Essential Question: Why is finding supersymmetric particles and important task for physicists to undertake?
Answer: The lightest supersymmetric particle (LSP,) if stable, is a very good candidate for Weakly Interacting Massive Particles (WIMPs) or dark matter.
1. Supersymmetric neutralinos (gravitinos, axinos, singlinos, higgsinos, binos, winos, photinos, etc.) can be thermally produced in the early universe and leave exactly the right relic density to constitute the Cold Dark Matter of the universe.
2. Detecting supersymmetric dark matter may be the best way to find SUSY particles. SUSY particles are expected to be extremely heavy (reaching into the multi-TeV range) and thus are likely out of reach of collider physics. However, dark matter detection experiments (such as Ice Cube in Antarctica) can be specifically calibrated to find neutralinos.
3. There can be multiple possible models of SUSY dark matter, as different SUSY models yield different LSPs. For example, the Next-to-Minimal Supersymmetric Standard Model yields an LSP called the singlino, which is a good candidate for dark matter should the Minimal Supersymmetric Standard Model become too constrained. In addition, it is possible for neutralino dark matter to be non thermally produced, as well as in a "mixed" state such as with axions.
I plan on taking my science project on neutralino dark matter to the science fair. I am interested in hearing feedback on it as well as what others think the most likely neutralino dark matter model is.
Jedamzik, Karsten and Maxim Pospelov. "Big Bang Nucleosynthesis and Particle Dark Matter." Cornell University Library, 11 Jun. 2009. Web. 21 Feb. 2013.
Wednesday, February 27, 2013
Wednesday, February 20, 2013
Blog 17: Fourth Interview Questions
1. Why is finding supersymmetric particles an important task for physicists to undertake?
2. What do you believe is the most accurate model of supersymmetry proposed today?
3. What are the implications for the Cold Dark Matter search if supersymmetry is found not to exist?
4. How might scientists go about disproving supersymmetry if there is no empirical evidence found?
5. How might scientists go about narrowing down proposed supersymmetric models?
6. How might scientists go about narrowing down supersymmetric dark matter models?
7. What do you believe is the next step we must take in our efforts to locate supersymmetric particles?
8. If a spontaneously broken supersymmetry does not solve the problem of the vacuum energy all the way, what are the implications?
9. In what way, if any, can the problem of the vacuum energy be resolved without supersymmetry?
10. If supersymmetry is discovered, what are the implications for string theory?
11. Is it necessary for us to narrow down the number of superstring theories? If so, how can we do it?
12. How can theoretical physicists avoid being "not even wrong" about supersymmetry?
13. If supersymmetric particles are self interacting, how will this change our search for them as dark matter?
14. How to you believe an experiment solely dedicated to looking for supersymmetric particles would be received by scientists and donors?
15. If another, lighter Higgs Boson is found, what are the implications for supersymmetry?
16. What theories, if any, do you believe can explain the Hierarchy Problem in place of supersymmetry?
17. Can string theory be complete without supersymmetry? Why or why not?
18. Do you believe superstring theory is the "best" theory of quantum gravity? Why? If not, what other theories do you believe are better?
19. What, if anything, does the quantum vacuum say about dark energy?
20. What is wrong with very heavy sparticles?
No need to worry about the end of the universe, for those who saw the article. Supersymmetry will save us! Maybe...
2. What do you believe is the most accurate model of supersymmetry proposed today?
3. What are the implications for the Cold Dark Matter search if supersymmetry is found not to exist?
4. How might scientists go about disproving supersymmetry if there is no empirical evidence found?
5. How might scientists go about narrowing down proposed supersymmetric models?
6. How might scientists go about narrowing down supersymmetric dark matter models?
7. What do you believe is the next step we must take in our efforts to locate supersymmetric particles?
8. If a spontaneously broken supersymmetry does not solve the problem of the vacuum energy all the way, what are the implications?
9. In what way, if any, can the problem of the vacuum energy be resolved without supersymmetry?
10. If supersymmetry is discovered, what are the implications for string theory?
11. Is it necessary for us to narrow down the number of superstring theories? If so, how can we do it?
12. How can theoretical physicists avoid being "not even wrong" about supersymmetry?
13. If supersymmetric particles are self interacting, how will this change our search for them as dark matter?
14. How to you believe an experiment solely dedicated to looking for supersymmetric particles would be received by scientists and donors?
