The BaBar Collaboration Meeting

This past week was what is usually called “BaBar Collaboration Week”. This is a week of morning to night meetings of the entire collaboration. This typically involves something like 1/3 – 1/2 of the collaboration all showing up at the same location (SLAC) and presenting their progress in research. The collaboration meeting is a mixture of two kinds of meetings (or “sessions”, as we call them): plenary and parallel. The plenary sessions are attended by all members of the collaboration, while the parallel sessions are topical and atttended by interested parties.

Collaboration meetings are growing more and more draining as I get older. This has less to do with age and more to do with involvement. As a convener of a BaBar analysis working group (AWG), I organize parallel sessions that center on the topic of my AWG: leptonic decays of the bottom or charm quark/mesons. I also have grown more interested in a wide variety of topics as I’ve spent more time in physics. For instance, I am interested in generic decays and physics of charm mesons; I enjoy the any topics worked on my me and my colleagues in what are called “radiative penguin decays”; and of course, I enjoy leptonics decays of b and c quarks IMMENSELY.

But a physics collaboration is so much more than just the research it produces. It’s also defined by how it does that research. That means equipment and computers. I am always attracted to the discussions of detector hardward developments and analysis computing topics, a huge part of modern particle physics. One of my pet peeves is the sheer number of my colleagues who avoid the computing plenary and parallel sessions as the meetings. For instance, one of the most important sessions dealt with the global distribution of computing resources by BaBar. This affects EVERYONE. However, less than 1/5 of the collaboration attended those meetings. Sad. Do they all think data just comes magically out of the ether and is handed to them polished and primed?

I’ve taken today to recover from the meeting. Like I said, it was draining. I was attending meetings from 8 in the morning to 8 at night for four days straight, with a closeout morning session on the fifth day. My wife just left for Minnesota at 5:30 this morning, leaving me alone on a very rainy Sunday. Not the best way to cap off the draining collaboration week…

I got a **lot** out of this meeting, however. I have three new ideas for developing my research topic: invisible decays of heavy quarkonium. I hope to use these decays to constrain models of physics that claim to tell us how nature operates outside the bounds of the Standard Model of Particle Physics. This could be a very powerful probe of nature.

So that’s BaBar collaboration meeting week. We do this about 4 times a year, with lots of little meetings in between. Whew. Time to regroup and head back into my research!

Library Card!

After weeks of putting it off, I finally went to the Redwood City Library and picked up my library card. It’s been ready for several weeks, but I just wasn’t making the time for it. However, I am certainly glad I did get it, because it led me to a storehouse of great books.

Being a devout scientist, the first thiing I did was hit the physics section. It was a goldmine of both textbooks (Misner et al’s “Gravitation”, for example) and popular books. The find that Jodi made, however, was priceless – to me, at least. She produced from a shelf the two-inch-thick volume “The Stanford Two-Mile Accelerator”, edited by R. B. Neal. This book, finished just after the successful turn on of SLAC, details the history of the project, the accelerator physics and engineering, and the details of every aspect of that then world’s most luminous electron accelerator.

What I find particularly spelllbinding about the book is the historical context. While the idea of quarks was clearly around, SLAC had not yet completed the work which would lay the groundwork for the proof of the quark hypothesis. It’s amazing to read that sense of hope and expectation, that experiments yet to be conducted at SLAC might explain the particle zoo known in the 50’s and 60’s.

All right, I’m getting back to my book!

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.