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Three Paths to Particle Dark Matter

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Three Paths to Particle Dark Matter Three Paths to Particle Dark Matter Thesis by Samuel K. Lee In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2012 (Defended April 16, 2012) ii c 2012 Samuel K. Lee All Rights Reserved iii Some realize the Supreme by meditating, by its aid, on the Self within, others by pure reason, others by right action. Others again, having no direct knowledge but only hearing from others, nevertheless worship, and they, too, if true to the teachings, cross the sea of death. | The Bhagavad Gita (13.25{26) Forgotten rimes, and college themes, Worm-eaten plans, and embryo schemes;{ A mass of heterogeneous matter, A chaos dark, nor land nor water... | An Inventory of the Furniture in Dr. Priestley's Study (37{40), Anna Lætitia Barbauld (1825) iv Acknowledgments Astronomy now demands bodily abstraction of its devotee. To see into the beyond requires purity. and the securing it makes him perforce a hermit from his kind. | Mars and Its Canals, Percival Lowell (1906) I first encountered the above words on my recent cross-country emigration from Caltech to Johns Hopkins; they were engraved as an epitaph on Lowell's mausoleum, which is located on the grounds of the observatory bearing the learn'd astronomer's name. Upon reading them, I felt grateful that I could count myself luckier than Lowell in two respects: first, that we can be reasonably sure that dark matter will not follow the canals of Mars into the forgotten annals of science, and, more importantly, that my experience as a scientist thus far was neither as lonely nor as forsaken as Lowell's profound yet depressing words suggest it should have been. I have no quarrel with Lowell | and perhaps I have not achieved sufficient purity to see into the beyond just yet | but if ever my life's deeds are enough to warrant a mausoleum of my own, I will be sure that my epitaph not imply that those deeds were a solitary effort. In contrast, my pursuits and ambitions have always been supported by a large number of people; I hope they will accept the humble and sincere thanks I offer here. First and foremost, I am indebted to my adviser, Marc Kamionkowski. The possibility of working with Marc was perhaps the primary reason I decided to attend Caltech for graduate school. Since he has afforded me the opportunity of working on a number of fascinating and intellectually stimulating research topics, it a decision I am very glad to have made. As an adviser, Marc has always been extremely generous with his encouragement and support, as well as with dispensing thoughtful advice that has proved invaluable in matters academic and otherwise. As a scientist, Marc has never failed to impress; many are the times I have been sitting in a colloquium or seminar, usually on a subject far afield from my own interests and expertise, admitting to myself that I have become hopelessly lost and perplexed by the presentation | it is usually at this point that Marc raises his hand and asks some piercing question, physically insightful yet completely clear even to one as confused as me. Although humbling, it is a great source of inspiration to realize that despite the years invested in this thesis, I still have a long way to go before I can hope to match his versatility as a physicist. v Next, I would like to thank those that I collaborated with to produce the work presented in this thesis. To Shin'ichiro Ando, Jonathan Feng, and Annika Peter | I learned many things from the science we did together, for which I am grateful; I am also immensely appreciative of the support you provided during the postdoctoral application process. I would also like to thank Kirill Melnikov and Andrzej Czarnecki for teaching me a thing or ten about thermal field theory. Furthermore, although not presented in this thesis, the work I have completed (or started...) with Savvas Koushiappas, Stefano Profumo, Lorenzo Ubaldi, Michael Dine, and Chris Hirata and the interactions we have had have also been important to my development as a physicist. I would also like to express gratitude to the students, postdocs, professors, and staff that make Caltech such A Nice Place To Live (And Do A Ph.D.). I am glad to number myself among the Caltech Astronomy graduate students, and am proud of the community we have built during my time in the department. However, were it not for the friendship of my fellow classmates | Mike Anderson, Krzysztof Findeisen, Vera Glu˘s˘cevi´c,Tucker Jones, Elisabeth Krause, Tim Morton, Drew Newman, and Gwen Rudie | the first year of graduate school would certainly not have been as enjoyable as it was, much less those years subsequent. I am also obliged to Gina Armas and Gita Patel for their diligence and assistance. Thanks goes to the numerous denizens of TAPIR: my most recent set