CLEO-c: Progress and Future

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1 CLEO-c: Progress and Future David G. Cassel Cornell University Outline Motivations CLEO-c and CESR-c Preliminary CLEO-c Results CLEO-c Gluonic Program Summary and Outlook SURA Washington February 10, 2005

2 Motivations for CLEO-c and CESR-c CLEO made substantial progress in measuring nonperturbative parameters that relate observables to underlying parton-level processes and CKM matrix elements. Much remains to be accomplished since we are rapidly approaching a situation where theoretical uncertainties will dominate all experimental CKM uncertainties. Theoretical uncertainties already totally dominate the uncertainty in V td. Theoretical uncertainties are still significant in measurements of V cb and V ub. Experimental uncertainties will decrease significantly when the enormous BaBar and Belle data samples are fully understood, evaluated, and utilized. Of course, to some extent, more precise measurements from BaBar and Belle will provide further constraints on theoretical uncertainties. Development of reliable theoretical methods for calculating these nonperturbative parameters is essential for precise determination of CKM matrix elements. Experimental verification is an essential element for ensuring reliability. Precise data in the charm sector can motivate and validate theoretical progress in nonperturbative heavy quark physics that can then be applied to b physics. Lattice QCD (LQCD) is a candidate for a theory to calculate these parameters. Providing precise charm data to motivate and validate theoretical progress in nonperturbative heavy quark physics is a major focus of the CLEO-c program. Exhaustive searches for glue-rich states is the other major focus of CLEO-c.

3 Testing the quark mixing (CKM) matrix ρ η ρ η ρ ρ

4 CLEO-c and CESR-c CLEO-c is a focused program of measurements and searches in e e collisions in the the s =3 5 GeV energy region, including: charm measurements absolute charm branching fractions the decay constants f D and f Ds semileptonic decay form factors V cd and V cs searches for new physics including CP violation in D decay D D mixing without DCSD rare D decays QCD studies c c spectroscopy searches for gluonic exotic states: glueballs measurements of R between 3 and 5 GeV direct between 1 and 3 GeV indirect (nitial State Radiation) τ studies The acceptance, resolution, and particle identification capability of the CLEO-c detector are substantially beyond those of any detector that has operated in the charm threshold region.

5 CLEO-c Run Plan 2002 Prologue Υ s > 1.2 fb 1 each Υ(1S), Υ(2S), Υ(3S) Completed Matrix elements, Γ, Γ ee, spectroscopy (η b, h b, D states,...) Υ(1D) already published Compare with LQCD calculations the previous world s data Act ψ(3770) 3 fb 1 30 M D D events, 6 M tagged D 310 MARK Act s 4.1 GeV 3fb M D s D s events, 0.3 M tagged D s 480 MARK and 130 BES Act J/ψ 1fb 1 1GJ/ψ decays 170 MARK and 20 BES Plan a year for each Act NSF support until Mar 31, 2008 The CESR-c Accelerator Running at all energies from the J/ψ to above the Υ(4S) is possible with existing superconducting R quads. Loss of synchrotron radiation damping at low energies reduces luminosity Compensate with wiggler magnets Designed, built, and installed 12 superferric wigglers (Fe poles & SC coils) Excellent prototypes for Linear Collider damping ring wigglers. The only substantial hardware upgrade in the program Expected luminosity s (GeV) L (10 33 cm 2 s 1 )

6 CESR-c Wiggler Magnets The 12 superferric wigglers are 7 pole, 1.3 m long, with B max =2.1 T Field quality and wiggler performance in CESR as predicted Lots to learn about the dynamics of a wiggler dominated storage ring CESR-c is the first wiggler dominated storage ring

7 The CLEO-c Detector and CLEO Collaboration CLEO-c SC Quadrupole Pylon Solenoid Coil Barrel Calorimeter Ring maging Cherenkov Detector Drift Chamber nner Drift Chamber / Beampipe SC Quadrupoles Rare Earth Quadrupole Endcap Calorimeter ron Polepiece Magnet ron Barrel Muon Chambers 140 Physicists in 14 nstitutions Carnegie Mellon, Cornell, Florida, George Mason, llinois U-C, Kansas, Luther College, Minnesota, Pittsburgh, Purdue, Rochester, Southern Methodist, Syracuse, Wayne State

