1. Studies of D Semileptonic Decay at CLEO-c Bo Xin Ph.D. Thesis Defense 1 Studies of D Semileptonic Decays at CLEO-c Bo Xin Ph.D. Thesis Defense West Lafayette, Indiana, April 14, 2009

2. Introducing Myself A one word definition –A HEP graduate Student from China, working on D semileptonic decays at the CLEO-c experiment Studies of D Semileptonic Decay at CLEO-c Bo Xin2 Ph.D. Thesis Defense

3. Introducing Myself A one word definition –A HEP graduate Student from China, working on D semileptonic decays at the CLEO-c experiment Studies of D Semileptonic Decay at CLEO-c Bo Xin3 Ph.D. Thesis Defense Before I came to Purdue –A Graduate Student working on Ψ(2S) decays at the BEijing Spectrometer (BES) experiment

4. Introducing Myself A one word definition –A HEP graduate Student from China, working on D semileptonic decays at the CLEO-c experiment Studies of D Semileptonic Decay at CLEO-c Bo Xin4 Ph.D. Thesis Defense Before I came to Purdue –A Graduate Student working on Ψ(2S) decays at the BEijing Spectrometer (BES) experiment A summary of my years at Purdue –5 years in graduate school –4 physics analyses –3 years of service work

5. Introducing Myself A one word definition –A HEP graduate Student from China, working on D semileptonic decays at the CLEO-c experiment Studies of D Semileptonic Decay at CLEO-c Bo Xin5 Ph.D. Thesis Defense Before I came to Purdue –A Graduate Student working on Ψ(2S) decays at the BEijing Spectrometer (BES) experiment A summary of my years at Purdue –5 years in graduate school –4 physics analyses –3 years of service work –2 great universities (Purdue & Cornell) –1 great adviser Thank you!

6. Physics Analyses Studies of D Semileptonic Decay at CLEO-c Bo Xin6 Ph.D. Thesis Defense 20052006200720082009 Jul 05 - Feb 07 Oct 06 - Jan 09 Jun 07 - Mar 09 Jan 07 - Oct 08 Batbold’s thesis Entered Purdue: Aug 2004 Qualifying exam: Aug 2004, Preliminary exam: Oct 2006 Graduating: May 2009

7. The CLEO-c detector Studies of D Semileptonic Decay at CLEO-c Bo Xin7 Ph.D. Thesis Defense CLEO III General purpose symmetric detector  p/p = 0.6% at 800 MeV/c  E/E = 2% at 1 GeV, 5% at 100 MeV 5% at 100 MeV 93% coverage (charged and neutral) Excellent electron and particle ID CLEO-c CLEO-c  CLEO III – SVX + ZD – 0.5 T Advantages of running at Charm threshold –Low multiplicity –High tagging efficiency Most relevant to D semileptonic decays

8. Studies of D Semileptonic Decay at CLEO-c Bo Xin8 Ph.D. Thesis Defense Analysis Technique  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:  For semileptonic D : Tagging creates a single D beam of known 4-momentum e + e -   (3770)  DD

9. Studies of D Semileptonic Decay at CLEO-c Bo Xin9 Ph.D. Thesis Defense Pure DD, zero additional particles, ~5-6 charged particles per event ~6.6x 10 5 D 0 and ~4.8 x 10 5 D + tags reconstructed from ~5.2 x 10 6 DD events We tag ~20% of the events, compared to ~0.1% of B’s at the Y(4S) D tagging at CLEO-c Plots from 818/pb D  K/πe + analysis 818 pb -1 @3770