7/4/08 Flavour physics at CLEO-c - Jim Libby 1 Jim Libby (University of Oxford) On behalf of the CLEO-c collaboration  Introduction to CLEO-c  Measurements related to D-mixing  Measurements related to the determination of  via B ±  DK ±  D→K − π + π + π −  D→K 0 S π + π − Flavour physics at CLEO-c

7/4/08 Flavour physics at CLEO-c - Jim Libby 2 Detector at the Cornell Electron Storage Ring (CESR) Operating at energies around cc threshold Relevant data sets for flavour measurements: E CM = 4170 MeV L int ~ 600 pb -1 Determination of form factor f Ds at CLEO-c is a critical test of lattice QCD and sensitive to new physics  ( 3770 ) L int = 818 pb -1 [This talk] Quantum correlated state: For example, reconstruct one D decay to a CP eigenstate uniquely identifies the other D to be of opposite CP C = −1 Introduction to CLEO-c CLEO-c - arXiv: v1 [hep-ex] f Ds =(274 ± 10 ± 5) MeV LQCD - arXiv: [hep-lat] f Ds =(241 ± 3) MeV

7/4/08Flavour physics at CLEO-c - Jim Libby3 CLEO-c results on D-mixing

7/4/08 Flavour physics at CLEO-c - Jim Libby 4 D mixing Rate of D mixing parameterised by: Time-dependent wrong-sign rate D 0 → K − π + :  Sensitivity via interference between DCS and mixing amplitudes  Ambiguity from strong phase: y′ = y cos  x sin  Direct comparison with y measurements from CP- eigenstate lifetimes and time-dependent measurements of D→K 0 S ππ Dalitz plot not possible without determination of   and other mixing parameters can be measured in quantum correlated DD decay at CLEO-c  D. Asner and W. Sun, P hys. Rev. D73, (2006) A DCS /A CF = / =  re  i 

7/4/08 Flavour physics at CLEO-c - Jim Libby 5 Coherent vs. Incoherent Decay We use yields for  single tags (one D reconstructed)  double tags (D and D reconstructed) Compare coherent/incoherent BFs Sources of incoherent BFs:  Externally measured BFs  Single tags at  (3770) DT KK e+e+ CP  CP  KK R M / R WS KK 1  2R WS  4rcos  (rcos  y) ee 1  r (ycos  xsin  ) 1 CP  1  (2rcos  y) / (1  R WS )1  y 0 CP  1  (2rcos  y) / (1  R WS )1  y 20 ST 1111 QC rate incoherent rate DD Xi DD ji Yield / No-QC prediction 012 Quantum correlations are seen in data! ST DT R M = (x 2 + y 2 )/2 and R WS = r 2 + ry’ + R M

7/4/08 Flavour physics at CLEO-c - Jim Libby 6 Yield measurements in 281 pb −1 1.Fully-reconstructed single tags:  Fit beam-constrained mass distribution 2.Fully-reconstructed double tags:  Two fully-reconstructed STs 3.Inclusive semileptonic DTs:  One fully-reconstructed ST  Plus one electron candidate  Fit e ± momentum spectrum 4.K 0 L  0 double tags:  One fully-reconstructed ST  Plus one  0 candidate  Compute missing mass 2 Signal peaks at M 2 (K 0 ) M BC ( GeV/c 2 ) e ± p ( GeV/c ) arXiv: [hep-ex] arXiv: [hep-ex]

7/4/08 Flavour physics at CLEO-c - Jim Libby 7 External inputs External inputs improve y and cos  precision All correlations among measurements included in fit Standard fit includes:  Info on r needed to obtain cos  : R WS = r 2 + ry’ + R M R M = (x 2 + y 2 )/2 Assume xsin  = 0  y′≈ ycos   K  and CP -eigenstate BFs Extended fit averages y and y′ :  CP+ lifetimes ( y )  K 0 S     Dalitz analysis ( x, y )  K  CP -conserving fits ( y′, r 2, R M )

7/4/08 Flavour physics at CLEO-c - Jim Libby 8 Results First determination Standard fit result important component in average of charm mixing Extended fit leads to measurement of: Future improvements:  Full ψ(3770) data set – 818 pb −1  WS semileptonics vs. Kπ  Additional K 0 L modes  C -even information from 4170 MeV data arXiv: [hep-ex] arXiv: [hep-ex] From likelihood scan of physically allowed region

7/4/08Flavour physics at CLEO-c - Jim Libby9 CLEO-c results related to  determination

7/4/08 Flavour physics at CLEO-c - Jim Libby 10 Status of direct determination of   is the least well determined angle of the unitarity triangle with an uncertainty of ~30  from direct measurements    = 1  Comparison of measurements of  in tree and loop processes sensitive to new physics  Side opposite - B-mixing measurements loop only

7/4/08 Flavour physics at CLEO-c - Jim Libby 11  from B ±  DK ± Extraction through interference between b→c and b→u transitions Require decay of D 0 and D 0 to a common final state, f(D) A theoretically clean determination of  SM ‘standard candle’ Colour/CKM suppressed – r B ~0.1

