A postulated symmetry between bosonic and fermionic fields in quantum field theories and string theories.

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310 views

What exactly is a gauge anomaly?

In lots of papers I read about gauge anomalies. For example, avoiding gauge anamolies in the MSSM is the reason for introducing an extra Higgs doublet. Gauge anamolies in the Standard Model are ...
8
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1answer
331 views

Supersymmetry calculations using computer algebra

Already the early papers on supergravity were written using computer algebra software to do some calculations. What modern packages do people normally use for doing such calculations? Of course ...
12
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1answer
535 views

What are the limitations of the superspace formalism?

Just from reading this slightly technical introduction to supersymmetry and watching these Lenny Susskind lectures, I thought that the Lagrangian of any "reasonable" supersymmetric theory can always ...
4
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97 views

What decides the signs and coefficients of terms in superfield?

I'm working on a problem in 3d field theory and I'm confused about how to write the superfields. Specifically, I'm not sure if the signs and coefficients of terms are purely a matter of convention or ...
3
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1answer
105 views

Supersymmetry definition

Can someone outline the difference between supersymmetry and supersymmetric quantum mechanics? I often hear the two used interchangeably but I'm almost certain they are not the same.
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289 views

Tangent bundles and $\mathbb{C}P^n$ and $\mathbb{C}^n$

As discussed here the complex projective space $\mathbb{C}P^n$ is the set of all lines on $\mathbb{C}^n$ passing through the origin. It would seem natural to assume that any $\mathbb{C}P^n$ can be ...
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77 views

Proof the superstring action is Weyl invariant

The superstring action is: $$ S = k\int \mathrm d\sigma \sqrt{-h} \left [ h^{\alpha \beta} \partial_\alpha X^\mu \partial_\beta X_\mu + 2i {\bar{\psi}} ^\mu \rho^\alpha \partial_\alpha \psi_\mu - i ...
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54 views

Finite corrections to the Higgs mass in SUSY

I am worried here about specific supersymmetric scenarios in which an energy scale above the TeV is introduces. An example would be the Seesaw extension of the Minimal Supersymmetric Standard Model. ...
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1answer
52 views

Local fermionic symmetry and GS action

I have a trouble understanding an argument which I think has a simple answer but I am not getting it. The question is that if you don't impose local fermionic symmetry the GS action has only one term ...
4
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1answer
97 views

Spurions in Anomaly Mediated Supersymmetry Breaking

When studying supersymmetry breaking, people often use a spurion chiral superfield to study the soft SUSY breaking terms which enter the Lagrangian ($X=\theta^2 F$). Since we let the spurion couple to ...
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1answer
117 views

Two definitions: 'semi-classical space-time' and 'supersymmetric Minkowski space'

By reading articles I ran several times into two terms, never being defined so I assume they must have well established definitions somewhere. The first is semi-classical space-time. If I where to ...
6
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1answer
163 views

Negative sign in the Dirac term from the SUSY Kahler potential

I want to calculate the Dirac term from the canonical Kahler potential, \begin{equation} K = \Phi ^\ast \Phi \tag{1} \end{equation} but I'm coming across a pesky negative sign in the final result. I ...
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1answer
129 views

Interpretation of the WIMP annihilation cross section graph

I have some trouble in the interpretation of the WIMP cross-section annihilation versus their mass. I understand that the lines represent a upper bound on the cross section from the observation. ...
2
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1answer
82 views

Majorana Superfields

so apologies if this is a silly question... In the type 1 see saw model we add extra Majorana fermions to our model. These fermions have to be total gauge singlets in order to have a Majorana mass ...
2
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1answer
117 views

Mathematical Physics SUSY QM Resource Recommendation

I want to study SUSY QM. I found some excellent physically motivated articles on Arxiv. Despite, I am especially interested in the mathematical structure behind SUSY QM. Does anybody know whether ...
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67 views

What is the advantage of supersymmetry?

what are the advantages of SUSY with respect to other theories? for example DIMENSIONAL REGULARIZATION can also deal with the UV and IR divergences too :D so what other advantages has supersymmetry? ...
5
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1answer
117 views

How do I deal with a quantum field in the denominator?

I am wondering how to deal with an expression like $$ \int d^4\theta \frac{1}{T + T^\dagger} \big( \dots \big) $$ If the denominator was of the form $1 + T + T^\dagger$, I could assume that $T \ll 1$ ...
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75 views

How come gravity is $\mathcal{N}=8$? Why is graviton spin 2 [duplicate]

I never understood why supergravity $\mathcal N=8$, nor why the spin of a graviton is 2. I've been reading around but I still don't have a back-of-the-envolope understanding.
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36 views

Do we have more than one $D$ term for a single gauge group?

