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Where to find data on sea quark distribution of protons?

by blue2script
Tags: quarks, sea, structure functions, valence
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blue2script
#1
Jul31-09, 09:37 AM
P: 49
Dear all!
I am currently searching for experimental data on the sea and valence quark distribution of the proton together with the gluon distribution.

You find plenty of F^p_2(x) structure functions but no consideration on how it splits in terms of sea and valence quarks.

A big thanks for all suggestions!
Blue2script
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humanino
#2
Jul31-09, 10:04 AM
humanino's Avatar
P: 2,828
F_2^p(x) alone is not sufficient to disantangle. You need separately F_2 for neutrino and antineutrino scattering, or alternatively you need data on the proton and the deuterium, and you use isospin.

For fits to data, there are several sets available.
http://www.phys.psu.edu/~cteq/
http://durpdg.dur.ac.uk/hepdata/mrs.html
http://durpdg.dur.ac.uk/HEPDATA/PDF
blue2script
#3
Jul31-09, 10:14 AM
P: 49
Hi humanino,
thanks for these data sets, they are a good point to start with! The problem is: I want to compare the sea and valence quark distributions of the proton with theoretical calculations in the 1+1 dimensional Gross-Neveu model. In this model I can calculate these two distributions for baryons but I can't find data on these two distributions for the proton (but I will check your links, seems to be a lot of stuff on them). That's why only F2 or F1 is interesting for me, anything like polarized structure function or other spin-related measures have no counterpart in 1+1 dimensions.

Also, if you know some good comparisons of these distributions with other quark models (like the bag model) I would be glad if you could share these sources! I searched for hours but there is so much data on everything related to this I am getting crazy...

Thanks again!
Blue2script

Parlyne
#4
Jul31-09, 12:36 PM
P: 546
Where to find data on sea quark distribution of protons?

Since the pdf sets have distribution functions for each type of quark and antiquark, you can get a great deal of physical information out by being a little clever. Consider a proton. Its only valence quarks should be up or down. So, the distributions of all types of antiquarks, as well as those of second and third generation quarks should be entirely the sea quark distribution. Then, since sea quarks appear only in quark antiquark pairs, the up and anti-up sea distributions should be equal (and the same for down and antidown), which means that the valence up quark distribution should be the up distribution minus the anti-up distribution.


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