The supersymmetry tag has no wiki summary.
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1answer
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Proof of S-duality between Type IIB, IIB and Type HO, I string theories
About every source on string theory I've read which do mention S-duality state that:
$$\begin{array}{l}
\operatorname S:\operatorname{IIB} \leftrightarrow \operatorname{IIB}\\
\operatorname ...
0
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0answers
32 views
Scalar-fermion bound state
Is it possible to have a bound state between a scalar and a fermion? For example, a squark--anti-squark bound state, provided that the decay width is sufficiently small compared to the binding energy?
...
4
votes
1answer
64 views
T-Duality between Type HE String theory and Type HO string theory
My question is regarding T-Duality between the 2 Type H string theories.
I know that the Type II String theories are T-dual to each other because T-Duality changes the sign of the Gamma Matrix so
...
3
votes
1answer
46 views
Question on Type HO/HE string theory
The Heterotic string state is a tensoring of the bosonic string left-moving state and the Type II string right-moving state. Therefore, I expect the spectrum to be:
$$\begin{array}{*{20}{c}}
\hline
...
3
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0answers
63 views
Bosonic-Fermionic interactions in supersymmetry
There are a lot of supersymmetric theories, and, sometimes,in the Lagrangian, there are interacting terms between bosonic and fermionic degrees of freedom, and sometimes not. Why ?
For instance, for ...
5
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2answers
136 views
How can string theory work without supersymmetry?
This question is inspired from reading Mitchell Porter's nice answer here to a question asking why supersymmetry should be expected naturally. Among other things, he explains that since weak scale ...
2
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2answers
76 views
Question on the Hagedorn tower in Type I string theory
In a previous question (Mass spectrum of Type I string theory), I had asked about the mass spectrum of Type I string theory. I got a response saying that it is a Hagedorn tower. However, my source ...
2
votes
1answer
69 views
Flavour diagonal SUSY breaking
Because there is a single Yukawa matrix for the SM leptons, the lepton mass and flavour states can be aligned, by diagonalization, even if the Yukawa matrix had off-diagonal elements.
SUSY breaking, ...
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Mass spectrum of Type I string theory
I understand that the massless fields of the Type I string theory are the described by:
[\begin{array}{*{20}{c}}
{{\rm{Sector}}}&{{\rm{Massless fields}}}\\
{{\rm{R - R}}}&{{C_0}}\\
{{\rm{NS - ...
3
votes
1answer
66 views
Spectra of the Type II String theories
The spectrum of the Type II string theory (both IIA and IIB) is given by:
\begin{array}{*{20}{c}}
\hline
& {{\text{Sector}}}& & {{\text{Spectrum}}}& & {{\text{Massless Fields}}} ...
3
votes
1answer
153 views
Why should SUSY be expected naturally?
In the last 40 years (approximately) people have been "discovering", "rediscovering" and "studying" SUSY as a powerful tool and "symmetry principle".
Question:
What if SUSY is not realized in ...
3
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Holonomy twisting
There is Witten's topological twist of standard SUSY QFTs with enough SUSY into Witten-type TQFTs. What is a holonomy twist?
2
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Holomorphic coupling as a source for gaugino condensation
On the top of page 23 of hep-th/03061119, it is pointed out that treating the holomorphic gauge coupling $\tau$ as a background (spurion) superfield allows one to think of its $F$-term, $F_\tau$ as ...
3
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0answers
44 views
Supersymmetric Chern-Simons theories in $d=3$
I am reading up on Chern-Simons matter theories in $d=3$. Here is the quote (from http://thesis.library.caltech.edu/7111 page 15) that I am having trouble with:
One could also add a supersymmetric ...
3
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0answers
49 views
Does the number of left handed chiral quark superfields always equal half the number of quark flavours?
In Weinberg's "The Quantum Theory of Fields Vol III" page 267 we're told that $n_f = 2N_f$. Where $n_f$ are the number of flavours and $N_f$ is the number of left chiral quark superfields (or the ...
3
votes
1answer
93 views
Supersymmetry and non-compact $R$-symmetry group?
The $R$-symmetry for $N$ supercharges is $U(N)$. Is it possible to generalize $R$-symmetry [let's take $U(4)$) to be something like $U(2,2)$ (maybe analogous to Wick rotation of $SO(3,1)$ to ...
