Neutron Star Wakes up and Stretches

I saw this article hit the mainstream press today, “concerning the huge emission of gamma rays back in December by a neutron star on the other side of our galaxy”: If we dig a little bit on this, we soon find mention of the “SWIFT”: gamma-ray burst (GRB) probe. A quick peek at the page they’ve setup concerning this once-in-a-lifetime event reveals a “nice array of illustrations and information”:

Not too bad. I like the point that was made about being thankful for the distance of this event. Too close, and a spectacle like this one can lead to mass extinctions on a world like ours. Good thing there aren’t too many restless neutron stars is our unfashionable western arm of this spiral galaxy.

What is a neutron star? Take a star like ours, but make it 20 times more massive. When a star like that gets very old, it burns out most of the nuclear fuel that is the source of its abundant energy. There comes a time when the outward pressure of the nuclear reactions can no longer counterbalance the gravitational pressure of the massive star, and it collapses.

This star’s collapse will cease when the electrons in its hydrogen get so close that Fermi pressure, a purely quantum mechanical effect, overcomes gravity and holds the star from collapsing completely. It’s amazing to me that this Fermi pressure, exerted when two electrons get too close to being in the same quantum state, is capable of overcoming the sheer brute mass of such a star.

That isn’t the end of the story. The core of the star fuses into iron, and this continues until the core is so large that gravity again overwhelms the star. It becomes energetically preferable for inverse beta decay to now occur. This is the process by which electrons and protons interact and produce neutrinos and neutrons. The neutrinos, untethered to the neutrons, escape the star (and can reach us, telling us about the star that birthed them!) while the neutrons remain bound in the star remnant. Again, if the star wasn’t too much more massive than originally posited, the neutron Fermi pressure will counterbalance gravitational collapse and sustain the star as a dense ball of neutrons. This is our neutron star.

I thought a neat resource for information about this phenomenon was “Dr. M. Coleman Millers”: site.

Coming down from the high

It’s been a remarkable week. First, I got back into my research at full speed and it felt **great**. Second, the reality of the President’s FY06 budget proposal has hit home. While the U.S. particle physics community, especially the national lab programs, is vigorously discussing the implications, some consequences have already become clear.

I think that my friends at “Fermilab”: are going through the most visible discussion right now. I was pointed to a “Fermilab Today article”: by a SLAC colleague, and it details the all-hands meeting the FNAL director gave yesterday, as well as Q&A at the end.

Fermilab is talking about staff reductions. They’ve already suffered the cancellation of the BTeV project. As the director, Mike Witherell, notes the focus of the lab’s physics research future is narrowing, along with the whole U.S. field, to neutrinos. I have a lot at stake in the health of neutrino physics research in the U.S.; my own developing career is tied to a proposed project. However, I see the point that this raised in the all-hands meeting. Where once a vibrant U.S. community of particle physicists participated broadly in a large number of topics – electroweak physics, QCD, large-scale nuclear physics, heavy and light quark physics – the discussions in the community, which trickle up into the decisions made by our guiding bodies (HEPAP and the P5), seem to be narrowing to neutrinos.

Ironically, if you look at the major discoveries in our understanding of the neutrino, the last two decades has premiered the dominance of Japan and Europe in this topic. While the neutrino was discovered by U.S. physicists, illumination of its deepest properties came from experiments like Super-Kamiokande. It seems the U.S. is trying to reassert itself in this field, and while I believe it is a rich and rewarding topic I worry that we’re going to hemorrage expertise in other topics to Europe and Asia. I welcome international collaboration, but I fear that the U.S. physics community will feel like rats on a sinking, burning ship.

The President and the Congress make a lot of very difficult decisions. Some of them landed us in the budget shortfall that we now face. To make up for that, it seems we’re taking chunks out of programs which make America worth defending. The largest cuts in the present FY06 proposal appear to be in Education. Many other departments, including the Department of Energy, are also trimming. While some targeted programs have fared well this year the broad vision of U.S. leadership in science is being sacrificed. I hope that the tough decisions that our leaders now make, tempered with the advice of the People, are not based on the kind of short-sightedness that seemed prolific in American government as this century began.

What the government needs to remember is that sometimes you have to go into debt to make a statement. California did this with stem cell research. If I look at our national budget, I see a statement that seems a bit misguided: the war above all else, because we’ll make it up from cuts in social programs, education and science.

Research High

I’ve been a bit glum these last few weeks. At first I wasn’t able to exactly pinpoint the problem, but given how well I’ve felt this week I think I’ve figured it out. I needed research, and I needed it **bad**.

Don’t get me wrong. I enjoyed my time at MIT, working on simulations for the neutrino experiment I work on in my “spare time”. But that’s simulation, not data. With the “BaBar”: experiment, I get my data fix. Oh yeah, I am a serious data-junkie, and this week I’ve started getting my steady I.V. drip once again.

I’ve got a pretty cool little project that I’m working on in conjunction with a “theory colleague”: of mine at UC Davis. I’m hoping to wrap it up for the summer, but I haven’t had a chance to work on it until this week. And boy, does it feel good. I’ve even got a plan all laid out for understanding the efficiencies of my analysis, a key ingredient in the extraction of the final result from the data.

What is that data? Well, that’s a good question. BaBar is a three-story-tall, multi-ton particle detector built around the collision point of the PEP-II electron-positron collider. PEP delivers high-intensity (*luminosity*) beams of bunched electrons and their anti-matter counterparts, positrons, and tries to smash each bunch together once every 4 nanoseconds. Electrons and positrons are so small that even with billions of them per bunch, we’re fortunate to get even one matter/anti-matter annihilation per crossing.

Each annihilation yields pure energy, energy whose value is roughly equivalent to that present in our universe when it was but a millionth of a second old. That’s right, I get data from the closest thing to a time machine we have on this planet. Well, let’s be fair – it’s really more like going to a theme park that recreates some ancient time. You do it in the lab and study what it was like, then report you findings.

I have a curiosity for the invisible. I had a chance to meet with a film maker a few months back who spoke of his fascination for physics and its pursuit of the innately unseeable. My current research is an attempt to look for the signature of an unseeable particle recoiling against things which are visible to BaBar.

So I’m back in the swing of my research. I hope it lasts!

Toss Up

When I was in high school, I participated in only one sport: quiz bowl. I know what you’re thinking: quiz bowl isn’t a sport. Only a stupid jock who’s never played would say that.

You stupid jock.

Anyway, this weekend is my chance to give back to the bowl. SLAC is hosting regional competition in the DOE Science Bowl, and I’m volunteering as a moderator. I get to read questions and oversee the students’ answers. I’ll be working with a scorekeeper and timekeeper for each round.

So here’s my chance to give back to the teachers who managed our quiz bowl team in high school.