Physics

Modern physics has disproved direct realism: There is no locally realistic description of our world possible. Although I have already explained this differently at several places, for example by refusing 'real stuff' as being a good explanation for what is ‘at the bottom’, it is worth to prove it once rigorously. Let me present the simplest established proof in the simplest possible version that I can come up with. Everybody claiming interest in the interplay between science and philosophy should have gone through this proof at least once and I did my utmost to make it as easy as possible:…

A question posed by Tony Smith in the thread of the previous post (which dealt with the choice of the bin width in histograms) triggered me to do a little work to produce a convincing answer to him. The issue is the following. Tony got interested in a few top candidate events in a few mass distributions published by CDF and DZERO quite some time ago, which seemed to all cluster in the surroundings of 145 GeV. Could those eight candidate events (once summed across the various channels and experiments) be the signal of some resonance different from top quarks ? There are various ways to address…

I was unaware of the following story, which was brought to my attention by Monica Pepe-Altarelli yesterday. Since I totally agree that nobody should be detained without proof of guilt for long periods of time, and since we are talking of a physicist, I am glad to broadcast the story here. A colleague from LHCb, Adlène Hicheur, of French-Algerian origin, was arrested on 8 October 2009 on suspicion of having contacts with a member of Al Qaeda in the Islamic Maghreb, through internet forums. After being detained for several days for questioning, Adlène was placed under formal…

This blog contains four snaky puzzle questions, their back stories, answers, and discussions. Due to family responsibilities, the video blog must be delayed until at least Thursday.click or skip a reading of this blog: April 18 - Higgs? We ain’t got no Higgs  The Snarky Puzzle Factor B2 - E2. That should remind you of problems back in high school, maybe junior high, maybe first grade if you are Gauss II. Earlier in this post, it was shown how to make a gauge invariant combo of -E + B. When the order of operators flip, only terms with a cross product or curl change signs. Do that here.…

The presentation of data is a very rich subject, on which there is a whole lot to discuss, even by restricting to the issues relevant to our dear field of experimental high-energy physics. Usually too little thought is given to it, even by expert researchers, so I thought that maybe today I would offer here some ideas on one very basic issue, the one of how to choose the width of the bins of a histogram. You all know what a histogram is: a set of bars whose height is proportional to some quantity one wishes to display, lined up along an axis which represents a parameter. For discrete…

Time to reveal the solution to the cat killing mystery introduced in “If Schrödinger's Cats All Die, Do the Alive ones go to Hell?” and further explained in “Rotating Schrödinger's Cat to Death”. The solution is a huge letdown for all cat haters. Instead of being send to hell or at least into a parallel universe where they won’t bother no more, the cats stay right here in our lab! (See Nina – I am not as bad as you think.) Remember, the question was: If we interact with the Schrödinger cat inside the box so that we will only have dead cats result, what do the alive cats see? There must be a…

The measurement of the production rate of top quark pairs at the Tevatron is by now a very well developed technology, where it is hard to invent anything new. Eight years ago, however, there was still the chance to develop new techniques and explore new land. A paper made public yesterday by the CDF collaboration reminds me of one very lucky new idea that I had, together with my then Ph.D. student Giorgio Cortiana, to collect a sample of top pair decays that nobody had yet thought of extracting. The resulting analysis, based on Giorgio's PhD thesis, as well as a few others which followed…

The measurement of the production rate of top quark pairs at the Tevatron is by now a very well developed technology, where it is hard to invent anything new. Eight years ago, however, there was still the chance to develop new techniques and explore new land. A paper made public today by the CDF collaboration reminds me of one very lucky new idea that I had, together with my then Ph.D. student Giorgio Cortiana, to extract a sample of top pair decays that nobody had ever thought of extracting yet. The resulting analysis, based on Giorgio's PhD thesis, as well as a few others which followed…

You may suspect the beating of a dead horse by now, but the problem is actually that the animals in question are still alive. As was discussed, the alive cats expect to see something when the box opens. If we interact with the Schrödinger cat superposition state inside the otherwise isolated box so that we will only have dead cats result, what do the alive cats see? There must be a place into which those cats can jump. However, it cannot be the room where the experimenter observes them, since the experimenter only observes dead cats after having applied the ‘rotation’. Judging from the…

This is a new title: Gotta Get 11 Dirac Gamma Girls, Plus 5 Doing an Imaginary Twist [Note: based on discussions below, I decided to alter the title from "Gotta Get 16 Gamma Girls". The core figure in the blog is not of the 16 gammas in the Dirac basis, but only 11 of them. 5 of them have an extra factor of i. I will have to consult a few articles on the subject to see how they handled this issue.] I spent a year playing around with gamma or Dirac matrices in a relativistic quantum field theory class at Harvard. It was like being at the World Economic Forum at Davos, Switzerland, and…