A Quantum Diaries Survivor

Just as you thought it was over for 2011, and you proceeded to hung the Higgs mass plots on the christmas tree as a wish for stronger signals next year, ATLAS comes out with a new particle discovery. That's what I like of particle physics - there's always so much going on that the excitement is never really over.

NASA is featuring the first high-resolution images of asteroid Vesta as taken by the DAWN spacecraft during a low-altitude orbit. The images show a very interesting surface, battered with old and more recent craters, plus "textures such as small grooves and lineaments that are reminiscent of the structures seen in low-resolution data from the higher-altitude orbits. Also, this fine scale highlights small outcrops of bright and dark material." (from the NASA piece).

Have you ever looked at a histogram with the data displayed as counts per bin in the form of points with error bars, and wondered whether those fluctuations and departures from the underlying hypothesized model (usually overimposed as a continuous line or histogram) were really significant or worth ignoring ?

Have you ever looked at a histogram with the data displayed as counts per bin in the form of points with error bars, and wondered whether those fluctuations and departures from the underlying hypothesized model (usually overimposed as a continuous line or histogram) were really significant or worth ignoring ?

Particle physics experiments usually invest a considerable part of the time used to produce a measurement in the task of determining the corresponding uncertainty on the estimate, or -when a new effect is observed (say a quantity is measured away from zero, when zero would be the "null hypothesis", predicted by the current model)- estimating the statistical significance of the observation.

Another confirmation of correct evaluation of controversial HEP measurements awaited me just after the Higgs evidence was presented at CERN. I am sort of embarassed by this compulsory self-promotion, but this is my blog so I will excuse myself ;-)So the story is the following... Some of you might still remember the controversy over the Omega b discovery, at the Tevatron a couple of years ago.

Eilam Gross is a professor of Physics at the Weizmann Institute of Science of Rehovot, Israel, and a distinguished member of the ATLAS collaboration. That makes him a competitor, since I work for the other experiment around the ring, CMS. But Eilam is also a colleague, especially since we are members of the Statistics Committees of our respective experiments and we cooperate in a joint group to try and converge on common practices for statistical procedures in data analysis at the LHC. Ah, and- I forgot to mention he is the convener of the ATLAS Higgs group| So I am very pleased to feature his own take on the LHC results on Higgs searches...

Updates:- Philip Gibbs does a great job, as always, at combining -albeit approximately- the results of different experiments in the Higgs search. He now has even a full combination of LEP II + Tevatron + CMS + ATLAS, where the signal strength, in SM units, fits absolutely bang on for a Higgs mass of about 125 GeV. Please see his article at the link above; but I cannot resist from stealing his most intriguing picture (sorry Phil!):

I received the text  below from Jim Markovitch, and decided it was fun enough to make a guest post entry with it. Markovitch worked for the world's largest supplier of corporate credit information, where he designed and implemented algorithms to estimate the probability of the equivalence, for credit purposes, of two name/address records. More recently he has adapted these algorithms to help identify unusually efficient approximations of fundamental constants. Let us see what this is about - TD---

Every once in a while Lubos pleases with one of his straight-leg tackles, as he deals with stuff he shouldn't be a-messing with (I am still giggling at an incident of a few years ago, when he publically apologized after a week of nonsense). Today it's one of those blessed moments.

It is so annoyingly sweet to be right, when being right means that one's job is not going to become more exciting in the near future... Today CDF published their analysis of CP violation in the Bs sector, where a very exciting three-sigma deviation from the Standard Model predictions had been a bit prematurely and uncautiously claimed by a group of phenomenologists in 2008.

As everybody knows, next Tuesday we will be treated with a CERN webcast of the analysis results on the Higgs boson searches by ATLAS and CMS. I imagine many of you will want to tune in, but fear you will not grasp much given the typically technical jargon that physicists use to communicate the details of their analyses. So I thought I would provide here a very short glossary of terms you are likely to hear, and which you might have a hard time understanding correctly. Let me see if I can do a decent job.