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Perturbation in Supersymmetric Quantum Mechanics.
To do perturbation analysis of Supersymmetric Quantum Mechanical Hamiltonian, the superpotential is first scaled by a constant $\lambda >> 1$ and then expanded about it's critical point. Finally ...
2
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1answer
50 views
Scalar top quark (stop) pair production
A rather simple question:
Starting from an electrically neutral state, pairs of top quarks are produced as top and anti-top, and denoted as $t\bar t$.
Now the production of pairs of scalar top ...
2
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0answers
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$\mathcal{N}=2$ susy hypermultiplet self-CPT?
Is the multiplet given by
$$\left( -\frac12,0,0,\frac12 \right)$$
self-CPT conjugate?
There seems to be no common agreement upon that:
Weinberg (QFT 3, page 47) and many others claim it is not, ...
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139 views
supersymmetric Noether theorem and supercurrents — invariance requirements
Consider $\mathcal{N}=1,d=4$ SUSY, $n$ chiral superfields $\Phi^i,$ Kaehler potential $K,$ superpotential $W$ and action ($\overline{\Phi}_i$ is complex conjugate of $\Phi^i$)
$$ S= \int d^4x \left[ ...
3
votes
1answer
118 views
Why does in string theory the amount of supersymmetry have to be $\cal{N} \leq 2 $?
Why is this, that in string theory the maximum amount of supersymmetry is $\cal{N} = 2$, whereas in supergravity one can have up to $\cal{N} = 8$ ?
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What is kappa symmetry?
On page 180 David McMohan explains that to obtain a (spacetime) supersymmetric action for a GS superstring one has to add to the bosonic part
$$
S_B = -\frac{1}{2\pi}\int d^2 \sigma ...
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0answers
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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 ...
4
votes
1answer
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Strange Grassmann double integration
I can unterstand why because the integration over Grassman variables has to be translational invariant too, one has
$$
\int d\theta = 0
$$
and
$$
\int d\theta \theta = 1
$$
but I dont see where ...
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0answers
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References for Understanding Minahan's N=4 SCFT review
This is about the same paper as this thread: Some questions about chapter I.1 (by Minahan) of the "Review of AdS/CFT Integrability" but it was never answered.
I have some different ...
3
votes
1answer
82 views
How to determine R charge?
Ref. 1, page 15, equation (23) defines the $U(1)_V$ and $U(1)_A$ actions as $$e^{i\alpha F_V}: \Phi(x,\theta^{\pm},\bar{\theta}^{\pm}) \rightarrow e^{i\alpha q_V}: \Phi(x,e^{-i\alpha ...
3
votes
1answer
98 views
How to determine predicted CP violation for a given SUSY point?
I'm currently studying at the spectra of some supersymmetric models, and would like to know whether the parameter points I'm looking at are ruled out due to excessive CP violation.
I am using SPheno, ...
0
votes
1answer
75 views
Is there a relation between supersymmetry and entropy?
Considering that entropy denotes the level of order/disorder in a system, would it be possible for entropy and supersymmetry to exist at the same time? Or, are they entirely unrelated?
4
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1answer
97 views
Soft Mass and Physical Mass in Softly-broken SUSY
In softly broken SUSY, the bare mass parameters may be specified at e.g. the GUT scale, and then we can run these down to another scale using RGEs, similar in form to the RGEs for gauge couplings, ...
5
votes
1answer
144 views
Geometric interpretation of hidden SUSY
Hidden supersymmetry, which is the classical(non-super) symmetry in the form of susy, acting on a non-Grassmann space (e.g., Grassmann space is $(t,x,\theta,\bar{\theta})$, corresponding ...
5
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1answer
86 views
Does anybody know of any good sources that explain (generically) how we form Lagrangians/Actions/Superpotentials for different field content?
I regularly find that I'll understand where the field content in a particular physics paper comes from, but then a Lagrangian or action or superpotential is stated and I don't know how it's derived. ...
5
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1answer
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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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What are the implications if Supersting theory is discredited? [duplicate]
Please forgive my ignorance, I am not a student of physics in any capacity, therefor my understanding of string theory is extremely limited to say the least. Based on the recent lack of evidence in ...
