A Quantum Diaries Survivor

I reported two days ago on the new measurements by the CMS Collaboration of the decay of B hadrons into muon pairs, revealed at the opening of the EPS 2013 conference in Stockholm and in a preprint. Funnily, I wrote the piece oblivious of the LHCb result, which is basically equivalent (in importance, precision, and sensitivity) to the CMS one; when I found out that LHCb had also a comparable result, I made up for that by pointing out the LHCb result in a "UPDATE" at the end of the post - I did not want to rewrite half of the piece!

Today I am quite happy to report of a new groundbreaking result from the CMS collaboration at the CERN LHC - the experiment to which I devote 100% of my research time. We published overnight a report on the Cornell arxiv, and will present this week at the EPS conference in Stockholm, of the observation of B_s meson decays to muon pairs, an exceedingly rare process which is of extreme importance for the searches of new physics beyond the standard model. And in so doing, CMS now leads this race, with better results than LHCb and ATLAS. (UPDATE: but see below, at the bottom of the article).

When we want to combine several estimates of a physical quantity, to obtain a more precise one that accounts for all inputs in the correct way, we routinely rely to the weighted average: we take each of the N independent, Gaussian-distributed measurements x_i +- σ_i (i=1,...,N) and compute with them the quantityto which we associate the error shown on the right above. The recipe above is simply the result of applying the method of least squares, or -equivalently- of a likelihood maximization.

When we want to combine several estimates of a physical quantity into a more precise one that accounts for all in the correct way, we routinely rely to the weighted average: we take each of the N independent, Gaussian-distributed measurements x_i +- σ_i (i=1,...,N) and compute with them the quantityto which we associate the error computed asThe recipe above is simply the result of applying the method of least squares, or -equivalently- of a likelihood maximization.

When we want to combine several estimates of a physical quantity into a more precise one that accounts for all in the correct way, we routinely rely to the weighted average: we take each of the N independent, Gaussian-distributed measurements x_i +- σ_i (i=1,...,N) and compute with them the quantityto which we associate the error computed asThe recipe above is simply the result of applying the method of least squares, or -equivalently- of a likelihood maximization.

The querelle on the device patented by Andrea Rossi, the E-CAT, which allegedly produces heat from nuclear fusion processes inside a small cylindrical reactor fueled with Hydrogen and Nickel powder, continues to draw the attention of the gullible as well as that of the knowledgeable. It is just entertaining to both!

Thanks to a Facebook friend, I got to give a look today at a very interesting pair of graphs. The first one shows the number of researchers per million inhabitants divided by country, in a world map. The second shows the fraction of female researchers. The data comes from UNESCO, and is based on surveys dated 2011.

This morning I had a funny dream, and as I woke up at the end of it and watched the clock with the only eye I had managed to open, I realized it was not yet really time to wake up. On the other hand, I really liked the dream I had had: it was quite vivid and detailed, plus it lent an occasion for a blog post! Hence I crawled out of the bed and reached for the nearest laptop in order to download the contents of my mind before it made room for something else and the dream got lost forever.

Like HAL 9000 in the wonderful movie "2001 -  the space odyssey", the CDF detector is being disassembled piece by piece, losing its functionality bit by bit, and turning from one of the most complex electronics systems ever built into a pile of junk in the course of a long, slow process. The central part of the detector has been transported out of the collision hall on rails, into the assembly hall, which is now serving the opposite purpose. If you ever visited Fermilab, the assembly hall is inside the big orange building you drove by as you got to the Wilson Hall from the east entrance.

Jacques Distler is a Professor of Physics at the University of Texas at Austin, and a distinguished theorist, as well as a physics blogger. Along with experimentalist Gordon Watts (who covered $250) he took my $1000 bet that the LHC would not discover new physics in its first 10/fb of proton-proton collision data. I discussed my take on the bet in a previous post; here Jacques explains his point of view, why he took the bet, and what he thinks of the present situation with new physics searches at the high-energy frontier. The article below has appeared today at Distler's blog, and I reproduce it here with his permission.

In September 2006 I was in Ponta Delgada, the main town of the island of San Miguel in the Azores, for a physics conference where I was presenting results of the CDF experiment. I remember listening to a very nice talk by Guido Martinelli, who was discussing the status of flavour physics, and getting rather depressed at the view of a very consistent picture of agreement between B physics observables and Standard Model predictions. This came at a moment when the CDF experiment had been probing the high-energy frontier with very detailed measurements, none of which appeared to show even the smallest glimpse of a departure from model predictions.

A thick paper by the ATLAS collaboration has been published by the Cornell Arxiv today. It is going to become a reference to all ATLAS analyses searching for new phenomena at high energy, or studies of boosted top quarks or vector bosons; and a good example of the new techniques that make sense of the energy distribution inside high-momentum jets.