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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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