Experimental Particle Physics at the University of Edinburgh

The Particle Physics Research Group at the University of Edinburgh participates in the programme of research at the Large Hadron Collider in Geneva. The LHC is the most complex machine ever built, and creates conditions of energy density and temperature which existed at approximately 10^-12 seconds after the big bang when particles existed under very different conditions. With these conditions new particles can be created which we can study. At Edinburgh we are working in two different areas.

In the first of these we work at the LHCb experiment. Prior to the 1960s, it had been thought that the laws of physics were symmetric under the combined operations of exchanging particle for anti-particle and reversing the parity of the particle. Under such conditions matter and anti-matter would behave in the same way. However, it was discovered that this symmetry was violated, and that matter does not behave in an identical way to anti-matter. In terms of the Standard Model (SM) of particle physics this is embodied in the phenomenon of CP violation arising through the CKM matrix. CP violation is essential to understanding the early universe. At early times there were equal amounts of matter and anti-matter. Under general assumptions of CPT symmetry and thermal equilibrium, this situation would have remained so as the universe expanded. During this expansion and cooling, matter and anti-matter would have annihilated into photons to leave a universe full of radiation, but no stars and galaxies. It was shown in 1967 by Sakarov that if three conditions were met, then it would be possible for a small imbalance of matter over anti-matter to accrue. This imbalance would be only 1 part in 10^9, but would be sufficient to explain the existence of the universe. These conditions demand that CP is violated in the laws of physics. Given this far-reaching link between particle physics and cosmology, experimenters have been seeking to understand this phenomenon for many years. The b-quark sector is the best place to further our understanding and this is domain of the LHCb experiment. LHCb is the next generation experiment to further these studies and will improve the accuracy of many measurements by orders of magnitude.

In the second area we work at the ATLAS experiment. ATLAS is one of two detectors able to study a wide variety of particles created from the collision of protons, and can address fundamental questions. The most well know question is that of the origin of mass, and the most famous particle being sought is the Higgs boson. The Higgs is necessary because the beautiful symmetry (gauge symmetry) which underlies our understanding of particle interactions inherently demands that all particles are massless. This cannot be the case and the elegant solution put forward is now known as the Higgs mechanism. Discovery of the Higgs boson would be the proof that that this is true. Another area addressed by ATLAS is that of the search for supersymmetry whereby all particles we know of have a so called super-partner differing by one half unit of spin. If this proved to be true it would help solve many problems. One of its most important consequences would be a candidate for dark matter, which makes up about 25% of our Universe, and about which we know nothing.

We are also working hard on the planning, design and development for the upgraded detectors at the LHC for around 2018. The intensity of the beans will be increased and the data rates recorded by the detectors will increase by orders of magnitude. This requires development of new detectors and electronics.

In this grant application we request support for the Edinburgh Particle Physics Research Group, including academic staff and post-doctoral researchers to further all of these areas.

Society will benefit from the wider implications of the work, for advancement in all areas of science is fertilised by advances
which originate in unlikely areas. This work will constrain some of the major outstanding questions about the Universe.
The origin of CP violation and the search for CP violating mechanisms beyond the standard model will provide valuable input to models
used to explain the matter anti-matter asymmetry in the early universe needed to understand why we exist.
The search for now particles appearing in quantum loops will provide insight into models needed to understand the the origin of
mass and the possible discovery of super-symmetry could help understand dark matter.

We will continue our programme to engage, enthuse and educate the general public,
pupils in secondary school education and
physics teachers, in science and in fundamental physics.
Due to our position as Peter Higgs' Institute and as one of only two LHC
groups in Scotland, with its own educational and political system, we have a
responsibility to engage with the local and national community to communicate
the benefits of our research.
A main resource for our public engagement activities will be the continuation and
extension of our Particle Physics for Scottish Schools roadshow programme
We will continue to exhibit the PP4SS at the Edinburgh International
science festival as well as using it in our calendar of visits to schools, both
local and further afield. With the phasing-in of the new Scottish Curriculum for
Excellence, particle physics is being
included in Scottish secondary school education for the first time.
We plan to host a residential weekend workshop for around 50 physics school
teachers from across Scotland.
Given the wide geographical spread of Scotland, using the teachers as
multipliers is a very effective way of targeting engagement at school pupils.
We also will continue to foster our existing links to the Scottish authorities
to promote our field as one which combines the generation of fundamental
knowledge with the driving of leading-edge technological developments, the
inspiration of the coming generations of students of scientific faculties and
the education of students to highest standards before they branch into
industry.

In addition to our public engagement activities we see new scope to facilitate knowledge
exchange with the commercial private sector.
We can share our experiences in the use and application of test,
measurement and analysis procedures and by providing access and training to
state-of-the-art technologies.
Small and medium size commercial players may not have the resources to set up
and develop the research and development capabilities we have.
Instead it may be efficient and cost-effective for them to set up project based
collaborations with us, to advance their innovation cycle.
We will offer the spectrum of capabilities of our Advanced Detectors
Development Centre (ADDC), comprising measurements in the dark, under
controlled illumination, in magnetic fields, under controlled irradiation and
climatic conditions, determining Quantum Efficiencies of photon detectors,
failure analysis on wafer and die samples under controlled temperature cycles
and ageing profiles.
The promotion of these opportunities for commercial partners will be facilitated
through the structures of the research services and commercialisation
company, ERI, of the University of Edinburgh in collaboration with the School
of Physics and Astronomy's Business Development Executive and the Knowledge
Transfer officer of the Scottish Universities Physics Alliance (SUPA).