Supersymmetry Definition and 132 Threads

In particle physics, supersymmetry (SUSY) is a conjectured relationship between two basic classes of elementary particles: bosons, which have an integer-valued spin, and fermions, which have a half-integer-valued spin. A type of spacetime symmetry, supersymmetry is a possible candidate for undiscovered particle physics, and seen by some physicists as an elegant solution to many current problems in particle physics if confirmed correct, which could resolve various areas where current theories are believed to be incomplete. A supersymmetrical extension to the Standard Model could resolve major hierarchy problems within gauge theory, by guaranteeing that quadratic divergences of all orders will cancel out in perturbation theory.
In supersymmetry, each particle from one group would have an associated particle in the other, known as its superpartner, the spin of which differs by a half-integer. These superpartners would be new and undiscovered particles; for example, there would be a particle called a "selectron" (superpartner electron), a bosonic partner of the electron. In the simplest supersymmetry theories, with perfectly "unbroken" supersymmetry, each pair of superpartners would share the same mass and internal quantum numbers besides spin. Since it is expected to find these "superpartners" using present-day equipment, if supersymmetry exists then it consists of a spontaneously broken symmetry, allowing superpartners to differ in mass. Spontaneously broken supersymmetry could solve many problems in particle physics, including the hierarchy problem.
There is no experimental evidence that supersymmetry is correct, or whether or not other extensions to current models might be more accurate. It is only since around 2010 that particle accelerators specifically designed to study physics beyond the Standard Model have become operational (i.e. the Large Hadron Collider (LHC)), and it is not known where exactly to look, nor the energies required for a successful search.
The main reasons for supersymmetry being supported by some physicists is that the current theories are known to be incomplete and their limitations are well established, and supersymmetry could be an attractive solution to some of the major concerns.

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  1. S

    Will Supersymmetry Remain Relevant in Theoretical Physics Despite LHC Results?

    In 5 years or so, if LHC fails to find any superpartners, are ALL supersymmetric theories dead? Skippy
  2. malawi_glenn

    Questions on chapter 95 in Srednickis QFT book, Supersymmetry

    Hello all Since there seems that quite many here have followed Professor Srednickis QFT book, I want to ask a couple of question I have from his chapter on Supersymmetry. i) on page 617 he defines the kinetic term of the Chiral Superfields as: L_{\text{kin}} = \Phi^{\dagger} \exp(-2gV)...
  3. E

    Could you have BOTH mirror matter and supersymmetry?

    I know that mirror symmetry resulting in mirror matter and supersymmetry resulting in SUSY partners are two completely distinct fields, and that the original bosonic string theory needs SUSY to get fermions. If mirror matter does exist in the universe, what would this mean in terms of SUSY...
  4. atyy

    String Theory and Supersymmetry

    Cargese lectures on string theory with eight supercharges Monica Guica, Andrew Strominger http://arxiv.org/abs/0704.3295 The authors state "Ultimately the most interesting and most physically relevant case is no supersymmetry at all. But at the moment analytic control in this case is quite...
  5. S

    Supersymmetry notation question

    In super yang mills theories in 4,6,10 dimensions, the supersymmetry transformation is often written as (ignoring color indices): \delta A_\mu = i \bar \alpha \gamma_\mu \lambda - i \bar \lambda \gamma_\mu \alpha \delta \lambda = c F^{\mu \nu} [ \gamma_\mu, \gamma_\nu] \alpha where c is...
  6. J

    Higgs particle, supersymmetry and dark matter.

    Could someone help explain how these are related? I kind of understand the Higgs particle/field. It is believed to be the reason why fundamental particles (fermions and bosons) have mass. So, then I read that one of the problems with the Higgs field is that if it is true things should be...
  7. J

    Falsifiable predicted consequences of SuperSymmetry?