15. If another, lighter Higgs Boson is found, what are the implications for supersymmetry?
16. What theories, if any, do you believe can explain the Hierarchy Problem in place of supersymmetry?
17. Can string theory be complete without supersymmetry? Why or why not?
18. Do you believe superstring theory is the "best" theory of quantum gravity? Why? If not, what other theories do you believe are better?
19. What, if anything, does the quantum vacuum say about dark energy?
20. What is wrong with very heavy sparticles?
No need to worry about the end of the universe, for those who saw the article. Supersymmetry will save us! Maybe...
Wednesday, February 6, 2013
Blog 16: 2-Hour Meeting Answer #2
Essential Question: Why is finding supersymmetric particles an important task for physicists to undertake?
Answer 2: Supersymmetry is the one of the only theories that can completely solve the hierarchy problem of the Standard Model.
1. The hierarchy problem is one of the biggest inconsistencies of the Standard Model. We have observed the mass of the Higgs Boson to be ~125 GeV. The trouble is that the mass should be much greater than that due to a phenomenon called "quantum corrections." Without some very tight fine-tuning between the quantum corrections and the regular mass, this seems impossible. However, physicists don't like unexplained fine-tunings.
2. The Higgs Boson will couple to the most massive particles in the Standard Model, thus most of the quantum corrections to its mass will come from those particles, such as the top quark, which is the heaviest Standard Model particle. Supersymmetry predicts the existence of a stop squark partner for the top quark. As it turns out, the corrections from the stop squark should cancel with those from the top quark, leaving just enough left over to give us the Higgs mass we see in nature.
![\Delta m_{H}^{2} = 2* \frac{\lambda_{S}}{16\pi^2} [\Lambda_{UV}^2+ ...].](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uqZS5MM-Caq4JKogZ6_PZtaiACTU14m_9UNwr3QYRmy_huVLyqeS9p5tSGNG8rltbshzqt_F1t58YWJhGuTgW34vZpFn5Uu-f322zRDJzRAnvWAxydMTBhZ7FfcrNXnIJrGcV9DB-rxcyHhlwm=s0-d)
(Contributions from both-assume one negative and one positive contribution, where UV is the Planck scale.)
3. There isn't a theory that explains the hierarchy problem so cleanly and accurately. If supersymmetry doesn't exist, it is important that physicists begin work on another theory so we do not have any unexplained fine-tunings. Therefore it is important that we continue the search for supersymmetric particles, just in case we have to start work on another theory.
Source: Warped Passages by Lisa Randall. I could never really wrap my head around the hierarchy problem but she made it very clear and understandable, and she explains why supersymmetry is such a good solution for it.
I plan to bulk up on my knowledge of Quantum Field Theory, and on Richard Feynman's work. I never cared for Feynman as a person, but as Einstein would say, "There is no emotion in science!*" I want to be able to create my own Feynman diagrams so I can better understand them.
*Einstein didn't really say this.
Answer 2: Supersymmetry is the one of the only theories that can completely solve the hierarchy problem of the Standard Model.
1. The hierarchy problem is one of the biggest inconsistencies of the Standard Model. We have observed the mass of the Higgs Boson to be ~125 GeV. The trouble is that the mass should be much greater than that due to a phenomenon called "quantum corrections." Without some very tight fine-tuning between the quantum corrections and the regular mass, this seems impossible. However, physicists don't like unexplained fine-tunings.
2. The Higgs Boson will couple to the most massive particles in the Standard Model, thus most of the quantum corrections to its mass will come from those particles, such as the top quark, which is the heaviest Standard Model particle. Supersymmetry predicts the existence of a stop squark partner for the top quark. As it turns out, the corrections from the stop squark should cancel with those from the top quark, leaving just enough left over to give us the Higgs mass we see in nature.
![\Delta m_{H}^{2} = 2* \frac{\lambda_{S}}{16\pi^2} [\Lambda_{UV}^2+ ...].](http://upload.wikimedia.org/math/0/a/2/0a2ccd5c4998ac5ee33bb920fd4fc0fe.png)
(Contributions from both-assume one negative and one positive contribution, where UV is the Planck scale.)3. There isn't a theory that explains the hierarchy problem so cleanly and accurately. If supersymmetry doesn't exist, it is important that physicists begin work on another theory so we do not have any unexplained fine-tunings. Therefore it is important that we continue the search for supersymmetric particles, just in case we have to start work on another theory.
Source: Warped Passages by Lisa Randall. I could never really wrap my head around the hierarchy problem but she made it very clear and understandable, and she explains why supersymmetry is such a good solution for it.
