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. E

    Exploring the Role of Superconformality in Coupling Supergravity to Matter

    I have been trying for a while to read a precise definition of a Vector Multiplet (to whom ##N=2## Supergravity theories couple to in ##4D##) but was not lucky in finding a self-contained one. The best I got was that on https://en.wikipedia.org/wiki/Supermultiplet though it was on...
  2. E

    How do scalars determine the geometry of a manifold?

    Crossing over the following paragraph: There are three types of special manifolds which we shall discuss, related to the real scalars of gauge multiplets in D = 5, the complex scalars of D = 4 gauge multiplets and the quaternionic scalars of hypermultiplets. Since there are no scalars in the...
  3. E

    Why a bosonic background in SUGRA?

    In this http://www.ulb.ac.be/sciences/ptm/pmif/Rencontres/specgeom.pdf, for example on p.7 and in many other references, people usually say: we will concentrate on the bosonic part of the Lagrangian in N=1 (sometimes N=2) supergravity. In other incidents, people say, that they are going to...
  4. P

    Lorentz Transformation on Left & Right Chiral Spinors

    I will start with a summary of my confusion: I came across seemingly contradictory transformation rules for left and right chiral spinor in 2 books, and am unable to understand what part is Physics and what part is convention. Or is it that one of the two books incorrectly writes the...
  5. haael

    Susskind on supersymmetry vs. cosmological constant?

    In one book of Susskind I found the following claim and I wanted to ask for its basis. Susskind says that each kind of boson gives positive contribution to the cosmological constant (the lighter, the better). Each kind of fermion gives negative contribution to the cosmological constant. Thus...
  6. K

    Scientific implications of latest LHC SUSY beauty quark

    http://news.discovery.com/space/lhc-keeps-bruising-difficult-to-kill-supersymmetry-150727.htm LHC Keeps Bruising 'Difficult to Kill' Supersymmetry Previous attempts at measuring the beauty quark's rare transformation into a so-called "up quark" had yielded conflicting results. That prompted...
  7. itssilva

    Supersymmetry: Theory and Experiments

    Supersimmetry, by itself, is a neat, elegant concept; I've read somewhere else (think Griffiths' Introduction to Elementary Particles, if memory serves me right) that it allows the various running couplings of the Standard Model to converge to a single value at high enough energies; however...
  8. Safinaz

    Calculating Cross Sections in Supersymmetry: A Comprehensive Guide

    Hi there, In particle physics there is famous books as Peskin's book " To Quantum Field Theory (Frontiers in Physics) " to learn matrix element amplitude and cross section calculations, like ee -> mu mu. Are there similar references for supersymmetry to learn how to calculate the cross...
  9. W

    Twice of supersymmetric transformation = translation

    Hello, I have one conceptual question. I have been working on Supersymmetry. Now, I understand that twice of supersymmetric transformation is equivalent to translation mathematically(naively). However, I don't quite understand why this should be the case conceptually. Supersymmetric...
  10. C

    Introductory textbooks for Supersymmetry?

    Hi everyone, As of late I've been really wanting to push on with my interest in particle Physics by tackling the rather daunting theoretical model that we call supersymmetry. However, to put it simply, I'm not entirely sure where to start! There's so many different textbooks on the subject out...
  11. Jesus

    SUSY N=1 masless supermultiplet

    In the massless case of N=1 simple supersimetry, the states are labeled by the helicity λ and the four-momentum. In this case we have two states in the supermultiplet plus CPT conjugates: |pμ, ± λ> and |pμ, ± (λ-½)> Then there is a λ= {0, ½} supermultiplet (where for example a quark with λ=½...
  12. S

    Novice's Question on Spontaneous SUSY Breaking & Goldstinos

    I'm a novice in SUSY and I'v got a question concerning spontaneous supersymmetry breaking and goldstinos. In Martin's review on page 68 there is a proof of a statement about existence of massless particle when one of ##F_i##'s or ##D_a##'s VEV is not zero. The thing I don't get is why vector...
  13. twistor

    How does Savas Dimopoulos' latest paper challenge current SUSY collider limits?

    http://arxiv.org/pdf/1412.0805.pdf Auto-Concealment of Supersymmetry in Extra Dimensions Savas Dimopoulos,a Kiel Howe,a,b John March-Russell,c,a James Scovillec,d aStanford Institute for Theoretical Physics, Department of Physics, Stanford University, Stanford, CA 94305, USA bSLAC National...
  14. P

    Substitution in the following supersymmetry transformation

    I was reading in this book: Supergravity for Daniel Freedman and was checking the part that has to do with Extremal Reissner Nordstrom Black Hole. He was using killing spinors (that I am very new to). I was understanding the theory until he stated with the calculations: He said that the...
  15. E

    Link between CP violation and supersymmetry?

    I have been looking in SUSY and have seen that the CP violation of B mesons into two muons is one of the key facts that has cast further doubt over SUSY. I don t really understand how the CP violation of B mesons is a sign of SUSY issues, so if you are able to clear this up for me that would be...
  16. wolram

    Is Supersymmetry still viable in cosmology?

