Photoproduction

To Study Jets via Photoproduction

Main program to generate charged hadron spectra from photon-initiated hard processes, by combining sub-runs with direct or resolved photons or by generating all with contributions in a single run (automaticmix)

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Further, I have set the flags for event production: bool photonProton = true; bool photonsFromElectrons = true; bool automaticMix = true;

I am only considering the beam particles for (electron -> photon) + proton, for: Resolved - Resolved, and Direct - Resolved contributions only.

BEAMS and ENERGIES:

• Beam1 : 11 : electron ("PDF:beamA2gamma = on" ie photons are produced by electrons)
• Beam2 : 2212 : proton
• Beams:eCM = 140. : com energy

HERA Energies: CoM Energy ranges from 134–277 GeV at HERA

1. pythia.readString("Beams:eCM = 140.");
2. pythia.readString("Beams:eA = 27.5.");
3. pythia.readString("Beams:eB = 820.");

EIC Energies: CoM Energy ranges from 30-140 GeV at HERA

1. pythia.readString("Beams:eCM = 140.");
2. pythia.readString("Beams:eA = 18.");
3. pythia.readString("Beams:eB = 275.");

CUTS: (and Initializations on Event Generation)

1. Virtuality : Photon:Q2max = 1.0 (pythia.readString("Photon:Q2max = 1.0");)
2. Invariant Mass : Photon:Wmin
3. Limit partonic phat : PhaseSpace:pTHatMin", 5.0
4. MultipartonInteractions:pT0Ref = 3.00
5. HardQCD:all = on
6. PhotonParton:all = on

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JETS:

The macro file 'jets_photoproduction.cc' is used for the formation of jets. Uses Fastjet+ROOT libraries.