The figure below from a DO Collaboration paper has been used as a proof for the non-existence of quark compositeness. But when we read the DO paper we clearly see that it refers to a very high compositeness scale in the TeV range (Take a look at the first three references of the DO paper), but as we see in the posts in this web page BIASED NUCLEON STRUCTURE and The article PLOT OF THE WEEK – QUARK COMPOSITENESS IS NOWHERE NEAR is wrong the true compositeness scale is just 1 GeV and quark compositeness has not already been established because there is a complete entanglement between primons (prequarks) and valence quarks, and between valence and constituent quarks, besides the fact that primons should be very light. What the quark compositeness searches in the TeV range yield is, actually, that primons (prequarks) are not composite. Therefore, the quark compositeness searches in the TeV range are completely misleading.
It is worth recalling that electrical charges do not appear in Bjorken scaling structure functions. And also we should have in mind that at high q square the de Broglie wavelength h/q is very small and, thus, we probe the 3 inner prequarks in the nucleon and identify them as being 3 valence quarks due to the lack of identification of their electrical charges.
The DO paper above mentioned: DO Collaboration, First Measurement of Dijet Angular Distributions in the TeV Regime nd Searches for Quark compositeness and Extra Dimensions, DO Note 5333-CONF.
The first three references of the above paper are:
 E. Eichten, I. Hinchliffe, K. D. Lane and C. Quigg, “Super Collider Physics,” Rev. Mod. Phys. 56, 579 (1984) [Addendumibid. 58, 1065 (1986)].
 P. Chiappetta and M. Perrottet, “Possible bounds on compositeness from inclusive one jet production in large hadron colliders,” Phys. Lett. B 253, 489 (1991).
 K. D. Lane, “Electroweak and flavor dynamics at hadron colliders,” arXiv:hep-ph/9605257.
This also means that other experiments on quark compositeness carried out in the TeV region produce null results, of course. A good account of this can be found in this ATLAS Report.
In almost all books of Introduction to Particle Physics one finds this picture of the proton structure function F2 in terms of x for q squared around 1 GeV squared. The authors state that this picture proves that there are 3 valence quarks in the proton, but this is completely false because the mass which is inserted into q squared is the proton mass divided by 3 and this means that one is proving that the proton has 3 constituent quarks and not 3 valence quarks because valence quarks are supposed to be very light. Have in mind that the sum of the masses of the 3 constituent quarks yields the proton mass of about 1 GeV.
As an example, I indicate Donald Perkins book Introduction to High Energy Physics, on p. 271. In my presentation at MORIOND 2014 on Quark Compositeness I show the internal structure of the proton which was experimentally found by the Nobel Prize winner R. Hofstadter at SLAC in the 1950s. Please click here for the presentation. Please, take a look at the post BIASED NUCLEON STRUCTURE.