    Is Supersymmetry still viable in cosmology, given that so far no supersymmetric particles have been found. From Wiki. SUSY is often criticized in that its greatest strength and weakness is that it is not falsifiable, because its breaking mechanism and the minimum mass above which it is...
  17. L

    Schouten's identity in Ian Aitchison's supersymmetry book

    In 'Supersymmetry in Particle Physics, An Elementary Introduction', the author Ian Aitchison used for several times the following identity: λa(ζ · ρ) + ζa(ρ · λ) + ρa(λ · ζ) = 0. I know that this identity is called Schouten's Identity, which is correct when all the variables are common...
  18. Greg Bernhardt

    Jim Gates live webcast on supersymmetry June 4th

    I hope to be able to watch. Should be very interesting! The link below should host the webcast at some point. http://www.perimeterinstitute.ca/node/92581
  19. J

    Supersymmetry - current status

    I wanted to ask wheter there is any progress when it comes to SUSY. Since LHC didn't find any superpartners and LUX found no neutralinos how much space does SUSY have left? I mean it can be fine tuned but that can't be done forever right? Or is there something I don't know that improves...
  20. A

    Uncovering the Truth: New Measurement Challenges Supersymmetry Theories

    maybe no supersymmetry... "The new result deals a significant blow to many new physics theories, most notably supersymmetry, a favored idea that suggests each known particle in the Universe has a supersymmetric twin particle that has yet to be discovered" "Although some basic models of the...
  21. N

    One quick question about Higgs boson and supersymmetry

    Peter Higgs is going to get a Nobel prize for physics, since Higgs boson's existence was confirmed in the experiments in CERN. But I do have some questions: I read the following, but I'm not qualified to say if this is true or not, so I'm asking you for help, and if the following statement is...
  22. M

    Supersymmetry vs minimalism: what is the Higgs mass telling us?

    We have had several threads that discuss the 2009 prediction of the Higgs boson mass by Shaposhnikov and Wetterich, which used the assumption that quantum gravity is "asymptotically safe". But it's also true that the observed value is within a range predicted by some orthodox supersymmetric...
  23. D

    What are the implications of supersymmetry for the Higgs boson and its mass?

    Hello all, How is it that super symmetry accounts for the Higgs having a mass and what would the 4 remaining Higgs bosons account for?
  24. atyy

    Strings without low scale supersymmetry

    Are there stringy candidates for reproducing the SM and dark matter etc without low scale supersymmetry?
  25. P

    Inflation, as a tool for supersymmetry breaking

    Hi I know that gravitninos are produced in the Early Universe in reheating (after inflation), is this because the end of inflation/reheating period where the inflaton is oscillating about the minima of the potential is analogous to symmetry breaking?
  26. N

    Supersymmetry and String Theory

    I just recently seen an article that the recent findings at the LHC seem to disprove supersymmetry. I would like to know how supersymmetry and string theory are connected and what the implications would be if the LHC totally disproves supersymmetry all together?
  27. T

    S. Martin's Supersymmetry primer Metric

    Hi all, S. Martin's Supersymmetry primer (http://arxiv.org/abs/hep-ph/9709356) is a wonderful source from which to learn SUSY. But, what really causes me (and others around me) huge consternation is Martin's use of mostly plus metric, when particle physicists use the mostly minus metric...
  28. B3NR4Y

    Superstring Theory problem. Infinitesimal supersymmetry transofrmations

    Homework Statement Let \begin{equation} \delta _{1} \, and \, \delta _{2} \end{equation} be two infinitesimal sypersymmetry transformations on xμ compute \begin{equation} [\delta _{1}, \delta _{2} ]x^{μ}. \end{equation} Homework Equations The commutator is: \begin{equation}...
  29. C

    Supersymmetry and Fusion Catalysis

    I've often been fascinated by the tantalising nature of muon-catalysed fusion, and have recently been pondering it in the context of supersymmetry. As a Chemist first and foremost, the nearly-chemical nature of the muon-catalysed fusion process really draws my attention. To my understanding...
  30. J

    Higgs Boson and Supersymmetry?

    Can someone explain to me in layman's terms why the Higgs Boson needs to be less than 130 GeV to prove Supersymmetry exists?
  31. A

    Algebra of the generator of supersymmetry transformations?

    We consider a superfield \Phi\left(x^{\mu}, \theta_{\alpha}\right). For a small variation \delta \Phi = \bar{\epsilon} Q \Phi where the supercharge Q_{\alpha} is given by: Q_{\alpha}=\frac{\partial}{\partial \bar{\theta}^{\alpha}}-\left(\gamma^{\mu} \theta \right) _{\alpha} \partial _{\mu}...
  32. R

    Spin of Particles Detected at LHC: Higgs Boson and Supersymmetry

    I tried searching through but didn't find this asked. If the spin of the particle detected at LHC comes back as 2, for instance, does it mean it's not a higgs boson? There are 5 higgs in supersymmetry, do they all have spin 0?
  33. ShayanJ

    What is Supersymmetry: Fermion-Boson Correspondence

    I've read in the wikipedia supersymmetry page,that supersymmetry is a symmetry which relates fermions to bosons. Can we tell that this means there is aOne-to-One Correspondence between fermions and bosons and we can substitute a fermion with its corresponding boson and vice versa,to get a...
  34. N

