Archive for September, 2006

Measuring Oscillations of Strange Bottom Mesons Is Hard Work

Posted in physics, Science on September 28, 2006 by Mike Procario

I read the preprint of CDF’s on the observation of Bs mesons. It took a remarkable amount of work. Large high energy physics collaborations have large author lists due to the large contributions made by many people to operate and calibrate the detector, simulate and process the data. But the analysis described in most papers is done by a very small group of people, usually a graduate student and his or her adviser or a postdoc.

This analysis requires the observation of Bs mesons and a measurement of their momentum and decay point. In addition it is necessary to determine whether it was produced as a Bs meson or the antiparticle. In order to get a large enough sample to be statistically significant, CDF had to use many decay modes of the Bs and some of these were only partially reconstructed, which means that one particle escaped detection which hurts the momentum resolution and can increase the background. CDF also had to use multiple techniques, called tags, to identify whether the original Bs was a particle or antiparticle.

A graduate student could be expected to do an analysis that used one tag and a small number of similar decay modes. Clearly this work had to split up among a number of people. Some of the partially reconstructed modes using leptons would require very detailed studies to understand the effect on the momentum resolution. Combining the results in the end is also a big job. Making sure that the various data samples were independent or that any correlations were understood is critical.

This is a very impressive result. Having studied B mesons for many years, I can appreciate the amount of work that must have gone into this analysis.


Speeding through Dulles Airport?

Posted in Travel on September 21, 2006 by Mike Procario

I arrived at Dulles Airport today on a United flight from Oakland, CA. I stepped off the plane at 3:10 PM and I left the parking garage at 4:10 PM. The airport was not very crowded. It was much more crowded on Monday when I flew out of town. There was no line today for the shuttle from the terminal back to baggage claim. When I arrived at the terminal on Monday the shuttle was greeted by a very large crowd waiting to board it. The longest time was spent waiting for my suitcase to arrive at baggage claim. I checked my bag due to the new no-carry-on-liquids rule.

Flying without Liquids

Posted in Travel on September 19, 2006 by Mike Procario

I took my first flight in the no carry-on liquid era. It is clear to me that the airlines and the terminal operators have not yet learned how to adjust on the fly to changing regulations. When I arrived at Dulles for my flight, the check-in line for United was badly backed up. I waited in line for awhile until a United employee came, sorted out the line, and directed us to a variety of shorter correct lines. Apparently one line got badly backed up, and that prevented people from seeing that the other lines were not backed up.

Much of this congestion seemed to be related to people checking luggage that they would not normally check. I checked my bag, since I prefer to extra room when flying a coast to coast. This allowed me to pack toothpaste and shampoo. For my next flight to Chicago I will have to choose between bringing those items or carrying my overnight bag abroad.

There seemed to be an inconsistency in the policies. You are not allowed to carry liquids through security, but you can purchase then in the terminal. I had coffee, while I waited. I did not finish it in time, and I had to throw it away. You cannot carry the coffee on the plane, but there is no check of your carry on luggage at the gate. I could have carried on a bottle of water in my briefcase without anyone noticing.

Both government bureaucracies and large customer service businesses work best with standard procedures that can be slowly refined over time. Neither is good at adapting quickly to new situations, which does not bode well for comfortable air travel in the future.

New Dell Battery

Posted in Technology and Software on September 11, 2006 by Mike Procario

The battery for my Dell Inspiron 6000 was recalled, and my new just arrived. The old one had been holding a smaller and smaller charge. It was down to lasting for about 30 minutes when my new finally arrived. The new one one is lasting over 2 hours now. Dell’s loss is my gain, unless this one also is discovered to be a fire hazard.

Protecting Privacy

Posted in Law & Politics, Technology and Software on September 11, 2006 by Mike Procario

I read Robert Scoble’s blog regularly. I enjoy hearing about new technology, but I almost never blog about it. Today there was a post on why he has been so critical of HP spying on its board of directors.

So, why did I care that HP’s board of directors pushed the boundary of where private information could be used? Because private data must be held sacrosanct. Private data is an electric rail. Use it properly and it will power your business. Use it improperly and you should get fired. There’s no other way to put it. It should be that clear. It IS an electric rail.

Protecting privacy has to be done multiple fronts. Legislation can help, but public scrutiny can respond faster when companies violate privacy.

Tevatron Running Great

Posted in physics, Science on September 11, 2006 by Mike Procario

Last week Fermilab Today published an article on the recent improvements in Tevatron performance which resulted in the peak luminosity breaking the 2×1032 cm-2s-1 barrier. Well they wrote it too soon since they set a new record this weekend of 2.25×1032 cm-2s-1. The CDF and D-Zero collaborators have had to make changes to their trigger to handle the high luminosity. I hope they got their changes in before the recent improvements.

Here is the graphic shown at the one of the weekly meetings.