7/4/08 Flavour physics at CLEO-c - Jim Libby 12 f(D) = non-CP Eigenstate (e.g. K +  - ) (1)(1) (3)(3) (2)(2) (4)(4) From counting these 4 rates, together with those from CP eigenstates ( KK,  ), a determination of  can be made Key measurement of LHCb and future e + e − B-factories For example ~10  precision with one year of LHCb running [LHCb ] Atwood-Dunietz-Soni (ADS) Method ~0.06

7/4/08 Flavour physics at CLEO-c - Jim Libby 13 Four-body ADS B→D(Kπππ)K can also be used for ADS style analysis  Double the branching fraction of B→D(Kπ)K However, need to account for the resonant substructure  D→K*ρ, K − a 1 (1260) +, etc  in principle each point in the phase space has a different strong phase associated with it Atwood and Soni (hep-ph/ ) showed how to modify the usual ADS equations for this case  Introduce coherence parameter R K3π which dilutes interference term sensitive to γ R K3π ranges from  1=coherent (dominated by a single mode) to  0=incoherent (several significant components)

7/4/08 Flavour physics at CLEO-c - Jim Libby 14 Determinations of R K3  and  D  can be are made from analysis of double- tagged D 0 D 0 at CLEO-c. The coherent production of this state causes the double-tagged rates of K  vs. X to be altered in the following ways: (R K3  ) 2 R K3  cos(  K3  ) R K3  cos(  K  –   ) Double Tag Rate Sensitive To We perform selections of these double-tags In addition, it is also necessary to perform selections of the opposite sign K ± modes to determine normalisation factors Measuring R  at CLEO-c

7/4/08 Flavour physics at CLEO-c - Jim Libby 15 KK,  K s  K S  (  +  -  0 )251 K S      K S     )31 K S        K S  ’      CP Tag 2,183 Yield Selections performed over all  ( 3770 ) data, corresponding to 818 pb -1. Consider 8 different CP tags: Assess flat background from mass side bands and peaking from MC: m bc 2 = (E beam ) 2 /c 4 – (p D ) 2 /c 2 Very low background levels K3  Opp. Sign 3,921 events CP = 1, CP = -1 Event selection

7/4/08 Flavour physics at CLEO-c - Jim Libby 16 2) (R K3  ) 2 = ± 0.23 ± 0.09 (R K3   at  sigma) 1) = ± 0.19 ± 0.24   /n.d.f = 9.7 / 8 3) :  sigma spread : physically allowed region R K3  cos(  K  –   ) = 0.00 ± 0.16 ± 0.07 Used to constrain coherence factor by taking  D  from TQCA CLEO-c Preliminary R  preliminary results

7/4/08 Flavour physics at CLEO-c - Jim Libby 17 Parameter Space Constraints Combination of the separate results together Low coherence preferred Allows accurate determination of r B useful for all B ± → DK ± Preliminary

7/4/08 Flavour physics at CLEO-c - Jim Libby 18 Impact of CLEO-c at LHCb These D→K3 π measurements have been input to ADS simulation studies by LHCb  Estimated yields documented in LHCb and LHCb One nominal year of running results see significant improvement with the addition of B→D(K3π)K and the CLEO-c constraints

7/4/08 Flavour physics at CLEO-c - Jim Libby 19 3-Body Dalitz: B ±  D(K s  +  - )K ± Exploit interference over Dalitz space Amplitude fit to D Dalitz plots from B+ and B- to extract r B,  and  B. Need to assume an isobar model for D-decay amplitudes  Measure amplitudes well with flavour tag sample Current best constraints from the B-Factories  But model assumptions lead to a ~10° error Binned analysis of Dalitz space removes model error  Need to measure strong phases averaged over bins at CLEO-c  Most sensitive binning w.r.t. strong phase diff.

7/4/08 Flavour physics at CLEO-c - Jim Libby 20 CLEO-c Impact on B ±  D(K s   +  - )K ± As in the coherence factor analysis, CP tagged decays are the key to accessing the parameter of interest. Specifically, the average value of cos(  D ) in each bin of the CP tagged Dalitz plot can be accessed from measuring the number of events in that bin with different CP-tags Measurements of K s  +  – vs. K s  +  – give sensitivity to sin(  D ) Preliminary studies presented at CHARM 07 indicate precisions that lead to 3-5  uncertainties on γ CLEO Prelim.  f 2 (1270 

7/4/08 Flavour physics at CLEO-c - Jim Libby 21 First determination of strong phase difference for D→Kπ Essential for interpretation of D - mixing CLEO-c data vital for for the purpose of  extraction strategies with B ±  D( Multi-Body )K ± A first determination of the D  K  coherence factor, R K3 , has been made (and its associated global strong phase,  D  ). Further improvements to this result are foreseen with the addition of K L CP modes in the selection. Additional ADS modes are being studied ( D  K   ). In addition, CLEO-c is measuring the average cosine and sine of K s  strong phase differences to allow model independent determination of γ with B ±  D( K s  )K ± Conclusion

7/4/08Flavour physics at CLEO-c - Jim Libby22 Backup

7/4/08 Flavour physics at CLEO-c - Jim Libby 23 TQCA extended fit likelihoods