First Results from CLEO-c

Transcription

1 First Results from CLEO-c Thomas Coan Southern Methodist University CLEO Collaboration CLEO-c Physics Program D + µ + ν µ Decays Absolute Br(D hadrons) e + e - σ (DD) Summary 1

2 CLEO-c Physics Focus Heavy Flavor Physics: overcome QCD roadblock CLEO-c: precision charm absolute Br measurements Leptonic decays decay constants Semileptonic decays Vcd, Vcs, V_CKM unitarity check, form factors Absolute D Br s normalize B physics Test QCD techniques in c sector, apply to b sector improved Vub, Vcb, Vtd, Vts Physics beyond SM will have nonperturbative sectors CLEO-c: precise measurements of quarkonia spectroscopy & decay provide essential data to calibrate theory. Physics beyond SM: where is it? CLEO-c: D-mixing, charm CPV, charm/tau rare decays. 2

3 Why Charm Threshold? I I Large production σ, low decay multiplicity Pure initial state (DD): no fragmentation Double tag events: no background K + + Clean neutrino reconstruction e Quantum coherence: K aids D-D mixing and CPV studies D 0 K I + D 0 K + e I 3

4 CLEO-c Run Plan 2004: ψ(3770) 3 fb -1 18M DD events, w/ 3.6M tagged D decays (150 times MARK III) 2005: s 4100 MeV 3 fb M D s D s events, w/ 0.3M tagged D s decays (480 times MARK III, 130 times BES) 2006: ψ(3100) 1 fb -1 1 Billion J/ψ decays (170 times MARK III, 15 times BES II) 4

5 Tagging Technology Pure DD/D s D s production: ψ(3770) DD s ~4140 D s D s Large branching fractions (~1-15%) High reconstruction efficiency High net tagging efficiency ~20% M(D) 5

6 Absolute Br s w/ Double Tags ~ Zero bkgnd in hadronic modes D 0 K π + w/ D 0 tag D + K π + π + w/ D - tag w/ 3 fb 1 M(D) (GeV/c 2 ) Mode s (GeV) PDG2k CLEOc (δb/b %) (δb/b %) D 0 K - π D + K - π + π D s φπ

7 f Dq from Leptonic Decays Γ ( D q l ν ) f_dq 2 V_cq 2 f D 2 V CKM 2 l ν D s + µν τν K L µν D + µν w/ 3 fb-1 & 3-gen CKM unitarity: Decay Constant Reaction PDG δf/f CLEO-c δf/f f Ds D + s µν 12% 1.9% f Ds D + s τν 33% 1.6% f D D + µν ~50% 2.3% 7

8 Semileptonic Decays V CKM 2 Br ( D P l ν ) / τ = Γ = γ V_cq 2 D dγ ( D P l ν ) / dq 2 V_cq 2 f(q 2 ) 2 f(q 2 ) 2 1 fb-1 1 fb-1 D 0 π l ν Measure f(q 2 ) 2 Klν U=E_miss P_miss Mode PDG04 (δb/b%) CLEOc (δb/b%) D 0 K l ν D 0 π l ν D + π l ν Ds φ l ν q 2 (GeV 2 ) δv cd /V cd & δv cs /V cs 1.6% δv cd /V cd = 5.4% (PDG04) 8 δv cs /V cs = 9.3% (PDG04)

9 Probing QCD Gluons carry color charge binding: Glueballs = gg > and Hybrids = qqg > Radiative Ψ decays: ideal glue factory CLEO-c: 10 9 J/Ψ decays 60M J/Ψ γx Partial Wave Analysis Absolute Br s: ππ, KK, pp, ηη,... E.g.: f J (2220) c c π π + X γ CLEO-c: find/debunk f J (2220) Κ Κ + π 0 π 0 9

10 CLEO-c Detector B=1.0 T 93% of 4π σ E /E = = 83% of 4π 87% Kaon ID with 0.2% π 93% of 4π σ p /p = de/dx: 5.7% Data Acquisition: Event size = 25kB Thruput 6MB/s Trigger : Tracks & Showers Pipelined Latency = 2.5 µs 85% of 4π p>1 GeV 10

11 Leptonic Decays: D + µ + ν µ Br(D q lν) = 2 G F 8π m_d q m 2 l m 2 l 2 2 (1 - ) f_d q V cq τ_d q 2 m_d q Weak Physics Strong Physics Seek to measure f D+ f D+ provides iron post of observation for Lattice QCD f D+ useful for checking potential models Calibrated Lattice QCD (f B /f D ) + f D f B f B + B-mixing m ments V td /V ts precision 11

