Jason Underdown’s Blog

I found this article in today’s New York Times to be very fascinating:
The Subconcious Brain – Who’s Minding the Mind?

Michael Peskin recently posted an article to the arxiv entitled “Dark Matter and Particle Physics”. The article is an almost layman’s guide to how the WIMP model of dark matter might soon be partially validated experimentally at the LHC.

In the article he outlines the reasons why most matter in the universe is dark or in other words does not emit light or radiation, and thus is normally only detected via its gravitational effects. He then goes on to describe the WIMP model for dark matter and its predictions. Next he talks about how the LHC might detect WIMPs:

The discovery of events at the LHC with apparent unbalanced momentum will signal that this accelerator is producing weakly interacting massive particles. However, it would be far from clear that this particle is the same one that is the dominant form of matter in the universe. To demonstrate this, we would need to correlate properties of the WIMP that we observe at the LHC with astrophysical observations.

There are two possible ways to observe WIMPs outside of the LHC. First is the direct approach of observing the scattering of a WIMP from a nucleus in an extremely sensitive detector located deep underground in a mine to minimize noise. The second method is to observe gamma rays emitted from pairs of WIMPS annihilating each other. These gamma rays should have a characteristic spectrum and be most commonly found coming from parts of our galaxy where the concentration of dark matter is highest, namely near the center of the Milky Way.

If the mass of the WIMP seen at the LHC is the same as the mass from astrophysical detection experiments, this will provide strong evidence that the LHC is producing the true particle of dark matter.

Thanks to Hwasung “Mars” Lee for pointing out this article in his blog.

If you would like a great summary of differences between versions 2 and 3 of the GPL check out Mark Radcliffe’s blog post: General Public License Version 3: A Legal View on his blog entitled Law & Life: Silicon Valley.

I added an RSS feed to update anyone interested on changes I’ve made to my Math and Physics flash cards page.

In my last post, I mentioned that I had created some flash cards for Real Analysis that had definitions on them. I recently created a set with many of the relevant theorems, and I will be updating them as the summer progresses. Thanks to Erin Chamberlain for providing the source TeX code for the theorems. You can find them at

http://www.physics.utah.edu/~jasonu/flash-cards/

Enjoy!

I’ve been busy this summer studying Real Analysis, and in the process I’ve made a set of printable flash cards in PDF format. They’re still a work in progress, but I have over 90 cards full of definitions. Cards with theorems on them will probably come some time later. The pictures below show what the typical front and back of a card look like.