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0answers
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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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A puzzle from 'The origin of the hidden supersymmetry'
In the paper arXiv:1004.5489 The origin of the hidden supersymmetry, the author use {Qa,Qa}={Qb,Qb}=2H, {Qa,Qb}=0 for N=2 hidden SUSY, which is different from what I was taught: {Qa,Qa}={Qb,Qb}=0, ...
2
votes
1answer
76 views
Hamiltonian in SUSY (SUSY algebra)
I was reading the book Supersymmetry, Theory, Experiment and Cosmology by P. Binétruy, and on page 25 the author goes from
$$ 1)[Q_r,Q_t]_+ \gamma^{0}_{ts}=2\gamma^{\mu}_{rs}P_{\mu} $$ $$ ...
1
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1answer
85 views
Differences between Goldstone bosons and fermions
I have been looking into basic SUSY and SUGRA theory and have a question relating to Goldstinos (particles giving gravitinos mass).
Simply are these analogous to Goldstone bosons produced in the ...
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0answers
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sigma model on $S^1 \times S^3$
In arXiv:1207.3497 - 4D partition function on $S^1 \times S^3$ and 2D Yang-Mills with nonzero area, Yuji Tachikawa explains the partition function for an 4d $\mathcal{N}=2$ sigma model on $S^3 \times ...
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2answers
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What is the current status of string theory (2013)?
I've seen a bunch of articles talking about how new findings from the LHC seem to disprove (super)string theory and/or supersymmetry, or at least force physicists to reformulate them and change ...
2
votes
1answer
61 views
Induce a Fayet-Iliopoulos term
In a supersymmetric U(1) gauge theory, if I leave off the Fayet-Iliopoulos term $\kappa [V]_D$, what keeps it from being induced in loop corrections?
5
votes
1answer
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CP-violation in SUSY QED?
I have just gone through the exercise of constructing the supersymmetrized QED action.
In the end, I get a reasonable action which matches literature. But after a little analysis, I find that the ...
6
votes
0answers
97 views
How to perform contour integral in Nekrasov's formula
My question is technical. It is about instanton counting calculation (see this paper).
The partition function of SU(N) gauge theory with $N_f$ fundamental multiplets in k instanton background is ...
1
vote
2answers
275 views
Mathematically: What is SUSY?
Wikipedia says:
In particle physics, supersymmetry (often abbreviated SUSY) is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and ...
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Supersymmetric Sigma Model
I was working through the Mirror Symmetry book by Clay Math Institute. It deals with supersymmetric sigma model in 10.4 section. It doesn't derive how the action is invariant under the variation. I am ...
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About defining “baryons” and “mesons”
I want to understand the proof of the claims (of the construction as well as of its uniqueness) of gauge singlet states given around equation 2.13 (page 10) of this paper.
Also does the listing of ...
7
votes
1answer
193 views
Canonical quantization in supersymmetric quantum mechanics
Suppose you have a theory of maps
$\phi: {\cal T} \to M$
with $M$ some Riemannian manifold,
Lagrangian
$$L~=~ \frac12 g_{ij}\dot\phi^i\dot\phi^j + \frac{i}{2}g_{ij}(\overline{\psi}^i ...
1
vote
1answer
107 views
Divergence in Supergravity
I'm not familiar with supergravity so here's my question: I've heard in talks that if one finds divergence for five-loop 4-graviton scattering amplitudes in five dimensions this translates to a ...
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73 views
Can mass dimension of a field be viewed as another 'quantum number'?
While studying SUSY in 4D, I noticed the dynamical chiral superfield has dimension [GeV], whereas the dynamical vector superfield (for gauge theories) is unitless. Because I was introduced to the ...
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0answers
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Are irrelevant terms in the Kahler potential always irrelevant, even at strong coupling?
I've been reading about the duality cascade in Strassler's TASI '03 lectures (hep-th/0505153). He reminds us of the non-renormalization theorem theorem for the superpotential so that the beta ...
3
votes
1answer
97 views
Why does unbroken supersymmetry imply the absence of tachyons?
Just a quick question, same as in the title. I'm trying to understand stable D-branes.
