Seminars - Summer 2010

UO Center for High Energy Physics

July 13, 2010 (Tuesday) John BackusMayes, University of Washington

July 14, 2010 (Wednesday) Tai Sakuma, Massachusetts Institute of Technology

July 15, 2010 (Thursday) Paul Lujan, University of California, Berkeley

Past Seminars

July 13, 2010 - Tuesday

John BackusMayes, University of Washington

Search for Associated Production of Z and Higgs Bosons in llbb Final States in ppbar Collisions at sqrt(s)=1.96 TeV

Abstract: We present a search for a low-mass Standard Model Higgs boson produced in association with a z boson decaying to charged leptons at a center-of-mass energy of s\sqrt{s}=1.96~TeV with the D0 detector at the Fermilab Tevatron collider. The search is performed in a large data set of events containing two opposite-sign leptons (electron, muon) and one or two b-tagged jets.

4:00pm, 472 Willamette Hall

Refreshments served at 3:45

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July 14, 2010 - Wednesday

Tai Sakuma, Massachusetts Institute of Technology

Proton Spin Physics in Polarized Proton-proton Collisions at STAR

Abstract: Is the proton's spin carred by only the spins of the three quarks? No, an experiment in 1988 found that the quarks'spin carries only a small fraction of the proton's spin. This experimental result was so unexpected that it was called the "spin crisis", and prompted many theoretical and experimental studies on the spin structure of the proton. At brookhaven National Laboratory, we have been investigating the role of gluons in the protons' spin by using polarized proton-proton collisions at RHIC (RHIC-Spin). In this talk, I will discuss the status of proton spin physics and show recent results from the STAR experiment. I will give emphasis to measuing jet production in polarized proton-proton collisions and constraining the polarized gluon distribution of the proton.

4:00pm, 472 Willamette Hall

Refreshments served at 3:45

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July 15, 2010 - Thursday

Paul Lujan

Precision Top Quark Mass Measurement with a Matrix Element Method

Abstract: I will present a precision measurement of the top quark mass using 5.6 fb-1 of data collected by the CDF detector during Run II of the Fermilab Tevatron. The measurement uses a matrix element method, in which, for each event the matrix element for top pair production and decay is integrated over unkown or poorly-measured quantities. We thus obtain a likelihood of seeing the observed events as a function of top mass. This likelihood technique offers improved statistical resolution compared to traditional template methods, and our method includes several features which make it currently the most precise top mass measurement in the world.

4:00pm, 472 Willamette Hall

Refreshments served at 3:45

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