    What are some falsifiable predicted consequences of SuperSymmetry? Clearly, if super particles are found, people can rejoice in this new fundamental knowledge of nature. But if it turns out to be a incorrect alley that some theorists journeyed down, do we at least have a way to prove this to...
  8. Jim Kata

    N = 4 supersymmetry & Pati Salam

    I was reading a little bit about N = 4 SUSY, and I couldn't help but think that it's like the Pati Salam GUT. To get an N = 4 SUSY theory you can take SO(1,9) and compactify it to four dimensions. In doing so, you get Spin(1,3)XSU(4), where SU(4) is the R symmetry of the theory and Spin(1,3)...
  9. G

    Could Supersymmetry Explain Dark Matter?

    Hello: I`ve heard that supersymmetry predicts new fundamental particles that may explain dark matter, and that dark matter and dark energy is 95 percent of the total mass of the universe... What are these fundamental particles predicted by supersymmetry?, and how...
  10. G

    Supersymmetry and String Theory

    I am reading Michael Hines new book, Supersymmetry and String Theory. He keeps referring to "tree-level". What is this?
  11. malawi_glenn

    Is Supersymmetry the Future of Particle Physics?

    http://www-thphys.physics.ox.ac.uk/users/IanAitchison/susy.pdf http://www.cpt.dur.ac.uk/~georg/ss/ss.htm
  12. Jim Kata

    I'm trying to teach myself about supersymmetry

    Ok, I'm trying to teach myself about supersymmetry, using Weinberg III. My learning style is I don't really read things I just kind of infer what the author means. So I need clarification on a lot. Lets start with the basics, from a mathematical point of view. Where I'm at is at Haag...
  13. E

    Supersymmetry O'Raifeartaigh model negative fermionic masses

    Greetings, I calculated a basic O'Raifeartaigh model, using the following potential f = \lambda Y_1 (X^2 - M^2) + \mu Y_2 X , where Y_1, Y_2 and X are chiral superfields. Assuming that the vacuum expectation value of y_1 is zero (where y_1 is the scalar component of Y_1), I get a fermionic...
  14. E

    Supersymmetry: Understanding Weinberg's Formula on Page 78

    Greetings everyone, I have to give a lecture about supersymmetry, so I started reading Weinbergs quantum theory of fields vol 3, which is quite of a task. Sometimes I've trouble with some of his conclusions, and I hope you could help me there. I really do not understand how he got to the...
  15. Demystifier

    LHC, supersymmetry and strings

    One of the things that LHC will experimentally search for are supersymmetric partners of the Standard-Model particles. Maybe it will found them, maybe it will not. But what if it will? The existence of supersymmetry does not imply the existence of superstrings. However, string theory is...
  16. A

    Solving Supersymmetry Q: U_R(1) Symmetry & theta*Q

    Hi I have a question concerning the anticommuting variable theta of the superspace manifold: For a proof of some renormalisation theorems I have seen the author make use of the transformation properties of theta under the internal U_R(1) symmetry i.e. he said theta -> exp(-i alpha)*theta ,under...
  17. A

    Exploring Supersymmetry Breaking & Poincare Invariance

    I recently studied supersymmetry breaking and read there that for Supersymmetry breaking we have the energy of the vacuum state >0. However what I do not really see is why such a vacuum would not break Poincare invariance as well as the energy is part of the momentum 4-vector and so transforms...
  18. A

    Solving Exercise I.2 on Supersymmetry Algebras

    Not sure if this is something you'd put in the homework help area or not, but I've started learning supersymmetry and seem to have hit a bump within the first few pages. \delta_{\lambda}\varphi = \frac{1}{2}\lambda^{\mu\nu}M_{\mu\nu}.\varphi for some field \varphi, which is one of S, P or...
  19. A

    Beginner: Strings and space-time supersymmetry

    I was wondering, OK it is a gedakenexperiment because it is beyond observation, but... how is space-time supersymmetry (no worldsheet susy) supossed to appear from the point of view of states of the fundamental string? Do we observe entities with spin 0 and spin 1/2 having the same mass? And...
  20. S

    Teaching myself supersymmetry and supergravity

    Hi, I am interested in teaching myself supersymmetry and supergravity. I have a decent qft background. I know of several good online notes,, but what I really need is a source of good problems. Anybody know where I can find such a source? Does the Wess and Bagger book have good problems...
  21. S

