Register to reply

Nucleon constituents

by mathman
Tags: constituents, nucleon
Share this thread:
mathman
#1
Jan15-13, 03:35 PM
Sci Advisor
P: 6,027
I understand that nucleons (protons and neutrons) consist of 3 valence quarks and a sea of other stuff, virtual quark-antiquark pairs and gluons. Question: are the virtual quarks only up and down or may there be heavier quarks?
Phys.Org News Partner Physics news on Phys.org
New study refines biological evolution model
Fiber optic light pipes in the retina do much more than simple image transfer
Production phase for LSST camera sensors nears
fzero
#2
Jan15-13, 08:05 PM
Sci Advisor
HW Helper
PF Gold
P: 2,606
Quote Quote by mathman View Post
I understand that nucleons (protons and neutrons) consist of 3 valence quarks and a sea of other stuff, virtual quark-antiquark pairs and gluons. Question: are the virtual quarks only up and down or may there be heavier quarks?
All flavors contribute because of [itex]g\leftrightarrow q\bar{q}[/itex] processes. A quick search didn't turn up any sort of canonical reference, but http://cerncourier.com/cws/article/cern/29441 explains some experimental measurements related to the strange component of the proton.
mfb
#3
Jan16-13, 09:12 AM
Mentor
P: 11,570
This pdg review has (predicted) parton distribution functions on page 12. Heavier quarks are suppressed, but they are present.

mathman
#4
Jan16-13, 03:38 PM
Sci Advisor
P: 6,027
Nucleon constituents

Quote Quote by fzero View Post
All flavors contribute because of [itex]g\leftrightarrow q\bar{q}[/itex] processes. A quick search didn't turn up any sort of canonical reference, but http://cerncourier.com/cws/article/cern/29441 explains some experimental measurements related to the strange component of the proton.
I would guess that it is possible that the other heavier quarks may be present, but the experiments might be difficult. Maybe LHC might find something?
Bill_K
#5
Jan16-13, 03:55 PM
Sci Advisor
Thanks
Bill_K's Avatar
P: 4,160
Naturally if you hit a proton hard enough, heavy quarks will be produced. I thought your question was, is there a significant percentage of heavy quarks already in the proton. And to answer this, as described in the ref, you want to do low energy experiments with high accuracy.
mathman
#6
Jan17-13, 03:27 PM
Sci Advisor
P: 6,027
Quote Quote by Bill_K View Post
Naturally if you hit a proton hard enough, heavy quarks will be produced. I thought your question was, is there a significant percentage of heavy quarks already in the proton. And to answer this, as described in the ref, you want to do low energy experiments with high accuracy.
My confusion is how do you tell what was there already as compared to what happens when protons collide with something.
mfb
#7
Jan18-13, 09:05 AM
Mentor
P: 11,570
With simulations - you cannot "see" this directly in detectors, you can just compare (statistical) experimental results with the simulated results.


Register to reply

Related Discussions
Nucleon-nucleon scattering problem Advanced Physics Homework 0
Field constituents Quantum Physics 10
Does the nucleon-nucleon interaction depend on momentum? High Energy, Nuclear, Particle Physics 4
The constituents of a neutron? High Energy, Nuclear, Particle Physics 4
What is the constituent material of the universe? General Physics 3