1. DØ and Hunting the Higgs at Arizona
Faculty: Erich Varnes
Postdocs: Amitabha Das (departing in January for postdoc at SMU), Xiaowen Lei (joined in Summer 2011), Ruchika Nayyar (joined January 3)
Students: Fionbarr O’Grady (half-time, joined in summer 2011)
Thanks to DOE for continued strong support of the DØ program!

2. Physics in 2011 Completed top quark analyses
Measurement of W helicity fractions in top quark decays published in PRD
Working with CDF on Tevatron combination
Paper has been ~ready to go for some time, waiting for final approval from CDF
SM is safe on this front
Presented as preliminary result in Summer 2011:

3. Physics in 2011 Example: better c jet identification to reduce
Transitioned to Higgs boson search (Varnes, Lei, O’Grady)
Looking in ZH  nnbb channel, which is complementary to LHC search (and sensitive at low mass)
Contributions include:
Increasing signal acceptance (for WH) by improving sensitivity to spurious missing ET and expanding trigger menu
Updating analysis software to use newer data and Monte Carlo
Studies of optimal use of b ID information (both in terms of statistical and systematic uncertainty)
Example: better c jet
identification to reduce
background

4. Physics in 2011
Limit on Higgs production cross section from DØ in ZH nnbb shown at EPS’11:
Aiming for update at Moriond, followed by publication
Additional data + analysis improvements should increase sensitivity by ~30%

5. Service in 2011 Varnes: DØ algorithms/physics coordinator
Preparation of new data reconstruction and MC versions
Coordinating selection of subset of data that is being reprocessed for “final” DØ results in summer 2012
One of three nominees for spokesperson in 2011 election
Das: shifts, L1MU trigger expert, refined version of fake track discriminant
Lei: contributing to b ID studies
Focusing on introducing additional information into boosted decision tree used to classify jets
Preliminary estimate is ~5% improvement in b ID efficiency for the same background rejection
Nayyar: EM ID convener
Will oversee measurements of EM ID efficiency on reprocessed data