It depends. The traditional answer is three quarks (2 “up” plus 1 “down”) and the gluons required to mediate the force between them. But how many gluons? And is that all there is?

As a June 13, 2019 article from CERN: The proton, a century on makes clear, the number of gluons and the number of additional quarks depends upon the energy involved. Above is an artist’s impression of a proton with a high energy level.

As stated in a CERNCOURIER article: The proton laid bare, ” A proton at rest is therefore very different to a proton, say, circulating in the Large Hadron Collider (LHC) at an energy of 7 TeV. “