UK news from CERN Issue 30: 8 October 2013

In this issue:  Nobel news! – time to celebrate  Cows, clouds and climate – new results re’veal’ important mechanism that cools our climate  In the hot seat – new Physics Coordinator for ATLAS  Our universe is yours – CERN’s public open days  Dates for the diary

Nobel news! The CLOUD collaboration has published results in Nature that show that amines - atmospheric vapours closely related to - combine with sulphuric acid to form highly stable aerosol particles at rates similar to those observed in the atmosphere. The collaboration has found that typical atmospheric concentrations of only a few amine molecules per trillion air molecules are sufficient for rapid particle production.

Increases of atmospheric aerosol particles cool the planet by reflecting sunlight and by forming smaller but more numerous cloud droplets, Peter Higgs and the CMS experiment © CERN which makes clouds brighter and longer-lasting.

Warmest congratulations to Professor Peter According to current estimates, about half of all Higgs (Edinburgh) and Professor Francois cloud drops are formed on aerosol particles that Englert (Universite Libre de Bruxelles) who have were ‘nucleated’ from trace atmospheric vapours rather than being directly emitted from been awarded the 2013 Nobel Prize for Physics. The award is made “for the theoretical discovery Earth’s surface, like sea spray particles. Despite of a mechanism that contributes to our its importance for climate, atmospheric particle understanding of the origin of mass subatomic nucleation is poorly understood – and even the particles and which recently was confirmed vapours involved are not yet established. through the discovery of the predicted fundamental particle by the ATLAS and CMS The team chose to study amines because they experiments at CERN's ”. are known to form strong chemical bonds with sulphuric acid and their presence might help stabilize embryonic sulphuric acid clusters Cows, clouds and climate against evaporation, allowing new aerosol particles to form. Amines arise from human The CERN CLOUD experiment has just made a activities - primarily animal husbandry such as major step forward in the understanding of a cattle - and also from natural sources. Amines critical aspect of our climate. The experiment is are responsible for the familiar odours being carried out by an international and emanating from the decomposition of organic interdisciplinary team of 19 institutes which matter that contains proteins. For example, the include the Universities of Leeds and smell of rotten fish is due to trimethylamine. Manchester.

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Written and edited by Stephanie Hills, UK Communications and Innovation Officer @ CERN [email protected] or Stephanie.hills@.ch

activities, but they have not been considered so

Cattle are one source far by the Intergovernmental Panel on Climate of amines, and are Change (IPCC) in their climate assessments. more photogenic The CLOUD experiment has therefore revealed than rotting fish an important new mechanism that could © S Hills contribute to a presently unaccounted cooling effect. This will need to be considered in future by the IPCC when assessing the impact of human activities on past and future climate. In Using CERN know-how, the CLOUD chamber particular, amine emissions from human has achieved much lower concentrations of activities are expected to increase rise amine contaminants than all previous experiments, scrubbing is likely to become the dominant allowing the collaboration to measure nucleation technology to capture carbon dioxide from due to controlled amounts of selected trace fossil-fuel power plants. gases without the complicating effect of unwanted gases. State-of-the‐art instruments In the hot seat connected to the CLOUD chamber measure extremely low concentrations of atmospheric ATLAS has a new Physics Coordinator. Bill vapours and the molecular makeup and growth Murray (RAL and Warwick) will be in the hot of newly‐formed molecular clusters from single seat for the next 12 months. molecules up to stable aerosol particles. As a long-standing member of the ATLAS Another unique feature of CLOUD is the collaboration, Bill has held a number of roles, capability to measure nucleation enhanced by until being elected as Deputy Physics cosmic rays at intensities between ground level Coordinator. Any assumption that stepping up and (using a CERN pion beam) the top of the from the deputy role just means more atmosphere - or with the effects of all ionisation responsibility is misguided; the jobs are very completely suppressed by an internal electric different. “I’m now supposed to know the field. The CLOUD results show that physics output of 3000 people,” says Bill. ionisation has only a small effect on the “That’s an impossible challenge!” formation rate of amine-sulphuric acid particles but they don’t rule out more significant effects if sulphuric acid particles nucleate with other vapours in the lower atmosphere. Bill Murray in Atlas

© Richard Prolifka The CLOUD collaboration has made the first ever measurements – either in the laboratory or in the atmosphere – of the formation rates of atmospheric aerosol particles that have been identified with clusters of precisely-known molecular composition. The precise laboratory measurements have allowed the authors to The one thing that Bill definitely won’t be doing develop a fundamental understanding of the in the next year is any physics. He sees the new nucleation process at a molecular level. The role as being a manpower manager and trouble- scientists can even reproduce their experimental shooter, working closely with ATLAS Deputy results using quantum chemical calculations of Spokesperson Beate Heinemann to keep the molecular clustering. collaboration working smoothly.

