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

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7
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1answer
260 views

alternatives to supersymmetry and Coleman-Mandule theorem

Humour me for a minute here and let's imagine that all interesting and plausible supersymmetry models have been "cornered" out by the experimental data; what sort of alternatives are there for having ...
4
votes
1answer
274 views

What interaction does a Fayet-Iliopoulos coupling parameterize the strength of?

Couplings give the strength of interactions. They appear in a Lagrangian as a coefficient to the two (or more) interacting fields. Unfortunately, I'm struggling to find a source that describes what it ...
4
votes
1answer
3k views

How would the discovery of Higgs Boson affect superstring theories?

As we probably all know, a new particle similar to Higgs Boson has been discovered. If this turns out to be true, standard model will get a boost (as the discovered mass almost equals to the ...
10
votes
1answer
463 views

What does the latest $B_s^0\rightarrow \mu^+\mu^-$ results mean for SUSY?

A paper from the LHCb collaboration just came out last week, stating basically that the $B_s^0\rightarrow\mu^+\mu^-$ decay matches standard model predictions, and people are already shouting that SUSY ...
3
votes
1answer
633 views

Does the Photino have mass or is it mass-less like the photon

Does the photino in super-symmetry have a mass, Or is this different in different super symmetric models?
7
votes
1answer
390 views

What do the supercharges in extended supersymmetry do?

What do the supercharges in extended supersymmetry do? In $N=1$ supersymmetry there are a certain number of fermions and and equal number of bosons. You can transform all fermions to the bosons (and ...
4
votes
1answer
528 views

What is the hierarchy problem?

BACKGROUND So far I understood that the hierarchy problem was the large difference between the gravitational scale, $M_{pl}\sim 10^{18}\; [GeV]$, compared with the electroweak scale, $M_{ew}\sim ...
6
votes
1answer
1k views

Relationship between hierarchy problem and higgs fine tuning?

I often hear of hierarchy problem being used synonymous with Higgs fine tuning (esp with regards with motivations for SUSY). What exactly is the relationship between the two problems? As I understand ...
7
votes
1answer
430 views

Why is the lightest Higgs not a free parameter in SUSY?

In the Standard Model, the Higgs mass doesn't really have any theoretical constraints. It could have basically any value and nothing 'breaks'. However, in MSSM models, we often see the tree level ...
6
votes
2answers
470 views

Can auxiliary fields be thought of as Lagrange multipliers?

In the BRST formalism of gauge theories, the Lautrup-Nakanishi field $B^a(x)$ appears as an auxiliary variable $$\mathcal{L}_\text{BRST}=-\frac{1}{4}F_{\mu\nu}^a F^{a\,\mu\nu}+\frac{1}{2}\xi B^a B^a + ...
3
votes
1answer
447 views

Basic Grassmann/Berezin Integral Question

Is there a reason why $\int\! d\theta~\theta = 1$ for a Grassmann integral? Books give arguments for $\int\! d\theta = 0$ which I can follow, but not for the former one.
1
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1answer
249 views

dimensional analysis of Grassmann integration/differentiation

There is another paradox that I need to resolve: The Berezin integration rules for Grassmann odd variables give the same result as differentiation: If $f=x+\theta\psi$ is a superfunction, the ...
1
vote
1answer
230 views

How does a supersymmetry transformatio relates bosons to fermions?

A superfield is defined as a function of of a spacetime coordinate and two spinor coordinates, $\Phi (x, \theta, \theta^*)$. A supersymmetric transformation is then generated by the operator ...
5
votes
5answers
716 views

The observation of a non-SM resonance at 38 MeV

Was reported here. Of course if this is real it is very exciting. It leads me to the question: given that it took so long to find this resonance at a meager 38 MeV, is it possible that all SUSY ...
4
votes
1answer
449 views

Boundary conditions in AdS/CFT

This question is in reference to this very famous paper of Witten. In general through the whole paper why is the author able to just focus on the scalar field propagating in the bulk and not need ...
3
votes
1answer
108 views

what is universality (with respect to SUSY and neutral kaon oscillations)?

