I'm having some difficulty finding some clear data on the relationship of the average mass of emitted particles in collision experiments with respect to the center-of-mass energy. My understanding is that the average mass does generally increase with energy but due to parton saturation and perhaps other effects, heavier particles are less favored in these highly-dense conditions. This seems to suggest that as $\sqrt{s}$ increases, the contribution of the rapidity to the momentum of outgoing particles would increasingly dominate the contribution of their mass. Or am I missing something here?

Bonus for any references to data on this. Thanks!

  • $\begingroup$ Maybe you are missing that particle scattering obeys the laws of quantum mechanics and not of classical mechanics? In the standard model of particle physics en.wikipedia.org/wiki/Standard_Model everything is organized with individual particles interactions and decays, so the concept of average mass has no meaning as well as rapidity. $\endgroup$
    – anna v
    Mar 13 at 18:59
  • $\begingroup$ If one can tabulate the masses of particles produced in a collision, what is stopping one from calculating the average mass and plotting it against the energy? If you know for a fact that there is no trend produced from such data, please provide a source. $\endgroup$ Mar 13 at 20:53
  • $\begingroup$ Nothing prevents it, but it is not useful in verifying or falsifying the predictions of the models. $\endgroup$
    – anna v
    Mar 14 at 4:25
  • $\begingroup$ Hm, if a trend does exist, then the models better be able to explain it, no? $\endgroup$ Mar 14 at 10:00
  • $\begingroup$ The current standard model reproduces well the data, any discrepancies are in special cases and with very low numbers in the discrepancy. They are sought after all, in order to find new physics. By the way, the higher the energy the more probable is the creation of heavy particles, like the W and Z and the Higgs boson. $\endgroup$
    – anna v
    Mar 14 at 11:36


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