No-one expected that the formation rate of It’s a critical time for the physics coordinators in aerosol particles in the lower atmosphere would all the LHC experiments. There are data be so sensitive to amines. A major fraction of analyses to complete and preparation for not amines in the atmosphere arise from human only the second experimental run scheduled to Page 2

Written and edited by Stephanie Hills, UK Communications and Innovation Officer @ CERN [email protected] or [email protected] start in 2015 but also the physics value of analysing ATLAS data. As he points out, “The possible upgrades to be evaluated. Managing collaboration has so far completed seven computing resources is top of Bill’s ‘to do’ list. papers which use the full 2012 data - there are at least another 100 to come!” “With more collisions, we’ll be generating twice as much data. That data needs to be captured, But that’s the long-term plan – for the next 12 but our computing resources won’t be months Bill’s mandate is to have ATLAS fully increasing. This gives us a major challenge; prepared for Run 2. we’ll have to reduce the data density, but that restricts the physics that members of the Our universe is yours! collaboration can do. For example, in Run 1 we recorded every W boson decay. We might not Curious families mingled with die-hard physics be able to do this in Run 2.” fans to see behind the scenes at CERN on 28 and 29 September. CERN open days are rare A big part of Bill’s job will be to manage the (the last one was in 2008) and a packed expectations of members of the ATLAS programme of talks, tours, exhibitions and collaboration. hands-on fun entertained and inspired more than 70,000 people. With each post holder only being Physics Coordinator for 12 months, there is limited All four LHC experiments and two tunnel access scope for starting projects and seeing them points were open for members of the public to through to conclusion. Many members of the go underground along with 42 different activities collaboration are still poring over the data points aboveground. generated in the first experimental run, but Bill has his eye on the future. He is keen to get The success of the open days depended on more members of the collaboration to think more than 2300 volunteers from CERN staff and about the ATLAS physics goals from 2022 the user community. UK News from CERN onwards. “The technical design reports for the asked some of the British volunteers to share next major upgrade are being produced at the their reasons for getting involved. moment and we’ll be drawing up the spec. for the new tracker. That spec. is going to define the type of physics that we’ll be doing in 15+ Even the CERN years’ time so people need to give us their DG volunteered proposals now.” © CERN

Bill has his own research ideas; as a physicist who spent 20 years looking for the Higgs boson, he’s interested in finding out more about this new particle. One theory that interests him is James the existence of a ‘heavy’ Higgs boson that Catmore (Lancaster) is a post doc in the ATLAS decays into two Higgs bosons of the type that collaboration. He spent the weekend talking to CERN discovered last year. His own post-2020 visitors about the Higgs discovery and particle proposal is to look for evidence of Higgs self- physics in general, as well as grid computing interaction. and superconducting magnet technology. He also helped children design and build their own Having recently taken a joint appointment with particle detectors using Lego. University of Warwick, Bill has joined a department that has a presence on two of the “The Open Days were enormous fun, if a little four LHC experiments; Tim Gershon, the tiring - explaining what a dipole magnet is to a Physics Coordinator at LHCb is also from group of 50 people, in a tent upon which Warwick. Bill will be setting up a small research torrential rain is falling, needs a very loud voice team and he’s looking forward to getting back to and a lot of stamina! Page 3

Written and edited by Stephanie Hills, UK Communications and Innovation Officer @ CERN [email protected] or [email protected]

weekend. The two sons aged 12 and eight had “There were quite a few highlights for me: being asked to visit the LHC as a reward for doing well asked by a visitor from New Zealand when our at school. This was quite a surprise to their dad discoveries would make his car start first time; who had expected them to want to go to Alton watching an older sister steal her little brother's Towers or Disneyland. Lego bricks in order to build a better detector, and seeing the astonishment in people's eyes as we told them about the scale and Riding the significance of the work we are doing here.” maglev scooter

© CERN

Seeing ATLAS for the first time

© CERN Sue Foffano (CERN) was showing people

around the Computing Centre. Her day job is as the Worldwide LHC Computing Grid Resource

Manager and Scientific Assistant to CERN That sense of wonder was a little more personal Director, , “I spoke with people for Conor Fitzpatrick, a CERN Fellow working from the US, New Zealand, Finland, Sweden, on LHCb. Conor was an underground guide Italy, Germany, UK and, of course, France and and crowd marshal at LHCb, “I finally got to see Switzerland, all of whom had organised their the LHC tunnel after six years of being involved vacation or visit to the area based on the dates with CERN; I was able to tell my first group of of the Open Days. It was a rewarding visitors that it was as new to me as it was to experience to see the high levels of interest them! The other highlight was opening the amongst our visitors.” cavern door to the LHCb experiment and watching the smiles break out on the faces of “It’s just great to be part of this fascinating each visitor as they entered the cavern, one by place”, adds Sharon, a member of the CERN one; you could see the amazement and sense Recruitment team, “and the open days mean of awe as the scale and complexity of the that we can share our enthusiasm with others experiment came into view. That was easily the too. What we do here is no longer a mystery – best part of the tour as a guide, and it happened sharing is so important. I met so many people for every group I took down.” who had come over from the UK just for the day – first flight out and last one back – amazing!” Conor is very clear about the importance of the CERN Open Days: “they give the public an How to subscribe opportunity to put a human face to the science they hear snippets of in the news, they inspire To subscribe to (or unsubscribe from) UK News future generations of young researchers, and from CERN, please contact Jill Little. they give us a chance to share our enthusiasm in our work with the people whose taxes are Back issues of UK News from CERN are funding these incredible machines.” available from the archive.

People travelled from all over the world to come Diary dates to the Open Days including many from the UK. Conor spoke to an A-level student who had Public Engagement Symposium – 25 November brought her family over to see CERN, and was CERN Council – 9 – 13 December taking notes throughout the tour. Sharon

Hobson (CERN) was delighted to meet another family who had travelled to Geneva for the

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Written and edited by Stephanie Hills, UK Communications and Innovation Officer @ CERN [email protected] or [email protected]