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Studies of Rare Semileptonic D Meson Decays

Studies of Rare Semileptonic D Meson Decays. Introduction Analysis Technique Testing the procedure Results (e, ’e, e) Systematics Summary. Bo Xin Purdue University – CLEO collaboration. APS April Meeting Apr 22-Apr 25, 2006. Introduction.

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Studies of Rare Semileptonic D Meson Decays

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  1. Studies of Rare Semileptonic D Meson Decays • Introduction • Analysis Technique • Testing the procedure • Results (e, ’e, e) • Systematics • Summary Bo Xin Purdue University – CLEO collaboration APS April Meeting Apr 22-Apr 25, 2006 Bo Xin

  2. Introduction • The results with 55.8pb-1 CLEO-c data have been published: Phys.Rev.Lett.95:181801,2005 Phys.Rev.Lett.95:181802,2005 • Summing up all exclusive semileptonic branching fractions measured in this analysis we find: • These are consistent within errors but somewhat smaller than CLEO-c inclusive semileptonic branching fractions (281/pb): • There is room left for new semileptonic modes with small branching fractions, e.g. D e, ’e, e Bo Xin

  3. p/p = 0.6% at 1 GeV/c E/E = 2% at 1 GeV, 5% at 100 MeV Excellent electron and particle ID CLEO-c Pilot run starting in the fall of 2003 Over 20 years of data taking at Y(4S) Note: Log Scale The CLEO-c detector and data sample CLEO III SVX • Advantages at (3770) • Pure , no additional particle • Low multiplicity • High tagging efficiency • Data sample ~281/pb at (3770) • The generic MC sample (40X luminosity of the data). Beam Energy (GeV) Beam Energy (GeV) Bo Xin

  4. Candidate events are selected by reconstructing a D, called a tag, in several hadronic modes Then we reconstruct the semileptonic decay in the system recoiling from the tag. Two key variables in the reconstruction of a tag: Define U  Emiss  |Pmiss| The absolute branching fraction is where  is the efficiency of finding a signal in events with reconstructed tags. Analysis Technique Bo Xin

  5. Reconstruction of tags One D tag candidate per D tag flavor per mode is chosen. Examples of fits to Mbc for the following tag modes in 281 pb-1data: Bo Xin

  6. Same tests were made using the data, the results agree with other CLEO-c analyses very well. Test (1): DK//Ks/0 e - Generic MC & Data Test the analysis method using semileptonic modes with large yields for each tag separately and for all tags combined Bo Xin

  7. Test (2): D/’/ e - Generic MC Procedure tested with Generic Monte Carlo Input BFs reproduced successfully Bo Xin

  8. Two  submodes give consistent results Results (1): De (DATA – 281/pb) First observation of De! Preliminary Bo Xin

  9. Feldman & Cousins Phys.Rev.D57:3873-3889,1998 Results (2): D’e, e (DATA – 281/pb) Preliminary Bo Xin

  10. Systematic Uncertainties and Results Systematic Uncertainties OUR PRELIMINARY PDG-2004 Bo Xin

  11. Summary • Rare D semileptonic modes: De, ’e, e, have been studied using 281/pb of data at the (3770) • D e is observed for the first time in two  submodes:  and +-0 • No signal candidates are observed for D ’e and D e. Upper limits are set for these modes. • CLEO-c is going to collect a much larger sample at the (3770). This sample will improve statistical precision of existing measurements and allow observations of new modes. Bo Xin

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