Physics

CMS Discovers New Xi Baryon!

No, unfortunately not yet the discovery of the century. Still, the new particle found by CMS in its 2011 dataset is a very important piece of the puzzle of low-energy spectroscopy. Here "low" should be taken with a pinch of salt: the new particle ...

Article - Tommaso Dorigo - Apr 30 2012 - 10:35pm

The dineutron has finally landed

In a recent PRL article Artemis Spyrou and collaborators have reported on the first observation of an exotic form of nucleons, the long-sought dineutron. Dineutron was predicted theoretically as a short-lived bound state of two neutrons emitted from a nucl ...

Blog Post - Theo Mertzimekis - Apr 29 2012 - 2:15pm

Excited Xi(b) Baryon- New Particle Discovered At LHC

Researchers have discovered a previously unknown particle composed of three quarks in the Large Hadron Collider (LHC) particle accelerator. The baryon known as Xi_b^* confirms fundamental assumptions of physics regarding the binding of quarks.  The baryon ...

Article - News Staff - Apr 29 2012 - 4:46pm

RETRACTED: It's a bug of general relativity

[Retracted: In this blog I hope to get to a well known issue in general relativity, namely that gravitational energy needs to be defined for a spacetime volume instead of at a point.]  The [new] goal is to sketch the Riemann curvature tensor... ...

Blog Post - Doug Sweetser - Jun 16 2012 - 11:03am

What Is The Geometry Of Spacetime? — What Is Space? — Inner-Product Spaces

Since "spacetime" is simply a term for a space that has a component we call "time", we need only concentrate on spaces in a somewhat general sense.  Now, as Derek Potter, on this site, pointed out to me, a little while ago, "To us, ...

Article - David Halliday - Nov 26 2012 - 7:26pm

What Is Entropy?

Entropy. A subject that comes back again and again and again and again and again in this blog. And so does the question in my inbox: " what exactly is entropy? " On the internet you can find a plethora of answers to this question. The quality of ...

Article - Johannes Koelman - May 6 2012 - 1:35am

The Stuff From Which We Are Made

The medium in which light propagates is space. This space can curve. The curvature is not static. So, this space moves. Its behavior can be analyzed by a kind of fluid dynamics. Let us call this method quantum fluid dynamics. It differs from conventional ...

Article - Hans van Leunen - Oct 6 2012 - 5:31pm

The Plot Of The Week- No SUSY In New CMS Search

This week's graph comes from a recent publication by the CMS experiment, the one I am a proud member of together with about 3000 colleagues from all over the world. ...

Article - Tommaso Dorigo - May 7 2012 - 8:30pm

GR versus QFT, Discuss

Since 1930, efforts have been made to get our best theory for gravity- general relativity (GR)- to work with our best theory for atoms- quantum field theory (QFT) in the forms quantum electrodynamics (QED) and quantum chromodynamics (QCD).  In this compar ...

Blog Post - Doug Sweetser - May 7 2012 - 11:06pm

New Exclusive Upsilon Decays Observed By Belle!

The family of Upsilon resonances is among the few things that can always cheer me up and remind me about my fascination for elementary particles when I get bored about my job. The sight of their mass peaks implies that heavy quarks bind together exactly as ...

Article - Tommaso Dorigo - May 11 2012 - 2:58am