# Bhabha scattering with photon radiation

Dear Experts,

I have generated e+ e- > e+ e- events in Madgraph for a center of mass energy of 500 GeV setting 'set no_parton_cut.' I am then passing those events through Pythia-6 with initial and final state radiation switched on. I am finally counting mono-photon events where I am selecting photons with pT > 1 GeV. Now, I am seeing one discrepancy here. When I am counting more than 2 photons, I am observing the cross-section for e+ e- > e+ e- na (where n>2) is larger than that for e+ e- > e+ e- a or e+ e- > e+ e- 2a final states. I would expect, with increase in the number of photons in the final state, the cross-section should diminish. However, I am getting expected results where the final state has missing energy (e.g., neutrino or dark matter) instead of a charged particle. I am unable to understand where I am going wrong. Could you please let me know the possible source of error?

Thank you for your kind help.

## Question information

- Language:
- English Edit question

- Status:
- Answered

- Assignee:
- No assignee Edit question

- Last query:

- Last reply:

## Can you help with this problem?

Provide an answer of your own, or ask Basabendu for more information if necessary.