Monday, December 8, 2014
Higgs Boson discovered! June 2014 article
extreme tech article
Two years after CERN announced that it had discovered a particle that was probably a Higgs boson particle, the folks at the Large Hadron Collider have now confirmed that the newly discovered particle is definitely theHiggs boson as predicted by the Standard Model of particle physics. On the one hand, this is obviously a huge win for science — but on the other, there will be many scientists who are disappointed that, yet again, the Standard Model has held up to another round of immense scrutiny. If you were hoping for the Higgs boson to be the weird particle that led us towards the weird and wonderful nether regions of science beyond the Standard Model — supersymmetry, dark matter, dark energy — then sadly this is not the particle you were looking for.
This new study, published in Nature Physics, is confirmation from the LHC’s CMS experiment that the particle observed in 2012 decays into fermions. Previously we had only confirmed that this particle decayed into bosons. Bosons are force-carrying particles (like photons and electrons), while fermions are mass-carrying particles (like protons and neutrons). The Standard Model predicted that the Higgs boson is the particle that actually gives fermions their mass — and now, by smashing protons together at the LHC, the CMS detector has finally confirmed that Higgs bosons decay into fermions (bottom quarks and tau leptons). [doi:10.1038/nphys3005 - "Evidence for the direct decay of the 125 GeV Higgs boson to fermions"]
Following this study, we now have confirmation that this is the Higgs boson as predicted by the Standard Model of particle physics. It sits in the mass-energy region of 125 GeV, has no spin, and it can decay into a variety of lighter particles (pairs of photons, fermions, etc.) This means that we can say with some certainty that the Higgs boson is the particle that gives mass to… well, everything. “Our findings confirm the presence of the Standard Model Boson,” says Marcus Klute of the CMS Collaboration. “Establishing a property of the Standard Model is big news itself.”
There are two key takeaways here. First, it’s hard not to be slightly disappointed that the Higgs boson is behaving exactly as expected. If its decay path had been slightly different — if it coupled with fermions slightly differently — then whole new avenues of research would’ve opened up. This confirmation from CERN’s CMS detector, though, reaffirms that — yet again — the Standard Model stands up. On the flip side, it means we’re no closer to pushing beyond the Standard Model. The Standard Model doesn’t account for gravity, dark energy and dark matter, and some other quirks of reality.
While we can only really guess at what causes these quirks, one of the most popular theories is supersymmetry. Supersymmetry postulates that every Standard Model particle also has a superpartner (called a sparticle, believe it or not) that is incredibly heavy (thus accounting for the 23% of the universe that is apparently made up of dark matter). It is hoped that when the LHC turns back on in 2015, after upgrades that will almost double its collision energy to 13 TeV, that it will have energy to discover these sparticles. If that doesn’t work, supersymmetry will probably have to wait for LHC’s 60-mile-long successor, which is already being planned.