The Standard Model: a brief interlude

There is a similar concept in particle physics. It is the parton distribution function.

I am taking the following picture from Wikipedia:

    @misc{ wiki:xxx,
      author = "{Wikipedia contributors}",
      title = "Standard Model --- {Wikipedia}{,} The Free Encyclopedia",
      year = "2021",
      url = "https://en.wikipedia.org/w/index.php?title=Standard_Model&oldid=1001081091",
      note = "[Online; accessed 24-January-2021]"
    }

Basically, this shows all the known elementary particles up to now. It is these bricks that make up all the matter that surrounds us. Actually, this is also not true. All that surrounds is can be surmised mostly to up, down and gluons! This can also be shown thanks to the parton distribution functions. The only mystery at the moment is to understand the behaviour of the gluon pdf, and this is one reason why we are studying UPC events…