radial, orbital, resonant, nonresonant…

•HQET predicts splitting of states vs mQ

•Narrow states are widely observed objects

•The large statistics of charm at CDFII gives access to D**

•What can we learn from these samples?

D**0 Properties

D1,2 D*+-

D*+D0+

D0K-

+

D2 D+-

D+K+-

-

•Huge sample of narrow D** resonances

•Competitive in measuring prompt D** properties!

•… and non prompt

Prompt D1,2

Secondary D**

Prompt D1,2

D**0 mass from prompt charm

New CDFII

Resu

lt

M(D1)-M(D*)=411.70.70.4 MeV

M(D1)=2021.70.70.6 MeV

(D1)=20.01.71.3 MeV

M(D2)-M(D*)=594.00.60.5 MeV

M(D2)=2021.70.70.6 MeV

(D2)=20.01.71.3 MeV

Impro

ved S

tati

stic

s and S

yste

mati

cs!

D1 Mass D2 Mass

D1 Width D2 Width

CP Violation in the c sector•CP in c is expected to be small

•SM: 0.1-1%

•Direct CP would be a hint of non SM mechanisms!

•Two methods are being explored to tackle this:

•Direct CP: D*+D0[fCP]+

•Mixing:

(D0K+-)/(D0K-+)

2

1sincos1 m

CP

Rxy

KKD

KDy

2222

20

4sin'cos'

)(

txyR

txyRRR

AeKtD

mm

K

t

Cabibbo suppressed modes

Mode D0 D0 Total

K 88310330 92600340 180910 480

KK 8190 140 8030 140 16220 200

366069 367468 733497

•Interesting measurement

•A good benchmark for ACP!

Precision width ratios•Use of K as a reference helps dealing with:

•Charge/particle asymmetry

•Production rate and spectra

•Detector acceptance

)(034.0)(040.0760.2

)(00040.0)(00054.003594.0

)(0012.0)(0011.00992.0

sysstatKK

sysstatK

sysstatK

KK

Submitted fo

r

publicatio

n

www-cdf.fn

al.gov/physic

s/new/botto

m/

040428.blessed-bphik_a

cp/

Syst. source (KK/K) % (/K) % (KK/) %

Fit Model 0.64 0.54 0.67

MC Stat. 0.67 0.63 0.62

Trigger Sim. 0.34 0.31 0.37

BeamSp. Size 0.35 0.24 0.35

Material 0.28 0.30 0.59

c 0.55 0.55 -

Spectra 0.05 <0.01 <0.01

Secondary D* 0.16 0.08 0.24

Total 1.2 1.1 1.2

Direct CP asymmetry

0 0

0 0cos sin

2m

CP

D K K D K K AA f y x

D K K D K K

On our way towards time dependence…

Submitted for publication

www-cdf.fnal.gov/physics/new/bottom/

040428.blessed-bphik_acp/

PDG 2004 averages:

A(D0KK): 0.51.6 %

A(D0): 2.12.6 %

Best single exp. (CLEO02):

A(D0KK): 0.02.20.8 %

A(D0): 21.93.20.8 %

Plan for Doubly Cabibbo Suppressed decays

KD

KD0

0

:Aim

2222

20

4sin'cos')( txy

RtxyRRRAeKtD m

mK

t

We expect about 2.8 DCS decays per pb-1! (and right now we have ~250pb-1)

Key will be being able to control systematics and pollution from other D decays (using kinematics+PID)

D+ Dalitz Properties

•Large statistics gives access to detailed features!

•We will soon improve the knowledge of BR(D++--)

•Theory predicts that direct CP asymmetry could be O(10-3) [hep-ex/9612005]

•E792: -0.0170.042 [hep-ex/9612005]CDFII PR plots

www-cdf.fnal.gov/physics/new/bottom/040422.dplus/

Conclusions•CDF II is a successful charm factory!

•Unprecedented clean and large statistics charm samples

•New and exciting CP results in the charm sector

•Cross sections and prompt fractions

•Relative lifetimes

•Direct CP

•Expect more soon!

•BR and CP in D+

•DCS decays of the D0

Backup Slides

CDF II•Renewed detector & Accelerator chain:

Higher Luminosity higher event rate

Detector changes/improvements:

DAQ redesign

Improved performance:

Detector Coverage

Tracking Quality

New Trigger strategies for heavy flavours: displaced vertex triggerpp 50mb

bb 0.1mb

cc 0.025 mb

D** massBackup: mass stability

D+ mass vs Pt D*-D0 mass vs Pt

D0 mass vs Pt D0 width vs Pt

CP Violation in the c sector

bb mixing cc mixing•intermediate up-type quarks• SM: t-quark contribution is dominant• Rate mt

2

(expected to be large)

• intermediate down-type quarks• SM: b-quark contribution is negligible due to VcdVub

*

• Rate f(ms)-f(md)

(zero in the SU(3) limit)

1. Computable in QCD (*)2. Large in the SM: CKM!

1. Sensitive to long distance QCD2. Small in the SM: New Physics! (must know SM x and y)

*

Direct CP asymmetry

X(3872)

(2S)

?M(J/ +-)M(J/) GeV

Events

/10

MeV

Belle 304M B’s

Properties:

•~10 evidence in BK+X (35.76.8 events)

•Mass: 3872.00.60.5 MeV

•Signal is at high (>500 MeV) di-pion mass

•Width: compatible with experimental resolution ( < 2.3 MeV at 90% C.L.)

??? Who ordered this ???

•DD* molecule, charmonium [(13D2)] or ???

Shortly afterwards CDF observes:

•73090 candidates in 220pb-1

•Mass: 3871.30.70.4 MeV

•High di-pion massSo we went back and started investigating production:

•Most of our X(3872) are prompt

August 2003

September 2003

CDFII ResultPRL 93, 072001 (2004)

X(3872) Prompt fractionNew CDFII Resultwww-cdf.fnal.gov/physics/new/bottom/040624.blessed-xlonglived/xlonglivedWWW.ps

28.31.0 (stat.)0.7 (syst) %

16.14.9 (stat.)2.0 (syst) %

Non-Prompt Fraction:

Non-Prompt Fraction: