Recent content by Lester

You can find a simple definition of http://en.wikipedia.org/wiki/Mass_gap" . A Yang-Mills theory, in the limit of the coupling gauge going to infinity, displays at the classical level a mass gap. This because there is a theorem proved in http://arxiv.org/abs/0709.2042 (appeared in Physics...

Indeed, Yukawa model is the low-energy limit of QCD reducible yet to a Nambu-Jona-Lasinio model. Quanta are not pions or other mesons but possibly glue excitations. See http://arxiv.org/abs/1002.4600

The question went this way. I have got a paper published on Physics Letters B http://arxiv.org/abs/0709.2042" where I stated some theorems producing as a final result the infrared gluon propagator. This propagator displays a spectrum of excitations with a massive ground state. This result...

People interested about this matter should check this http://marcofrasca.wordpress.com/2009/04/26/gluon-condensate-the-situation/

What is the currently accepted value for the gluon condensate? How much different is from SVZ value? I would appreciate any reference, mostly from experiments. Jon

Lattice computations of gluon and ghost propagators seem to show that Gribov ambiguity is not a concern in the infrared limit. Indeed, ghost propagator is that of a free particle. This matter is hotly debated yet as it would imply that a lot of work about gauge theories is wrong and does not...

Daniel, the right link is http://marcofrasca.wordpress.com/2009/03/05/ted-jacobsons-deep-understanding/ and the right name is Marco Frasca. Jon

Thanks a lot, Sam. This is what I was looking for. Jon

If I have a product like [tex] \bar\ psi\gamma^\mu\psi\bar\psi\gamma_\mu\psi [tex] how can i rearrange with Fierz transformations?

Thanks a lot Sam. This was the formula I was looking for. Jon

Photons do not couple to Higgs field by an experimental fact as we now that the photon is massless. It is not a mathematical reason but an experimental datum. Instead, neutrinos have mass and this somewhat changed the way standard model should be formulated.

Hi there, Does anybody know how to exploit the product of structure constants of SU(N) through Kroenecker deltas? I mean \sum_a f_{abc}f_{ade} I know this for SU(2) as in this case I have the Levi-Civita symbol but in other cases I was not able to recover it in literature. Any...

The meaning of what I am saying is the following using a more mundane argument. Consider a parabolic function y=x^2+kx This function has a minimum at x_m=-\frac{k}{2} with the value of the minimum y_m=-\frac{k^2}{4} and this is quite general. But if you insist to demand the minimum in zero...

The functional should be defined as S=\int_{t_1}^{t_2} dt \frac{1}{2}m\dot{x}^2 and computed between two points x_1=x(t_1) and x_2=x(t_2) keeping these points fixed. Then, you take all the possible paths between these two points and you uncover that the only one being an extremum of this...

Dear humanino, Thanks for your answer. Here is the link http://pdg.lbl.gov/2007/listings/m014.pdf There is a lot of literature about this resonance (initially people did not believe at it). E.g. look at http://arxiv.org/abs/0804.4452 but also for a different view...