2 The CDF Experiment at Fermilab Contents - Harvard University ...

Section 2: Missing Energy + Jets 73
In pp collisions a signature of the massive spin-2 graviton escaping into the extra dimensions
and thus escaping detection, is large 6E T plus one jet. Peskin et al. [21] used the CDF
Run 0 analysis of events with 6E T 30 GeV and one jet (rapidity < 1:2) put a limit on graviton
production by comparing the cross section of the graviton signal and the Standard Model
processes that give such a nal state. The CDF results are based on only 4:7 pb ,1 and thus
greater sensitivity can be obtained simply by studying the data from Run I. Fig. 36 (from
hep-ph/9811337) shows the 6E T
background.
spectrum of the graviton signal and the Standard Model
Fig. 36 shows the 6E T distribution of a subset of the CDF Run Ib 6E T data sample and with
the requirement of exactly one jet. The main backgrounds is Z QCD associate production
where the Z decays to , W production where the W decays to a tau lepton and a neutrino
and residual QCD background from mismeasurements and jet resolution. By raising the 6E T
rrequirement to 60 GeV and estimating the Standard Model backgrounds we expect to be
sensitive to the graviton production process in the 6E T plus monojet channel.
The reach in the (size of extra dimension, eective Planck scale) plane, compiled based
on the study of Peskin etal: and for LEP2, TeVatron, TeV II, Linear Collider (LC) and LHC
is given for number of extra dimensions N=4,6 (which are favored cosmologically) in Fig. 37.