Interesting calculation about the possible solution to the FTL.
http://www.technologyreview.com/blog/arxiv/27260/
I'm not buying into this theory tho. Surely they would have checked their local clocks against more than just other GPS clocks. Since the sync of the clocks is the crux of the issue then getting that right in 3 years would have been top priority.
Last edited by Redrobes; 10-15-2011 at 11:29 AM.
Interesting article. It's not really about the synching in this version - this is saying that from the point of view of the satellite, the distance from A to B is actually shorter - because it's moving relative to the experiment. If this all turns out to be down to a version of the 'pole in the barn' problem set for undergrads learning special relativity there will certainly be embarrassment in the OPERA collaboration.
But this is saying that they have static atomic clocks at each end and they are synced with GPS clocks which could be slightly in error due to the satellite path. But you would surely check that sync with other ground based atomic clocks as well so that at the point of sync the error would be shown up and not necessarily at the time of doing the experiment. Once your clocks are synced and verified with multiple other clocks then you can start the experiment and the satellite position, path and velocity are irrelevant. As an example, the USNO have a mobile truck with atomic clock which can be synced. I cant believe that at this stage of finding such odd results that they would not employ some similar checks.The time of neutrino flight is harder to measure. The OPERA team says it can accurately gauge the instant when the neutrinos are created and the instant they are detected using clocks at each end.
But the tricky part is keeping the clocks at either end exactly synchronised. The team does this using GPS satellites...
Gotta put my two cents in although it's late to the thread,,,dark matter is the slight effect the mass of all the alternate universes have on ours,,, and they're populated by Leonard Nimoy with a goatee.
I'll let the physicist chime in on this one because I seem to recall he knows a little something about the subject matter.
http://www.msnbc.msn.com/id/45422811.../#.Ts85ZLJC_4E
Bill Stickers is innocent! It isn't Bill's fault that he was hanging out in the wrong place.
Please make an effort to tag all threads. This will greatly enhance the usability of the forums.
I love how they wrapped with a quote from a comment on a blog. Now that's journalism!
Bryan Ray, visual effects artist
http://www.bryanray.name
Journalism is a dying art ...
Sorry to have been off the site for a few weeks. We actually had a lunchtime seminar today from one of the ATLAS guys on the Higgs search.
Basically there's a range of masses that the Higgs can have in the Standard Model - from around 90GeV to a few hundred GeV. The last big accelerator at CERN proved the Higgs must be heavier than 114GeV *but* they reported hints of a Higgs boson at around 114GeV. However that hint wasn't enough to keep the accelerator running. It was shut down to make way for the LHC.
The LHC has now ruled out a Standard Model Higgs that's heavier than 141GeV. So the window that is left for a Standard Model Higgs is just 114GeV to 141GeV. They haven't been able to see if it's in the remaining region due to having too little data. This limit (above 141GeV) was setusing the data collected up to June. They now have 4 times the data and can set better limits. The LHC is shut down for winter right now (they're using it to fire lead ions around the ring right now instead of protons) and the experiments are doing analysis on their data over the winter.
*If* there's no Higgs then with 4 times more data then they'll be in a good place to show that over the winter. The first deadline is the 16th of December when the experiments show what they've managed to do to Rolf Hauer - the director general. That may or may not be made public. Then the next deadline is the Moriond high energy physics conference in the ski resort of La Thuile (yep, there are some nice conferences). That's traditionally where the big collaborations release the results of their winter analyses. If they've ruled out the Higgs that's when they'll announce.
At the moment they have some excess events in the regions where you'd expect to see a Higgs. I know that's quite an obscure sentence. Basically if you produce a Higgs boson you don't actually see the particle in your experiment. The Higgs will decay and you'll pick up the things it decays into. It's those that you see. Say it decays into a b-quark and an anti-b-quark. Then you pick those up. They'll each have some portion of the Higgs mass as energy. So if the Higgs has a mass of 130GeV, then you'd expect to pick up some b,anti-b pairs with around 65GeV of energy each. There's some statistical spread in that (you don't always get precisely half in each) so what you see is a bump in your detected events around 130GeV in the combined energies of the b,anti-b quarks detected.
Currently they have some broad excesses in events around 130-140GeV. There's certainly not enough that anyone's actually saying they've found anything, but more than you'd expect if there were no Higgs boson. If those excesses are really signals, then 4 times the data will help them to them down. If it's not there, then with 4 times the data we'd expect those excesses to disappear. We'll know the answer to that pretty quickly.
The one other thing that came out of today's lunchtime talk was that all the news you hear about the Higgs searches is done on the basis that the Standard Model is the be all and end all of particle physics. It's widely believed that there's a lot more to it than the standard model - one possibility being something called supersymmetry that adds new particles, resolves the mystery of dark matter and ... changes how the Higgs boson behaves. The analysis is similar. So it's quite possible (even likely) that over the winter the LHC will rule out the existence of a Standard Model Higgs, but will find a more exotic version of the Higgs boson that tells us what the next big theory is and helps us to resolve the mystery of dark matter and other big questions.
So take any announcement like 'scientists disprove the existence of the Higgs boson' with a hefty pinch of salt.
@Midgardsommer: The blog in question is by the press spokesperson for ATLAS - and so is cleared by the ATLAS committee so it's about as official as you can get. But yes, a comment by a non-physicist on that blog is not really relevant for the news story
Just a quick note - it appears there's an announcement on Tuesday about the Higgs. It looks like it'll be strongly indicated, but that they won't yet be able to claim a discovery (you need a 5 sigma signal - or be able to say there's less than a 1 in a million chance of it being a fake signal). If it is a clear indication, then hopefully by next summer they'll have enough data to formally announce a discovery. If so, this is the end of a 50 year marathon in fundamental physics research.
There's a nice article on the rumour on the BBC - and I can confirm that the experimentalists I've talked to are also smiling (but remaining tight lipped).
http://www.bbc.co.uk/news/science-environment-16074411
Posting Permissions
Reply With Quote
