# Presentation: 925138

## 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
- Near term prospects
- D+ BR and CP violation
- Conclusions

- Not Covered Here:
- D
- X(3872)

## Swamped by Charm

- CDFII Published
- PRL 91, 241804 (2003).

|  | Pt thr.
GeV/c | 
b |
| --- | --- | --- |
| D0 | 5.5 | 13.30.20.5 |
| D*+ | 6.0 | 5.20.10.8 |
| D+ | 6.0 | 4.30.10.7 |
| Ds | 8.0 | 0.750.050.22 |

## 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

- D**0 Properties

- D1,2 D*+-
-           D*+D0+
-                    D0K-+

- 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 D(1,)2

## D**0 mass from prompt charm

- New CDFII Result

- M(D1)-M(D*)=411.70.70.4 MeV
- M(D1)=2021.70.70.6 MeV
- (D1)=20.01.71.3 MeV
- M(D2)-M(D*)=594.00.60.5 MeV
- M(D2)=2021.70.70.6 MeV
- (D2)=20.01.71.3 MeV

## Improved Statistics and Systematics!

- D1 Mass

- D2 Mass

- D1 Width

- D2 Width

**Belle03**

**CDFII**

## 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:
- (D0K+-)/(D0K-+)

## Cabibbo suppressed modes

| Mode | D0 | D0 | Total |
| --- | --- | --- | --- |
| K | 88310330 | 92600340 | 180910 480
 |
| KK | 8190 140 | 8030 140 | 16220 200 |
|  | 366069 | 367468 | 733497 |

## Precision width ratios

- A good benchmark for ACP!

- Use of K as a reference helps dealing with:
- Charge/particle asymmetry
- Production rate and spectra
- Detector acceptance

- Submitted for publication
- www-cdf.fnal.gov/physics/new/bottom/
- 040428.blessed-bphik_acp/

| 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

- On our way towards time dependence...

- Submitted for publication
- www-cdf.fnal.gov/physics/new/bottom/
- 040428.blessed-bphik_acp/

- PDG 2004 averages:
- A(D0KK): 0.51.6 %
- A(D0): 2.12.6 %

- Best single exp. (CLEO02):
- A(D0KK): 0.02.20.8 %
- A(D0): 21.93.20.8 %

## Plan for Doubly Cabibbo Suppressed decays

- We expect about 2.8 DCS decays per pb-1! (and right now we are using ~250pb-1 in most analyses)

- 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: -0.0170.042 [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 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 trigger

- pp  50mb
- bb  0.1mb
- cc  0.025 mb

## D** massBackup: 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 mt2
       (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 QCD
2. 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 BK+X (35.76.8 events)
- Mass: 3872.00.60.5 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:
- 73090 candidates in 220pb-1
- Mass: 3871.30.70.4 MeV
- High di-pion mass
- So we went back and started investigating production:
- Most of our X(3872) are prompt

- August 2003

- September 2003

- CDFII Result
**PRL 93, 072001 (2004)**

## X(3872) Prompt fraction

- New CDFII Result
- www-cdf.fnal.gov/physics/new/bottom/
- 040624.blessed-xlonglived/
- xlonglivedWWW.ps

- 28.31.0 (stat.)0.7 (syst) %

- 16.14.9 (stat.)2.0 (syst) %

- Non-Prompt Fraction:

- Non-Prompt Fraction: