2011 QCD and High Energy Interactions - Rencontres de Moriond ...

ut also for valence quarks involved in the highest energy interactions. Global Parton Distribution
Function (PDF) fits are currently in progress at HERA, involving exclusive jets and charm cross
sections in addition to inclusive structure functions. The LHC experiments have also started to
contribute to the control of PDF’s through cross-section measurements of weak boson production,
with LHCb extending the range of measurements to lower x than at HERA.
The phenomena of primary interest for search of new physics at LHC involve inclusive signatures
like dijets (figure 2), di-leptons (figure 3) and lepton+missing PT (figure 4).
Figure 2:
Inclusive dijet mass distribution measured by ATLAS, compared to possible excited quark signals.
Figure 3: Dielectron (left) and dimuon (right) mass spectra measured by ATLAS and CMS
respectively, compared to possible Z’ signals.