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One Neutrino’s Trip to Washington D.C.
by David Neto, Rhode Island College [an error occurred while processing this directive]
2010 APS/AAPT Meeting  
Snowy D.C. 2010 APS/AAPT Meeting.
Photo courtesy David Neto.

On my way to the APS April meeting, a thought popped into my head (and no, it wasn’t the fact that I was headed to an April meeting in February). I was wishing I did not have mass. Photons have no rest mass and they can go from here to there in no time. I, however, have mass, and therefore must take a train. A non-relativistic train, mind you.                  

Nine hours and one Sam and Dave mix tape later I arrived in Washington DC. For five days, Washington DC was going to be the physics capital of the world. Some of the greatest minds to ever calculate a Lagrange density or gaze at the stars through a telescope were going to be here.

I couldn’t wait to get to the meeting. My school has a rather small physics department; there aren’t exactly a lot of physics majors. In fact, there is one, and it is me. The only people I can really talk physics with are the four faculty members, and the occasional neutrino willing to exchange a boson or two.

I made my way to the conference through the snowy streets. I was not disappointed when I arrived. The entire hotel was filled with physicists. In one corner I heard people talking about charginos. In another corner, I heard a heated debate on galaxy evolution. This was the place all right.

Not knowing where to begin I made the obvious choice, the registration desk. Five minutes later, with my official meeting badge on, I was ready. My first stop was the SPS undergraduate research session. The most interesting presentation, in my opinion, talked about an unlikely piece of lab equipment. One might not usually see a video game remote in a physics lab, but if late one night you find yourself in need of an accelerometer, simply grab a Nintendo Wii remote.

The Wii remote comes equipped with accelerometers that can measure motion in three directions and an infrared sensor. After a slight warranty-voiding software modification, you basically have a hand-held physics lab.

  2010 APS/AAPT Meeting


The exhibit hall at the 2010 APS/AAPT Meeting. 
Photo courtesy David Neto.

Unfortunately, the Wii remote cannot unlock all of the mysteries of the cosmos. Luckily, astrophysicists have a new Swiss-army knife of a gamma-ray research, called the Fermi Gamma-ray Space Telescope. Fermi is being used to study black holes, dark matter, neutron stars, gamma-ray bursts, and more.

Fermi is also being used to study blazars. Blazars are a type of Active Galactic Nuclei (AGN). AGN’s are supper massive black holes found in the middle of some elliptical galaxies. These black holes devour gas and dust, producing jets of relativistic particles and photons. If our telescopes look down on a jet from one of these AGN’s, we see a blazar. “No one knew blazars were gamma-ray sources, until we had a gamma-ray observatory” says Dr. Erin Wells Bonning, who studies blazars. “Expanding past optical wavelengths has enormously opened the field.”

The best part about going to a large meeting is the shear breadth of talks. So when I started to feel the quantum blues coming on, I knew some theory would be the cure. And, wouldn’t you know it, the state of theory was down the hall. A quick glance at the topics assured me this was a theoretical talk. I also knew I was going to have to hit the books later to decipher the avalanche of conformal field theory and Grassmannian vector spaces coming my way. 

Of the three presentations, the most understandable to me (though just barely) was by Dr. Petriello of the University of Wisconsin, on perturbative QCD. Quantum Chromodynamics (QCD) is the mathematical engine of the strong force. The strong force is responsible for binding quarks into hadrons (like the proton) and holding together atomic nuclei. There is a problem though. Many of the calculations in QCD are very hard, so hard that even modern supercomputers can’t handle some of them. Perturbation theory allows for certain approximations that make the calculations much simpler.

The Large Hadron Collider (LHC) will be creating giant messes of particles from proton/anti-proton and lead nuclei collisions. There will be lots of data, and most likely new phenomena. If we cannot perform the calculations we may miss new discoveries. Dr. Petriello mentioned the importance of expanding certain terms in the calculations to improve accuracy. Something all too important if you are going to calculate a particle’s mass or decay modes.    

