Hot answers tagged supersymmetry
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Noncompact internal symmetries – and R-symmetry is an internal symmetry (it doesn't transform positions in the spacetime) – are unacceptable in a physical theory because they would lead to negative-norm states.
Consider the $i$-th superpartner of a bosonic particle state, $|i\rangle$, where $i=1,2,\dots,N$. The inner product $\langle i|j\rangle$ of such ...
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There are two aspects. One is sort of trivial and comprehensible; the other is a bit technical.
The trivial reason is that $\tilde t \bar{\tilde t}$ has two "accents" on top of each other and the symbol therefore occupies too much vertical space which is undesirable because we may get overlapping characters and/or non-uniform spacing between lines. The ...
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There is a standard paradigm for thinking about the new physics that lies beyond the standard model, at higher and higher energies: weak-scale supersymmetry, grand unification, string theory. The purpose of weak-scale supersymmetry is to stabilize weak-scale physics (i.e. everything we know about) against quantum corrections. Grand unification can explain ...
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The NS-NS sector is the same in type IIA and IIB, but the R-NS and NS-R sectors differ. The type IIA theory is non-chiral, so the R-NS and NS-R fields transform in $\mathbf{8}_s \otimes \mathbf{8}_v$ and $\mathbf{8}_v \otimes \mathbf{8}_s'$, where $\mathbf{8}_s$ and $\mathbf{8}_s'$ are the two eight-dimensional spinor representations of $SO(8)$. Type IIB, on ...
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If you spend some time looking in detail at the arguments that string theory requires supersymmetry, you'll find that they are not watertight. (How could they be, since we still can't say/don't know precisely what string theory is?)
Basically, some string theorists argue that that the usual classification depends too strongly on choosing nearly trivial ...
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Hagedorn spectrum just means that the density of states varies exponentially with the energy/mass. $m^2$ (asymptotically) given by the "level" (N) of the state (upto a sqrt). The number of states at level $N$ corresponds to the possible partitions of $N$ into different oscillator modes. That means that the number of states at level $N$ will increase ...
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p-adic strings or the adelic approach created by B.Dragovich don't require SUSY at all. At least, not the usual SUSY symmetry...
Non-critical string theory, the so-called Liouville theory, is based on the hypothesis of non-imposing the condition that critical strings with fermions (superstrings) impose on the space-time dimension due to internal ...
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The physical masses should be independent of the renormalization scale. We, however, only calculate a finite number of loop corrections, resulting in a scale dependence in the physical mass. This scale dependence can be used to estimate the error in the mass calculation from the missing higher orders.
In principle, one could calculate the sparticle mass ...
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I would really recommend a study in QFT before going on to study SUSY. QFT has many quirks that make supersymmetry a very interesting expansion of the regular framework. You'd miss out on all that as you just had to believe the facts presented w/o following the thought that lead to the results in detail.
On the Mathematical level you will need Grassmann ...
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There are lots of questions here! I think I can answer at least some...
First of all, you are aware that the fields in $W$ and $K$ are superfields? These contain the entire supermultiplet, so they must be complex in general. This is a short entry but it links to others: http://en.wikipedia.org/wiki/Superfield
As mentioned by Jose in his comment, the ...
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"Falsifying supersymmetry" is a phrase that has to be properly qualified. Our ability to falsify with experiment is limited. We can rule out the existence of supersymmetry only at accessible energy/distance/density scales. LHC, for example, is not able to resolve physics at distance scales much smaller than $\frac{\hbar c}{7\mbox{ TeV}} \simeq ...
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