I'm reading this note in chapter 6 which discusses $ {\cal N} = 2 $ supermultiplets, though the discussion is quite general and applies to $ {\cal N} = 1 $ fields in the adjoint representation. I ...
5
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1answer
90 views

What's the Noether charge associated with Kaehler invariance of SuGra?

What is the Noether charge associated with Kahler invariance of supergravity (SUGRA)? As the question is rather tangential to what I need to do, I have not tried explicitly calculating it myself, but ...
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260 views

Interpretation of the Instanton in SUSY QM

This is a loose follow up to this question: Interpreting Argyres' spectrum of spontaneously broken SUSY QM. In SUSY QM, the Hamiltonian can be cast as a 2x2 matrix $$ H = \frac{1}{2}p^2 + ...
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32 views

$\mathcal N=2$ Weyl multiplet and chiral superfields in 4d

It is more or less known that a given antisymmetric tensor $F$ in two indices can be written in terms of spinorial indices, splitting into self-dual and anti-self-dual parts $$ F_{\mu\nu} = ...
8
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2answers
314 views

Do exact beta functions exist in (super)gravity theories and string theory?

An exact beta function exists for Super-Yang-Mills theories in 4D without matter - the so-called NSVZ beta function. Does a similar exact beta-function exist in gravity or supergravity theories? In ...
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1answer
573 views

A question about Feynman diagram and symmetry factor

Consider a $\varphi^3$ theory: $$ Z_1(J) \propto \exp\left[\frac{i}{6} Z_g g\int \mathrm{d}^4 x \left(\frac{1}{i}\frac{\delta}{\delta J}\right)^3\right] Z_0(J), $$ where $$ Z_0(J) = ...
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45 views

Seiberg Duality Applications

I am interested in why people are interested in Seiberg duality? Can it be used for something? Does it (or may it) correspond to any 'real world' physics? I don't have enough background to understand ...
17
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2answers
576 views

S-Matrix in $\mathcal{N}=4$ Super-Yang Mills

This is a general question, but what is meant when people refer to the S-Matrix of $\mathcal{N}=4$ Super Yang Mills? The way I understood it is the S-Matrix is only well defined for theories with a ...
5
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1answer
189 views

Interpreting Argyres' spectrum of spontaneously broken SUSY QM

I can't understand the spectrum in the figure on page 19 from Argyres' lecture notes on supersymmetry: http://www.physics.uc.edu/~argyres/661/susy1996.pdf Argyres is considering a supersymmetric ...
2
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1answer
84 views

Can symmetry generators anticommute with the S-matrix?

In Coleman and Mandula's proof of the Coleman-Mandula theorem, they define a symmetry transformation as an unitary $U$ which, turns one-particle states into one-particle states, acts on ...
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131 views

Book with solved examples and exercise problems for SUSY

I am learning supersymmetry right now. I am mostly following Bailin and Love. I try to connect all the steps from the book and complete the derivations in order to get comfortable with the ...
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2answers
136 views

Number of supersymmetric charge and the meaning of $\cal N$

I have been thinking about the definition of the notation $\cal N$ and its relation to the number of supercharges in SUSY, but still feel a little confused. In dimension 2, we usually denote, for ...
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96 views

How do messenger fields break SUSY in the MSSM?

I have been reading the notes on Supersymmetry by Martin. I am trying to understand gauge mediated symmetry breaking. From what I understand, there is a hidden sector where SUSY is spontaneously ...
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107 views

String theory and space-time supersymmetry

I actually want to know whether space-time supersymmetry is important for string theory consistency? I see that NS and GS supersymmetric strings have worldsheet supersymmetry, but the first one does ...
2
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1answer
63 views

BPS state and annihilation of SUSY charges

As we all know that anticommutator of one set of supercharges in massive extended supersymmetry is something like $$\{b_\alpha, b_\beta^\dagger \} = \delta_{\alpha \beta} (M-\sqrt{2} Z).$$ My question ...
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71 views

Unbroken Supersymmetry and the higgs mass

Supersymmetry should cancel the radiative corrections to the Higgs mass and solve the hierarchy problem. If Supersymmetry would be unbroken, would the higgs mass be 0?
5
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102 views

R-symmetry commutator

I've seen the claim made several placed; Terning's "Modern Supersymmetry" p. 5 on N=1 SUSY algebra states it as well as anyone: The SUSY algebra is invariant under a multiplication of $Q_\alpha$ ...
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4answers
152 views

why do the electroweak vacuum have to be charge and color neutral?

