The Working Group IV Program
60 GeV/c2 -> 120
5 fb-1 -> 25 fb-1
Present plans are to have 2 fb-1 for Run 2A,
10 fb-1for Run 2B and 100 fb-1 for Run 3. This
is 20, 100, and 1000 times LRun1 respectively. Run 2 may
increase its integrated luminosity to 20 fb-1
for the reasons stated above.
Which Higgs decay is most accessible at the
Tevatron? The branching fractions for the Higgs
are listed below for some interesting modes.
Hence , if one understands backgrounds for H-> b bbar then the Tevtraon is a place with excellent potential to discover a law mass Higgs.
As a demonstration of understanding a resonant
decay to b bbar at a hadronic collider Z-> b
bbar has been observed at the Tevtraon/CDF for the first time.
A data set of inclusive muon (5.106 ) is required to have two secondary decay vertices and also pass some cuts on kinematic variables driven by the difference between QCD background (qq->bbbar, gg->bbbar), where there is a color connection between the initial state partons and final state quarks, and an electroweak color singlet resonance final state such as the Z. The final results for the counting experiment is ~70+-20 events, and for the maximum likelihood analysis 91+- 30 events.
The Z PT distribution has an impact on resummation calculations of multiple soft gluon emissions at low PT ( CDF: < 20 GeV). At high PT NLO QCD perturbation theory agrees with CDF data better than 20% for momenta < 100 GeV. The data at low PT is magnified and shown here. The W PT distribution is fit with the Z PT data and additional theory input. It is show in both momentum space and impact parameter space. This distribution introduces a 20 MeV uncertainty into the W mass measurement. The D0 results for W PT including the theoretical calculation of Arnold and Kaufman and Z PT results are shown.
The issue of whether the W/Z cross section will
be used as a luminosity monitor for Run 2 will be discussed in detail by
Gervasio Gomez in WG IV sessions. One can ask what processes might
make good luminosity monitors....y -> mm
or ee, Dijets,
Y-> mm or ee. It is believed that theoretical calculations
on the W and Z cross section are good to 2-3%. However, theory predicts
a shift in the cross section upwards by 30% when Tevatron cm energy increases
from 1.8 to 2 TeV. Hence this cross section has not yet been measured
for Run 2. Also, in the equation for the rate R=LsAe
the acceptance and efficiency enter. After the run starts the acceptances
(dead channels) and efficiencies of the detectors involved in the monitoring
will change, hence one could imagine several luminosity monitors running
on different processes and having none of them agree.
At present the CDF and E710+E811 total cross sections for Run 1 (measured by the extrapolating the slope of the elastic cross section at low -q2 down to zero, counting elastic and inelastic events, and using the optical theorem) do not agree. (CDF ~80+-2 mb and E710/E811 ~72+-2 mb).