1. Introduction to DsJ Analysis and D(*)D(*) reconstruction at CDF
UCLA group meeting
June 19, 2006
Yangheng Zheng
Introduction & Motivation
Analysis strategy & Status

2. Narrow Multi-quark Mesons?
In 2003
CLEO
M(Ds*p) - M(Ds*)
2457 MeV
2317 MeV
BaBar
M(Dsp)
CS bond states?
UCLA group meeting
06/19/2006

3. cs in Chiral Model Not observed Observed by SELEX(E781)
but not by Belle and BaBar
Parity doubling
Angular excitation
Jq in heavy quark limit
UCLA group meeting
06/19/2006

4. DsJ (2573)→ D0 K ~200 pb-1 SELEX DsJ(2632) Mark Neubauer
UCLA group meeting
06/19/2006

5. More Narrow Multi-quark Mesons?
In 2004 & 2005
Y(3940)
Y(4260)
X(3872)
BaBar
M(J/ψπ+π-)-M(J/ψ) GeV/c2
CC bond states?
UCLA group meeting
06/19/2006

6. What are they? X(3872) Y(3940) Y(4260) JPC = 1++ cc content is small
matches all(?) expectations for a D0D*0 bound state
Y(3940)
Charmonium? (unlikely: Above DD & DD* threshold and decay to wJ/y)
DsDs bound state?
cc-gluon hybrid? (masses expected to be 4.3 ~ 4.4 GeV )
Y(4260)
JPC = 1--
Exotic meson: (diquark antidiquark cscs L=1)?
cc-gluon hybrid?
UCLA group meeting
06/19/2006

7. Probe QCD non-qq or non-qqq hadron spectroscopies: s Pentaquarks:
e.g. an S=+1 baryon
Glueballs:
gluon-gluon color singlet states
Multi-quark mesons:
qq-gluon hybrid mesons d u u d s u c u c c c
UCLA group meeting
06/19/2006

8. Motivation of D(*)D(*) analysis
Test Multi-quark and hybrid models in QCD
Cross section measurements for known states, like ψ(3770)→ D0 D0
UCLA group meeting
06/19/2006

9. Analysis strategy in CDF
Data sample: Two-Track-Trigger (TTT)
Data pre-selection: BStntuple
Double charm modes existing in BStntuple productions (D0 D0, D+ D-, D*+ D-, D*+ D*-, Ds+ Ds- +C.C.)
Dataset: xbhd0{h,d,i} ~1fb-1
Kaon ID with dE/dx and TOF
UCLA group meeting
06/19/2006

10. Track/Vertex refitting
Analysis Frameworks
Typical B-physics analysis Data flowchart
Track refitting
Reassign the track mass  decay products
Energy loss correction for K/p hypothesis
Vertex and Kinematical fitting (CTVMFT)
Constrain tracks from same vertex
Mass constrain
Particle ID (probability ratios)
RAW DATA
RECONSTRUCTED
DATA
Track/Vertex refitting
Kinematical fitting
Particle ID
BSTNTUPLE
DATA
USER Analysis
Skimming
USER
NTUPLE
DATA
HISTOGRAMS / PLOTS
UCLA group meeting
06/19/2006

11. Why Kaon ID?
Combinatorial background dominated in D0K+ , D(*)D(*), Dsp+p-
K-p separation can reduce the combinatorial background in DsJ→D0K+ , D0→K- p+ and f→K+ K- decays.
KID efficiency and fake rate  Cross section measurements.
UCLA group meeting
06/19/2006

12. Study KID with D* D*+ → D0 π+ └ K-π+
Trigger Sample: Two Track Trig (TTT).
TTT cut condition applied to all D0 candidates
Track Quality required
D*+ → D0 π+
└ K-π+
UCLA group meeting
06/19/2006

13. Purified D* candidates
Extra Cuts:
D_SwapMass
<1.833 or D_SwapMass
<1.897
Pt_pis > 0.5 GeV
Chi2_D* < 30
Lxy_D > 250 μm
Δr_d0pis <0.1
Right Sign
Selection Window
(Purity ~95%)
Wrong Sign
UCLA group meeting
06/19/2006

14. K-π separation (dE/dx)
Tracks w/o
dE/dx info
Pions
Kaons
UCLA group meeting
06/19/2006

15. K-π separation (TOF) Tracks w/o TOF info Pions Kaons
UCLA group meeting
06/19/2006

16. K-π separation (combined)
Kaon Candidates
Selection
Pions
Kaons
UCLA group meeting
06/19/2006

17. Efficiency & Fake Rate Efficiency Fake Rate Kaon Candidates Selection:
Log(ProbRatio)>0
Efficiency
Fake Rate
UCLA group meeting
06/19/2006

18. D0 D0 Invariant Mass 340 pb-1 Ψ(3770) All candidates in
BStntuple Data:
Track Quality Cut
Applied
340 pb-1
UCLA group meeting
06/19/2006

19. Right Sign vs Wrong Sign
Combination
Ψ(3770)
Kid Cut:
Log(ProbRatio)>0
D_SwapMass
<1.833 or
<1.897
Wrong Sign
Combination
340 pb-1
UCLA group meeting
06/19/2006