Measurements of Jet Substructure

One of the hot topics in the particle theory community at the moment is the use of jet substructure.  Jets are one of the most common types of objects we actually see in colliders: streams of roughly collinear particles.  They arise due to the fact that the strong nuclear force is, well, strong.  The fundamental particles that interact through this force---quarks and gluons---can not exist in isolation.  If you try and pull two quarks apart, for example, the energy in the interaction between them is so great it can spontaneously create more particles from the vacuum.  This means that when a particle collider like the LHC creates a quark or gluon in an interaction, that quark or gluon quickly acquires a number of followers which bind into (meta-)stable particles like pions, kaons, protons and neutrons.

These collections of particles are what show up in the actual detectors.  In older experiments, all we really cared about was the direction and energy of these things, which is roughly the same as the original quark or gluon.  You can do a lot of good physics just on that information alone.  But two things are different about the LHC.  First, the angular resolution of the experiments is much better, allowing us to truly resolve the individual particles within the jet.  Second, the large energy of the collisions leads to new types of events where heavy objects like Ws, Zs and tops can be produced with relativistic velocities.

Apollo 11 Engines to be Recovered

According to the Guardian, the Apollo 11 engines have been found on the Atlantic Ocean floor by a team lead by the Amazon Chief Executive, Jeff Bezos.  He has plans to attempt to recover them, with the goal of placing them on public display.

This is very exciting news.  The Apollo missions were an excellent example of what we can achieve as a species through science and engineering.  The Saturn V rockets are pretty awe-inspiring, too; I saw the one on display at the Kennedy space centre, and it's huge.  But to see the actual ones to propel the first humans to ever walk on another celestial body would be magnificent.  The only problem is that by the time they are put on display, I'll probably have left North America!  But I'm sure I can wangle a visit before or after a conference.

Angband

I was first introduced to roguelikes through Angband.  About three years ago, a friend lent me an old laptop on a long-term basis that eventually became a donation.  (It was a really old machine.)  I found Angband hidden on the hard drive, and started playing it; it wasn't long before I was hooked.

Really Big Microscopes

One natural question for the non-scientist is why we need to build particle accelerators and colliders.  I don't mean why in the sense of what we hope to learn, and why it's important [1]; I mean why these are the best tools for the job.  After all, when most people want to look at something small, they use a magnifying glass or microscope.  What's wrong with just building a more powerful lens to study the smallest scales of nature?

Evil, or Just Stupid?

It's really tempting, as a non-American, to laugh at the problems the USA has with religion.  Of course, no small amount of that is nervous laughter at the prospect that the religious fanatics might get serious power, and then we're all in trouble, but most of it is the hope that we're superior in some way.

We aren't, of course, and news like this reminds us of that fact:

Anti-abortion campaigners in Britain are making controversial claims that abortions are linked to an increased risk of breast cancer, in a presentation to children in school which has been obtained by the Guardian.

 That link to breast cancer?

A study co-ordinated by Cancer Research UK and published in the Lancet has shown that abortion does not increase the risk of breast cancer.

But why let facts get in the way religious dogma?

This group also opposes abortion in the case of rape, saying that it can be a "second trauma".  Well, I'm sure that would be true for some people, but certainly not for all; surely, the only person who can make that choice is the woman involved.

This group also opposes sex education, of course, because why endorse something that stops unwanted pregnancies?  It's almost as if the entire thing is about controlling people's sex lives, forcing those dirty sluts who have sex to be punished, and generally reducing women to the role of breeders!

Now if you'll excuse me, I need to go look at pictures of cute animals till I no longer need to vomit.

It's Impossible to Disagree

I've just found out about Aumann's Agreement Theorem, a mathematical proof that (rational) people cannot agree to disagree.  That's got to be up there with the Banach-Tarski paradox for mathematical results that make me laugh.

Another Tuesday, Another Primary

So Romney has won Illinois by more than ten points over Santorum.

Santorum's failure to win Ohio back on Super Tuesday probably marked the end of his chances of winning the nomination through delegates.  This defeat likely ends his other option, stopping Romney getting a majority and successfully appealing to unbound delegates.  The thing I can't help but wonder, though, is if Santorum himself knows this?  He certainly didn't seem to treat Illinois with the importance it deserved, travelling to Puerto Rico (and promptly putting his foot in his mouth).  Nate Silver suggested that Santorum might have decided to be an honourable second place, angling for Romney's running mate.  Then Santorum accused Romney of lacking a core.

Still, if Santorum really thinks he can still turn things around, I'm not going to complain.  I'll just make some more popcorn.