International Masterclasses-bringing LHC data to school children

International Masterclasses provide an opportunity for high school students to be "scientists for a day". 15to 19-year-old students in countries around the whole world are invited to one of about 160 nearby universities or research centres for one day in order to take part in an authentic research process. Lectures from active scientists give insight in topics and methods of basic research at the fundaments of matter and forces, enabling the students to perform measurements on real data from CERN's Large Hadron Collider. At the end of each day, like in an international research collaboration, the participants join in a video conference with other students groups and CERN for discussion and combination of their results. In 2013, about 10.000 students from 37 countries participated in the program. International Masterclasses are organised by IPPOG (International Particle Physics Outreach Group) and have the potential to add valuable experiences to physics education in school environments. 1 Bringing LHC Data to School Children With the start-up of the new and powerful particle accelerator LHC, a new era in research has dawned. The LHC is used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionize our understanding of nature, from the minuscule world deep within atoms to the vastness of the Universe. Results of the experiments are followed with great interest, not only by physicists but also by the general public. International Masterclasses allow high school students to experience this research at close range. The basic idea of the annual program is to let students work as much as possible like real scientists. Figure 1. Logo International Masterclasses a Corresponding author: uta.bilow@physik.tu-dresden.de DOI: 10.1051/ C © Owned by the authors, published by EDP Sciences, 2014 , / 00017 (2014) 201 epjconf EPJ Web of Conferences 47100017 71 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Article available at http://www.epj-conferences.org or http://dx.doi.org/10.1051/epjconf/20147100017 International Masterclasses bridge the gap between science education at school and modern scientific research. High school students can explore the fundamental forces and building blocks of nature and are informed about the new age of exciting discoveries in particle physics. Moreover, they can actively take part in cutting-edge research and improve their understanding in science and the scientific research process. The program offers authentic experience and adds valuable experiences to physics education at school. In this way, the students ́ interest in science is stimulated, as an evaluation has shown. 2 The Concept “Masterclass” In general a Masterclass is a class given to students of a particular discipline by an expert of that field. Usually Masterclasses are on arts music, painting, drama – but here the subject is particle physics data analysis. The students work with an expert, a particle physicist, who gives them advice on how to analyse data from particle physics experiments. This unique hands-on approach ensures that the knowledge and insight that students acquire during the Masterclass is action-orientated. Figure 2. High school students in a particle physics Masterclass 3 How the program developed Masterclasses in particle physics began in April 1997 in the United Kingdom as an initiative from Roger Barlow, Huddersfield University. The European program started in 2005, the World Year of Physics, when the European Particle Physics Outreach Group (EPPOG) adopted the idea and organised Masterclasses in 17 countries throughout Europe, with 3000 students participating. Since then the program is organised each year in spring and has grown steadily (Figure 3). In 2006, American students participated for the first time. Nowadays 37 countries from all continents (Figure 4) are represented in International Masterclasses, and the number of students participating is estimated at 10.000. The worldwide participation reflects the international collaboration in particle physics. EPJ Web of Conferences


Bringing LHC Data to School Children
With the start-up of the new and powerful particle accelerator LHC, a new era in research has dawned. The LHC is used by physicists to study the smallest known particles -the fundamental building blocks of all things. It will revolutionize our understanding of nature, from the minuscule world deep within atoms to the vastness of the Universe. Results of the experiments are followed with great interest, not only by physicists but also by the general public. International Masterclasses allow high school students to experience this research at close range. The basic idea of the annual program is to let students work as much as possible like real scientists. International Masterclasses bridge the gap between science education at school and modern scientific research. High school students can explore the fundamental forces and building blocks of nature and are informed about the new age of exciting discoveries in particle physics. Moreover, they can actively take part in cutting-edge research and improve their understanding in science and the scientific research process. The program offers authentic experience and adds valuable experiences to physics education at school. In this way, the students´ interest in science is stimulated, as an evaluation has shown.

The Concept "Masterclass"
In general a Masterclass is a class given to students of a particular discipline by an expert of that field. Usually Masterclasses are on arts -music, painting, drama -but here the subject is particle physics data analysis. The students work with an expert, a particle physicist, who gives them advice on how to analyse data from particle physics experiments. This unique hands-on approach ensures that the knowledge and insight that students acquire during the Masterclass is action-orientated.  In 2014, a measurement from LHCb will also be available. More experiments have expressed their interest to join the program in the next years.

Masterclass Agenda
Masterclasses are organized at more than 160 universities or research centers throughout the whole world. High school students aged 15 -19 are invited to a research institute or a university to be "Scientist for one day". The size of the groups varies largely, from 15 up to 300, depending on the capacity of the inviting institution. The period for International Masterclasses covers four weeks in spring. Participating institutes choose their preferred date and sign in. Each day, up to 15 institutes can register. Although the participating institutions are able to configure some aspects of the event individually, each Masterclass follows a uniform scheme. In the morning of the day students listen to introductory talks about high energy physics. Presentations are adjusted to students´ level and given by the masters -scientists familiar with outreach and education. In the lunch break, there is the opportunity for the students to talk to undergraduates, graduate students, and professors.
After the lunch break the practical part follows, which takes place on PCs. Students work with data from particle collisions recorded at the LHC on an own measurement. After an appropriate introduction to the programs they perform the measurement task autonomously, supported by the masters. At the end their findings are discussed with the group.
At the end of a Masterclass, students can expect a special highlight: an international video conference, where the students connect with more student groups from other countries and with a pair of moderators at CERN. All student groups of the given day have performed the same measurement, but with different data. Thus the video conference allows them to compare and combine their results and share their experiences. The focus is not just on results, but also on methods and research processes. The LHC is an example where the students can learn how a real research process proceeds.

