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We can produce energetic gamma-rays on Earth in nuclear reactions but also among the decay products of LHC particle collisions.

So I was wandering which are exactly the highest energy man-made gamma-rays we have produced so far?

My intuition is that they come from the decay of neutral pions $\pi_0 \rightarrow 2 \gamma$ at LHC collisions, if yes, which energy can they reach? Or is there some other process I am not considering? I dismissed nuclear reactions as they typically produce MeV particles while, even though I am not an expert, I am sure LHC produces at least GeV pions.

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This needs an answer from somebody in an LHC experiment having access to energy distributions of gamma rays, as this is not a plot of high priority in publications.

I can guess at a limit at LHC on the low side:

As the prominent channel for the Higgs is the two photon one, and the Higgs has a mass of 125 GeV, certainly gammas of at least 7o GeV in the detectors must have been measured. Depending on the kinematics of the momentum that the Higgs carried this could go quite high, considering that the available energy is now is at 14TeV. The photons from pio will be right there as the background contribution to the higgs.

enter image description here

The latest plot goes up to background masses of 180 GeV plus. So the smallest values are over 100GeV at the center of mass of the pair, and could be much more depending on the kinematics.

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  • $\begingroup$ Hi @anna v, two weeks have passed and nobody with access to the data has replied. Can you provide an estimate for the energy in the lab frame? You said mass (energies) on the x axis are in the centre-of-mass of the pair, what is the Lorentz factor of such a frame with respect to the lab? If you add this final information (or at least make a rule-of-thumb estimate) I'll accept this as final answer. $\endgroup$
    – cosimoNigro
    Commented Jun 2, 2019 at 6:59

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