2010 APS/AAPT Meeting  
Dr. Francois Englert J.J. Sakurai Prize, 2010 APS/AAPT Meeting.
Photo courtesy David Neto.


Of course one of the primary goals of the LHC is to find the Higgs boson. This the year the APS awarded the J.J. Sakuri Prize for Theoretical Particle Physics to the founders of the Higgs mechanism: Dr. Robert Brout, Dr. Francois Englert, Dr. Peter Higgs (who unfortunately could not attend the meeting), Dr. Gerald Guralnik, Dr. C.R. Hagen, and Dr. Tom Kibble were recognized for their work on spontaneous symmetry breaking. Their papers laid the foundation of electroweak unification and the birth of the standard model of particle physics.

Each of the five physicists gave a speech detailing the events that lead up to the resulting papers. We don’t often hear about the actual processes that lead to discoveries in modern physics, so it was really cool to learn how an idea so important to physics was built up from the ground. It was also really interesting to learn that at one time, quantum field theory was not well respected; a far cry from today.

Monday was my last day, and apparently I had saved the best session for last. When I first looked at the talks being presented at the APS meeting, one in particular caught my attention. The session was on dark matter. One presenter wrote in his abstract, “provocative statements will be made.”

Dr. Marla Geha of Yale University started the session with an overview of our current understanding of dark matter. Many observational measurements over the years have hinted at dark matter. One example is the Bullet cluster, otherwise known as 1E 0657-56. The Bullet cluster consists of two individual galaxy clusters that collided with one another. When astronomers looked at gravitational lensing around the clusters, they noticed that the lensing was strongest in two places, both of which were away from the gas situated in the middle of the Bullet cluster. This could only happen if cold dark matter halos surrounded the two colliding clusters. This result agrees with the Lambda-CDM model. The Lambda-CDM model is the leading cosmological model of our universe. It includes a cosmological constant (Lambda), and cold dark matter (CDM).

For the most part, computer models of dark matter resemble what we see through telescopes—current computer simulations cannot model both dark matter and normal luminous matter. “The simulations predict very steep slopes in the density distribution in galaxies, and we don’t see that very often. We usually see something that is flatter,” says Dr. Geha. “That’s probably an issue with only simulating dark matter.”  

  2010 APS/AAPT Meeting
  Dr. Gerald Guralnik J.J. Sakurai Prize, 2010 APS/AAPT Meeting. 
Photo courtesy David Neto.

Dr. Douglas Finkbeiner followed with a discussion of methods for the indirect observation of dark matter. Although dark matter is not very talkative, there are ways that it can be indirectly detected. For instance, by the photons created when a dark matter particle decays.  Dr. Finkbeiner outlined a process by which data from several telescopes, including Fermi, can be used to form a composite map. Then, one by one, known processes could be modeled and subtracted from the map. The excess left over would be the result of dark matter decay/annihilations. Well, a map was made using this process and it did contain additional signals that may have been caused by dark matter! A provocative statement indeed.

Closing out this dark matter session was Dr. Simona Murgia, presenting results from Fermi’s first year of observations. Fermi’s data has also found signals pointing towards dark matter decay/annihilation, although a larger sample size is needed to confirm the indirect detection of cold dark matter. It is very exciting to think we are a little closer to understanding one of the big questions of the universe.

Unfortunately, my time at the meeting had come to an end. I left carrying a notebook filled with all of the questions and ideas I had accumulated over the past three days. I boarded the train, and found an empty seat. Looking out the window, I could see the stars and I couldn’t help but smile.

Thank you to Kendra Rand and SPS for allowing me this opportunity. Thank you also to Dr. Erin Wells Bonning, Dr. Matthew Duez, Dr. Marla Geha, and Dr. Gerald Guralnik for not only speaking with me, but offering kind words of advice to an aspiring physicist. Thanks also go to the local DC neutrinos.

Free 1-Year Membership in APS
When you join SPS national as an undergraduate, you get free one-year membership in one of ten other physics societies, including the American Physical Society (APS). APS is a professional membership association of scientists dedicated to promoting the advancement and diffusion of the knowledge of physics and all branches of fundamental and applied physics.  

SPS Reporter Program
SPS national sends student reporters to most major AIP Member Society meetings, where they are treated like other members of the press. Many ambitious student reporters succeed in securing interviews with society leadership and prominent invited speakers on such occasions.

SPS Travel Awards
A limited number of grants, on the order of $200 each, are offered to help fund SPS members' travel to national meetings of AIP Member Societies holding a "SPS Session" co-organized by SPS and the Member Society.

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