I'm having trouble putting the pieces together. In SM, neutral kaon oscillation is heavily constrained. This means, roughly, that the squark mass matrices have to be diagonal. And this is called ...
9
votes
2answers
534 views

Interpretation of “superqubits”

Two very intriguing papers recently appeared on the arXiv, claiming that one can use "superqubits" -- a supersymmetric generalization of qubits -- to violate the Bell inequality by more than standard ...
1
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0answers
94 views

Some questions about flavour and R-symmetry in $2+1$ ${\cal N}=3$ theory

I have heard this fact that for ${\cal N}=3$ theories in $2+1$ with $N_f$ ${\cal N}=3$ matter fields the flavour symmetry group is $USp(N_f)$, $U(N_f)$ or $SO(2N_f)$ depending on whether the gauge ...
2
votes
1answer
539 views

Wilson loops and gauge invariant operators (Part 1)

I guess the Hilbert space of the theory is precisely the space of all gauge invariant operators (mod equations of motion..as pointed out in the answers) Is it possible that in a gauge theory the ...
2
votes
1answer
120 views

Hypothetical very massive particles

I'm looking for a table or compilation of hypothetical very massive ($m\gtrsim 1$ TeV) particles and their expected masses (or bounds on them or relation with other scales). All I know is (please, ...
6
votes
0answers
115 views

R charge of the chiral multiplet in $2+1$ dimensions

These are two examples that I am puzzled by, One can see in this paper on page 16 that for ${\cal N} =2$ theory on $2+1$ the R-charge of the $\phi$ and the $\psi$ is determined to be $\frac{1}{2}$ ...
5
votes
2answers
382 views

How convincing is the evidence for dark matter annihilation at 130 GeV in the galactic center from the Fermi Satellite data?

I listened to Christoph Weniger present his results at SLAC today. See his paper is here: http://arxiv.org/abs/1204.2797 and also see a different analysis here: http://arxiv.org/abs/1205.1045. The ...
1
vote
1answer
147 views

Superspace Uncertainty Principle

Do the "operator for translations in superspace" and the "position in superspace operator" follow an uncertainty principle? How "real" is superspace? Aside from being weird (and possibly just a ...
5
votes
1answer
243 views

About 2+1 dimensional superconformal algebra

I would like to get some help in interpreting the main equation of the superconformal algebra (in $2+1$ dimenions) as stated in equation 3.27 on page 18 of this paper. I am familiar with supersymmetry ...
-1
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1answer
201 views

What is Supersymmetry (SuSy)? [closed]

In particle physics, supersymmetry (often abbreviated SUSY) is a symmetry that relates elementary particles...etc. what is symmetry breaking? What is supersymmetry (SUSY)? What is spontaneous ...
6
votes
4answers
1k views

What's the distinctions between Yang-Mills theory and QCD?

So Yang-Mills theory is a non-abelian gauge theory, and we used a lot in QCD calculation. But what are the distinctions between Yang-Mills theory and QCD? And distinctions between supersymmetric ...
5
votes
0answers
211 views

The ${\cal N} = 3$ Chern-Simons matter lagrangian

This question is sort of a continuation of this previous question of mine. I would like to know of some further details about the Lagrangian discussed in this paper in equation 2.8 (page 7) and in ...
10
votes
3answers
520 views

In what sense is SUSY a spacetime symmetry?

Clearly the SUSY anti-commutation relations involve momentum, and thus the generator of translations in spacetime: $\{ Q_\alpha, \bar{Q}_{\dot{\beta}} \} = 2 (\sigma^\mu)_{\alpha \dot{\beta}} P_\mu ...
1
vote
1answer
202 views

1-Dimensional Sigma Models

I'm currently interested in 1-dimensional (linear) Sigma Models. In the theory of 2-Dimensional GLSM, the fields can be viewed as an embedding of the worldsheet in some target Manifold of higher ...
3
votes
2answers
572 views

Supersymmetry in Quantum Field Theory

I have an idea of supersymmetry in quantum mechanics, can you suggest a book on "supersymmetry in quantum field theory", which has sufficient mathematical rigour like "Peskin and Schroeder"
3
votes
1answer
124 views

Sources for new experimental limits on susy models?

I know the LHC people are publishing new limits every now and then, but as a non-expert in reading experimental papers (yet), I was wondering if there's a friendly website that collects and presents ...
3
votes
0answers
174 views

Some more questions on conformal spinors of $SO(n,2)$

This is somewhat of a continuation of my previous question. I had stated there that a conformal spinor ($V$) of $SO(n,2)$ can be created by taking a direct sum of two $SO(n-1,1)$ spinors $Q$ and $S$ ...
9
votes
1answer
351 views

Does the ruling out of TeV scale SUSY breaking disfavor grand unification?

