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

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8
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2answers
168 views

Can a superpartner be less massive than its SM counterpart?

Theoretically, can a superpartner be less massive than its standard model counterpart? I realize there are experimental constraints.
2
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0answers
35 views

How well theoretically motivated is $R$-parity?

I understand that $R$-parity is empirically necessary in order to avoid proton decay, but theoretically I'm worried that it amounts to a tune or "hack" that spoils the naturalness argument for ...
4
votes
1answer
71 views

What does the discovery of the Higgs boson mean for SUSY?

I've seen many differing opinions on how the discovery of the Higgs boson (specifically due to its mass) has effected theories of Super Symmetry, but all seem fairly biased. I'm wondering if someone ...
1
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0answers
19 views

Introducing inert superfield in R-symmetry model in extended MSSM

Some papers, e.g, Chakraborty et al, Frugiuele and Gregoire introduce inert superfield doublet $\hat{R}_d$ and $\hat{R}_u$. I have a question, what is the role of these inert superfields?
2
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1answer
63 views

Supersymmetry transformations as coordinate transformations

Usually, a supersymmetry transformation is carried out on bosonic and fermionic fields which are functions of the coordinates (or on a superfield which is a function of real and fermionic ...
1
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0answers
42 views

Forming massive $\mathcal{N} = 2$ supermultiplets

This question stems from page 14 of John Terning's Modern Supersymmetry. Suppose we consider $\mathcal{N} = 2$ supersymmetry, and denote the spin-0 Clifford vaccuum by $\Omega_0$. Now, the ...
1
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0answers
26 views

Why in SQCD $R_{\psi}= R_{\phi}-1$?

In SQCD = suspersymmetric QCD, in 4 dimensions and with one SUSY generator how do we determine the $R$-charge of the $U(1)_R$ symmetry of the various operators in a chiral supermultiplet? Say for ...
2
votes
0answers
39 views

Moduli space for $CP^N$ and $T^{*} CP^N$ in $\mathcal{N}=2$ SUSY

For complex $\phi$ in $U(1)$ gauge theory, \begin{align} |\phi_1|^2 + |\phi_2|^2 +\cdots |\phi_N|^2 =r \end{align} This equation $|\phi|^2=r$, describes sphere $S^{2N-1}$. Dividing the space of this ...
1
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1answer
49 views

Color factor for squark-quark-antiquark vertex

I am trying to do a tree level calculation of cross section in a process that involves sbottom exchange. There is a $ \widetilde{b} q \bar{q} $ vertex, where $q$ and $\bar q$ are quark and anti-quark ...
5
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0answers
70 views

Is there a soft Goldstino theorem?

For ordinary spontaneously broken symmetries, you can demonstrate relations between S-matrix elements with a soft goldstone emission and another S-matrix element without the emission. If I break ...
4
votes
0answers
58 views

Why the bosonic part of the superconformal group $SU(2,2|1)$ is $SO(4,1) \times U(1)_R$?

Why in $d=4$ $\mathcal{N}=1$ SCFT the bosonic part of the superconformal group $SU(2,2|1)$ is $SO(4,1) \times U(1)_R$? More generally how can I determine the such a thing in other theories? Is there ...
0
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0answers
28 views

Why is there an Euler density in SCFT $T_{\mu}^{\nu}$?

The super conformal field theories are above all conformal. Conformal theories are defined on flat space-times. Despite that, if one looks at the stress tensor trace of a SCFT in 4d you get a ...
7
votes
2answers
482 views

Dynamical supersymmetry breaking and Witten index

Witten index, defined as ${\rm Tr}(-1)^F$, determines if supersymmetry is spontaneously broken or not for a given model. However, it is also known that supersymmetry can be dynamically broken. One ...
3
votes
1answer
69 views

Why do we need frame-fields to describe fermions in SUGRA?

I'm learning about the frame formalism and read that to couple fermions to gravity you need to go to the frame-formalism. As a motivation to learn more about frame-fields would someone sketch me why ...
5
votes
2answers
199 views

Problems book recommendation on supersymmetry, supergravity and superstring theory

I'm learning supersymmetry, supergravity and superstring. I want some problems books to have some idea in this area. Is there this kind of books? Or are there some papers that have many solved model?
3
votes
1answer
47 views

Understanding the $\mu$ problem

I am going through the motivation to introduce singlet extensions of the MSSM (like for instance the NMSSM), and of course such a motivation is naturalness. Here, one argues that the $\mu$ parameter ...
0
votes
0answers
48 views

SUSY condition on string theory

In each string theory, there is some condition so called SUSY condition. I want to know susy condition for Type I, Type II, and Heterotic string. Can anyone give some brief explanation about ...
2
votes
1answer
105 views

