CERN - at the heart of a network of excellence

CERN's new Chief Scientific Officer, Jos Engelen, is looking forward to a diverse research programme for CERN, but not simply for diversity's sake. He sees the Laboratory playing an important role in the most challenging developments. In an interview this week, he told the Bulletin about his dreams for the coming five years.

As the particle physicist on CERN's new Directorate, Jos Engelen carries a heavy responsibility. He brings to the Laboratory a wealth of experience - his most recent role was as Director of the Netherlands' National Institute for Nuclear and Particle Physics, NIKHEF - and he is determined to look to the future.
On questions of how the new slim-line Directorate can carry the workload of its predecessor, Engelen is very clear. "I'm not going to look back with you", he told the Bulletin, "after five years I'll be ready to do that." Today, what he sees is a distributed and highly inclusive management structure where everyone has a role to play. "There is not only a new structure," he explains, "there is also a new way of working, and there is a very explicit re-definition of how we deal with responsibility." In the new scheme, responsibility will be devolved, people will be empowered at all levels of hierarchy, and they will be judged on their results.

Exploiting synergies
In the new structure, it is not only the Directorate that is slimmed down, the number of Departments is also reduced. This responds directly to a recommendation made by the External Review Committee (ERC) established in 2001 to examine the CERN programme. The ERC's goal was to ensure that CERN's Executive board be of manageable size, and to assure a critical mass for each operational unit at CERN through exploiting synergies between different units. A case in point is the merger of the Experimental Physics and Theory Divisions. The end of an era? Not at all, according to Engelen. "There is absolutely no history that comes to an end there," he says, "it is very natural to merge the big Experimental Physics Division and the much smaller, but very important, Theory Division."
In Engelen's view, the new PH Department as a whole will become bigger than its EP and TH Division parts. Moreover, in determining the long-term strategy for CERN, he believes that theory has a vital role to play and is better placed to play it in the new structure. Theorists will continue to be involved in the research board, and they can now take on a greater role in the experimental life of the Laboratory than before. "The next PH Department head could be a theorist," says Engelen to underline the point.

Diversity where it counts
With some 5000 of the Laboratory's 6500 strong user community involved with LHC experiments, there's no question where CERN's immediate priorities lie. But short-term focus does not preclude long-term diversity. "Now is definitely the time to talk about post LHC start-up," says Engelen. The LHC programme will begin with beams bright enough to generate some 800 million collisions per second inside the big detectors. As if that were not enough, there is already talk of increasing the machine's luminosity. As Engelen explains, this means more than just adding to the number of collisions. "The protons are swarms of quarks and gluons distributing the proton's energy among them", he explains. "Higher luminosity means that the chance of two very high energy quarks or gluons colliding becomes a little bit bigger." At the LHC, this could lead to an effective energy increase of at least 20%. "That is definitely a possibility," he says "but it's not for tomorrow."
Coming back to diversity, Engelen points to the CLIC linear collider concept as a top priority for CERN-based accelerator R&D, underlining the Director General's wish for Member States to contribute more resources to the project. He also stresses the management's wish for CERN to fulfil its mandate to the letter, becoming not just a centre of excellence but a driving force in a network of excellence, a place where the European strategy for the whole field is discussed. "I see it as a challenge for us to enable development through collaboration with other high-energy physics labs and institutes in Europe," he says. This collaboration would cover the whole range of CERN's activity from pure physics to accelerator and detector R&D.
Turning to the research programme at CERN, Engelen sees a future programme that could be every bit as varied as in the past, but he wants to be convinced that everything that happens at CERN is of world-leading quality and is taking place at CERN because CERN is the best place to do it. If other laboratories are better placed, then CERN should support their programmes and work with them. As an example, Engelen points to the recently approved international facility to be built at the GSI laboratory in Germany providing high-intensity beams of heavy-ions and antiprotons. "This will have a realistic possibility to address part of our current fixed target programme," he says. "We will have to take this into account, as GSI will take our ideas into account." To Engelen, this kind of dialogue is vital to the continued good health of fundamental physics.
It all comes down to the concept of a network of excellence. "Should CERN pursue the whole breadth of the field?" asks Engelen. "My answer would be as diversified as possible, but not for the sake of diversification. CERN needs to be at the frontier."
Ambitious as that sounds, Engelen sees many potential avenues for diversifying the programme. In neutrino physics, CERN has a long tradition, but we need to keep a close eye on what is happening elsewhere in the world. In addition to the approved CNGS programme further very interesting ideas on CERN's role in this field are already emerging. In muon and hadron fixed-target physics, the COMPASS experiment continues an equally long CERN tradition. Kaon physics continues to deliver good physics, and the fixed target heavy- ion programme may have a complementary role to play to the ALICE experiment when the LHC comes on-stream. At lower energies, Engelen recognises the uniqueness of the antihydrogen programme, the ISOLDE facility and the n-ToF. In all of these, Engelen believes that CERN should examine very closely what its unique contribution might be.
So for the long term, CERN can look forward to a rich and varied programme of research. In the short term, Engelen makes it very clear where he believes the Laboratory's priorities lie - with the LHC, its experiments, and the LHC computing Grid. "We all know where we should be in twelve months," he says, "and I have every confidence that we'll be there."