Search for Anomalous Production of Photon + Jets + MET

This page summarizes the present work on model independent resonance search for anomalous production of photon+jets. We are in the hunt for new physics beyond the current theory predictions. The plan is to scan many kinematic plots, including photon energy for an excess (a bump) over the current theory predictions. We have used 2 fb-1 of CDF Run II data.

Tree level feynman diagrams for Standard Model production of photon+jets production mechanisms are,

  • Annihilation: where a quark and an anti-quark interact to produce a photon and gluon in the final state.
  • Compton: A quark and a gluon scatter and in the final state, the quark radiating a photon to produce the photon+ jets signal.
  • Bremsstrahlung: In this situation, a quark and a gluon in the initial state interacts and produce a photon and a quark in the final state.

    The gluon or the quark will decay and hadronizes to form a jet. The final state quark or the gluon radiation or splitting will produce additional jets.

    Tree level diagrams for GMSB (Gauge Mediated SUSY Breaking) model photon+jets are following.

    The quark and anti-quark interation producing a neutralino which decays into a photon and a gravitono. One or more of other final state particles will decay into jets, producing the photon+jets signal.

    There are many fake photon sources that mimics the photon+jets signal.

  • Cosmic photons - A cosmic muon interating with the detector to create photon.
  • Beam halo photons - This is a stray proton or anti-proton upon hitting the beam pipe decays into muons and the muons travel through the detector and produce a photon.
  • Leptons faking photon - In this situation, a lepton is reconstructed wihtout any track associted with it which qualifies it as a photon.
  • Standard Model Photons - These are true photons predicted by the Standard Model theory.
  • Jets faking photons - Here a jet passes all the photon selection cuts qualifying it as a photon.

    Blessed Figures for ICHEP08