    How to build supersymmetry lagrangians

    Hi, In SUSY we introduce chiral superfield, vector superfield, then build some invariants and get the SUSY lagrangians which after decomposition into normal fields (F and D terms) gives us for example ordinary QED plus some other terms. And we call this SUSY-QED. I have following question...
  35. L

    Solving Supersymmetry Questions: A Beginner's Guide

    I haven't done any supersymmetry before and am probably going to need it in the future (hopefully anyway). Anyway, I've been reading through these online notes: http://www-thphys.physics.ox.ac.uk/people/JosephConlon/LectureNotes/SUSYLectures.pdf I have a problem with p7: (i) What is the...
  36. C

    Is Supersymmetry Really the Answer?

    Researchers failed to find evidence of so-called “supersymmetric” particles, which many physicists had hoped would plug holes in the current theory. Before the start of LHC, I expected early discovery of supersymmetry in the jets+MET signature. Many other theorists also had this belief. But...
  37. Dotini

    Simple Supersymmetry Bites the Dust

    http://www.bbc.co.uk/news/science-environment-14680570 Results from the Large Hadron Collider (LHC) have all but killed the simplest version of an enticing theory of sub-atomic physics. Researchers failed to find evidence of so-called "supersymmetric" particles, which many physicists had hoped...
  38. C

    Solve Supersymmetry n=8: Degrees of Freedom for Supergravity

    Someone can helpme finding the number of degree of freedom for supergravity n=8?
  39. J

    What is Supersymmetry? Overview & Explanation

    I have been seeing the word supersymmetry, and I recon that it's the unification of quantum theory and relativity or is ot not?...what is it. I looked it up on wikipedia but didn't really get it, just something about particle spinning and affecting other particles. Could you give me a rough...
  40. J

    Finding Supersymmetry: What will it mean?

    Layman's terms what doors will be opened by proving it? What will it say about reality? Will it mean the universe is bigger than we know? Am I right when I tell my kids that Supersymmetry are mirror images of partials that are symmetrical in shape, but heavier than their partner? Thank you
  41. J

    Latest results from the LHC are casting doubt on the theory of supersymmetry

    Latest results from the LHC are casting doubt on the theory of supersymmetry http://www.scientificamerican.com/article.cfm?id=beautiful-theory-collides "I'm wouldn't say I'm concerned," says John Ellis, a theorist at CERN, Europe's particle-physics lab near Geneva, who has worked on...
  42. W

    How Does Supersymmetry Demystified Compare to Other Titles in the Series?

    I'm wondering what this book is like in relation to QM, QFT, and String Theory Demystified which have mixed reviews: https://www.amazon.com/dp/0071636412/?tag=pfamazon01-20
  43. E

    Can Supersymmetry be harmonized with technicolor/topcolor models?

    Suppose the LHC discovers that EW is dynamically broken by technicolor, topcolor, top quark condensate models. Can these be harmonized with SUSY? If new strongly interacting dyanmics breaks EW, how would that modify SUSY, including SUSY particle content? Or, would discovery of technicolor/top...
  44. marcus

    Immanuel Kant on Supersymmetry: a Practical Evaluation

    http://arxiv.org/abs/1003.2967 Immanuel Kant on Supersymmetry: A Practical Evaluation Alexander Unzicker 4 pages (Submitted on 15 Mar 2010) "A short review of the motivations for supersymmetry in astrophysics and particle physics is given. Despite the amount of theoretical research...
  45. P

    How will our world be different if supersymmetry is an unbroken symmetry?

    With all kinds of low energy superpartner particles floating around, do we get the same types of atoms and molecules that build up our world? Will the periodic table of elements be larger or smaller? Is this world friendly to the evolution of intelligent life?
  46. W

    Exploring the Complexities of Space-time Supersymmetry and Supergravity

    Hi there, What is the difference between Space-time Supersymmetry and Supersymmetry? Is Space-time Supersymmetry the same thing as Supergravity? What is Supergravity... All these terms make me very confused... Thanks a lot!
  47. P

    Can string theory include fermions without supersymmetry?

    I'm taking an introductory string theory course which focuses on bosonic string theory. The lecturer says to include fermions supersymmetry must be included (aka. superstrings). If we face the event that the LHC fails to find any supersymmetry at TeV scale and the physics community lose faith in...
  48. N

    New introductory book on supersymmetry

    I hope it's ok to post this here. I have written an introductory book on supersymmetry, which assumes only some basic knowledge in quantum field theory. I made it as detailed and pedagogical as possible. Basically I wrote the book that I wish had been available when I first learned SUSY. The...
  49. N

    New pedagogical book on supersymmetry

    I hope it's ok to post this here. I have written an introductory book on supersymmetry, which assumes only some basic knowledge in quantum field theory. I made it as detailed and pedagogical as possible. Basically I wrote the book that I wish had been available when I first learned SUSY. The...
  50. MTd2

    How many string theories with more than one supersymmetry?

    With one, we have 5, what about more than one? What are they? What are the importance of these, phenomenologicaly saying?
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