Welcome to CERN!

What is CERN? European Organization for Nuclear Research, founded in 1954 Currently 20 member countries It’s my pleasure to give you an introduction to CERN. In 15 minutes I will tell you a little bit about what CERN is, what we do at CERN and how we do it. This will hopefully also give you an overview of the things that you will hear and see during your visit. My presentation will surely generate plenty of questions and you will have plenty of opportunities to ask these questions during the day. So what is CERN? CERN is the European Organization for Nuclear Research or better in french Conseil Europeen pour la Recherche Nucleaire. It was founded in 1954 with the aim of gathering Europe’s scientist under one roof to start up serious scientific European wide collaboration, something which of course had been practically stopped by the second World War. 12 European countries joined up and became CERNs first members. Over the years CERN has expanded and today includes 20 European member countries.

World laboratory Model for international collaboration - 80 nations represented at CERN 6500 scientists, in total about 10000 people are involved at CERN However, CERN is more than European, the initial ambition was already to make CERN a world laboratory. Although CERN remains by constitution a European laboratory, CERN has today visiting researchers from 60 countries outside Europe as you can see from this map. In total there are about 10 000 people involved in the projects at CERN, out of which 6500 are scientists. Only 800-900 of these are actually employed by CERN. The power of CERN is that most of its scientists are travelling back and forth between their home institutes and CERN. This means that they can spread the knowledge and the technologies of CERN in their contact with national industry, in teaching and to public.

Mission CERN’s objective is pure basic research in particle physics However, results and spin-offs are of four major kinds: - Progress in particle physics - Developing tomorrow’s technology - Training of tomorrow’s scientists and engineers - Informing and stimulating the public

What is particle physics? Quest to understand: Fundamental constituents of matter - Matter particles Interactions with which particles act on each other - Interactions Particles propagating the interactions - Messenger particles Ultimately describe: Birth of the Universe, the Big Bang Passed and future Evolution Particle physics is about answering the very same questions man asked himself as soon as he gained his self-consciousness. How did we come into existence and why are things like they are? We have made some progress in the methods used to answer these questions and today the quest to understand these questions is focused on: Strong link between the infinitely small (particle physics) and infinitely large (cosmology)

Constituents of Matter Greeks (Empedocles) 500 BC

Constituents of Matter Periodic table (Mendeleev) ~1870 Eightfold Way (Gell-Mann) ~1960 Electron, proton, neutron 1897-1932

Constituents of Matter Quarks (Gell-Mann) 1964 Proton Today’s periodic system of the fundamental building blocks

Seeing Finer Structures 10-1m 10-6m 10-9m 10-12m 10-15m 10-18m Electron microscope Light microscope

Seeing Finest Structures CERN Accelerator ~27 km! Resolution ~10-18 m 1000 times smaller than a proton!! ? Proton - With the LHC we will improve on this by a factor of 10

Interactions Energy = Temperature Time Electricity Magnetism Light Terrestrial Gravity Planetary Electromagnetism Maxwell’s Electromagnetism Newton’s Gravitation Energy = Temperature General Relativity Radioactivity Atomic nuclei Quantum Electrodynamics Weak nuclear force Strong force Super Unified Theory Time Electroweak force “Standard Model” Grand Unified Theory

What do we not know? What do we know? How did the forces and the particles behave in the very beginning? Why does Nature have a preference for matter over antimatter? What caused the small density variations that seeded galaxies? How did the particles acquire their masses? In which way were the protons, the neutrons, and their relatives formed? Under which conditions were the nuclei formed? What is 96% of the Universe made of - the Dark Matter and the Dark Energy? What do we not know? The Universe begun as an extremely hot and dense soup of energy and particles The rapidly expanding Universe is already endowed with an excess of matter over antimatter by one in a billion and small density variations The soup of quarks condenses into protons, neutrons,.. The first light nuclei are formed Atoms are formed This marks the limit between the use of telescopes and accelerators! Recent research shows that we only know what 4% of the Universe is and that its expansion is accelerating What do we know? CERN Let’s take a look at what we do know about the Universe. The cone is supposed to represent the expansion of the Universe and shows four different stages during its evolution from the beginning until today 13.7 billion years later. The fact that the Universe have a beginning was already very hard to swallow 50 years ago but since then we have found out many similar surprises. Thus, the Universe started out as a hot and extremely dense soup of energy and particles. As it expands it So all this understanding is often summarized in what we call the standard model of particle physics and cosmology. Now let’s take a look at those particular questions that we are in fact attacking with the next project at CERN. First of all we would like to know how the particles and the forces behaved in the very beginning to understand how they decided the course of the Universe, so it would be good if we could recreate these conditions. Not long after the beginning, only a 10th of a billionth of a second.

High Temperature CERN Accelerator ~27 km! Temperature ~1016 K : 1000 000 000 x !!! The energy in the LHC collisions corresponds to a temperature of 1000 million TIMES the temperature in the center of the sun, which is about 10-20 million degrees We look at a corner of the Big Bang

How to find out? Large Hadron Collider (LHC) is a 27 km long particle collider Recreate conditions at “small scale”: Temperature 1016 K that is 1 000 000 000 x 0.00000000001 second after Big Bang

CMS ALICE ATLAS LHCb

How to find out? cont’d Four experiments – detectors – record the particle collisions ALICE ATLAS CMS LHCb

General detector

How do we work? Experimentalists Phenomenologists Theorists CERN Experiments: Accelerator Detector Analyses Just about every type of scientist and engineer you can name is involved in the construction of the CERN experiments. Varying career. The idea is to be mobile in the career, not become just an expert. It’s the learning phase that allows you to look at a problem from new angles. Out of 10 questions, 9 are stupid ideas due to inexperience but that 10th is a grain of gold which makes science and technology jump forward. Working in fundamental science, in particular particle physics, puts you in contact with physics, math, electronics, engineering, instrumentation and computing at the frontier of knowledge In a society where even the educational interface between scientists and public, the media, is corrupt by commercial and political pressure, fundamental science is also about spending a part of your time reaching the public directly and devising strategies to improve on general education! Technology Public awareness Training