A new exercise, part of the International Masterclass outreach program, will use data gathered by ALICE to introduce school children to particle physics. ALICE put forward a proposal for this during the last meeting of the European Particle Physics Outreach Group (EPPOG), which was held at CERN mid-October this year.
EPOGG has been running masterclasses for high school students since 2005. Each year, thousands of students from twenty-three different countries - from Europe to the United States - go to universities and research centers around the world for a day of total immersion in the world of particle physics.
Here, they follow lectures on the standard model of particle physics and beyond, covering the principles behind detectors and experimental methodology. They then analyse collision data and perform measurements. At the end of the day, as in real experimental collaborations, all the participants join in a video conference to discuss their results.
ALICE's event display showing proton-proton collision with V0 decay. The students will analyse events like this in the masterclass.
Until recently, the analysis exercises were conducted mainly using data from the Large Electron-Positron Collider, looking at the decays of Z0 and W, the carriers of the weak force. With the Large Hadron Collider now up and running, however, EPPOG wishes to move on and use data from the LHC for the masterclasses instead. Given the complexity of the events from the LHC compared with the cleaner signatures from electron-positron interactions, however, finding an easy channel is no trivial task.
The exercise developed by ALICE consists of a search for V0-decays of neutral strange hadrons, such as ? and Ks and cascade decays of charged strange hadrons, such as ?. The visual V0 and cascade finder, used by the standard ALICE event display, has been incorporated by Pawel Debski of the Warsaw University of Technology into the ROOT framework in such a way that it can easily be ported to any computer without the need to install the whole ALICE software package.
The classification of the strange particles is achieved by studying the path of the decay tracks, combined with the identification of the products of the decay. In addition, the track information is also used to calculate the mass of the parent particles.
Twenty-four students from Geneva’s Collège Sismondi will visit CERN on 17 November and will be the guinea-pigs for a test run of the new masterclass. For 2011, the international masterclasses will take place during 4-26 March; with the ALICE institutes participating encouraged to opt for the ALICE exercise.