12 Single D ± Tag Signal side e + e Ψ(3770) ν D + D µ D-Tag side L dt = 57 pb s = Ψ(3770) D tag side: D K + π π, K + π π π 0, K s π, K s π π π 0, K s π π 0 π ± /K ± ID: de/dx + RICH π 0 recon: γ shower shape/location in CsI K s recon: π ± kinematic fit to displaced vertex Signal side: 1 track from event vertex, min_i in CsI small (< 250 MeV) neutral E in CsI no reconstructed K s Key analysis variables: 2 2 M D = E beam (Σ p i ) 2 MM 2 = (E beam E µ ) 2 ( p D p µ ) 2 12

13 M D Distribution v. D Tag K + π π Data K + π π π 0 Data K s π Data K s π π π + Data S: ± 286 B: 8765 ± 784 K s π π 0 Data 13

14 MM 2 Distribution v. D Tag σ(mm 2 ) GeV 2 14

15 Leptonic Decays: Signal Region Check σ(mm 2 ) w/ data: D K s π Scale σ(mm 2 ) w/ data: σ = (0.024/0.021) = GeV 2 σ = 0.024±0.002 GeV 2 8 evts ±2σ Data σ = 0.021±0.001 GeV 2 D + K 0 π + K s π π + π + Tag µ 15

16 Background + Results Background estimates via D ± Background: Mode D + π + π 0 D + K 0 π + D + τ + ν D + π 0 µ + ν D 0 D 0 Background: 0.16 ± 0.16 events e + e continuum: 0.17 ± 0.17 events # of Events 0.31 ± ± ± 0.08 negligible O all Bkg: 1.07 ± 0.25 events 1.07 ± 1.07 events N sig Br(D + µ + ν) = ε Ntag & ε = 69.9% for D + µ + ν recon. Br(D + µ + ν) = (3.5 ± 1.4 ± 0.6) x 10 4 f D+ = (201 ± 41 ± 17) MeV Preliminary 16

17 Br(D) & σ(dd) M s = Ψ(3770) K + X Single Tag π Double Tag D 0 D 0 e + e e + D 0 e D 0 K π + K π + S = 2N DD Bε 1 D = N DD B 2 ε 2 B = 2D S ε 1 ε2 2 w/ ε 2 ε 1 : σ(dd) = N DD = S2 4D S 2 4DL i.e., B & ε independent 17

18 Single and Double Tags Determine 5 Br s and σ(e + e D 0 D 0 ) & σ(e + e D + D ) 10 Single Tag + 13 Double Tag modes D 0 K π +, K π + π 0, K π + π π + + c.c. D + K π + π +, K s π + + c.c. Event selection similar to f D+ analysis Key analysis variables: E = E beam ΣE i 2 M BC = (E beam (Σ p i ) 2 ) 18

19 Single and Double Tag Yields N(single tags) from ML fit to M_BC Line shape parameters from D and D fit together: same signal param s, indep. bkg. D 0 K π + D 0 K π + Data N(double tags) from 2-D ML fit to 2-D M_BC K + π π 0 v. K π + π 0 Data 19

20 Fit Results for Br(D) and σ(dd) χ 2 fit to account for correlations btwn single/double tags, bkg Fit Output: Br(D 0 K π + ), Br(D 0 K π + π 0 ), Br(D 0 K π + π π + ) Br(D + K π + π + ), Br(D + K s π +) and N(D 0 D 0 ), N(D + D ) Fit Input: S.T. & D.T. yields, ε_tag, ε_bkg + errors χ 2 /ndof = 9.0/16, C.L. = 91.4% CLEO-c Preliminary Br(D0 K π+) = ±? ±? Br(D0 K π+π0) = ±? ±? Br(D0 K π+π π+) = ±? ±? Br(D+ K π+π+) = ±? ±? Br(D+ Ks π+) = ±? ±? PDG04 Need pdg comp N(D0D0) = 1.98 x10 5 σ(d0d0) = 3.47 ± 0.07 ± 0.15 nb N(D+D ) = 1.48 x10 5 σ(d+d ) = 2.50 ± 0.11 ± 0.11 nb σ(dd) = 6.06 ± 0.13 ± 0.22 nb 20

21 Summary I need nicer plots for Br(D hadrons) 21

22 Backup 22

23 1.5 T 1.0T 93% of 4π σ p /p = de/dx: 5.7% 83% of 4π 87% Kaon ID with 0.2% π 93% of 4π σ E /E = = CLEO III Detector CLEO-c Detector Trigger : Tracks & Showers Pipelined Latency = 2.5 µs Data Acquisition: Event size = 25kB Thruput 6MB/s 85% of 4π p>1 GeV 23

24 J/Ψ γ X Inclusive γ - Spectrum Inclusive γ -spectrum Search for monochromatic γ E.g., 24% efficient for f J (2220) 10 4 sensitivity for narrow resonances Modern 4π detector Suppress hadronic bkgnd: J/ψ π 0 X Huge data set Plus γγ and Υ(1S) data Determine J PC and gluonic content 24