Lectures -conveying basic knowledge
Many students visiting a Masterclass already have some ideas and knowledge about particle physics. Keywords such as CERN, quarks, black holes and the LHC are mentioned. This information is often based on media reports, as the field of particle physics is often only marginally represented in the curricula. Sound knowledge is usually not available. Therefore, in the morning lectures a basic introduction is provided. The talks cover the Standard Model of particle physics and the different types of elementary particles with their corresponding charges. Students hear about the four interactions, which mediate the dynamics of the known subatomic particles.
They usually are familiar with the best-known effect of these interactions, the electromagnetic force. This interaction, among other things, describes the attracting behaviour of oppositely charged particles, which causes the cohesion between the electron shell and positively charged atomic nucleus. New content, however, are often the strong force and the weak force. In addition, participants have to learn that force carrier act as mediators of interactions: For example, photons that are emitted by electrically charged particles in all directions and "captured" by other particles, are the force carriers of the electromagnetic force.
The lectures also have to cover, how particle accelerators and detectors operate and in which way different elementary particles interact with the detector. Students learn that particle accelerators are used on the one hand similar to optical microscopes, making possible the discovery of quarks in the interior of nucleons. On the other hand, the machines can be used to produce new particles in collisions of particles and their antiparticles: The annihilation of matter and antimatter creates force carriers, from which then in turn new, possibly even previously unknown particles can be formed. The basic idea of all measurements is a question related to particle physics. The outcome of each measurement should lead students to new and fundamental insights in this field. All tools and programs used in Masterclasses have been adapted to high school students´ needs. For example, the measurements include event displays ( Figure 6) where the detector signals are graphically implemented, or start at least with a visual analysis. Students can follow the processing of results, and their results are presented in a graphical way (histograms or tables). For example, they learn to identify particles in event displays and to classify signal events. By simply counting the event types and comparing their relative abundances students achieve their result, thus copying the scientists´ procedures. Other possibilities are measurements of the distribution of mass or angle or investigations on data quality.

Measurements -hands-on activities
One of the objectives of International Masterclasses is to let students follow up closely what the scientists are doing. Therefore consequently new measurement tasks are developed. In 2011, students could exploit known standard model processes, e.g. the W + /Welectric charge ratio (reflecting the dominance of positive u over negative d quarks inside the proton), or they were guided to understand the mass peaks of J/Psi and Z. In 2012, the discovery of new particles was added. Simulated data was included to give students the possibility to find extra Z´ bosons or Higgs bosons decaying into WW. In 2013, real Higgs candidates have been included in the analysis.

Video Conference -experiencing an international collaboration
International Masterclasses are completed by a video conference. At the end of each day three to five student groups from different countries connect to CERN or Fermilab, where a pair of young scientists moderates the video conference (Figure 7). On the one hand this establishes a direct connection between the student groups and the research centre. On the other hand, the students receive an authentic impression of modern research. In particle physics, typically very large collaborations exist, including 3000 or even more scientists. For these scientists video conferences are a common working tool. A training for moderators is offered. Given a maximum of 15 institutes participating on one date, up to three video conferences are held in parallel. The video conferences have a duration of 60 minutes, are conducted in English and follow a fixed scheme. After a short welcome students present their results. All student groups in a given video conference have performed the same measurement, but with different data. Thus the video conference allows them to compare and combine their findings. After a discussion of the results, students have the opportunity to ask a broad range of questions to the moderators. As a final point, students complete a quiz with multiple choice questions about particle physics. The presentation is based on the famous TV-show "Who wants to be a millionaire?". Scoring is done by the students themselves, and the measure of the score is electron volts.

Organisation
International Masterclasses is a key project of IPPOG, a network of scientists, informal science educators and communication specialists working across the globe in informal science education and outreach for particle physics. The program is steered by a committee. The steering group includes project leader, coordinators, one person from each measurement, and other consultants. Further, a working group for the video conference has been established for the quality assurance of this item. International Masterclasses maintain a website (www.physicsmasterclasses.org) where all material is available. Measurements are free to use, not only in the framework of International Masterclasses., but for any educational purpose. All participating countries and institutes are presented with a profile, where contact details are included as well as information on research and teaching and outreach activities (Figure 9). Furthermore, details for the participating institutes are provided on the website, e.g. step-by-step lists for preparation, manuals, or corporate material to prepare invitation letters and certificates of participation. The conditions for participating institutes are manageable: Rooms (lecture hall, PC pool) and equipment for the video conference have to be provided. A scientist holds the lectures, tutors help during the measurement (1 master per 10 students). There are no financial requirements for the program.

International Masterclasses -a successful program
During a Masterclass students get to know the fundamental building blocks and interactions. They deal with current issues of basic research and methods of particle physics and learn about the importance of physics for the modern view of the world. The program aims to convey an authentic picture of the daily life of a scientist, to fascinate students about modern research in physics and to encourage their involvement with science. A refereed evaluation [11] investigated to what extent these objectives are achieved. 1291 Students from 18 European countries were included in an evaluation study in 2005. The students´ perception of the program was rated on a five-point Likert scale. An overwhelming majority of the students liked the Masterclass "much" or "very much" (82 %), while only 4 % did not enjoy the program. Figure 10 shows that this high appreciation does not depend on the preknowledge of particle physics, and that there are no significant differences between the feedback from males and females. The perception of the lectures turned out to be the most important factor for the overall rating of a Masterclass. Further questions asked about the increase in knowledge in particle physics and insight into to the way in which scientific research is organised. Students become the more interested in learning about physics and dealing with modern science in school the better they understand how scientific research is organized (Figure11). How much the students actually learned about particle physics only weakly influenced their overall appreciation of Masterclasses.