Birmingham Experimental Particle Physics Consolidated Grant

Particle physics in general, and particularly the quest to understand the origins of mass through the Higgs boson, are in the mainstream of current public consciousness. With the CERN Large Hadron Collider (LHC) going from strength to strength, there has never been a more exciting time in the field. Birmingham is unique among UK universities in being involved in three of the four main LHC experiments, as well as a smaller scale CERN experiment which uses a fixed target. We study the particle collisions and decays observed in these experiments with the aim of determining the ultimate structure of matter and the forces of nature.

Our biggest activity is with the ATLAS collaboration, for which group member Dave Charlton is the deputy spokesperson. ATLAS is designed to study wide-ranging aspects of particle physics at the highest energies ever reached in the laboratory, the first priority being the search for the Higgs boson. From up to a billion collisions taking place per second, only around 400 can be permanently recorded and analysed. Our ATLAS group built, maintains and operates a major part of the ATLAS `trigger', the electronic brain of the experiment, which has the task of selecting interesting events such as candidate Higgs bosons, and reducing the data rate by a factor of 1000 within two millionths of a second after collisions take place. We are also very active in analysing the resulting data, with a particularly strong team working on Higgs searches and another investigating the production and decays of top quarks. Being the heaviest of the known particles, top quarks offer excellent sensitivity to previously unknown physics. Whilst top quark samples were small before the LHC era, ATLAS has already collected approaching 100,000 events.

The LHC is expected to operate until around 2030, but will need several shut-down periods during its lifetime, when the accelerator and detectors will be improved. We are already working towards an upgrade of our trigger to improve its selection capabilities and enable it to cope with the increased collision rates expected from 2018. Looking even further to the future, we will use our expertise in the bonding of electronics directly onto silicon-based detectors to make major contributions to a replacement for the inner part of the detector, which will be needed in around 2022.

Beyond ATLAS, our second key area of activity is in understanding the complex decays of heavy quarks. At the LHCb experiment, we are investigating the origins of the matter-antimatter asymmetry of the Universe by searching for tiny differences between the decay characteristics of b quarks and their antiquarks. We are relative newcomers to LHCb, having joined in March 2011 and taken on essential technical responsibilities in simulating the detector and enabling the use of the world-wide computing grid to perform distributed analysis. In the next few years, we aim to further develop these roles as well as our physics analyses, which are currently focused on rare decays of b flavoured particles.

Our NA62 group studies the decays of strange particles to search for new physics such as supersymmetry. The next grant period will be crucial for NA62, as it takes data to study an ultra rare process in which a strange particle, the kaon, decays to produce a pion, which is made of light quarks, and two neutrinos. This process occurs only once in every 10 billion kaon decays and only 80 events are expected in a two year run. Any hint of a larger rate would be a very clear indication of new physics. The group is leading several aspects of NA62 detector construction and data analysis.

Finally, the group contains central proponents of a possible future `LHeC' project to collide electrons with the LHC proton beam, as well as the long-standing linear electron-positron collider project. We will continue in these leadership roles and be ready to step up our involvement should the opportunity arise.

The group's work leads to high impact levels to society in general, to the physics community and through our knowledge transfer activities.

The group is internationally leading in its outreach work, introducing particle physics to wide audiences of both the general public and school students. For the general public, the impact is at a cultural level: people are ever more curious to understand the basic building blocks of nature and their imagination is captured by the LHC more than by any previous scientific endeavour. Our work with schools helps to engage students in science in exciting ways. As is by now well documented for example by the IOP, the effects of the high profile developed through particle physics outreach work has a measurable effect on numbers of students applying to study physics at University. Some examples of our outreach work are briefly outlined below.

Our `Discovering Particles' display was staged at the British Science Festival 2010 and the Royal Society Science Exhibition 2011. The latter stand attracted about 8000 visitors over 6 days. The associated resources which we developed are widely used. Similar planned events for 2012 include the NEC Big Bang Fair and participating in BBC ``Bang Goes the Theory LIVE" roadshow. Together with the Birmingham Think Tank museum, we have created a display of a set of short videos, introducing physicists, engineers and technicians from ATLAS, which have been used to form an exhibition visited by more than 10000 people. We have developed a simplified version of our ATLAS event visualisation package, which is freely downloadable for members of the public to learn about particle physics signatures and detectors and has been used by more than 8000 school students in Europe and the USA in masterclass events. We demonstrate our spark chamber, cosmic ray scintillator and cloud chamber in schools more than 20 times per year, run `CASCADE' competitions in which schools produce particle physics outreach material of their own, and we have developed a `Particle Physics Manager' computer strategy game. We have a strong media presence, with group members making regular appearances on TV, radio and in the printed press. Group members also give frequent lectures on particle physics and the LHC in schools, scientific societies and elsewhere.

Our primary current knowledge exchange activities are based on exploitation of our expertise and facilities in silicon / electronics assembly and distributed computing. The silicon work has grown out of the high-performance ultrasonic wire-bonding work which the group did in constructing the ATLAS semi-conductor tracker. In collaboration with industrial partners, Aero Engine Controls, we have constructed 20 prototype electronic boards, designed to function at very high temperatures, for example in aircraft engines. Together with the new West Midlands Manufacturing Technology Centre (MTC), we are in the process of gathering collaborators to secure Technology Strategy Board funding with a view to developing a manufacturing process to commercialise this work.

We are exploiting our distributed computing / grid knowledge obtained in the context of the `Ganga' grid interface framework in collaboration with computer science start-up companies, to develop tools for web search engines. For example, we have deployed a `web-spider' on the grid, which searched the content of billions of web pages and built unprecedented levels of statistics on relative occurrences of different combinations of words, with applications from predictive text to understanding sentence structure.