Physics

The slide below was shown yesterday at an invited talk that Antonio Masiero gave in the University of Bologna, during an open session of the CMS Physics week (see, I am careful to note I am not breaking any rules by showing material relevant to internal CMS business: the session was open!). The slide, inspired by a note by Altarelli at the Lepton-Photon conference this year, summarizes in a strikingly concise way one simple concept: much of our theoretical troubles in the Standard Model nowadays have origin in the Higgs potential V, i.e. the formulation of the energy associated with the…

Can we bring life forms into pure quantum states? Will we ever manage to elevate Schrodinger's cat from thought experiment to real-life experiment? A recent publication suggests the answers to above questions are affirmative. In 1935 Erwin Schrodinger proposed a famous thought experiment in which a cat was brought in a coherent quantum state and thereby rendered alive and dead at the same time. Schrodinger used this thought experiment to illustrate conceptual problems in the interpretation of quantum mechanics. In the years thereafter, and in fact throughout the twentieth century,…

The CDF collaboration has recently released a study of the production of pairs of W bosons in a large bounty of proton-antiproton collisions produced by the Tevatron collider -3.6 inverse femtobarns of them, or roughly 300 trillions, give or take 6%. The measurement of the production cross section of this clean and rare electroweak process (its absolute rate, that is) is the most precise ever obtained so far, and reaches down to a level of uncertainty which cannot be improved further significantly at the Tevatron, because it is now limited by the uncertainty in the overall integrated…

Sometimes I come to think this blog is overextended: it happens when I realize it contains more things than I can remember, even ones I would really like to have at my fingertips. I was reminded yesterday of a very funny story which a reader left in the comments thread of a rather meaningless post, and decided I should make a separate post of it, since it made my day reading it and it might make yours too... The story was told by Leon Lederman in an introduction to Carlo Rubbia in the proceedings of a conference held in 1984 in Santa Fe: "... Now I have some interesting news, a story that is…

Started a unit on Force&Motion with my 5th grade class last week.  So far they are loving it!  My general style is to let them discover and play first, and explain the science behind it later.  If we start out reading about concepts or a lecture style, it generally goes over their heads.  If they have the hands on experiences first- then they can connect the 'jargon' to what they experienced. Day 1: Cups and Pennies LabStudents were given a penny, and index card, and a paper cup (6 oz.).  Step one: Observe the penny.  What is it doing?  Nothing! …

"It is better to treat p values as nothing more than useful exploratory tools or measures of surprise. In any search for new physics,  a small p value should only be seen as a first step in the interpretation of the data, to be followed by a serious investigation of an alternative hypothesis. Only by showing that the latter provides a better explanation of the observations than the null hypothesis can one make a convincing case for a discovery." Luc Demortier, "p values and nuisance parameters", CERN-08-001, p.24.

A few days ago I produced a summary of a poster I presented at Physics in Collisions this week, which dealt with the searches for the Standard Model Higgs boson that CMS will undertake, and the results it can obtain in a scenario when a certain amount of data is collected at the full design energy of the LHC. Here, instead, I wish to summarize the other poster I presented at the same venue, which concerned the combination of the most sensitive search channels, the sensitivity of CMS with a given amount of data, and the derating of its significance reach or observation power entailed by the…

Was an almighty God required to boot up the universe, or would a blindfolded monkey have sufficed? What a silly question. Isn't it obvious that truly divine powers were needed to create our amazing universe capable of evolving systems of supreme complexity called 'life'? Maybe. Maybe not. It all boils down to the question: How special was the big boot, the mother of all boot-ups commonly referred to as the big bang? Physicists have a well-defined and precise measure that describes how special, or rather how common, the state of a system is. This measure is called entropy. A system with high…

The Physics in Collisions conference in Kobe is over, and I am packing up. Tomorrow morning I will leave from KIX to FRA, and later FRA to VCE, hopefully making it home for dinner. I learned a few interesting things on physics at the conference, and I hope I will share some of the highlights with you in a post tomorrow. But I also learned quite a few things about Japanese culture, which probably was a more valuable experience for me. For now, I will just offer you the picture below, which portrays a rather overaged student in front of his two posters. Regulars of this site will not fail to…

This morning I attended the first session of the Physics in Collisions conference in Kobe, which dealt with Electroweak Physics. The four talks I could listen to were all of very good quality, and I am not ashamed to say that I did learn a thing or two, despite this is a field of investigations on which I have focused for over a decade. Also, I decided that conferences featuring few, long talks are definitely better than ones which try to cram dozens of small contributions in tight schedules: at least, the session conveners are not required to play the watchdog and struggle to keep people…