Physics

Microwaves are a low frequency light, at least compared to visible light, say, or ionizing radiation like gamma rays. Thus, microwaves are quite harmless. A microwave oven baths the food in an oscillating electro-magnetic field. Molecules with permanent electrical dipole moments wiggle in the field and thus heat up the food. Ok, lets google “microwave danger”. Wow, a barrage of pseudo-science about how microwaves slowly kill you and your family. Microwaves supposedly distort the molecules and natural energy in the food and of course, they were invented by the Nazis during the third Reich –…

As beautiful as they get, or even more so. It is hard to express the beauty of the event that the CMS collaboration published today. CMS, which stands for "compact muon solenoid", is one of the two main detectors operating at the CERN Large Hadron Collider (the other is ATLAS). The duo is seeking evidence for the Higgs boson, the only elementary particle predicted by the Standard Model that still awaits to be discovered. CMS is a multi-purpose detector, with very strong tracking and electromagnetic calorimetry in addition to the excellent muon system which gives the M in the acronym. All of…

Giorgio Chiarelli is a particle physicist. His research activity has been based largely at the Fermi laboratory near Chicago, US, at the CDF experiment. In 1994-96 he actively participated in the discovery of the top quark and in the first measurements of that particle's properties. Later, after directing the construction of a part of the new CDF detector, he moved its research interests toward the search for the Higgs boson. Currently he is a INFN research director in Pisa, where he leads the CDF-Pisa group. In the most recent years he dealt with problems connected with the communication of…

The ATLAS collaboration has just released an important study of the sensitivity to a standard model Higgs boson. For the first time precise predictions are made for LHC running at a centre-of-mass energy of 7 TeV (but also 8 and 9 TeV are considered, given the possibility that next year the energy is bumped up a bit), and for most of the sensitive channels together. The public document is long and detailed, and I have no time to discuss its intricacies with you here, nor do I believe that you would actually want me to. But I do want to discuss one of the most significant figures in the note.…

Special Guest Post From A Far Boundary Of Our Universe By Richard P. Flatman "I call our world Flatland, not because we call it so, but to make its nature clearer to you, my happy readers, who are privileged to live in Space." This is how my great-grandfather, Albert Square, started his memoirs. Memoirs he wrote in solitary confinement. Years later he died, still imprisoned and alone, and unaware that his ideas slowly but steadily started to change the views and imagination, not only of his fellow Flatlanders, but also of you Spacelanders.*  How time has progressed! My great-…

News from the LHC: the integrated proton-proton luminosity at 7 TeV centre-of-mass energy has generously passed the mark of 40 inverse picobarns yesterday. The CMS experiment alone has integrated over 42 inverse picobarns, as shown in the graph below (the blue curve shows the data collected by CMS, the red one the data produced by the LHC). The closeness of the two curves demonstrates how the CMS experiment is operating at full functionality, collecting data with high efficiency. Actually, it should be mentioned that a 100% data collection efficiency at a hadron collider is not the best of…

In one description, an observer falls freely through empty space, in another one, she hits a surface smack on, yet both descriptions are completely equivalent. This example for a duality in modern physics was explained the last time in this series. There we saw that a black hole can also be described by a string theoretical membrane at the event horizon. The observer cannot escape the black hole because she literally gets stuck to the black hole’s event horizon, glued to it via strings.Now it is obvious that this second description of falling into, or here better onto a black hole has no…

Physical reality is composed of properties like distance, duration, velocity, area, volume, mass, energy, and temperature. To quantify these properties you need to measure them. And the act of measuring boils down to comparing against an agreed yardstick, a unit of measurement such as a foot, a gram, etc.  Do you need a dedicated yardstick for each quantifiable property? Would the answer to this question be 'yes', then physics as we know it, would not be possible. We would not be able to relate the various properties to each other, physics laws would not exist. Fortunately, the answer to…

The CMS experiment has just released a new result which excludes the possibility that quarks have a substructure at energy scales below 4 TeV. The result comes from the analysis of just a handful of inverse picobarns of collision data -2.9 to be precise- and shows excellently just how well suited are the LHC collisions for this business. The limit is extended by over one TeV above the former result of the Tevatron experiments, and some 600 GeV above the results of the ATLAS collaboration, who also recently reported on their search for of quark compositeness in 7 TeV collisions, finding a…

Week number one of my course on Subnuclear Gauge Physics is over. I think that in the first five hours of lesson I have given to my students a reasonable picture of the early experimental attempts and theoretical developments aimed at understanding the structure of atomic nuclei and individual nucleons with electron scattering. So I thought I might try and simplify the picture further, to reach a wider audience here. Of course, the topic is not terribly entertaining, unless one understands fully just how important these studies are for fundamental physics even nowadays -despite having started…