A search for new physics with a signature of missing energy in events with high
pT jets is presented. The analysis is performed with 1.1 fb-1 of 7 TeV data taken
using the Compact Muon Solenoid detector at the Large Hadron Collider in 2011.
The kinematic variable α T is used to control the dominant QCD background that
exhibits fake missing energy originating from mismeasurment. The remaining
electroweak backgrounds are estimated using data-driven techniques through
the use of two control samples. The background from boosted W decays is
estimated with the use of a dedicated µ + jets control sample, while the irreducible
background from Z → [Symbol appears here. To view, please open pdf attachment] is estimated using a
γ + jets control sample. A
shape analysis is performed across eight bins in HT , with the signal selection
and the two control samples treated simultaneously in a likelihood fit. The
data was found to agree very well with the Standard Model only hypothesis
with a p-value of 0.56, which indicates no evidence of new physics. The results
are interpreted in the scope of a possible new physics model, the Constrained
Minimal Supersymmetric Standard Model. Exclusion limits are set at the 95%
confidence level on the parameters m0 and m1/2 that set the mass hierarchies of
the sparticles. An extension is also presented allowing additional signal into the
muon control sample. The effect on the limit is negligible, although adopting
a leptonic variable of the αT variable increases the ratio between signal and
background events significantly. This approach is recommended for searches with
higher statistics in 2012.