One of the arguments in favor of TeV scale SUSY breaking is that it leads to the appropriate running of the gauge coupling strengths leading to grand unification, i.e. $k_Y = \frac{5}{3}$ instead of ...
3
votes
1answer
214 views

Lorentz spinors of $SO(n,1)$ and conformal spinors of $SO(n,2)$

It would be great if someone can give me a reference (short enough!) which explains the (spinor) representation theory of the groups $SO(n,1)$ and $SO(n,2)$. I have searched through a few standard ...
7
votes
1answer
249 views

Reference for the ${\cal N}=3$ Chern-Simons Lagrangian at general $N_c$, $N_f$

I was wondering if someone could give me a reference where someone has explicitly written the Lagrangian for ${\cal N}=3$ $SU(N_c)$ Chern-Simons theory coupled to $N_f$ fundamental hypermultiplets. ...
3
votes
1answer
186 views

Supergroup action on $AdS_5XS^5$

In the context of the AdS/CFT correspondence I was trying to understand how the symmetry group of the underlying space $AdS_5 X S^5$ comes out to be the supergroup $SU(2,2|4)$. I can see how the ...
1
vote
0answers
44 views

How to obtain deconfined theory from an s-confined N=1 susy gauge theory?

Is there a systematic procedure for obtaining a deconfined theory from an s-confining theory (as defined in hep-th/9610139 for example)?
5
votes
1answer
453 views

CY moduli fields

When one does string compactification on a Calabi-Yau 3-fold. The parameters in Kähler moduli and complex moduli gives the scalar fields in 4-dimensions. It is claimed that the Kähler potentials of ...
5
votes
0answers
86 views

Defects in 3+1 TFTs/2+1 CFTs

I would like to know of good pedagogic references to learn about the notion of "defects" in TFTs and CFTs. I am specially interested in 3+1 TFTs (.and probably about their relation to 2+1 CFTs..) In ...
3
votes
0answers
215 views

Central charge at the fixed point of the ${\cal N}=2$ Landau-Ginzburg theory in $1+1$ dimensions

Let me first believe that the ${\cal N}=2$ Landau-Ginzburg theory does in the IR flow to a non-trivial fixed point and that if the potential is of the form $\Phi ^k$ then the central charge of the CFT ...
2
votes
1answer
219 views

A certain $\cal{N}=2$ superconformal theory (or is it?)

I want to look at the following theory in $1+1$ dimensions with $\Phi$ being the chiral superfield, $L = \int d^2x d^4\theta \bar{\Phi}\Phi - \int d^2x d^2\theta \frac{\Phi^{k+2}}{k+2} - \int d^2x ...
6
votes
2answers
416 views

Classifying all possible BPS configurations in string theory

Is there a classification of all possible BPS configurations in string theory? It has to include Calabi-Yau orbifolds, intersecting D-branes, coincident D-branes, etc. . To simplify matters, take the ...
1
vote
1answer
197 views

Are there any models for two light Higgs?

The LHC results today seem to have two possible Higgs peaks, one at 119 GeV and the other at 125-126 GeV. All the multi-Higgs supersymmetry models I've seen that have multiple Higgs have only one ...
6
votes
1answer
74 views

References for phase-transitions in supersymmetric field theory

Apart from other reasons, recently my interest in this area got piqued when I heard an awesome lecture by Seiberg on the idea of meta-stable-supersymmetry-breaking. I am looking for references on ...
4
votes
2answers
355 views

Sterile Neutrinos as Dark Matter

There has been recent activity by astrophysicists to determine whether a fourth flavor of neutrino, a sterile neutrino, exists. It would likely be more massive than electron, muon or tau neutrinos. ...
12
votes
2answers
412 views

Alejandro Rivero's correspondence: diquarks and mesons as superpartners of quarks and leptons

The idea of “hadronic supersymmetry” originated in the mid-1960s and derives from the observation that baryons and mesons have similar Regge slopes, as if antiquarks and diquarks are superpartners. ...
2
votes
1answer
132 views

Which low energy SUSY models are compatible with LHC and tevatron data so far?

The LHC data has eliminated huge swaths of permissible low energy SUSY breaking models. But not all. Which regions of parameter space are still open?
6
votes
1answer
502 views

Fundamental particles with spin > 1

I am in undergraduate quantum mechanics, and the TA made an off-hand comment that currently no one knows how to describe fundamental particles with spin > 1 without supersymmetry. I was curious and ...
3
votes
1answer
189 views

Question about the parity of the ghost number operator in BRST quantization

Given a Lie algebra $[K_i,K_j]=f_{ij}^k K_k$, and ghost fields satisfying the anticommutation relations $\{c^i,b_j\}=\delta_j^i$, the ghost number operator is then $U=c^ib_i$ (duplicate indices are ...
6
votes
1answer
226 views

About unitarity and R-charge in 2+1 superconformal field theory

How does unitarity require that every scalar operator in a $2+1$ SCFT will have to have a scaling dimension $\geq \frac{1}{2}$ ? Why is an operator with scaling dimension exactly equal to ...