The Intersecting Storage Rings

CERN 60 Years

In 1965, CERN Council approved a project that was to go beyond the basic programme agreed in the convention signed in 1953 ("CERN and UNESCO celebrate signing the CERN Convention"). The Intersecting Storage Rings not only greatly extended the energy reach of experiments at CERN by being the world’s first hadron collider, the project also required the extension of CERN’s site into France, in an agreement signed in September 1965. The black-and-white photo shows the ISR under construction in September 1970. While the fields in the foreground are in Switzerland, the building site is all in France, since the border dog-legs in the direction of the woods to the top left. Meyrin village is dimly visible to the top right. The colour photo shows the site taken from the opposite direction in January 2004, with the Jura mountains in the distance. The water tower is clearly visible in both images.


Half a century of Bell’s theorem

This year sees the 50th anniversary not only of the proposal of quarks, but also of what is arguably one of the most groundbreaking theoretical findings in physics: Bell’s theorem (Bell 1964).

To celebrate the theorem and the work of the Irish physicist John Stewart Bell, who was on leave from CERN when he wrote his seminal paper, the University of Vienna held the conference Quantum [Un]Speakables II on 19–22 June. Distinguished invited specialists in the question of non-locality brought up by Bell’s theorem discussed the impacts of the theorem and the future of scientific investigations, together with 400 participants.

John Clauser, who was the first to investigate Bell’s theorem experimentally, mentioned the difficulties he had in acquiring money for his experiments. The breakthrough did not come until the 1980s, when Alain Aspect measured a clear violation of Bell’s proposed inequalities. The philosophical debate between Niels Bohr and Albert Einstein on whether quantum mechanics is complete or not thus seemed also to be settled experimentally – in favour of Bohr. In his talk, Aspect stressed Bell’s ingenious idea to discover the practical implications of what had until then been merely a philosophical debate.

An important further development of Bell’s theorem was the Greenberger–Horne–Zeilinger experiment, in which the entanglement of three instead of only two particles was considered. Another important contribution was achieved with the Kochen–Specker Theorem – next to Bell’s theorem, this is the second important "no-go" theorem for hidden variables in quantum mechanics. In their talks, Daniel Greenberger, Michael Horne and Simon Kochen focused on current questions in their research. Anton Zeilinger, who was co-chair of the conference with Reinhold Bertlmann, stressed the huge impact of Bell’s theorem for technical applications: quantum computing, quantum teleportation and quantum cryptography, which are based on the concept of non-locality as outlined by Bell.

More personal remarks came from Bertlmann, who had worked with Bell as a postdoc at CERN and is the protagonist of his famous paper "Bertlmann’s socks and the nature of reality", and from Bell’s widow Mary Bell, an accelerator physicist.

The conference title refers to a paper that Bell wrote in 1984, in which he identified what he called "unspeakables". These are notions that he wanted to eliminate from the vocabulary of physics, because for him they did not qualify as well defined – among them measurement, apparatus and information. However, the title also allowed for another meaning. After 50 years, many important implications of Bell’s theorem have been found, but there is much that follows from the theorem that no one talks or even thinks about yet, and so is still to discover.

Further reading
Videos of the talks will be available on the website of the Austrian Central Library for Physics of the University of Vienna. Visit http://bibliothek.univie.ac.at/zb-physik-fb-chemie/austrian_central_physics_library.html.
J S Bell 1964 Physics 1 195.


MoEDAL prepares for new physics at LHC restart

The MoEDAL (Monopole and Exotics Detector at the LHC) collaboration – which now consists of 64 physicists from 21 institutes worldwide – held its second CERN-based collaboration meeting on 19–21 June. There were many new collaborators at the meeting, from Canada, Finland, Italy, Korea and the UK. Notably, the most recent addition to the MoEDAL collaboration – the Langton Star Centre based at the Simon Langton Grammar School for Boys in the UK – was represented by Becky Parker and Tom Whyntie. A high school as a collaborating institute in a high-energy-physics experiment is surely a world first.

