Anwar A Bhatti
The Rockefeller University
1230 York Avenue
New York NY 10065-6399
(212) 327-8821 (NYC)
(630) 840-5111 (Fermilab)
Jet Energy Scale
Anwar A Bhatti
Super-symmetry in all-hadronic channel
I am searching for physics beyond the standard model using multijet events which have large
missing transverse energy. This a classic signature of Super-symmetry theory, one of the promising BSM scenarios.
Super-symmetry is a space-time symmetry in which each Standard Model particle has a super partner which differ by
spin=1/2. In R-parity conserving models, the lightest super symmetric particle LPS is stable. These LSPs are produced
in pairs and leave the detector without interacting with detector, leading to large missing transverse energy in the events.
The LSP is one of the candidate of dark matter. I was con-convener of the CMS group searching for SUSY using jets and missing transverse momentu,
I was also co-leader of Jet+MET topology group at LHC Physics Center. during 2008-2010.
Dark Matter Production
I am searching for direct production of dark matter at the LHC. Dark matter particles when produced in association with a jet give rise to classic mono-jet signature. Using 5 fb-1 of CMS data from 2011, we were able to extend the excluded DM masses below 3.5 GeV for DM-nucleon cross section of 10-39 cm2, a region not explored by the direct detection experiments for spin-independent interactions. For spin-dependent interactions, we have the best limits.
Large Extra Dimensions
I am working on trigger studies, jet algorithms, calorimeter simulation, jet energy scale determination and understanding of
missing transverse energy.
At CDF, I have worked on many different subjects.
Inclusive Jet Cross Section Jets are the highest energy probe in particle physics and
can be used to study the structure of matter to a distance scale of 10 -17 meters. We determined that quarks are point-like
particles at this distance scale. This measurement lead to a new understanding of the parton distributions of the proton.
Quarks and gluon, the constituents of proton are collectively called partons.
Variation of strength of strong interactions with the distance scale
Diffractive dijet production
Diffractive processes constitute about 90% of the strong interactions and are mediated by a color singlet
object with quantum numbers of vacuum. No such object has been directly observed. The diffractive
jet events combined with other measurement by our group confirmed that the object exchanged in diffracive interaction consists of gluons and quarks.
Dijet production without particle production between jets
W/Z bosons decaying into jets This was one of the first analysis at CDF which used a multi-variant technique to extract a small
signal over a huge background.
Search for new particles decaying into dijets In many extensions of SM, new particles decay into quarks and gluons. We searched for excited quarks, axigluon, Randal-Sundram gluons, and coloron. However, the measured spectrum was in very good agreement with the NLO QCD predictions and
we could exclude new particles decaying to dijet with masses upto ~1 TeV/c2.
Jet Energy Scale and Resolution Determination
L2 Calorimeter Trigger Upgrade