I plan to bulk up on my knowledge of Quantum Field Theory, and on Richard Feynman's work. I never cared for Feynman as a person, but as Einstein would say, "There is no emotion in science!*" I want to be able to create my own Feynman diagrams so I can better understand them.
*Einstein didn't really say this.
Thursday, January 31, 2013
Blog 15: Independent Component 2 Approval
For my second independent component, I plan on building a cloud chamber. A cloud chamber was one of the first particle detectors ever built. The positron (anti-matter electron) and the muon were actually found using a cloud chamber. A basic cloud chamber consists of a sealed environment and a supersaturated vapor of alcohol or water (I will probably use methanol.) Charged particles interact with the vapor, ionizing it. After condensation one can start to see "tracks" left by the particles and then you can deduce what they are.
I want to build something a little better than your standard classroom cloud chamber, and I don't want to do it from a kit. Obviously I can't get any kind of radioactive material so it will be more limited in the types of particles it can see. However, I want actual chamber to be fairly large, sturdy, and reliable (so I want it to be VERY much sealed) and this will take time and there will be math involved in building it. Also, when I am finished, I want to make a print of the particle tracks, and then I will identify what they are.
I feel that this will help me answer my essential question because a big part of finding supersymmetric particles is actually building something to find them with. I think that this experiment will give me a taste for the experimental side of physics that I really haven't gotten yet (because obviously I can't build a Large Hadron Collider in my backyard.) Also, this is a good exercise in identifying particles based on what they leave behind, which is how we would identify sparticles if we found them in a particle detector.
Thanks to Professor Sean Carroll from Caltech for this idea!
I want to build something a little better than your standard classroom cloud chamber, and I don't want to do it from a kit. Obviously I can't get any kind of radioactive material so it will be more limited in the types of particles it can see. However, I want actual chamber to be fairly large, sturdy, and reliable (so I want it to be VERY much sealed) and this will take time and there will be math involved in building it. Also, when I am finished, I want to make a print of the particle tracks, and then I will identify what they are.
I feel that this will help me answer my essential question because a big part of finding supersymmetric particles is actually building something to find them with. I think that this experiment will give me a taste for the experimental side of physics that I really haven't gotten yet (because obviously I can't build a Large Hadron Collider in my backyard.) Also, this is a good exercise in identifying particles based on what they leave behind, which is how we would identify sparticles if we found them in a particle detector.
Thanks to Professor Sean Carroll from Caltech for this idea!
Blog 14: Independent Component 1
I, Hannah Seymour, affirm that I completed my independent component which represents 30 hours of work.
My professor for the Physics 132 course was Dr. Jamshid Armand. He can be contacted via email at jarmand@csupomona.edu. I am very grateful to Professor Armand for letting me take this course, especially since I did not have the prerequisites for it. I also completed Physics 299A, which was a group activity class associated with the 132 lecture. I completed this with Linda Shareghi (lcshareghi@csupomona.edu) to whom I am also very grateful. She introduced me to some excellent people at the physics department.
Physics 132 is the second level of General Physics (there is 131 before it and 133 after it.) It is calculus-based and covers gravity, fluid dynamics, simple harmonic motion, waves, and thermodynamics, among others. The class consisted of two midterms and a final, weekly homework, weekly quizzes, and challenging problems (these I did very well on-if I can find them I will post them.) We learned mostly about the mathematical concepts in this class. In the activity class, we worked in groups to solve concept-based worksheets and mathematical problems.
I will email the unofficial transcript to Mr. Purther, as I do not want to post that for all the world to see (I am paranoid about the interwebs.) I did not miss a single hour and fifty minute lecture the whole quarter (they were twice a week)-that alone represents 30 hours of work. The homework (the most challenging part of the class) typically took me 2-3 hours a week to complete. I tried to study the material for at least 30 minutes-1 hour every week to prepare for the big tests. The activity class was every Friday and was 2 hours and fifty minutes. I usually didn't have homework for this class since my group would always finish the assigned problems. This is a difficult class, and many people are unable to pass it. I believe the average grade in the class was a D, when all was said and done.
