Discovery of Matter Anti-matter Asymmetry in the Charm Sector

Symmetries play an essential role in our understanding of the universe. Nature exhibits a stunning level of symmetry across all scales, from the bilateral symmetry of many animal's bodies to the mathematical symmetry of the fundamental physical laws. But only the imperfections of symmetries reveal the full picture. In astrophysics for example, the anisotropy of the cosmic microwave background radiation has given insight into the structure of the universe roughly 300,000 years after the big bang.

At the Large Hadron Collider (LHC) we study the type of physics which governed the processes just a fraction of a second after the big bang. The LHC, located 100m underground just outside Geneva, collides protons at energies that have never previously been reached in a laboratory on earth. The smallest of the four large experiments at the LHC is known as LHCb, and is specifically designed to discover asymmetries in the behaviour of matter and antimatter.

In our current understanding, matter consists of twelve fundamental particles: the six quarks (u, d, s, c, b, t ordered by increasing mass), and an electron with its heavier partners muon and tau and their three associated neutrinos. These interact by the exchange of so-called bosons, which are fundamental force carrying particles. The standard model of particle physics (SM) explains these matter interactions and has so far held up to all experimental tests. However, it fails to give explanations to basic questions like the reason why the t-quark is over 50,000 times heavier than the u-quark. Another is the puzzle that perfect symmetry would lead to equal amounts of matter and antimatter and the annihilation of the universe shortly after the big-bang. Questions like these tell us that the SM does not cover all aspects of fundamental interactions and therefore has to be extended.

Nature has given us three special laboratories to study matter and antimatter interaction: neutral mesons (called K, B and D-meson), particles consisting of one quark (matter) and one antiquark (antimatter). Studies of the decays of these mesons have proven to be an excellent laboratory for discovering differences between the matter and anti-matter world. The studies of two of these systems (K and B mesons) have led to Nobel-prize winning breakthroughs. Together with a post-doctoral researcher, I will search for tiny differences of decays of D-mesons and anti-D-mesons. Half a year ago, scientists from the LHCb experiment have published a measurement showing a first indication for such a matter anti-matter asymmetry.

Our group will focus on complementary measurements that are necessary to understand the origin of this asymmetry. Within the SM the relations between our measurements are predicted to high precision. Deviations from these predictions will unveil the presence of thus far unknown particles which are involved in this process.

Particle physics research continues to lead to technological benefits to society, from the World Wide Web to medical imaging, but its true purpose will always be the search for fundamental understanding of our universe. My goal is to further this understanding, using the matter-antimatter asymmetry to reveal nature's beauty. And true beauty lies in imperfections.

Particle physics experimentation is a technologically demanding discipline, and the innovations it generates have wide economic and societal benefits. It is also a key subject in attracting young people to study science and generating public interest in physics.

1.Educational Activities

Nearly 300 of the UK's top students choose to study physics at Manchester each year. Students are attracted by the strong research programme in fundamental physics and the close contact they will have with leading researchers. The school is keen to ensure that forefront research is taught to undergraduate students. I plan to contribute with the PDRA to

a) Lectures in the "Frontiers in particle physics" course for final year MPhys students on matter anti-matter asymmetries.

b) Laboratory based particle physics projects for 3rd year students.

c) Supervision of MPhys student final year projects to support new avenues of my research in charm CP violation.

d) Supervision of Manchester and CERN summer student projects in support of my research programme.

e) The Manchester group will support my charm physics programme with the appointment of at least two dedicated PhD students. One student will work on the time-dependent analysis that form the core component of my Fellowship, and a further student will utilize the new techniques for time-integrated analyses that will be developed by the PDRA on this grant to perform a complementary analysis.

The broad range of skills in particle physics from detector development via theoretical modeling to data analyses provides every student an excellent starting point for a wide range of future career opportunities.

2. Technological Developments with Economic and Societal Impact

The activity on silicon detectors for the LHCb Vertex Locator (VELO) upgrade which I will pursue in my fellowship will have direct economic impact.

a) This research is achieved through collaboration with partners in industry, and the current VELO led to the introduction of new product lines at two UK companies.

b) The detectors developed would have wide ranging potential impact for use in fields as disparate as next generation light sources (e.g. Diamond), neutron detection for the security sector, or medical imaging applications (e.g. Medipix Collaboration).

3. Outreach and Dissemination Activities

I recognise the importance of outreach activities for the promotion and dissemination of scientific results to all members of the academic community and the public. I plan to contribute with the PDRA to

a) In September 2013 I will host the "6th International Workshop for Charm Physics" at the University of Manchester, the leading conference in this field of research. The PDRA will take a leading role in the preparation and execution of the conference.

b) Since 2005 I have participated in numerous outreach activities: science festivals, open days, media events, exhibitions, and press interviews (printed and radio). The PDRA will participate in my activities through the presentation of the LHCb experiment to groups of students, journalists, and politicians. In the UK, the PDRA will participate school visits and science fairs.

c) I am applying for a grant from the STFC Small Award Scheme for Public Engagement. With this grant I will produce, with the Manchester technical staff and the assistance of the PDRA on this grant, a set of coupled swings. Using this setup children and adults alike can experience the equivalent physics of meson mixing on themselves. This exhibit will be used at science fairs and outreach activities across the UK.