The meeting had two main themes: first, the installation of the full detector system around the LHCb experiment’s relatively open interaction point; second, the exploitation of the extensive and potentially revolutionary fundamental-physics reach of the experiment. MoEDAL’s purpose is the search for highly ionizing particle avatars of new physics, such as the magnetic monopole and massive (pseudo)-stable charged particles. In this way, it expands the discovery horizon of the LHC in a complementary way. Unlike other LHC detectors, MoEDAL is largely passive, except for its system of TimePix pixel devices (TMPX) for real-time radiation monitoring. It has a dual nature, capable both of "photographing" signals for new physics via its nuclear-track detector system (NDT) and of capturing highly ionizing particles in its magnetic monopole trapper (MMT) volumes. Importantly, it is the only LHC detector that can trap and detect magnetic and electric charge.

The first day of the collaboration meeting concentrated on physics issues. Nick Mavromatos of King’s College London, the physics co-ordinator, set the scene with a review of the MoEDAL experiment and its aims. The first invited speaker was Yongmin Cho from Konkuk University, who was the first to show that there is a singular topological monopole solution of the Weinberg–Salam model – an "electroweak" monopole. Next, Philippe Mermod of the University of Geneva reminded participants that the hunt for cosmic monopoles is a vital complementary aspect of the search for magnetic charge.

The final talk of the first day introduced a poignant note to the proceedings, as Laura Patrizii from INFN Bologna spoke of the seminal contributions that Giorgio Giacomelli made to the quest for the magnetic monopole. Giacomelli, who was MoEDAL’s deputy spokesperson, died early in 2014 (CERN Courier June 2014 p45). He was remembered not only as a leading experimental particle physicist but also as a great human being. As a token of respect, the collaboration dedicated its recent paper on MoEDAL’s physics programme to his memory.

The second day was devoted to detector issues and to how the data will be gathered and analysed. Vasliki Mitsou of the University of Valencia started the day with a report from the MoEDAL software group, which has the important task of understanding how the detector will respond to the highly ionizing particles of various new-physics scenarios. MoEDAL’s technical co-ordinator, Richard Soluk of the University of Alberta, then described the plans for the detector installation. The main challenge here is the need to co-ordinate with the LHCb collaboration, which shares the same intersection region.

The next order of business concerned the reports from the sub-detector groups: Mermod for the MMT, Petr Beneš of the Czech Technical University for the TMPX, and Vincent Togo of INFN Bologna for the NTD. A member of the University of Münster’s MoEDAL group gave the last presentation of the day, before the attendees went to visit the experiment site. He described the development of an exciting new computer-controlled ultra-fast scanning microscope for analysis of the NTDs.

At the end of the three-day meeting, the mood of the collaboration was buoyant and optimistic. Although there are challenges to face, there are no show-stoppers. The MoEDAL experiment is well on its way to meeting the discovery challenge of its first data run at the next high-energy frontier of 13 TeV, which will open up in the spring of 2015.


Visits

The Georgian minister of education and science, Tamar Sanikidze, centre right, visited CERN on 4 June. Before seeing the CMS experimental cavern with deputy spokesperson of the CMS collaboration Kerstin Borras, right, she was shown a scale model of the detector.

On 6 June, Ying-tai Lung, Taiwanese minister of culture, centre, witnessed an "Accelerate@CERN" agreement between Taiwan and CERN, signed by the director of the Taiwan Cultural Centre in Paris, Hsiao-ying Tsai, left, and CERN’s director-general, Rolf Heuer, right. This agreement allows Taiwanese artists to apply for a one-month residency at CERN.

K Kellie Leitch, centre right, Canadian minister of labour and minister of status of women, came to CERN on 10 June, visiting the ATLAS underground experimental area, in the company of ATLAS collaboration spokesperson, Dave Charlton, right.

During a visit to CERN on 11 June, Seán Sherlock, Irish minister of state, Department of Enterprise, Jobs & Innovation and Department of Education & Skills with responsibility for research and innovation in Ireland, left, was shown the LHC tunnel by CERN’s director of accelerators and technologyFrédérick Bordry, right

Right to left: Japanese vice-minister of education, culture, sports, science and technology Tsutomu Tomioka, in the LHC tunnel during his visit to CERN on 2 July, where he saw the inner triplet magnets constructed by KEK in Japan and Fermilab in the US, accompanied by ATLAS physicists Katsuo Tokushuku and Tatsuo Kawamoto, and Yuko Nagano, Japan’s Strategic Programs Division.