Consolidated Grant 2015

The research of the experimental particle physics group addresses some of the main questions in fundamental physics. One of the most pressing is what is the mechanism that is behind the overwhelming dominance of matter over anti-matter in the Universe? Matter and anti-matter should have been created in equal quantities in the early Universe, yet the gross difference in their natural occurrence is a defining feature of what we observe. Without this asymmetry life could not exist. We believe that neutrinos may hold the key to understanding the matter-antimatter asymmetry. Neutrinos, discovered almost a century ago, are the most evanescent of particles. They have no charge, barely interact with matter and were long thought to be completely massless (like a photon). They can travel through the earth with only the tiniest probability of leaving a trace. To detect neutrinos we have had to build enormous but very sensitive detectors. Our experiments show that neutrinos actually have a very small but significantly non-zero mass. This small non-zero mass allows them to drive the matter-antimatter asymmetry in the early Universe. An important part of our research is to make detailed measurements of the neutrinos, to understand their masses and to calculate if their properties are indeed those required to explain the matter-antimatter dominance.

The discovery of the Higgs particle was one of the most important in the last decade. It confirmed the existence of a fundamentally new type of "force" that pervades all of nature and gives mass to elementary particles. Without the Higgs, particles such as electrons could not bind to protons to make hydrogen atoms. Thus normal atomic matter, even stars, could not be formed. We continue to study the Higgs to measure and understand its properties. We are especially interested to see if the Higgs particles provides a window to what we call the "dark universe". It has long been known that there is not enough visible matter in the Universe to explain the speed at which galaxies rotate. There are simply not enough stars. The only explanation appears to be that surrounding us, and in all galaxies, there is a halo of invisible matter which exerts a gravitational influence (hence why the galaxies spin as fast as they do) but which does not interact with light. Calculations suggest there is 5 times more of this dark matter than visible matter in the Universe. The Higgs could interact with dark matter, thus we can use the Higgs to "illuminate" the dark sector for the first time. This is an important part of our research.
Observations also suggest that the Universe is inflating, as if there is pressure created by space itself. This process is observed but non-understood. It strongly suggests there is another form of dark energy at work. Altogether the dark universe accounts for 95% of the matter/energy in the Universe with only 5% (that we can observe) being luminous. This makes the study of the dark matter and energy absolutely central to our understanding of the fundamental nature of our world. Thus we have joined experiments whose aim is to try and study and uncover the true nature of dark energy.

Our theory of how all particles interact is embodied in what is called the Standard Model. With the exception of neutrinos and their masses it has enormous predictive power and provides a simple framework for elucidating the nature of the universe. Following the scientific method we continue to refine and test the SM at the energy frontier and with dedicated precision experiments. This provides another, and well tested route, to the discovery of new physics.

The impact of the group's research can be summarized in two main areas. First in terms of the direct economic and technological outputs which support industry and R&D outside of our own research base. Second in terms of the societal impact beyond the research itself.

The economic and technological impact is driven in our group by our detector R&D. Our traditional area of strength being radiation hard position sensors, neutrino detector technologies and recently atomic interferometry. Before 2011 the group's strategy was largely serendipitous, and concentrated on low TRL level projects. Translation of our R&D into the economy was performed by long standing partners (Micron Semiconductor, Hawk Electronics, Stevenage Circuits) with whom we built the LHC detectors. Micron and Hawk have won industry awards for their work with us and both improved their sales, product catalogue and capabilities. Our LHC era silicon technology still remains at the forefront of sensor production world-wide with companies (e.g. HPK) providing offerings whose origins lie in the devices we have developed. However, since 2012 we have aimed at revitalising our impact. We are now trying to take all our projects through to commercial exploitation retaining direct involvement. We expect first results to appear in the period 2015-2020.(See our pathways to impact document). We list here the projects underway.
1) GAMBE: This is a gamma blind neutrino detector technology with substantial IP. This is being extended to both hand-held devices and for oil well explorations. A company will be formed to sell and market this product.
2) Reactor Monitoring: This is a TRL-6/7 level project that has just received over £1M from Innovate UK. It permits "stand-off" monitoring of the state of a reactor. Working with JCS Ltd. we are striving to make this the IAEA mandated/approved standard.
3) We were funded in FP7 (Modes - Special Nuclear Materials) to create a low-cost high sensitive scanner for ports of entry. This has been successfully tested at Heathrow and Rotterdam. Commercial exploitation will take place with our partners Arktis.
4) During the last grant round we developed water based phantoms for hadron therapy ( with Clatterbridge Oncology Centre). Based on our early work on using LHC sensors in Clatterbridge we joined a consortium (Pravda) funded by the Wellcome Trust to build the sensors for a Proton Computed Tomography system. Liverpool provided the high precision sensors and readout system. This will move to a clinical evaluation stage in the next 24 months.
5) At the lowest TRL level, but with support from industry, our work on atomic interferometry is focussed on producing gravitometers and gradiometers for remote scanning.
Over the next year Sensor City UEZ will be built in Liverpool. This is a £15M University Enterprise Zone, and the idea was originated in PP. This promises to be transformative for the local economy. It is supported by over 100 companies and we are asking STFC to follow EPSRC and use it as a platform for developing PhDs with entrepreneurial skills.

Our societal impact is directly manifested through our outreach, and is mostly focused on school children and their parents. We are aiming to expand this programme to put small PP experiments into schools, and to involve parents from non-scientific backgrounds. This is now performed in concert with the Ogden trust (see the CG) and we reach out to over 10,000 students a year. We are aiming to bring a new generation of PP experiments to schools in the NW. Through Prof. Tara Shears we have presence on television and radio and in print media. She has presented at Ted-X and at other cultural events. In 2014 an entire floor of the Victoria Gallery and Museum in Liverpool was given over to the history of PP. This will be on show for 3 years. Through the efforts of Dr. Girish Patel LHCb VELO detectors were exhibited at the London Science Museum.