8 Determining D Meson Decay Constants l D q c q The factor f Dq V cq occurs in the decay amplitude for the c qw vertex The decay widths for leptonic D and D s decays are: Γ(D q l ν l )= 1 ( ) 8π G2 F M D q m 2 l 1 m2 l f MD 2 D 2 q V cq 2 q Measurements of B(D l ν l ) and B(D s l ν l ) Determine f D V cd and f Ds V cs Conventionally measure f Dq V cq and use unitarity for V cq to get f Dq We will also measure V cd and V cs accurately with semileptonic D decays Challenge theorists with values of f D and f Ds with errors O(1%) Lead to understanding of the level of reliability of f B 0 and f Bs calculations f B 0 uncertainty dominates error in V td from value of m d in B 0 B 0 mixing ν l

9 e e - cc D 0 D 0 D 0 K -, D 0 K - e

10 D Br D f D MeV

11 Semileptonic D decays D 0 K - e D 0 - e δb B % PDG '04 Projected CLEO-c data set 1:D 0 K - e 2:D 0 K *- e 3:D 0 - e 4 :D 0 - e 5 :D K 0 S e 6:D K *0 e 7 :D 0 e 8:D 0 e 9:D S 0 KS e 10 :D S K *0 e 11:D S e

12 Hadronic D decays Br D K - Br D K - Br D K - Br D - K - -

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14 Searching for Gluonic Matter Since gluons carry color charge, they self-interact and should bind A rich spectrum of glueballs or glue-rich states is expected in the few-gev region J/ψ γx decays are an ideal hunting ground Caveat glueballs may mix with nearby conventional q q mesons The hermetic CLEO-c detector with its excellent γ, π ±, and K ± detection and resolution is nearly ideal Observe glueballs in many different modes (signature) Facilitates angular analysis to establish J P r 0 m G Glueball Spectrum (Morningstar and Peardon) 3 0* 2 0 2* 0* m G (GeV) 2 3 S 1 QQ g* g* S 0 qq 2 0 PC 1 0

15 Search for the f J (2220) The f J (2220) candidate for a glue-rich meson has been rather elusive: Observed by MARK Most robust signals came from BES from J/ψ events Not observed by Crystal Barrel Most other sightings have disappeared f BES branching fractions were correct CLEO-c rates would be enormous BES f J (2220) Signals f J (2220) BES CLEO-c Decay Mode Yield Yield π π 74 23,000 π 0 π ,000 K K 46 15,600 KS 0K0 S 23 4,500 p p 32 8,500

16 Search for the f J (2220) n the CLEO-c detector f J (2220) signals would stand out clearly above backgrounds in many modes Monte Carlo studies with 150 M J/ψ decays ( < 1/6 of the projected CLEO-c data sample) show clear signals

17 Glueball search and study at BES (58M J/ψ) PWA of J/ψ γkk shows a dominant 0 in 1.7 GeV mass region. PWA of J/ψ γππand γππππ to study 0 glueball candidates. PWA of J/ψ γηππand γkkπ to study 0 - structures around 1.44 GeV. ξ(2230) was observed by MARK, BES etc.. Not seen in the mass spectra of KK, ππ and pp by BES. Careful PWA is being performed by BES.

18 BES J / ψ γ K K and γ K 0 K 0 S S f ' 2 (1525) f 0 (1710) K K - BES 58M J/ψ BKG K K 0 s 0 s After acceptance and isospin corrections

19 J /ψ γηπ π J 0 / ψ γπ π 0 J / ψ γk ± Ksπ m J /ψ γπ π J / ψ γk K π 0

20 The inclusive J/ψ γx spectrum is also a hunting ground for new states Monte Carlo studies with only 60 M J/ψ decays show a clear f J (2220) signal if B(J/ψ γf J )= With the full 1 G J/ψ CLEO-c data sample, B(J/ψ γx) > 10 4 should be observable for any X with reasonable width. nclusive J/ψ γx Measurements

21 Summary and Outlook CLEO-c is working very well and preliminary D decay results from 60 pb 1 are already competitive with or better than world averages. CESR-c has not yet reached its luminosity goals and massive efforts are underway. The CLEO-c detector is an excellent venue for studying glueballs produced in radiative J/ψ decays. With the demise of the BES f J (2220) signals, CLEO-c needs crisp objectives for glueball searches! Jim Napolitano and Anders Ryd will discuss more hopeful prospects. Perhaps interactions among us in this workshop can help to provide clear crisp objectives for the CLEO-c gluonic program.