In a guest post written three years ago Giorgio Chiarelli told us the story of how the CDF detector saw its first proton-antiproton collisions, during the night of October 13th 1985. It was a very important moment for the history of the collaboration, the start of a data collection campaign that would last over a quarter of a century. Below I wish to tell you the story of one of the worst radiological incidents in the history of the experiment, which happened a few months after those first collisions were recorded.


A newly discovered system of two white dwarf stars and a superdense pulsar, all packed into a space smaller than the Earth's orbit around the sun, could allow astronomers to tackle the very nature of gravity itself.

The pulsar is 4,200 light-years from Earth and is spinning nearly 366 times per second – it was found to be in close orbit with a white dwarf star and the pair is in orbit with another, more distant white dwarf. 

The three-body system is scientists' best opportunity yet to discover a violation of a key concept in Albert Einstein's theory of General Relativity: the strong equivalence principle, which states that the effect of gravity on a body does not depend on the nature or internal structure of that body.

This blog is straight old Newtonian gravity. A goal is to understand where the three kinds of masses in Newton's Universal Law of Gravity live in the context of the action.

I been having nightmares (a little exaggeration) on trying to contemplate if the arguments stated in EPR paper may have been correct. It is not clear to me whether Bell really did disprove the hidden variables theory.
Is the reality of Quantum Entanglement still an open question?

If we have two entangled particles A and B as an example, has there been any experiment measuring particle A's and freezing that state for a time and measuring B's value anytime later? Most of the experiments I see are continuous streams of photons or particles, split-ted and fed to detectors. But not two isolated systems clearly showing that "spooky action at a distance".
The DZERO experiment is one of the two multi-purpose detectors that have collected 1.96 TeV proton-antiproton collisions at the Fermilab Tevatron collider until two years ago, when the machine was decommissioned.

Experiments of this kind out-live the demise of the hardware, since the extraction of precise physics measurements from the large datasets accumulated may take several years to complete. And in fact, it is not a surprise to see two new preprints in the Arxiv (here and here) which describe in detail the experimental techniques that the collaboration uses to extract jet physics results from the data.
I'm sorry I've been away so long:  The "press of life" got the "better of me".  Sometimes, life just "gets in the way".  (No excuses.  I simply had other "things" that needed to take priority.  Unfortunately, I don't see that changing any time soon.  So, unfortunately, I cannot promise to have an especially active presence here for the foreseeable future.)

[Note:  Since the creation of footnotes and cross references can be so tedious on this site, I shall go ahead and publish this version of this article without such, at first.  However, I shall endeavor to add such in as I can find the time.  I apologize for the lack of "polish" or completeness this will produce, at this time, but feel it will help me get this out to you in a more timely mann

Physicists at Yale and Harvard have thrown a new curve at Supersymmetry, the popular hypothesis about what lies beyond physics' reigning model of fundamental forces and particles, the Standard Model. And it involves the electron's almost perfect roundness.

The researchers have reported the most precise measurement to date of the electron's shape, improving it by a factor of more than 10 and showing the particle to be rounder than predicted by some extensions of the Standard Model, including Supersymmetry. Supersymmetry posits new types of particles that help account for ideas like dark matter, a mysterious, unknown substance estimated to make up most of the universe.

Another year, another card inspired by what I am thinking about in physics.

Inside the card it reads...

Time is not space,

I met George Zweig at a conference in Crete last Summer. He impressed me with the multidisciplinarity of his interests and his quite entertaining career. He has a degree in mathematics, and did quite a bit of experimental physics work before finally turning to theoretical physics; but he did not stay there for long...

But I do not want to summarize more of the interesting life of Zweig, since there is now an interview with George on the online newsletter of the physics department of CERN, which is quite detailed and fascinating, and deserves a read. Enjoy!

Since the discovery of the charm quark in 1974, physicists have postulated a rare process in which a charm particle spontaneously changes into its antiparticle. Evidence for this behavior was uncovered three decades later by experiments in the US and Japan. However, conclusive observation did not emerge until this year from the CERN laboratory in Switzerland and Fermilab in the U.S. 

What is a charm quark? Protons and neutrons, the particles in an atomic nucleus, are made of smaller pieces called quarks and some types of quarks can form particles that exhibit surprising behaviors.