QED Proton Size: 4% Smaller Than Thought?

[ZapperZ]

Two different threads on the same topic have been merged.

Zz.

 

[petergreat]

Forgive me for asking a naive question. Is it possible to determine the proton size using muon-proton scattering in an accelerator? Would this method be sufficiently accurate to shed light on this problem?

 

[sanman]

Proton Smaller Than Previously Thought?

There have been a spate of articles about the size of the proton being measured as smaller than previously believed:

http://arstechnica.com/science/news/2010/07/-we-may-have-been.ars

What is the significance of this finding? What impact does it have on the broader picture?

This sounds like some basic things in physics are going to have to be revised, no matter what.

Does this affect things like nuclear cross-section values for nuclear energy applications?

 

[jtbell]

Threads merged. Sanman, check out the previous posts. I left your post intact because it has a reference to another article on the subject.

 

[sanman]

I found the following ...
http://physicsworld.com/cws/article/news/43128
Proton is smaller than we thought
Jul 7, 2010

...

Meanwhile, Pohl's team will repeat its experiment and do a new series of measurements on muonic helium to measure the radius of the helium nucleus.

What about experimenting with μ+ and the anti-proton?

Shall we hope for similar results there? Or could you see a CP-violation on top of everything?

 

[Dadface]

What about experimenting with μ+ and the anti-proton?

Shall we hope for similar results there? Or could you see a CP-violation on top of everything?

Interesting I think but so incredibly difficult and I would guess impossible at the present time.Just one problem that comes to mind is how are you going to get and keep a sufficient supply of anti protons or anti hydrogen?Another incredibly difficult experiment would be to test tauonic hydrogen.Experiments for the future perhaps.

 

[Orion1]

Rydberg constant...

Our result implies that either the Rydberg constant has to be shifted by −110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient.

Was the Rydberg constant and proton radius QED equation published in the Nature article?

Does anyone disagree with this quantum mechanical definition of the Rydberg constant?

Rydberg constant:
R_\infty = \frac{m_e e^4}{8 \epsilon_0^2 h^3 c}
[/Color]
Reference:
http://en.wikipedia.org/wiki/Rydberg_constant"[/URL]
http://www.nature.com/nature/journal/v466/n7303/abs/nature09250.html"
[URL]http://books.google.com/books?id=DliKdTg8GHQC&pg=PA146"[/URL]