PhD in the Spotlight: Rosemarie Aben

9 June 2015

Rosemarie Aben (1985) will be awarded her doctorate at the University of Amsterdam on 17 June. Her doctoral research was carried out at the Institute of Physics (IoP) and the Dutch National Institute for Subatomic Physics (Nikhef) where she investigated the Higgs-like boson discovered with the Large Hadron Collider (LHC) in Geneva.

What did you do?

‘I searched for evidence to establish that the Higgs-like boson discovered in 2012 was indeed the Standard Model Higgs boson. About 40 years ago it was predicted that a Higgs boson must exist. The Higgs boson completes the Standard Model , but experimental proof is required for verification. The Standard Model is a theory describing these particles and forces. In Geneva, in 2012, the discovery of a Higgs-like boson was announced, after analysis of millions of collisions in the LHC. The LHC forces protons to collide with each other. Scientists are now attempting to discover whether the discovered particle has the properties to be expected according to the Standard Model. That would form additional evidence for this definitely being the Higgs boson.’ 

Which properties did you examine?

‘I looked at the parity and spin. Simply put, parity is the way in which properties of a particle change when it is observed in a mirror. If a particle has even parity, then the properties observed in the mirror are identical. If it has uneven parity, the properties are the opposite. The spin is the rotation of a particle on its axis. I formulated various hypotheses and simulated collisions for each one, then compared the collision data of 2012 with the simulations.’

And the result?

‘It emerged that the parity of the particle was even and the spin zero. This was evidenced by my analysis, but also by other analyses. The Higgs-like boson found in 2012 thus seems to have the spin and parity of the Standard Model Higgs boson. Further research is necessary to determine this with greater certainty. We now need to measure other properties and compare them with the Standard Model prediction.’

What was it like undertaking your doctorate?

‘It was fantastic working in an international environment. For the first two years I went to Geneva nearly every month and I lived there for a whole year. In retrospect my timing was perfect. The LHC had just opened when I began in 2010. The last data was collected at the end of 2012 before shut down began. It closed for two years for a planned upgrade early in 2013, and that’s when I started writing. The generation of PhD’s that came before me was not so fortunate, because they would have done their research based on the first LHC data set. That went wrong due to an accident with the LHC in September 2008. I was very lucky.’

What are you going to do next?

‘First of all I'm going to travel around South America for a few months with my partner. I don't yet know what I'll do after that. The LHC is working again and new data is being generated. I'm itching to start working on that. However there's also a lot of interesting work to do outside science, in industry for example. It would also be fantastic to work in the Klokhuis (popular science TV programme for children) editorial team. I would like to do something relevant to society, but still have to think hard about whether that should be in science journalism, industry or the business sector.’

Text: Carin Röst

Published by  Faculty of Science