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Jacob Anderson | USLHC | USA

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It is possible to have a life outside of the lab.

Wednesday, July 21st, 2010

“Get a life!” seems to be a tried and true TV line when talking to geeks, nerds and the like. I’d like to think I have one. It must be the birth of my third son that has me reflecting on a larger scale than usual, but I haven’t found that being a physicist has been a significant burden on my personal life.

I know there are stereo types of physicist spending day and night at the lab working. My wife often likes to tease me that when I get home late from work it isn’t because of anything she needs to worry about; I was engrossed in my work and lost track of time. I’ll admit that it has happened (ok more than once), but I don’t make a habit of it. Most of the people I work with keep regular, sane hours, and all have what seem to be normal personal/work lives. Sometimes we have to put in extra hours at the lab, like now as the ICHEP conference is upon us, but most jobs have deadlines and extra hours to meet them.

Physicists and scientists in general are often unfairly considered to lack a personal life. I’ll admit that I have met some, but the vast majority are able to relax and have some fun most days. In fact, I get to have fun just about all day everyday since I find physics fun most of the time in addition to having fun away from work, and isn’t that the measure of having a really good life.


Matter and anti-matter

Tuesday, May 18th, 2010

Recently the D0 collaboration at the Tevatron announced an interesting result.  Having come from the BaBar experiment and worked on CP violation, I found it exciting.  Our universe is dominated by matter.  It’s everywhere and there is almost no anti-matter to be found.  This is one of the principle questions in our sub-atomic understanding of the universe.  The answer to this was put forward many years ago by Sakharov; there has to be CP violation, meaning that the swapping a particle with its anti-particle and looking at the interaction in a mirror can’t be the same as the original.

CP violation was discovered several years ago and has already won Nobel prizes.  The B-factories have measured many of the CP violating parameters of the Standard Model and come up with a rather coherent picture.  These measurements and constraints are embodied in the CKM triangle, where the height of the triangle is a measure of the amount of CP violation.

CKM Triangle

Recent CKM fitter result

It’s beautiful really.  Like a piece of fine art.

Kandinsky composition VIII

Kandinsky Composition VIII

There is just one problem; the amount of CP violation is insufficient by about 10 orders of magnitude. This means that there has to be more CP violation out there that we don’t know anything about.

This is where D0 comes in. They have been looking at CP violation in decays that aren’t accessible at the B-factories, and they found something. The Standard Model says they shouldn’t find much at all, but they did. I think it’s exciting. This isn’t the first sign of stress on the Standard Model, and there will undoubtedly be more coming in the next few years from LHC and other experiments. I think it is an exciting time to be involved in fundamental science research since we will be revising and rewriting many long held theories in the coming decades.

D0 result

D0 asymmetry result is separated from the Standard Model representing the blue point.

Making Improvements

Monday, May 10th, 2010

The LHC has only had collisions for a little over a month now, and I’m as excited as the next scientist about the new data that is coming in.  With it we will hopefully be able to push existing boundaries in new ways.  The detectors are running well and I think that is a testament to all of the years that went into their development.  (Even if some of those years weren’t planned.)

For my first US LHC blog post, I want to write about something I’ve been working on.  Even though things are looking rosy right now, I’m in the business of improvement.  I work on the hadronic calorimeter (HCAL for short) for the CMS detector.  It is a large heavy detector system charged with trying to stop any hadrons (pions, kaons, protons, neutrons, etc.) from the collisions and measure their energy.  The CMS calorimeter is a sandwich of brass and plastic scintillator planes.  We measure the energy of the hadrons based on the amount of light we collect from the scintillator material.

Here is where the improvement comes in.  The HCAL design was essentially finalized in 1997.  That’s right 13 years ago.  And this was after several years of R&D to come up with a good design.  It then had to be manufactured and installed to be ready for what has been a very exciting commencement to data taking.

In the years since the HCAL was specified and built, new and exciting technologies have emerged that could potentially improve the performance of our calorimeter.  One of these is the silicon photomultiplier.  This device could allow us to better measure the light from the scintillators thereby improving our measurement of the hadron energy.  However, because it took 13+ years to get the original HCAL to a fully integrated system, it will probably take several years for the new upgrade to be designed, specified, prototyped and produced and then it must be integrated into the existing CMS detector.  All this means that although beam operations have been going on for months, upgrade plans have been going on for years.

I’m excited about what we can learn from the data being taken now with CMS and the other LHC detectors, and I looking forward to improvements that are coming in the future years to better exploit the discovery potential of this remarkable machine.