Conformal Standard Model is consistent with the observed Higgs particle

12/04/2013

ResearchBlogging.org

Robert Garisto is an Editor of Physical Review Letters, the flagship journal of American Physical Society and the one with the highest impact factor in physics. I follow him on twitter (@RobertGaristo) and he points out interesting papers that appear in the journal he works in. This time I read the following

Tweets from Garisto

and turned immediately my attention to the linked paper: This one (if you have not a subscription you can find it at arxiv) by Tom Steele and Zhi-Wei Wang showing, with the technique of Padè approximants and an average method how to compute the exact mass of Higgs particle from Coleman-Weinberg mechanism arriving to estimate the ninth order contribution. This is so beacuse they need a stronger coupling with respect to the original Higgs mechanism. They reach an upper bound of 141 GeV for the mass and 0.352 for the self-coupling while they get the mass of 124 GeV for a self-coupling of 0.23. This shows unequivocally that the quadratic term, the one generating the hierarchy problem, is absolutely not needed and the Standard Model, in its conformal formulation, is able to predict the mass of the Higgs particle. Besides, the production rates are identical to the original model but differ for the production of Higgs pairs and this is where one could tell which way nature has chosen. This implies that, at the moment, one has no way to be sure this is the right solution but we have to wait till 2015 after LHC upgrade. So, once again, the precise measurements of these decay rates are essential to tell if we are coping with the original Higgs mechanism or something different or if we need two more years to answer this question. In any case, it is possible that Nobel committee has to wait yet before to take a decision. However, in the sixties that formulation was the only possible and any other solution would have been impossible to discover for the lack of knowledge. They did a great job even if we will prove a different mechanism at work as they provided credibility to the Standard Model and people could trust it.

Finally, I would like to note how the value of the coupling is consistent with my recent estimation where I get 0.36 for the self-interaction. I get different production rates and I would be just curious to see how pictures from ATLAS and CMS would change comparing differently from the Standard Model in order to claim no other Higgs-like particle is seen.

What we can conclude is that the conformal Standard Model is in even more better shape than before and just a single Higgs particle would be needed. An astonishing result.

Steele, T., & Wang, Z. (2013). Is Radiative Electroweak Symmetry Breaking Consistent with a 125 GeV Higgs Mass? Physical Review Letters, 110 (15) DOI: 10.1103/PhysRevLett.110.151601

Marco Frasca (2013). Revisiting the Higgs sector of the Standard Model arXiv arXiv: 1303.3158v1

Advertisements

Quantum mechanics and gravity

11/11/2008

Reading the daily by arxiv today I cannot overlook a quite interesting paper that will appear soon on Physical Review Letters. This paper (see here), written by Saurya Das and Elias Vagenas, presents some relevant conclusions about the effects of gravity in quite common quantum mechanical systems. The authors rely their conclusions on an acquired result, due mostly to string theory, that a fundamental length must exist and this fundamental length modifies in a well defined way the indeterminacy principle. So, one can quantify this effect on whatever quantum mechanical system through a correcting Hamiltonian term and evaluating the effect of gravity on this system. In this way one can obtain an estimation on how relevant is the effect and how far can be an experimental measurement of this. The conclusions the authors reached are quite interesting. Of course, all of the cases imply a too small effect to be in the reach of a laboratory observation but, the most not trivial conclusion is that could exist an intermediate fundamental length that could be observed e.g. at LHC. This intermediate length should be placed between the electroweak and the Planck scale.

It is the first time that I see such estimations on quite simple quantum mechanical models and I would expect more extended analysis on a similar line. Surely, it would be striking to see in laboratory such a tiny effect correcting the Lamb shift. But, working in quantum optics, I learned that progress experimentalists are able to put out can be very impressive in a very short time. So, I would not be surprised if in some years Physical Review Letters should publish some experimental letter about this matter being the first evidence of a quantum gravity effect in a laboratory.


%d bloggers like this: