Skip to main content Accessibility help
×
Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-09T13:42:42.281Z Has data issue: false hasContentIssue false

8 - The Structure of the Nucleon

Published online by Cambridge University Press:  31 March 2010

Robert N. Cahn
Affiliation:
Lawrence Berkeley National Laboratory
Gerson Goldhaber
Affiliation:
University of California, Berkeley
Get access

Summary

Elastic and deep inelastic scattering from nucleons, 1956–1973.

Hadronic scattering experiments produced extensive and rich data revealing resonances and regularities of cross sections. While the quark model provided a firm basis for classifying the particles and resonances, the scattering cross sections were less easily interpreted. The early studies of strong interactions indicated that the couplings of the particles were large. This precluded the straightforward use of perturbation theory. While alternative approaches have yielded some important results, it is still true that even processes as basic as elastic proton–proton scattering are beyond our ability to explain in detail. In contradistinction, scattering of electrons by protons and neutrons is open to direct interpretation.

For the scattering of an electron by a proton it is a good approximation to assume that the interaction is due to the exchange of a single virtual photon. The small corrections to this approximation may be calculated if necessary. Each coupling of the photon gives a factor of e in the scattering amplitude, so a virtual photon's two couplings typically provides a factor α = e2/4π ≈ 1/137. It is this small number that makes the approximation a good one.

The scattering of relativistic electrons (E > > me) by a known charge distribution can be calculated using the standard methods of quantum mechanics.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×