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AIS Visit 2013

What could be more fun bright and early on a sunny Monday morning than to learn a bit about current research and methods in particle physics?  Not much of course.  

While it’s often primarily physicists that would answer this way, we were fortunate enough on August 18, 2013 to be joined by a group of Art Institute of Seattle students who gave just such an answer.

The AIS Masterclass was a phenomenally successful attempt to reach out to the community and to share the work currently being done at the LHC.  It was a great opportunity to separate fact from the science fiction that is often generated about the LHC and CERN. The masterclass included video conferences with researchers at CERN, tours of working research labs, and roundtable discussions about science and the community.

The morning started with a video tour of the control room and Pixel lab (Is that where Bing was working?) at CERN.  The talk laid out, very clearly, the basic research projects at CERN and how the  process of scientific research proceeded at one of the most state-of-the-art research facilities in the world. This not only gave the AIS students a great view of the “big picture” at CERN, but also gave the seasoned scientists, graduate students, and post-docs a chance to step back and remind ourselves of our greater collective goals.

After a stimulating coffee break, the students were ready to discover some particles themselves. One of the volunteer students, Seyda, gave a short presentation about the Standard Model particles, and what kind of “signatures” they leave in the LHC detectors so that physicists can identifythem. Some pre-generated LHC events in which a Z-boson decays to two leptons (either an electron-positron pair, or a muon-antimuon pair) were shown using  a program called HYPATIA. Hypatia is designed to help to visualize LHC events, and how to analyze them by giving easy options for selecting and identifying particle tracks. After the presentation, students had half an hour in which they correctly identified two lepton tracks coming from a decaying Z-boson in more than 20 events. Identifying the correct tracks was not easy, since in each event there are many tracks that are not associated with the desired Z-boson. Students, remembering the signatures of the electrons and muons coming from a heavy boson, were able to re-discover the Z boson by correctly finding its mass (The class average was around 88 +/- 3 GeV/c2). A group of students even got to analyze some Higgs events, which was also very exciting for the volunteer physics students.

The students also got to see, first hand, the lab here at UW which will serve as a R&D lab on the future upgrades and detector tests.  They not only saw an FE-I3 chip (the same type of chip responsible for the Higgs discovery) but also the new FE-I4B chip which, with higher resolution and surface area, give a very tangible example of the increased potential of the phase-1 upgrade for novel scientific discoveries.  

Through looking at the Data Acquisition boards currently in the lab, the students got a great first-hand view of how information was transferred from particles to histograms.  When a particle goes through a silicon pixel, it deposits some energy, creating a small current pulse.  The pulse is then transferred to a circuitboard which converts the pulses from the pixels into a data stream to be read into the computer.  This data stream then becomes a data file on the computer and can be used to reconstruct tracks, events, and finally to be analyzed.

- By Jordan Raisher Aug 2013