Canadian Particle Astrophysics Research Centre

CPARC Science Program and Technology Development

Overview of the Scientific Context

Particle astrophysics is a branch of physics that views astronomical objects along with the early Universe as arenas for the study of elementary particle physics. This relatively new multi-disciplinary field draws on laboratory experiments, astronomical observations, theory and computational physics. Canada's strong presence in all aspects of this endeavor is already well established. The Canadian Particle Astrophysics Research Centre will foster a collaborative environment for different research groups within this multi-disciplinary field and oversee our growth in this area supported by the CFREF funding that Queen's University is requesting.

Beginning in the 1960's, particle physicists formulated what has come to be known as the Standard Model, which combines electromagnetism and the weak nuclear force into a single phenomenon known as electroweak interactions. The Standard Model also describes strong nuclear interactions and explains the masses of known particles through the Higgs mechanism. The past decade has seen great advances in particle physics, cosmology and astroparticle physics, and has led to a much better understanding of the related problems of the composition of the universe, the accuracy of the Standard Model, and possible new physics beyond the Standard Model.

In the short period since the release of the original SNO results, six Nobel prizes have been awarded in recognition of advances in these fields:

  1. for the detection of cosmic neutrinos (2002)
  2. for measuring the anisotropy of the cosmic microwave background (2006)
  3. for theoretical work on spontaneous symmetry breaking (2008)
  4. for the observation of an accelerating expanding universe (2011)
  5. for the discovery of the final element of the Standard Model, the Higgs, (2013)
  6. and culminating in the 2015 Nobel prize to Arthur McDonald of Queen's University and Takaaki Kajita (Tokyo) for the discovery of neutrino oscillations showing that neutrinos have mass

Although experiments at particle accelerators from SLAC to Fermilab to the LHC have confirmed predictions of the Standard Model with exquisite accuracy, the Standard Model is widely regarded as incomplete. For one, the masses of known particles appear to depend on fine-tuned model parameters. Moreover, unification of the strong nuclear force with electroweak interactions seems to require physics beyond the Standard Model. In addition, the Standard Model leaves open key questions about the fundamental nature of neutrinos. Finally, the model says nothing about the quantum nature of gravity or the existence of dark matter.

Particle astrophysics presents an opportunity to explore new physics that is distinct from and complementary to research at particle accelerators. In fact, the only experimental observation of physics beyond the Standard Model comes from the measurement of neutrino oscillations. These were first discovered with underground experiments studying solar and atmospheric neutrinos.

The Sudbury Neutrino Observatory played a pivotal role in this discovery, leading to aforementioned Nobel Prize and the designation of the SNO team as co-recipients of the 2016 Breakthrough Prize. The SNO results, the expansion of the SNO laboratory, and the creation of a strong infrastructure support team has secured SNOLAB's place as a premiere site for underground science.