Recent content by franoisbelfor

Can you explain the symbols in the expression? Thank you already! François

This is a somewhat unusual question. I am looking for any physics problem in which the number or factor exp(-4pi^2) appears. If you know one, I'd like to hear about it! François

Almost: the result is 85 GeV, the measured mass is 80.4 GeV. Is there anybody who has ever looked at this coincidence? François

Many articles and papers say that 4% of all energy in the universe is baryonic. How many baryons does that make? I do not seem to find any wikipedia article or paper that gives an absolute number. Can anybody help? Thank you! François

If I look up how the mass of the electron runs with energy between low energy and the Planck energy due to renormalization, the difference is only a few percent. I never found such a calculation of the W or the Z bosons. Is the effect equally small? Or is there a difference? Thank you very...

Yes, the only hint I got was that the mass gap is "necessary to explain why the nuclear force is strong but shortranged". (The rest of the text is not about motivation, but only about why the problem is hard.) But why is QCD shortranged only if there is a mass gap? How do the two aspects...

Ok, but why do we *need* a mass gap in QCD? What are its implications? What would happen if QCD had no mass gap? François

Ed Witten was essential in organizing the 1 million dollar prize for clarification of the mass gap in QCD that is offered by the Clay institute. But why is this issue so important? Wouldn't all the successes of QCD stay also if no glueballs existed? Can somebody explain why Witten wants the...

I have tried a few products, and it seems to work out. The rest of the file is more intriguing: the guy is going for the holy grail of physics... It is quite a change in approach to what is seen around. Unification in 3 d , unusual SU(2) symmetry breaking proposal, no GUT, non Susy - that is...

The Earth is a boson. Fermions are only the same after rotations by 4 pi, the Earth is the same after 2pi, I would say. François

The question says it all. Black holes have mass, and they have angular momentum. - Is the angular momentum an integer or half an integer? Or neither/both? - What happens when two black holes are exchanged? François

Hi Franca, the only place I have seen something similar is the last manuscript on http://www.motionmountain.net/research where Schiller uses the triple belt trick to model the strong interaction. Does this help you? François

D M Fradkin discussed the physics very clearly in the 1964 American Journal of Physics, I found out. The symmetries are the angular momentum and the Runge-Lentz tensor (for the harmonic oscillator in 3d, it is a tensor, not a vector). That makes 3+5=8 generators The generators shift energy...

The 3-dimensional harmonic oscillator has SU(3) symmetry. This is stated in many papers. It seems to be due to the spherical symmetry of the system. (After all, the idea of a 3d harmonic oscillator is that a mass is attached to the origin with a spring, and that the mass can move in 3...

Now I am completely confused. The HERA collider had polarized electrons, and they call longitudinally polirezed electrons those with "spin" (?) in the direction of motion, as can be seen on many Powerpoint presentations online. On the other hand, it makes sense to say that spin in direction of...