The Higgs Boson at 125 GeV, or much ado about nothing

[Ryft]

Would one of you theoretical physicists types please explain what this might mean to the standard model? Does it lend itself to supersymmetry or ... kill it?

The following is taken from James Gillies, “Evolution or revolution? The search for the Higgs boson puts particle physics on the threshold of a new era,” Quantum Diaries (2011, December 13). I just read this article yesterday, and seeing your questions here I thought it might provide some answers for you. (Incidentally, I subscribe to Quantum Diaries in my news reader; I highly recommend that like-minded geeks who love particle physics and whatnot do the same. They produce eminently readable and highly informative articles.)

(All emphases mine.)

The Higgs mechanism in its basic form is the simplest theoretical model that could account for the mass difference between photons and the W and Z particles, and by extension could account for the masses of a range of fundamental particles. But the simplest form of the Higgs mechanism is not the only possible explanation. There are many others, linked to theories such as supersymmetry, which could account for the mysterious dark matter of the universe, or theories predicting extra dimensions of space, which, if verified, would truly revolutionize our understanding of the universe we live in. These searches in turn are just a part of the very wide program of research that is ongoing at the LHC ... (para. 3).

The basic form of the Higgs mechanism forms part of the Standard Model of particle physics ... The Standard Model works extremely well, but we know that it cannot be a complete theory. It describes beautifully the ordinary matter from which we and the entire visible universe are made. But it does not describe the invisible 96% of the universe that we know to be there, but which has thus far evaded detection. The Standard Model is nevertheless such a good theory that it will always remain valid over the range it has been tested. Today’s scientists are therefore looking for a theory that builds on the Standard Model ... (para. 4).

A Standard Model-like Higgs particle could yet point the way to new physics through subtleties in its behavior that would only emerge after studying a large number of Higgs particles. A Standard Model-like Higgs particle might also be one of several types of Higgs particles, pointing the way to new physics, and this would only become apparent after detailed scrutiny. A non-Standard Model Higgs particle linked to a theory like supersymmetry that goes beyond the Standard Model would immediately open the door to new physics. And finally, if a Standard Model Higgs particle were definitively ruled out at the LHC’s current operating energy, that would point either to a non-Standard Higgs particle that could be discovered with more luminosity or to the existence of new physics at the LHC’s full design energy where the Standard Model without the Higgs particle starts to break down. (para. 8).

With respect to the possible mass ranges for the Higgs (referring to that bit you quoted from another thread),

The status of the search for the Standard Model Higgs particle at the end of the 2011 LHC proton run in October was based on experimental work involving scientists from around the world. Direct searches from CERN’s previous flagship research facility, the Large Electron Positron collider, LEP, had excluded the mass range up to 114 GeV. Results from the Tevatron collider at Fermilab in the USA, and from the LHC, had excluded the range from 141 GeV to 476 GeV. Indirect searches, in which scientists try to detect tell tale signs that a Higgs particle has influenced their measurements rather than looking for the particle directly, exclude the range above 200 GeV or so. That left just the region 114-141 GeV, which is precisely where theoretical and experimental considerations say a Standard Model Higgs particle is most likely to be. By December 2011, analyses by the ATLAS and CMS collaborations had further narrowed the range of masses available for the Standard Model Higgs particle to just 116-127 GeV, with both experiments seeing tantalizing signs that a Standard Model Higgs particle might be starting to emerge in the region of 124-126 GeV. Only time will tell. (para. 7).

Of course, see the article for a good deal more information. Gillies explains the issues in non-technical language that's easy to digest.

[houseofcantor]

You cats familiar with Lubos Motl? The last happy string theorist? Check this quote:

However, the exciting question that remains is whether or not the LHC will see something else beyond the 125 GeV Higgs. The very likely mass near 125 GeV makes both possibilities – yes and no – approximately equally likely. Stay tuned.

The link to the whole post is under his name, above; for myself, if I had the scratch, I'd be organizing a party.

(What I'm seeing, if it isn't apparent, is a prominent supporter of stringiness guessimating a 50% chance the patient did not survive "black monday." I just don't like string theory. )

[little_monkey]

You cats familiar with Lubos Motl? The last happy string theorist? Check this quote:

However, the exciting question that remains is whether or not the LHC will see something else beyond the 125 GeV Higgs. The very likely mass near 125 GeV makes both possibilities – yes and no – approximately equally likely. Stay tuned.

The link to the whole post is under his name, above; for myself, if I had the scratch, I'd be organizing a party.

(What I'm seeing, if it isn't apparent, is a prominent supporter of stringiness guessimating a 50% chance the patient did not survive "black monday." I just don't like string theory. )

A lot of this fuss about the 125 Gev Higgs boson comes from a paper by Mikhail Shaposhnikov and Christof Wetterich ( two names which will soon become famous in the physics community). Several years ago, they argued that if one assumes no new particles or forces beyond the Standard Model (BSM), they calculated that the minimum mass of the Higgs boson would be 126 GeV. Since the finding at CERN indicates that the Higgs boson would be around the 125GeV, this has given hope to the SuSy, Technicolor, and others, that BSM is not ruled out.

Link: http://arxiv.org/abs/0912.0208