Physics

A couple of weeks ago I reported here about the new measurement of the Higgs boson mass produced by the ATLAS experiment. That determination, which used the full dataset of Run 1 proton-proton collisions produced by the LHC in 2011-2012, became and remained for two weeks the most precise one of the Higgs mass. Alas, as I wrote the piece I already knew that CMS was going to beat that result very soon, but of course I could not say anything about it... It ached a bit!

In cosmology, cold dark matter is believed to be a form of matter which moves slowly in comparison with light and interacts weakly with electromagnetic radiation. It is estimated that only a minute fraction of the matter in the Universe is baryonic matter, which forms stars, planets and living organisms. The rest, comprising over 80%, is dark matter and energy.


In quantum physics, you can't precisely measure momentum and position simultaneously. They are an example of conjugate variables, connected by Heisenberg's Uncertainty Principle. There are workarounds, such as "weak measurement," to measure both at the same time but a new study says that a technique called compressive sensing also offers a way to measure both variables at the same time, without violating the Uncertainty Principle.


Do you remember the top quark asymmetry measurements of CDF and DZERO ? A few years ago they caused quite some excitement, as both experiments were observing a departure from standard model expectations. This could really be the place where one would first observe new physics associated with top quark production, so the analyses triggered quite some theoretical investigations, deeper studies, and model building.

By trapping a magnetic field with a strength of 17.6 Tesla, roughly 100 times stronger than the field generated by a typical fridge magnet, in a high temperature gadolinium barium copper oxide (GdBaCuO) superconductor, researchers not only beat the previous record by 0.4 Tesla, they harnessed  the equivalent of three tons of force inside a golf ball-sized sample of material that is normally as brittle as fine china. 


You wouldn't think that mechanical force, like kicking a ball in the World Cup or embossing letters on a credit card, could process nanoparticles more subtly than the most advanced chemistry but a current paper in Nature Communications describes a now patented method to use simple pressure — a kind of high-tech embossing — to produce finer and cleaner results in forming silver nanostructures than do chemical methods.

All without harmful byproducts to dispose of.


What is believed to be the smallest force ever measured, 42 yoctonewtons, has been detected by at the Lawrence Berkeley National Laboratory.

A yoctonewton is one septillionth of a newton and there are approximately 3 x 1023 yoctonewtons in one ounce of force.
 That's tiny. Using a combination of lasers and a unique optical trapping system that provides a cloud of ultracold atoms, the researchers detected the minute force.


The Higgs boson was detected using its decay into bosons but scientists from the CMS experiment at  the Large Hadron Collider have found evidence for the direct decay of the Higgs boson into fermions.

If the Higgs particle can decay into both bosons and fermions, we can exclude certain theories predicting that the Higgs particle does not couple to fermions. As a group of elementary particles, fermions form the matter while bosons act as force carriers between fermions.  


The Cornell arxiv is known to not accept preprints without a minimal screening of their contents. Still, I am sometimes led to wonder if a similar attention is paid to the liberty that authors at times take with the titles of their papers.

I am officially on vacation since yesterday, so you should not expect the list below to be a very comprehensive one. I just offer four examples of titles that might have been considered for some form of moral suasion toward the author by the arxiv managers, but apparently haven't. I just quote some titles below which struck me as kind of odd.
After great pains to simulate the foreground dust the Cosmic Microwave Background, gravitational wave result of BICEP2's B-Mode observations is still in question.  The simple fact is we do not really know what the foreground dust contamination really is right now.   The PLANCK collaboration will release that data, and sometime this year, their own map of CMB B Modes.   PLANCK's release of a real foreground dust map, not one based on a presentation slide, which is what the BICEP2 team first used, will settle this once and for all.    All of that said, the work of the BICEP2 team is good and worthy science, weather they are shown to be right, wrong, or only partially right  (i.e. if there is an effect but not as big as they claim).