Gravitinos and hidden Supersymmetry at the LHC - Universität ...

2.4. ORIGINS OF SUPERSYMMETRY BREAKING
10 6 mass [GeV]
ψ µ
10 5
10 4
g,˜q
b,w,˜l
H,A 0 ,H ±
1000
g,˜q
b,w g,˜q
A 0 ,H
H ± ,˜τ 1
100
H,A 0
H ± ,˜t 1
h 0 ,˜l
b w h ψµ
h 0 ,h ±
h
ψ µ
h 0 ,h ±
h
CMSSM
hybrid mediation
AMSB
Figure 2.2: Possible mass spectra of supersymmetric particles in different scenarios of SUSY
breaking. The blue lines indicate colored particles, while the green [red] line indicates the
lightest neutral Higgs [gravitino]. Neutralinos and charginos are written in terms of the
dominant gauge-eigenstate contribution. In case of the CMSSM the NLSP is a bino-like
neutralino, while it is a higgsino-like neutralino in the case of hybrid gauge-gravity mediation.
In the heavy gravitino scenario the LSP is also the higgsino-like neutralino. The CMSSM
spectrum was obtained by means of SOFTSUSY [110] with m 0 = m 1/2 = 350 GeV, A 0 = 0,
tan β = 10, sign(µ) = 1. The hybrid spectrum is taken from [75], while the AMSB spectrum
is taken from [73].
The discussion above does not constrain the supersymmetric higgsino mass parameter and
allows for following hierarchical mass spectra:
µ ≪ m soft ≪ m 3/2 , (2.89)
for example with µ ∼ O(100) GeV, m soft ∼ O(10 4 ) GeV, and m 3/2 ∼ O(10 6 ) GeV. Such
extreme hierarchy could for example solve the µ problem [73] and give rise to a Higgs mass
compatible with the current experimental bounds and close to the current hints at the LHC.
In general, such scenarios involve superheavy gravitino, heavy scalars and gauginos, the only
light SUSY particles being the higgsinos.
Figure 2.2 summarizes the possible supersymmetric mass spectra in different SUSY breaking
scenarios. Although the CMSSM is the most studied case it is obvious that SUSY breaking
can be realized in nature in many different ways which can lead to a dramatically different
LHC phenomenology. We will investigate in the following chapters why such unusual spectra
might be well motivated by cosmology and estimate their impact on the results of SUSY
searches at the LHC. As we have seen in this chapter the gravitino obtains a mass after the
breaking of supersymmetry and appears somewhere in the supersymmetric spectrum. In the
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