    Unraveling Supersymmetry: Questions and Evidence in Modern Physics

    These are questions for anyone who understands the modern theory of supersymmetry. I have recently read some articles on supersymmetry and its capacity to unify the forces of nature, along with providing a better explanation on the arisal of the higgs mechanism. Q1: Fermions and bosons are...
  22. A

    Mastering Supersymmetry: Solving the Algebra and Understanding Its Applications

    It's been bugging my for ages, but I cannot see to show the following supersymmetry algebra : \delta_{\epsilon} X^{\mu} = \bar{\epsilon}\bar{\psi} \delta_{\epsilon} \psi^{\mu} = \rho .\partial X^{\mu}\epsilon Using these show that [\delta_{\epsilon_{1}},\delta_{\epsilon_{2}}]X^{\mu} =...
  23. A

    Beginner: Strings and space-time supersymmetry

    I was wondering, OK it is a gedakenexperiment because it is beyond observation, but... how is space-time supersymmetry (no worldsheet susy) supossed to appear from the point of view of states of the fundamental string? Do we observe entities with spin 0 and spin 1/2 having the same mass? And...
  24. Robert100

    Good illustrations of String and supersymmetry theory?

    I have Brian Greene's "The Elegant Universe", and am thinking about getting Lisa Randall's "Warped Passages" Yet I'd appreciate any suggestions on books that contain a much larger number of illustrations and graphic analogies. Scientific American often has good articles on M-theory, branes...
  25. G

    How do I find the hermitian conjugate of this expression?

    Hi, I'm trying to do problem 3.5 of Peskin & Schroeder and I don't know where to start. First of all, I need to get the hermitian conjugate of the following expression \delta \chi = \epsilon F + \sigma^\mu \partial_\mu \phi \sigma^2 \epsilon^\ast where \epsilon is a 2...
  26. F

    What is Supersymmetry and How is it Used in Physics?

    Hello, My first post in the forums so please excuse me if there is already a post on this (I couldn't find one). I am not very technical in physics so can you please use simple language :shy: . I am not entirely sure on the concept of supersymmetry, I know stuff like partner of an...
  27. ZapperZ

    Supersymmetry, Extra Dimensions, and Higgs Bosons

    OK, this is so unlike me to advertize a theory activity on Supersymmetry, etc. But as a community service, I thought I should point out to those who are interested, that the Argonne Theory Institute will be starting it's Theory Institute 2005 workshop titled "Supersymmetry, Extra Dimensions, and...
  28. S

    A Brand New Idea in Supersymmetry

    Aaron Bergman has just called attention on science.strings to the new paper hep-th/0503249 which discusses the new idea of "split supersymetry". From the abstract: I don't know if this messes up current plans at Fermilab and CERN for hunting the Higgs. but it does look like it could give...
  29. D

    Supersymmetry and Superparticles

    In a nutshell, could someone refresh my memory on supersymmetry and superparticles. I have trouble understanding these subjects of string theory. Let's say we have a fermonic string of spin -1\2. What is it's superparticle's spin? Is it bosonic? Thanks to all
  30. U

    Unmesh Kamle: 17 Year Old Discussing Potential Wells and Supersymmetry

    My name is Unmesh Kamle. I have just passed high school and began reading about Potential wells and about electrons trapped inside them (from Resnick Halliday Krane). I m also reading about Supersymmetry. I m new member on this discussion forum. Could somebody reply to this message so that I can...
  31. J

    String Theory and Supersymmetry in Theoretical Physics Curriculum

    I'm sorry marcus, but as you probably know by now, familiarity with the main ideas of string theory and supersymmetry is pretty much mandatory for all students planning to go into theoretical physics, so courses in strings and supersymmetry continue to be a standard part of college syllubi (in...
  32. S

    The Mysteries of Supersymmetry: A Comprehensive Thesis Guide

    i am writting a thesis in supersymmetry if someone help me please
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