by Despina Hatzifotiadou. Published: 06 April 2011

The Seventh International Masterclasses - Hands on Particle Physics - took place between 4 March and 26 March this year, with the participation of 99 institutes from 24 countries.

More than 8000 high school pupils were introduced to the fascinating world of particle physics research. After following lectures, they analysed real data from ATLAS, CMS and ALICE and at the end of the day they discussed their results by video conference, as is so often the case in big collaborations.


Students partaking in the 7th International Masterclass

The innovation this year was that the pupils analysed data from LHC, rather than from LEP, as was done previously. It was not a trivial task to introduce exercises that, instead of having the clean signatures from electron-positron collisions, have the much more complicated patterns of hadron collisions.

The analysis exercise proposed by ALICE – looking for strange particles – was chosen by a total of 10 institutes and was conducted on two days. CERN’s Local Communications Group organised the CERN masterclass on the 25 March.

27 pupils from the Lycée International de Ferney participated, accompanied by three professors. In the morning Stephanie Beauceron gave them an introductory talk on particle physics and detectors while Giacinto de Cataldo introduced them to the ALICE experiment, the physics of heavy ions and the exercise they were to do in the afternoon.

Split into small groups, they visited the ALICE exhibition and Control Room at Point 2 or the CMS centre and LINAC and LEIR on the Meyrin site. After lunch they moved on to the Training Centre for the analysis exercise.

Using a simplified version of the ALICE event display – running under ROOT- they analysed data from the 900 GeV proton collisions recorded at the end of 2009. Their task was to look for hadrons containing strange quarks, such as Ks, ? and ?-, from their characteristic V0 or cascade decays.

At the end of the day, during a video conference, they reported their results, along with pupils from Heidelberg, Lodz, Torino and Nantes, who had analysed the same data. The event closed with a quiz based on what they had learnt during the day; and the lucky winners of the presents offered by CERN were Lucie Martin and Elsa Isere.

The pupils’ comments on their appreciation of the day cover the whole spectrum; some were enthusiastic whereas others found it difficult to understand; the general impression is that they have enjoyed the experience and feel that they learnt a lot. We have already received proposals for improvements and changes that will be implemented in the next version of the exercise for next year’s masterclasses.

In spite of some problems encountered, such as the occasional computer crashes, those participating as lecturers or instructors have also enjoyed the experience.

“It was fun and different from the usual work,” said Chiara Bianchin, who was instructing and supervising the pupils in one of the computer rooms.