Physics

With the approach of Summer conferences -most notably, ICHEP, which alone has set a make-or-die deadline for the LHC experiments- physicists in ATLAS and CMS are frantically producing their results with data collected in 2012. There is a lot at stake. Even leaving aside the Higgs hunt for a second, just imagine you are looking in a specific dataset for a high-mass new particle which most likely does not exist: you want to place "upper limits" on the mass M of the particle which are more stringent than previously published analyses. This is done by reconstructing the tentative mass of the…

This G is with us since last centuries. Of course, it is Newton gravitation constant. Traditionally it is written using a capital G, and yes! it is a big G!But this one, every universal constant in well known and calculated accurately. Why is this? G can be only measured by direct calculations. Since gravitation force is the weakest one -the force the Earth attracts an apple can be overcome with your hand, G is elusive... Scientists have made efforts to get its value as much accurately as possible.Newton did not measure the constant but henry Cavendish years later (1798). His instruments gave…

Two days ago I discussed at ICFP 2012 the most recent results of the CMS experiment at the CERN Large Hadron Collider. In the allotted time of my talk I could only cover few analyses, and I obviously chose some of the most interesting ones, so that was already a summary. Here I am bringing the information collapse one step further, by giving a itemized summary of some of the points I made, just in case you are interested. If you want to, you can also download the original slides of my talk from here (but be careful, it's a 8Mb file). - The LHC has yielded over 5 inverse femtobarns of proton-…

Everyone's introduction to quaternions always has the same math one-liner: This blog will dive into an issue that has bothered me for years, namely that the line assume the only coordinate system that can be used for quaternions are both normal and orthogonal.  It is the later property that stumped me, and I made a small step forward I will report on. It is convenient to work in orthonormal coordinates.  Really, really convenient.  Without anyone bothering to state as much explicitly, being orthonormal is assumed.  What happens if the coordinates are neither orthogonal…

The International Conference on New Frontiers in Physics (ICFP) 2012 started today with a rich program of experimental and theory talks. I should be swimming in the Cretan sea in front of the nice conference venue (which is 40 meters away from the water), but my sense of duty forces me to give you some impressions of the presentations I heard.So the opening talk this morning was given by Babis Anastasiou (see picture below), who discussed the state of the art of Higgs boson production rate calculations at the LHC. He started by describing the various production modes for Higgs bosons.…

The island of Crete, in the middle of the Mediterranean sea, is home to ICFP 2012, a conference in high-energy physics. I arrived yesterday night and this morning I woke up with a gorgeous view of the sun rising over a blue sea. (The picture shows a beach not far from here, which I'll visit on Wednesday. It is called "Balos beach" and it is a wonderful place). The conference should be interesting. In exchange for a report of new results of the CMS experiment -which are indeed new, but are still based on 2011 data- I will get to hear what is going on in the field. I plan to update the blog…

Last Transit of Venus was more fruitful than could be expected. Thousands of amazing images were taken and this is just enough to appreciate the high point of the event. Things more physical or astronomical were also concluded from it, of course.One of these was the recalculation of the Astronomical Unit (au). As you may know, the astronomical unit is defined as the distance between the Sun and the Earth. Then the Sun is 1 au far away from the Earth. The nearest star to our Sun, the red dwarf star called "Proxima Centauri" is 268,000 au from the Sun. AU definition as the distance between the…

Cosmological Constant - it's the blog's title, but something more, As you may know, Einstein himself called it his greatest blunder. Why did he say these words? Let us see...When Albert Einstein developed his General Theory of Relativity he found out that the Universe was expanding... Eh? Yes! Galaxies are moving away each other. He thought this was not possible because his working model was a perfectly spherically symmetric one. To stop this expansion (well from a mathematical point of view) he modified the equations and to get a stationary universe. This modification was carried out by the…

The CERN average of searches for rare B decays to muon pairs has been shown yesterday in a talk given by Mitesh Patel at the "Physics at the LHC" conference, which is being held in Vancouver (BC) this week. And the results are not very encouraging for supporters of Supersymmetry: the data is compatible with a Standard Model signal, but there is almost no space left for additional contributions due to the exchange of virtual SUSY particles in the loops producing the decays. The B_s meson decay to muon pairs has been one of the most appealing channels to search for effects of new physics in the…

The fourth FQXi essay contest “Which of Our Basic Physical Assumptions Are Wrong?” is underway.   Wittgenstein knew precisely which one; I am all about that one as you may know, but we are idiosyncratic, of German culture, and incomprehensible to many. Thus I humbly ask you to return the sweat I have put into this already and please criticize the following constructively in order to help me to get the difficult message across. Tell me where the text starts to sound awkward / idiotic / unintelligible/ hopelessly nonsensical; tell me in the comments or privately. All suggestions are…