The muon is a remarkable particle, and its characteristics continue to be of interest eighty years after its discovery despite the fact that we have measured them better than almost anything else around. So, for instance, the muon lifetime is known to better accuracy than that of any other unstable particle; and the muon anomalous magnetic moment remains at the top of our list of things to determine more precisely nowadays.
One and a half years ago ATLAS produced measurements for the Higgs boson mass using their selected sample of H->gamma gamma and H->ZZ*-> 4-lepton decay candidates, based on data collected in 2011 and 2012. That preliminary measurement was rather surprising as the two independent determinations appeared to disagree with one another at the 2.5-sigma level. The matter even spurred some online debate (see e.g. my blog entry
) and a few gambling addicts waged $100 on the fact that those might be two distinct particle states.
With still three months to go and 663 teams participating, the Higgs challenge has not even entered a hot phase yet, and still there is a lot to watch in the leaderboard at the kaggle site.
In the last few days, there has been a total revolution in the leading position, and a considerable increase in the best scores. And Lubos Motl is again third (and he would be first if there had been no movement in the other positions), implicitly answering some detractors who wrote comments in a previous post on the matter here. See the standings below.
Matter-antimatter asymmetry is one of the greatest challenges in physics - we know antimatter is out there, because it can be created at places like CERN, but the universe seems to be composed entirely of matter.
Theories predict that exactly equal amounts of matter and antimatter would have been created in the Big Bang. So where did all the antimatter go?
New research undertaken by the ALPHA experiment at CERN's Antiproton Decelerator (AD) in Geneva is the first time that the electric charge of an anti-atom has been measured to high precision. Measuring the electric charge of antihydrogen atoms is a way to study any subtle differences between matter and antimatter which could account for the lack of antimatter in the universe.
Today among the three top players -those in the money- at the Higgs challenge we see the appearance of Lubos Motl, whom I had signalled as a participant in an earlier posting. We all know that Lubos is a smart guy, but I doubted whether he would take this very seriously. However, it seems he is. As we speak he has submitted almost 100 solutions (you can submit up to 5 solutions per day, so that means having worked at this at least 20 days in a row).
In the clip below you see the top standers from the challenge site's leaderboard:
Two years ago, I expressed my doubts about the existence of a multiverse
(or at least it's portrayal by some cosmologists) in a blog post in this forum
. In the meantime, last March, the announcement about the discovery of gravitational waves got us perhaps closer to a multiverse--at least to one form of it, based on inflation. And then some problems with the Bicep data were discovered
For decades, physicists have searched for exotic bound states comprising more than three quarks.
In 2011, over 120 scientists from eight countries discovered strong indications for the existence of an exotic dibaryon made up of six quarks. Now, experiments performed at Jülich's accelerator COSY have shown that uch complex particles do exist in nature. This discovery by the WASA-at-COSY collaboration goes beyond what had been done before. Physicists were only able to reliably verify two different classes of hadrons: volatile mesons comprising one quark and one antiquark and baryons consisting of three quarks.
Space seems like an empty box that lives
through time. This can already be classified as a “better model”, as you can
see in the table below. However, this tacitly held model makes people wonder:
If I toss a coin and find myself with the result being “tails”, where is the other me, the one who
found “heads”, the other possibility which physics can no longer ignore, and which
good philosophy has always known to be equivalent?
Has a universe popped up
next door to this one?
If you’re flying in the vicinity of a black hole, seatbelts and a bumpy ride are really the least of your concerns, but we are in the world of the hypothetical, and the accepted wisdom among gravitational thinkers has been that spacetime cannot become turbulent.
An idea by the wizards at the Perimeter Institute is that such accepted hypothetical wisdom might be wrong.
The researchers followed this line of thought: Gravity might be able to behave as a fluid. One of the characteristic behaviors of fluids is turbulence – under certain conditions, fluids don’t move smoothly, they eddy and swirl.
Presto, let's put something on arXiv.
You are the first to arrive to a dinner party and must choose the table where to sit, relying on your past experience of how handsome members of the opposite sex (you're straight) usually choose their seat. You need to buy stocks based on past performances and trends. You travel to some distant location and would like to know what's the weather like there, but there is no forecast for that particular place. What do you do ?