Physics

Time for a quick compare-and-contrast. Here is what "Physics Today" lists as their top stories and most popular articles for July 2009:

Scientists at Penn State University, in collaboration with institutes in the US, Finland, Germany and the UK, have figured out the long-sought structure of a layer of C60 – carbon buckyballs – on a silver surface.  The results in Physical Review Letters and Physics  could help in the design of carbon nanostructure-based electronics.

Ever since the 1985 discovery of C60, this molecule, with its perfect geodesic dome shape has fascinated scientists, physicists, and chemists alike. Like a soccer ball, the molecule consists of 20 carbon hexagons and 12 carbon pentagons. The electronic properties of C60 are very unusual, and there is a massive research effort toward integrating it into molecular scale electronic devices like transistors and logic gates.
One year ago, a paper by a distinguished group of theorists announced first evidence of new physics from measurements of the properties of B_s mesons performed at the Tevatron by the CDF and DZERO experiments. They had combined all the available information, obtaining a result which disagreed with the Standard Model (SM) prediction by more than three standard deviations.
An article in the latest (August 2009) edition of Scientific American describes an astronaut floating motionless with respect to his distant spaceship. He is not tethered to the spaceship and has no objects available that can be hurled away or can in some other way create a thrust.

How is he ever going to make it back to his spaceship?
A new paper on the ArXiV caught my attention this evening for several reasons. First of all, because two of its five authors (J.Ellis, J.R.Espinosa, G.F.Giudice, A.Hoecker, and A.Riotto) are (or have been) my colleagues in Padova University; second, because the title is quite catchy; third, because indeed the results it presents are valuable food for thought.
"Other people's data ntuples are a bit like their genitals. You may occasionally be allowed to play with them, but you should not expect to be granted unhindered access."

Unknown (the previous attribution to M. F. is fallacious)
In Toledo, Ohio on June 26, 1914 -- a star was born. He was named Lyman Strong Spitzer, Jr. for good measure. An asteroid, a space telescope, and a building in the Princeton Plasma Physics Laboratory (PPPL) bear his name today. His theoretical and applied research contributions shaped three fields of science, namely, interstellar matter, the dynamics of star clusters, and the physics of plasmas.
In this two-parts article I wish to describe in some detail, but still at an elementary level, the characteristics of one of the most important probes of the physics of subnuclear collisions at today's particle physics experiments: jets of hadrons originated from energetic bottom quarks, or more familiarly, b-jets. By posting a dedicated article on b-jets, I hope I will be able to describe in more detail elsewhere other physics topics, such as Higgs boson decays or top quark signatures, without being hampered by having to introduce the phenomenology and detection of b-jets from scratch every time.


As silly as it may look, I am going to start this post by publishing for the third time in a row the same figure. That is because I want to keep the promise I made earlier that I would explain in terms as simple as possible (although not simpler) the details hidden behind the coloured curves and functions pictured there. I will also take this chance to come down a little from the level of technicality of the recent posts: after all, this blog is supposedly for everybody, and not just for Ph.D. students and recipients.



Stars don't die without being noticed and sometimes the results are pretty spectacular.  At the end of its life cycle, a star begins to collapse and throws new material into space, which eventually becomes incorporated into new planets and life.