• Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.


PO is now at the Physics Department of Bielefeld University!

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback


(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,047 questions , 2,200 unanswered
5,345 answers , 22,709 comments
1,470 users with positive rep
816 active unimported users
More ...

  Interpretation of the Bjorken x.

+ 3 like - 0 dislike

In the infinite momentum frame the Bjorken x, \(x_B\), is interpreted as the longitudinal momentum fraction  of a nucleon carried by the struck parton. How can \(x_B = \frac{Q^2}{2P.q}\) , where the symbols carry the usual meanings, be interpreted that way? What is the logic behind that interpretation? Could you please explain it in a rather intuitive way?

asked Jun 23, 2014 in Theoretical Physics by Nottherealwigner (135 points) [ revision history ]

Hm I know the infinite momentum frame from some other context, so the symbols used here are unfamiliar to me at least... ?

Dear Dilation

In a deep-inelastic scattering process, \(Q^2 = -q^2\) and P and are the four momenta of the nucleon and the virtual photon. Thanks.

Thanks, this already helps a bit. But thinking more about it I realize that I have some difficulties in figuring out what is the exact (scattering) process you are looking at? I do best understand things when they are pictured by Feynman diagrams, but I have not yet tried to produce them in LaTex, not sure if it would work here ...

Dear Dilation

The Feynman diagram will be the simplest in case of inclusive deep inelastic scattering: an electron scatters from a nucleon and only the electron is detected in the final state; for a deep inelastic process \(Q^2 > 1 \mathrm{GeV^2}\). Thanks

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
Please complete the anti-spam verification

user contributions licensed under cc by-sa 3.0 with attribution required

Your rights