These courses helped me understand more basic-intermediate physics concepts that I would not be familiar with otherwise. For instance, the explanation Professor Armand gave about constructive and destructive interference helped me understand particle wave cancellation and thus, supersymmetry. It also helped me understand what I'm good at and what I need a little more work on. It also helped me become more familiar with basic calculus (I am better at math in an applied setting like this.) Also, without this class I would not have gotten such a good score on the Physics SAT Subject Test. Now that I have been exposed to college-level physics, I feel more confident entering that world. I used to have so little intellectual confidence I refused to try anything I didn't think I would be perfect at right away. So I am very proud of the risk I took and the work I put in for these classes.
My professor for the Physics 132 course was Dr. Jamshid Armand. He can be contacted via email at jarmand@csupomona.edu. I am very grateful to Professor Armand for letting me take this course, especially since I did not have the prerequisites for it. I also completed Physics 299A, which was a group activity class associated with the 132 lecture. I completed this with Linda Shareghi (lcshareghi@csupomona.edu) to whom I am also very grateful. She introduced me to some excellent people at the physics department.
Physics 132 is the second level of General Physics (there is 131 before it and 133 after it.) It is calculus-based and covers gravity, fluid dynamics, simple harmonic motion, waves, and thermodynamics, among others. The class consisted of two midterms and a final, weekly homework, weekly quizzes, and challenging problems (these I did very well on-if I can find them I will post them.) We learned mostly about the mathematical concepts in this class. In the activity class, we worked in groups to solve concept-based worksheets and mathematical problems.
I will email the unofficial transcript to Mr. Purther, as I do not want to post that for all the world to see (I am paranoid about the interwebs.) I did not miss a single hour and fifty minute lecture the whole quarter (they were twice a week)-that alone represents 30 hours of work. The homework (the most challenging part of the class) typically took me 2-3 hours a week to complete. I tried to study the material for at least 30 minutes-1 hour every week to prepare for the big tests. The activity class was every Friday and was 2 hours and fifty minutes. I usually didn't have homework for this class since my group would always finish the assigned problems. This is a difficult class, and many people are unable to pass it. I believe the average grade in the class was a D, when all was said and done.
These courses helped me understand more basic-intermediate physics concepts that I would not be familiar with otherwise. For instance, the explanation Professor Armand gave about constructive and destructive interference helped me understand particle wave cancellation and thus, supersymmetry. It also helped me understand what I'm good at and what I need a little more work on. It also helped me become more familiar with basic calculus (I am better at math in an applied setting like this.) Also, without this class I would not have gotten such a good score on the Physics SAT Subject Test. Now that I have been exposed to college-level physics, I feel more confident entering that world. I used to have so little intellectual confidence I refused to try anything I didn't think I would be perfect at right away. So I am very proud of the risk I took and the work I put in for these classes.
Monday, January 14, 2013
Sunday, January 13, 2013
Blog 12: Third Interview Questions
1. Why is finding supersymmetric particles an important task for physicists to undertake?
2. What are some ways the heavier sparticles such as squarks can be detected?
3. If the Minimal Supersymmetric Standard Model is found to be too constrained by the Higgs mass, how can it be modified?
4. What theories, if any, can explain the Hierarchy Problem of the Standard Model besides supersymmetry?
5. If supersymmetric particles are found not to exist, how should physicists approach the vacuum energy problem?
6. What does a model of supersymmetry that can be spontaneously broken mean for our understanding of the vacuum energy?
7. How can existing dark matter detection experiments such as Ice Cube be better equipped to detect supersymmetric particles?
8. If the Large Hadron Collider does not, even at its full power, discover supersymmetric particles, where do physicists go from there?
9. How can theorists studying supersymmetry as we are now, without empirical evidence, avoid being "not even wrong?"
10. How can Cold Dark Matter be described without the existence of supersymmetric particles?
2. What are some ways the heavier sparticles such as squarks can be detected?
3. If the Minimal Supersymmetric Standard Model is found to be too constrained by the Higgs mass, how can it be modified?
4. What theories, if any, can explain the Hierarchy Problem of the Standard Model besides supersymmetry?
5. If supersymmetric particles are found not to exist, how should physicists approach the vacuum energy problem?
6. What does a model of supersymmetry that can be spontaneously broken mean for our understanding of the vacuum energy?
7. How can existing dark matter detection experiments such as Ice Cube be better equipped to detect supersymmetric particles?
8. If the Large Hadron Collider does not, even at its full power, discover supersymmetric particles, where do physicists go from there?
9. How can theorists studying supersymmetry as we are now, without empirical evidence, avoid being "not even wrong?"
10. How can Cold Dark Matter be described without the existence of supersymmetric particles?
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