Treating the spinors as Grassmann numbers or as c-number objects

In the literature on supersymmetry, the following spinor summation convention is often used (eg. Wess & Bagger's book Supersymmetry and Supergravity) $$ \psi\chi = \psi^{\alpha}\chi_{\alpha} = ...
3
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0answers
42 views

Spin of an operator in supersymmetric theories

How exactly is the spin of an operator in the context of a supersymmetric theory defined? For example, in page 25 of [1], $\mathcal{N} = 2$ supersymmetry is defined to have operators $J, G^{+}, G^{-}, ...
2
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0answers
88 views

Killing spinor equation [closed]

The Supersymmetry transformation is: $$\delta \psi_\mu^i=(\partial_\mu +1/4 \gamma^{ab}\omega_{\mu ab})\epsilon^i -1/8\sqrt{2}\kappa \gamma^{ab}F_{ab}\epsilon^{ij} \gamma_\mu \epsilon_j$$ For the ...
1
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0answers
82 views

Evaluation of the anomalous dimensions of fields in SUSY $SU(5)$

The general formula for the anomalous dimension can be found in Martin΄s review article (hep-ph/9709356), on page 62 relation (6.5.4). In the case of $SU(5)$ and especially in the paper of Kobayashi, ...
-2
votes
1answer
160 views

Explanation for the minus sign in $\Omega_3$ in the Kappa symmetry of the Green - Schwarz formalism for F1 strings

Just so that there can be more higher - level physics questions here, let me post this question + answer. Also because I'm a bit sad that there are almost no questions on the Green-Schwarz ...
5
votes
0answers
135 views

What is the fundamental difference between ghost and auxiliary fields?

I am somehow confused by the notion of auxiliary fields, such as for example the fields $F$ and $D$ which appear in supersymmetry, and the notion of ghost fields which appear for example in the BRST ...
1
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0answers
85 views

Heterotic Supersymmetric derivation of an integrality theorem for differentiable manifolds [closed]

Please consider the following integrality theorem for differentiable manifolds due to K H Mayer: I am trying to prove this theorem using Heterotic Super-symmetric Quantum Mechanics described by a ...
3
votes
1answer
192 views

Susy QM and Atiyah-Singer index theorem

Consider maps $t\mapsto x^i(t)$ from circle to some Riemannian (spin) manifold and lagrangian $$ \mathcal L = \frac12 g_{ij}(x) \partial_t x^i \partial_t x^j + \frac12 g_{ij} \psi^j \left(\delta^i_k ...
3
votes
1answer
53 views

Dirac operator partial integration

When you have an action with bosonic $X$ and fermionic $\psi$ (Majorana) fields and perform a SUSY transformation $\epsilon$ (the constant, infinitesimal parameter of transformation, a real, ...
5
votes
2answers
134 views

Why doesn't $h\rightarrow \gamma\gamma$ rule out two higgs doublet models?

In two higgs doublet models we introduce a down-type Higgs as well as an up type Higgs and typically (as I understand it) we take the down-type to be the 126 GeV resonance and the up type to be ...
3
votes
3answers
532 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 ...
2
votes
0answers
37 views

Why do electrons form Cooper pairs below certain temperature? [duplicate]

Just a heads up - please make this answer understandable to around 1st year degree level physics - not PhD research. So I can understand it - thanks. 1) In solid state physics, why is it that below a ...
2
votes
0answers
62 views

SUSY QM - working out energy spectrum and wavefunctions from a given superpotential

I'm currently self-studying F. Cooper and al.'s Supersymmetry in Quantum Mechanics, and I need help working out a particular case on shape-invariance. From a given superpotential of the form ...
1
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0answers
41 views

Charge Conjugation Operator in Supermultiplet

Consider an $\mathcal{N}=1$ left-handed chiral supermultiplet. The particle content is $$L = (\phi\quad e_L) $$ where $\phi$ is a complex scalar and $e_L$ a left handed Weyl fermion. People usually ...
0
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0answers
20 views

Supersymmetric Extension of Mirror Model

A brief description of Mirror Matter can be seen. Some papers about Mirror Matter : Berezhiani, Kolb, Seckel, Turner, Foot,Lew,Volkas Does anyone have some references about How to construct ...
1
vote
0answers
90 views

Mechanism of Supersymmetry Breaking (F-term, D-Term, Mediated)

I will make my question clear. SUSY is broken symmetry because we haven't seen superpartners. As far as I know, there are two mechanism of SUSY breaking, F-term and D-Term. Besides, there are some ...
3
votes
1answer
61 views

The differences of R parity and $U(1)_R$ symmetry

I know that we introduce R-parity to avoid proton decay. But some papers introduce $U(1)_R$ Lepton Number, e.g claudia, thomas. I have questions 1.What is the differences of R parity and $U(1)_R$? ...
1
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0answers
58 views

In SUSY, why do fermions and gauge bosons in the same multiplet both transform in the adjoint representation of the gauge group?

