Our universe expands, and this expansion is accelerating. Current consensus is to attribute this acceleration to a mysterious form of energy: dark energy. This dark energy density is very tiny and therefore only notable at cosmic length scales. When expressed in natural units, the cosmic dark energy density has a value of 10-123. This tiny value presents a big mystery. Straightforward estimates for the dark energy density based on quantum field theoretical considerations result in values (again in natural units) close to unity.
The success of today's particle physics experiments relies to a surprisingly large extent on a seldom told functionality of the giant apparata that detect the faint echoes of subatomic particles hitting or punching through their sensitive regions: the capability of triggering.
"The threat is much stronger than its execution"
Aaron Nimzovich (complaining to the arbiter of a chess match that his opponent had put a cigar in his mouth, after the arbiter had pointed out that the cigar was unlit).
The CDF Collaboration has recently produced a new analysis of proton-antiproton collisions at the now second-world-best collision energy of 1.96 TeV. They searched for very rare decays of the B mesons, particles composed of, would you guess, a b-quark and a lighter partner orbiting around each other.
As if taken by a spell, my joking claim to be on strike in the last post
grew to become one of the longest streaks of absence from blogging of the last few months, for a series of irrelevant reasons tightly packed together.
In the meantime I have tried to put together an article on a recent very interesting measurement performed by the CDF collaboration: a study of very rare decays of B mesons, which can now not only determine the rate of said decays, but also have a taste at subtle kinematical effects in the distribution of the final states. The distributions are a new key to discriminate the existence of new physics in these rare processes.
Shoot. Today I am on strike.
This morning I decided to post here an article describing the details of a new result just approved by the CMS collaboration, the observation of a nice signal of phi meson decays. It is a result of which I am quite proud, and although not really a big deal, it is a nice way to start the new year, while we wait for more data from the LHC.
I had just finished writing the 200-lines piece describing the likelihood fit to the mass distribution, when I decided to save the draft with the "publish" box unmarked, to give it a last reading before submitting it. And the crazy web interface logged me off the site instead!
Three weeks of speculations
have come to an end. Since this morning Verlinde's paper is available on arXiv.
Today's visit to the Cornell Arxiv
, the repository where scientific papers on physics, astrophysics, mathematics, and a few other disciplines are made publically accessible before getting published on paper, was a productive one. Some casual browsing allowed me to learn a few random things on topics I know little or nothing about; but what really made my day was reading study by a few distinguished theorists (Vernon Barger, Wai-Yee Keung, and Brian Yencho), who considered a collider signature I had been fantasizing about in the past.