My question is why the electroweak vacuum of the Standard Model have to electroweak charge and QCD color neutral? What goes wrong if electroweak vacuum has either non-zero charge or color quantum ...
12
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1answer
303 views

Supersymmetric Noether theorem and supercurrents — invariance requirements

Consider $\mathcal{N}=1,d=4$ SUSY with $n$ chiral superfields $\Phi^i,$ Kaehler potential $K,$ superpotential $W$ and action ($\overline{\Phi}_i$ is complex conjugate of $\Phi^i$) $$ S= \int d^4x ...
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3answers
382 views

Supersymmetry in Quantum Mechanics

I was reading Supersymmetry in Quantum Mechanics and got stuck in the various mathematical terminology like "Graded-Lie Algebra", "Super Algebra". Is there any good lecture notes concerning these ...
8
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3answers
140 views

“tmf$(n)$ is the space of supersymmetric conformal field theories of central charge $-n$”

I read this intriguing statement in John Baez' week 197 the other day, and I've been giving it some thought. The post in question is from 2003, so I was wondering if there has been any progress in ...
9
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1answer
187 views

The difference between $\mathcal{N}=2$ short multiplets and BPS states

I have some questions about the construction of $\mathcal{N}=2$ supermultiplets for chiral matter. I know that the supermultiplet should not include spin one states since they are always in the ...
3
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1answer
82 views

Neutrino Nuclei Coherent scattering and the Dark Matter lower wall

Suppose that current and new forthcoming dark matter direct detection experiments find no evidence of Dark matter events and exclude interactions of hypothetical DM particles (like LSP or similar) in ...
10
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1answer
234 views

Assumptions of the Coleman-Mandula Theorem

In the original paper All Possible Symmetries of the S-Matrix, by S. Coleman and J. Mandula, they prove their famous 'no go' theorem regarding the possible extensions of Poincaré symmetry. The ...
6
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1answer
129 views

WIMPs and Gravitinos

I was just wandering if a gravitino could be in the WIMP class, because they are both massive (admittedly WIMP's more so) and are both weakly interacting and predicted by R-parity. i.e Gravitinos are ...
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0answers
53 views

N=4 SYM in terms of N=1- SO(6) in the yukawa term

I'm trying to write N=4 SYM in terms of N=1 superfields. I have the lagrangian $$\mathcal{L}=\frac{1}{16 k} \int d^2 \sigma \text{Tr} \big[W^a W_a\big]+c.c+\int d^4\theta \text{Tr}\big[\bar{\Phi}^i ...
10
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1answer
427 views

Auxiliary fields in supersymmetry

I know that auxiliary fields can be used to close the supersymmetry algebra in case the bosonic and fermionic on-shell degrees of freedom do not match. Could somebody please elaborate on this concept ...
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39 views

Comprehensive list of $\mathcal{N}=2$ supersymmetric topological quantum field theories in $d=4$

Could anyone provide a comprehensive list of $\mathcal{N}=2$ supersymmetric topological quantum field theories in $d=4$? I know of one - Kapustin-Witten TQFT, but I do not know of any more. Thanks!
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1answer
84 views

Question about the vacuum bundle on A- and B-model

Let us consider the topological string A- and B-model (twisted SUSY non-linear sigma model on CY 3-manifold $X$). They are realization of $N=2$ SCFT and there are ground-states vector bundle ...
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40 views

$\mathcal{N}=2$ spin $1/2$ supermultiplet

In Freedman and Van Proeyen's Supergravity, in the footnote on pg. 128, they say There is a subtle hermiticity requirement for $\mathcal{N}=2$, which requires the multiplet $(-1/2,0,0,1/2)$ must ...
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202 views

What is the relation between the representation the Higgs field transforms under, the types of couplings in the theory and Higgs/Coulomb branches?

When reading about Higgs and Coulomb 'phases' I came across two separate definitions: The first tells us that the Higgs/Coulomb phases are determined by the representation that the Higgs field ...
4
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287 views

What's the Coulomb Branch and why is it important?

I'm studying the introduction of flavour degrees of freedom in the AdS/CFT correspondence and now I'm supposed to calculate the mass spectrum of mesons in the Coulomb branch. I have searched the ...