Far out cosmology: LHC spots a possible new particle (Introduction)

by David Turell , Wednesday, March 09, 2016, 19:24 (3179 days ago) @ David Turell

A new article on this possible new heavy particle:-http://www.nature.com/news/who-ordered-that-1.19514?WT.ec_id=NATURE-20160310&spMailingID=50877899&spUserID=MjA1NjE2NDU5MwS2&spJobID=881159065&spReportId=ODgxMTU5MDY1S0-"If the particle exists, the implications would be enormous. Precisely because it is so unexpected, it could be the most important discovery in particle physics since quarks — the elementary constituents of protons and neutrons — were confirmed to exist in the 1970s. Perhaps it would be the biggest deal since the muon itself.-"The evidence so far is scant, however. It amounts to a few too many pairs of ?-ray photons produced with combined energies of 750 giga­electronvolts when the LHC smashes protons together. The fact that two separate detectors spotted it at almost exactly the same energies gives some hope, but anomalous signals such as this often show up in experiments only to later vanish back into the noisy background.-"Still, people at CERN, the European particle-physics lab that hosts the LHC, have scarcely talked about anything else since. And theoretical physicists around the world have gone into overdrive: more than 200 papers have been posted online with theories that could explain the particle. One possibility is that it could be a heavier cousin of the Higgs boson; another, even more tantalizing one, is that it is a type of graviton, the particle hypothesized to carry the force of gravity. If so, it could point to the existence of extra dimensions of space beyond the familiar three.-***-"The current generation of young physicists was not even born when particle accelerators produced their last genuinely surprising results. Meanwhile, searches for physics beyond the standard model have so far come up empty — at accelerators such as the LHC but also in many tabletop experiments and at detectors built underground or sent into space to look for dark matter. The most notable exception to the standard model's standard fare has been the discovery, beginning in 1998, that the elementary particles called neutrinos spontaneously oscillate between their three known types, or flavours — something that the original version of the standard model had not predicted. That breakthrough earned two physicists a well-deserved Nobel Prize last year.-"The LHC is now providing the opportunity of a lifetime to break entirely new ground. In 2015, it restarted after a long shutdown that brought the energies of its collisions to a record 13 teraelectronvolts, from 8 TeV. This has put much more massive particles in reach — if any exist — but it will be the last substantial jump in collider energies in a generation. More-powerful machines, if they ever see the light of the day, will take decades to plan, develop and build.-"The good news is that whether the new particle exists or the data bump is a statistical anomaly is not a question that will leave us hanging for long. The LHC experiments had time to observe only relatively few collisions in their first 13 TeV run last year, before the experiment shut down for its winter recess."-Comment: We'll have to wait.