Quite some time ago I discussed here the tentative Y(4140) resonance  claimed by the CDF collaboration in their Run II data. This was a peak which was found in B-decay data containing a J/Psi signal, a phi meson, and an additional kaon track, and it resulted from the  study of the mass difference of the J/Psi + phi signal and the J/Psi alone.

Confused ? You have all rights to be. I will explain everything in good order, but be sure that the matter was puzzling not only for laymen but also for insiders: because the find was mysterious, not predicted by existing models, and potentially controversial.

B Decays and the CDF Claim

The Omega_b particle is a quite peculiar baryon, made up by three heavy quarks: a b-quark, and two s-quarks. Because of this composition, where only down-type quarks appear, the phenomenology of the decay of this particle is really spectacular: both the b-quark and the strange quarks take quite some time to decay, and as they take shifts to do it the Omega_b first transmutes into a Omega (a particle made up by three s-quarks!), then into a Lambda, and finally into a proton.

Each of these decays generates a reconstructable decay point, so one can reconstruct the whole chain perfectly. A sketch will clarify matters - see below.

Nowadays whenever I set out to write about CMS I turn on a self-censorship co-processor in the back of my mind, one which is instructed to check that all the sentences I write are completely free from any possible misinterpretation or slant that may cause some colleagues to complain. Oh, strike that, we're a big family and we all love each other.

The topic of today is in fact potentially explosive - how experiments perform their blind searches and the potential bias that results from the detailed procedures they employ. However, you will be disappointed by reading this article if you search for scandal and flame: I am going to explain why CMS does excellent science.

Today the arxiv features the paper describing the final word by the CDF experiment on its searches for the standard model Higgs boson. This paper supersedes previous ones describing searches performed in partial datasets and including only a subset of the decay channels that have been used, so if you are interested in knowing how CDF did in the end, that is the article to read. Or the present one, if you have less time to spend on the matter, or if you are interested in an ex-post evaluation of sensitivity predictions!

The DZERO collaboration has released last week the result of their search for the rare decay of B_s mesons into muon pairs, based on the full statistics of proton-antiproton collisions acquired during Run II - a total of 10.4 inverse femtobarns of integrated luminosity.

Sabine Hossenfelder is a well-known theoretical physicist as well as a successful blogger. In her blog today I read a letter she sent to Time Magazine. The letter was triggered by the following sentence in a piece by Jeffrey Kluger discussing the runners-up for "person of the year":

“Physics is a male-dominated field, and the assumption is that a woman has to overcome hurdles and face down biases that men don’t. But that just isn’t so. Women in physics are familiar with this misconception and acknowledge it mostly with jokes.”