Single Top Physics
Single Top Quark Physics at DØ
I am involved in many studies of single top quarks at DØ, the evidence and observation analyses and
several searches for new physics in the single top final state.
- We discovered single top quark production in 2009! The observation PRL paper and
much more information can
be found here. I was co-convener of the group,
responsible for the statistical analysis and the discriminating variables, and was involved in many other projects
like triggers or selection cuts.
- With the observation dataset, cuts, and multivariate methods we also separated out the t-channel mode of single
top production for the first time.
- We combined the single top observation results from CDF and D0
within the Tevatron Electroweak Working Group.
- We set the first direct limits on top quark anomalous couplings using single top final state information. We then
combined the single top anomalous couplings result with the W helicity analysis in top quark decays for
the most stringent limits on anomalous top quark couplings.
- We found evidence for single top quark production
in 2006. I was responsible for the statistical analysis and worked on the triggers and the
multivariate methods, in particular the discriminating variables.
- I searched for new heavy bosons W' that decay to a top quark and a bottom quark. This is the same final state as the
single top s-channel and I used that data sample to look for a resonance peak in the final state
invariant mass distribution. I didn't find any signal but was able to set tight limits on the
W'. The paper can be found here.
- I won the 2005 Tollestrup award for my postdoc work on single top at DØ!
A video of the award ceremony, including the talk I gave can be found
Images are in this folder. High-resolution
images are available from Fermilab Visual Media Services or directly
- Between September 2003 and July 2005 I was the co-convener of the Single Top
working group at DØ.
We have completed a search for single top quark production in the s-channel
and t-channel using 230pb-1 of data collected with the DØ
detector at the Fermilab Tevatron. We have set upper limits on the production cross
section that are a factor two better than any previous limits.
Our result is documented on the
single top public result web page
and has been published in Physics Letters B. We are
also working on a longer, more detailed article to be published in Phys. Rev. D,
which will contain both this neural network result and a cut-based result.
Single Top Phenomenology at Next-To-Leading Order
I am collaborating with Michigan State theorists C.-P. Yuan and Qing-Hong Cao
as well as with fellow experimentalists Chip Brock and Jorge Benitez on studies of single top quark production
at next-to-leading order in QCD. We have published a paper on
and a paper on
t-channel phenomenology at the Tevatron.