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Signature Redacted Thesis Supervisor Certified By MASSACHUSETTS INSTMITE A Tale of Two Particles OF TECHNOLOGY by AU6 15 2014 Katelin Schutz LIBRARIES Submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2014 @ Katelin Schutz, MMXIV. All rights reserved. The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part in any medium now known or hereafter created. Signature redacted Author .. .................................. Department of Physics Signature redacted May 9, 2014 Certified by. ........................... A. David Kaiser Germeshausen Professor of the History of Science Senior Lecturer, Department of Physics Signature redacted Thesis Supervisor Certified by.. ............................. Tracy Slatyer Assistant Professor of Physics Signature redacted Thesis Supervisor Accepted by.. ..................... Nergis Mavalvala Senior Thesis Coordinator A Tale of Two Particles by Katelin Schutz Submitted to the Department of Physics on May 9, 2014, in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics Abstract It was the earliest of times, it was the latest of times, it was the age of inflation, it was the age of collapse, it was the epoch of perturbation growth, it was the epoch of perturbation damping, it was the CMB of light, it was the dwarf galaxy of dark- ness, it was the largest of cosmic scales, it was the smallest of Milky Way subhalos, we had multiple nonminimally coupled inflatons before us, we had inelastically self- interacting dark matter before us, we were all going direct to the Planck scale, we were all going direct the other way. Motivated by apparent discrepancies between the standard theory and observation, we analyze two astrophysical systems in the context of new particle physics. Taking a phenomenological approach, we calculate observable consequences of novel particle models during two different stages in the development of our universe. First, we explore the possibility that nonminimally coupled multi- field inflation can generate a large primordial isocurvature fraction and account for the "low-multipole anomaly" in the Cosmic Microwave Background. Second, we con- sider the effects of dark matter that inelastically self-interacts to determine the effect on the structure and abundance of Milky Way satellites and dwarf galaxies. The dis- parity of time and energy scales examined in this thesis serves to highlight the range of ways to use observables in the sky as a probe of new particle physics that may be elusive at current experiments on the ground. Thesis Supervisor: David Kaiser Title: Germeshausen Professor of the History of Science Senior Lecturer, Department of Physics Thesis Supervisor: Tracy Slatyer Title: Assistant Professor of Physics 2 Acknowledgments They say that luck favors the prepared. While being an undergraduate at MIT made me work harder than I ever could have imagined, I also recognize that I was astonishingly lucky, particularly with regard to the people who helped me get to where I am today. In fact, my biggest motivation for writing a senior thesis was this acknowledgement section, since I am not required to write a thesis for my degree. So for all of you reading this, pay attention to this section because the science that follows is really just the icing on the cake, the victory lap, the symbol that I entered MIT as a kid and have emerged as a real scientist. My ability to complete this work is the direct product of the ample guidance from the people I am about to mention. First and foremost, I must thank my family. My mother tells me that when I was small, she used to think to herself "God, please don't let me mess this up." I think it's clear now that she and my father have done quite the opposite by raising me the way they did. Growing up, I always had the support that I needed to do whatever I was interested in doing. I had a huge library of books and I spent my summers at nerd camp learning number theory and philosophy. When I was bored by the pace of my 6th grade math class and began quickly losing interest in science, my parents fought the school so that I could take algebra and physics with the 8th graders. My parents also forced me to do things that normal kids do, like playing team sports. Though I resisted at the time, looking back on those experiences I am so grateful that I had a proper childhood and that I learned basic skills like how to work in a team and how to deal with other people who have different experiences from my own. In particular, when my dad had me play on a boys' little league baseball team with my brother and his friends, I had to learn grit in overcoming their teasing (one of the most clever and observant remarks I often heard was that I "throw like a girl.") I believe that the reason I was able to stay interested in math and science, even though those subjects are "for boys," was because I was already used to being "the girl," and that I had learned ways of dealing with that. And most importantly, my parents gave me a loving home and plenty of happy memories. Genetics aside, I would not 3 have gotten to where I am without my parents and the sacrifices that they made in order to be good parents. Before coming to MIT, there were many people who made me who I am, and I want to briefly mention them here. There was John Lawrence, who taught me the value of my own weirdness and showed me how to succeed in spite of real adversity. I didn't know him for long, thanks to a long-fought battle with cancer, but his role as my teacher and coach at the critical age of thirteen had a profound and lasting influence on my values in life. I would like to thank Chuck Fujita for forcing me to use my brain instead of reaching for my TI-89. I acknowledge coach Mancuso, who taught me the true meaning of hard work. I also wish to thank Ray Perez for all the life lessons learned and for helping me establish my personal motto: Sic Volvo. I want to thank Rhonda Brown and Eliza Coyle for being like second mothers to me. And finally, I wish to thank Gabby Perez and Lucy Coyle; though three of us have such different talents and passions, their trailblazing in other fields continually inspires me to be a more complete, well-rounded person. When I arrived at MIT, the first friend I made turned out to be the most im- portant friend of my life so far. I was a part of the first-ever PhysPOP, a freshman pre-orientation program for people interested in physics. I found my peers in the FPOP quite discouraging; many of them behaved as many MIT freshmen behave (particularly freshmen who went to prestigious high schools) and were eager to show how much they knew already. Feeling alienated by this, I befriended the PhysPOP counselors, and in particular I befriended Adrian Liu. It is because of Adrian that I decided to major in physics and he was the one who first got me interested in cosmol- ogy. After a talk he gave during PhysPOP, I was so fascinated with his research that I sought out a UROP with Adrian's thesis advisor, Max Tegmark, who was working on building a new kind of radio telescope. I really must acknowledge Max because he gave me a chance to work in his lab; I have no idea what he saw in me, as I had no clue what a Fourier transform even was at the time. Yet he chose to take me on as a UROP student, and during my time in that group I learned a staggering amount of physics, particularly from Adrian's summer cosmology boot camp. I ultimately 4 left the group because I was interested in more theoretical endeavors, but I stayed in touch with the group, particularly with Adrian who went on to co-teach me quantum mechanics. Though Adrian began a postdoc in California after my sophomore year, he has been my closest friend, my co-conspirator, my moral compass, my shoulder to cry on, my biggest cheerleader, and the love of my life. I learn new things from him every day, and I hold him responsible for a significant portion of my education as a physicist and as a person. I also want to thank the people that made MIT home for me these past four years, namely B Entry: Chris Kelly, Jamal Elkhader, Molly Kozminsky, Mary Knapp, Andy Liang, Kirsten Hessler, Jan Sontag, Michael Pearce, Jon Allen, Anne Kim, Nick Arango, Clarissa Towle, Nick Mohr, Lauren Wright, the list of crazy kids goes on. But of all these people I especially must acknowledge Emily Nardoni, who was both my suitemate and my physics sherpa. I followed her in a path that she forged for herself, always a year ahead of me. It is because of her that I took Alan Guth's Early Universe course, which solidified my decision to be a cosmologist. As a strong, beautiful woman doing theoretical physics, I always had her as a role model and I always had someone who I could vent to or ask for advice. Seeing the sheer amount of work she put into becoming a physicist was a huge inspiration to me and made me feel that the struggle would be worth it in the end.
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