I'm trying to understand a certain point about supersymmetry. We are dealing with a N=1 (i.e, one supersymmetric flavour), massless, four dimensional theory. Then the vector multiplet consists of a ...
3
votes
0answers
76 views

New Supersymmetry Algebra

We know that SUSY generators commute with translation $$ [P_\mu,Q_\alpha]=0 $$ I have some questions: What is this equation physical meaning? Is it possible to make "SUSY-like" generators that do ...
1
vote
1answer
86 views

Is it possible to make superpartner of Standard Model live in Mirror World?

In the ordinary Supersymmetry (SUSY), the superpartner of SM live in SM world (matter world). Then we introduce mirror world with mirror particle live there. I would like to make a new concept that ...
2
votes
1answer
157 views

Physics in torus, cylinder, Klein bottle and mobius strip

In string theory, or supersymmetric gauge theory, they often calculate the partition function on specific Riemann surfaces, such as torus, cylinder, Klein bottle, Mobius strip. Refer to the ...
0
votes
0answers
32 views

About $U(1)_A$ symmetry,

I know a $U(1)_A$ symmetry is related with a global symmetry. (Is it axial or anomaly ) What is A stands for? In the context of supersymmertry, Fundamental and anti-fundamental chiral multiplet has ...
8
votes
2answers
663 views

Does the commutator of anything with itself not vanish?

In a quantum mechanics exam one question was to write the commutator of a couple of operators. Everybody got points taken away since they did not write $[Q_i, Q_i] = 0$ for all the operators $Q_i$ in ...
3
votes
1answer
44 views

The criterion to obtain covariant spinor derivatives in superspace

It can be simply said that covariant derivatives in 4d superspace are given by $\mathcal{D}_\mu $, $\mathcal{D}_{\alpha}$ and $\mathcal{D}_{\dot{\alpha}}$, so that they commute with the ...
3
votes
1answer
233 views

Higgs branch and Coulomb branch

I heard that the distinguish between Higgs branch and Coulomb branch is the limit of some parameters. (If i remember correctly, something like FI parameters. ) Here i want to know what is FI ...
1
vote
1answer
62 views

What is the difference between $N=(2,2)$ with $N=(2,2)^*$ in 2d?

What is the difference between $N=(2,2)$ with $N=(2,2)^*$ in 2 dimensional theory? In some sense, i heard, they are totally different theory. I heard from breaking of $N=(4,4)$ supersymmetry it ...
3
votes
1answer
51 views

Recommendation of papers, or reading materials on N=2, N=4 supersymmetry

I am familiar with N=1 susy in the context of Wess and Bagger. For further progress, i want to study N=2, N=4 supersymmetry, to study seiberg-like duality. (I am not familiar with the notation ...
2
votes
0answers
46 views

Left (right) invariant vector fields on superspace

I read Freed'd book on "Five lectures on supersymmetry". For any vector space $V$ with metric of signature $(1,n-1)$ he constructs super Lie algebra $$ L=V \oplus S^*, $$ where $S$ is space of ...
3
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0answers
51 views

Highest weight unitary representations of $psl(2|2)$

I'm having some trouble understanding how to extend representation theory from Lie algebras to super Lie algebras, in particular with $psl(2|2)$. Ultimately I'm interested in 2D quantum sigma models ...
2
votes
1answer
54 views

How does the gluino change the strong force?

Given that the gluino is in the same representation of SU(3) that the gluon and so the same kind of interaction vertexes with quarks, I guess that it could have a role in the strong force. But there ...
6
votes
1answer
297 views

Naturalness and experiments

Is there an example where model building that is motivated only by Naturalness, has led to experimentally verified observations? If the question is unclear, or if the reader wants more elaboration, ...
1
vote
1answer
113 views

Does the gravitino contribute to the gravitational interaction?

I have a very basic question with respect to supersymmetry. Actually, I no clear idea at all what the effect of the superpartners (called gauginos??) of the exchange particles of interactions ...
1
vote
2answers
95 views

Converting two component product to four component notation

Consider the product of two left Weyl spinors in the notation commonly found in supersymmetry, \begin{equation} \chi ^\alpha\eta_\alpha = \chi ^\alpha \epsilon _{ \alpha \beta } \eta ^\beta ...