DEPARTMENT OF PHYSICS AND ASTRONOMY

PHY326 Dark Matter and the Universe (please note was PHY323 for 13/14) ​ PHY426

Autumn 10 Credits

Staff contact Prof Neil Spooner ­ [email protected] ­ 0114 222 4422 ​ ​

Outline The topic of Dark Matter in the Universe is arguably the most exciting and important area in physics Description and cosmology at the current time. It concerns one of the biggest mysteries in science, that the vast majority of the Universe is not normal baryonic matter but is something much stranger, something non­luminous and as yet of unknown form. The journey that scientists are undertaking now to understand this problem is already leading to new fundamental physics and is revolutionizing our understanding of the Universe. This course will explore the topic in detail. It will explain the overwhelming observational evidence for the existence of the so­called Dark Matter and Dark energy, explore what scientists believe it is most likely to be and study what is happening in the world­wide race to confirm the most likely explanation, that it is new fundamental particles from the Big Bang. Dark Matter determines our very existence, it holds galaxies together, makes life possible and is crucial to the eventual fate of our Universe. No topic in physics covers such a range of scale, from the smallest particle to the structure of the whole Universe, or holds such importance to our understanding of nature. To do this justice the course has a highly multidisciplinary flavour, combining work in astronomy, particle physics, solid state physics, detector technology and philosophy, encouraging development of skills in all these.

Restrictions None

Prerequisites First and Second Year Physics or Astronomy.

Co requisites None

Approx Time Lectures ­ 18, Revision Lecture ­ 1, Independent ­ 80, Examination ­ 2 allocation (hours)

Assessment (%) PHY326 Examination ­ 85, Class Test ­ 15%

PHY426 Examination ­ 75, Class Test ­ 15%, Written Report ­ 10%

Aims The aims of this module are: To examine our current understanding of the structure of the Universe and how this leads to the mystery that greater than 95% of the Universe is in the form of Dark Matter and Dark Energy.

To examine the observational and theoretical evidence for the existence of large amounts of Dark Matter in the Universe on all scales reaching from the Solar System to clusters of galaxies and beyond.

To study the possible candidates for what the Dark Matter might be, including both baryonic and non­baryonic possibilities.

To explore some of the latest experimental techniques being used in the laboratory to hunt for Dark Matter particles and discuss the latest results in this quest for new physics.

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DEPARTMENT OF PHYSICS AND ASTRONOMY

Outcomes 1. For students to gain a broad understanding of the arguments from cosmology and astronomical ​ observation that lead to the notion that the Universe is filled with dark matter and dark energy

2. To have understanding of the possible candidates to explain the dark matter including the possible ​ existence of new particles such as WIMPs and axions

3. To understand the basic particle physics concepts relevant to the interactions of dark matter with ​ normal baryonic matter

4. To have knowledge of some of the technology being developed to detect dark matter in the ​ laboratory and the latest results from experiments world­wide

5. To have an appreciation of dark energy and how together with dark matter this determines the ​ ultimate fate of the Universe

Recommended The Cosmic Cocktail ­ Three Parts Dark Matter Books by Katherine Freese, Princeton University Press, 2014, ISBN 978­0­691­15335­3

Syllabus The course will be divided into short topics covering the following themes:

Topic 1: Dark Matter, Dark Energy and the Cosmology Revolution ​ ​ What is the real structure of our Universe and how do we know it is so? Introduction to the structure of our Universe, including observations of galaxy clusters, the Big Bang and the cosmic microwave background. A review of the basic tools used in cosmology, including the critical density and density parameter. An introduction to the dark matter mystery.

Topic 2: Dark Matter Observation Nearby and in Galaxies Why don’t galaxies fly apart and how does this tell us dark matter exists? Galactic dynamics and galactic halos as relevant to understanding the origin of the dark matter problem. Oort observations, modified gravity and the isothermal sphere model of galaxies. Rotation curves of galaxies and the evidence for dark matter from these.

Topic 3: Dark Matter in Galaxy Clusters and Superclusters How does Einstein’s bending of light reveal the true picture of our Universe? Gravitational lensing and the evidence for dark matter that this brings from strong lensing and weak lensing. The evidence for dark matter from application of the virial theorem to clusters. Dark matter observations from large scale flows and x­ray gas.

Topic 4: Hunting for Baryonic Dark Matter Black holes, dead stars, neutrinos & the primordial soup ­ why is the dark matter not ordinary ​ matter we can not see? The hunt for baryonic dark matter including Brown Dwarfs, Massive Compact Halo Objects (MACHOs), other candidates and the use of gravitational microlensing to search for them. Primordial nucleosynthesis bounds on the abundance of baryonic matter and from observation of microwave background radiation. Neutrinos and the death of baryonic dark matter.

Topic 5: Cold Dark Matter and the Exotic non­Baryonic Particle Zoo From the Higgs Boson and Antimatter to WIMPs and Axions ­ why is the dark matter likely to ​ ​ be exotic new particles from the Big Bang? Particle physics discoveries, neutrinos as dark matter and introduction to non­baryonic particle dark matter candidates. Hot, cold and warm particle dark matter and their influence on structure formation in the Universe. Cold dark matter candidates and introduction to Weakly Interacting Massive Particles (WIMPs) and axions as the best motivated candidates.

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DEPARTMENT OF PHYSICS AND ASTRONOMY

Topic 6: Detecting Dark Matter Particles, Signals and Discoveries Why do WIMPs or axions most likely form the dark matter and how can they be detected? Dark Matter WIMP and axion interactions with matter. The properties of axions and how to detect them with resonant cavity detectors. The physics of WIMPs and the latest technologies used to search for them, including ionisation, scintillation and low temperature techniques. Results, possible signals and consequences.

Topic 7: Dark Energy and the Fate of the Universe What is dark energy and how does it overcome dark matter to determine our fate? Dark energy and the evidence for it from supernova and the cosmic microwave background. Dark matter, dark energy and the fate of the Universe.

Topic 8: Conclusion and Course Revision

Academic Notes The Level 3 version of Dark Matter and the Universe can only be studied in Level 3. ​

The Level 4 version of Dark Matter and the Universe can only be studied in Level 4. ​

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