of office mates Yacine Ali-Ha¨ımoud,Nate Bode, and Anthony Pullen, who deserve credit for not giving me too hard a time about my odd hours; the members of the Tuesday group meetings | especially my elder academic siblings Adrienne Erickcek, Dan Grin, and Tristan Smith, as well as Fabian Schmidt, who have all been welcoming whenever our paths were fortunate enough to cross again, and Donghui Jeong, my fellow Caltech expatriate here at Johns Hopkins; the staff members that kept things running smoothly | JoAnn Boyd, Shirley Hampton, and Chris Mach; and the graduate students that politely put up with my ramblings on particle physics at our Thursday lunch lectures | Esfandiar Alizadeh, Laura Book, Michael Cohen, Jeff Kaplan, Keith Matthews, David Nichols, Evan O'Connor, Chris Wegg, Fan Zhang, Aaron Zimmerman, and others. In particular, I would like to commend Chris Wegg for his excellent taste in music, and thank him for filling the time between the support and the headliner with entertaining conversation. I would also like to generally thank the graduate and undergraduate students of the physics department for many positive experiences, both academic and social. Some recognition is due to roommates I had through the years spent living in the Caltech Catalina Apartments; thanks to Steven Frankel, Zakary Singer, and Scott Steger for many memories in 201. Many enjoyable trips to the great outdoors | snowboarding, hiking, camping, and so forth | were had with Matt Schenker, who was always rather understanding of my general inexperience with much of the great outdoors. I had many stimulating talks with Thinh Bui during our frequent runs for Vietnamese food, and spent many equally stimulating hours in front of our CRT television vi digesting the great epics of our time with him. Finally, Ryan Trainor has been one of the most dependable, capable, and good-spirited friends I have had the pleasure to know | and his family has always been very good to me, as well. In the spring of my fourth year, I found myself volunteering to design and build handcrank- powered generators for a public-outreach installation promoting energy conservation and sustain- ability at the Coachella Valley Music and Arts Festival. I would like to thank Jelena Culi´c-Viskota,˘ Toni Lee, Jeff Lehew, Mike Shearn, and Ryan Trainor for entrusting a theoretical astrophysicist with the responsibility of engineering something remotely resembling a functional device (and for letting him use power tools in close proximity to you); the experience was a welcome diversion from my usual pencil-and-paper-and-programming routine. In my fifth year, I found myself moving across the country to Baltimore. The physicists of Johns Hopkins have been most welcoming, for which I am grateful. However, the chemists also let me occasionally infiltrate their ranks; thanks to Chris Bianco, Tyler Chavez, Mark Hutchinson, and Chris Malbon for times around our kitchen island and elsewhere. In particular, my current housemates Jacob Kravetz and David Wallace deserve special praise for always being scholars (albeit of chemistry) and gentlemen (usually in that order). As a physicist, I have been fortunate enough to attend a number of schools and conferences; I would like to thank the friends I have made during my travels for opening my eyes to the dedication required to do science in some parts of the world, and for showing me that physics is nevertheless a universal language. However, I would not be able to speak that language were it not for my experiences during my MIT years. Without my former classmate Duncan Ma, I never would have gotten past 8.012, and it was Scott Hughes's excellent 8.022 lectures that cemented my desire to follow my current career path. Paul Schechter and Harvey Moseley were also great mentors during this formative period. Outside of my physics studies, some of my most challenging and gratifying experiences were had with the MIT Pistol Team, coached by Will Hart. Even before MIT, several of my friends and teachers played important roles in shaping my growth. Although I have lost touch with some, time has not diminished their contribution; thanks to Anne Barrera (n´eeNugent), Dwo Chu, Johanna Chu (n´eeYu), Deborah Crawford, Robert Dennison, Jane Fain, Philip Ho, Jennifer Lee (n´eeYu), Matt Lee, Kanwar Singh, Chris Vollmer, and innumerable others. Charles Wei has proven to be an invaluable friend through the years. On a larger scale, I express thanks to those that make my somewhat impractical profession possible. The epigraph that opens this thesis, although a tongue-in-cheek comparison between the three paths leading to particle dark matter and those leading to enlightenment and salvation, may perhaps be more obliquely read as expressing my sentiments on the role of a scientist in a society that values knowledge and the pursuit of deeper truths.
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