Artikel über N.Tesla

III-74
3 Supersymmetry
where B is of order unity depending on the nature of the NLSP. Assuming m ˜G
< 1keV
as favoured by cosmology, typical decay lengths range from micro-meters to tens of
meters. Figure 3.6.1 shows the neutralino NLSP lifetime as a function of the messenger
scale and m˜χ 0
i
for various sets of GMSB parameters [29].
Inclusive GMSB Signal at the Linear Collider
√s - = 500 GeV
log 10 (Nr. of evts.) in 100 fb -1
e + e - → SUSY →
2 displaced γ s +X+E miss
m(N ∼ 1 ) [GeV]
Figure 3.6.1: Neutralino NLSP lifetime as a
function of a) the messenger scale M mess and
b) the NLSP mass m˜χ 0
1
. Each dot represents
a different choice of GMSB model parameters.
Figure 3.6.2: Event rate for displaced
photon signatures from e + e − → ˜χ 0 1 ˜χ0 1 X,
˜χ 0 1 → γ ˜G as a function of the NLSP mass at
√ s = 500GeV, L = 100 fb −1 .
A detailed simulation of inclusive ˜χ 0 1 production and decays ˜χ0 1 → γ ˜G, f ¯f ˜G is
presented in [29]. The proposed Tesla detector is capable of identifying neutralino
decays and measuring its mass to within a few per mil from the endpoints of the E γ
spectrum. The event rate for displaced photons, not pointing to the interaction vertex,
can be large even for NLSP masses close to the production limit, see Fig.3.6.2. Various
techniques, such as tracking, pointing calorimetry and statistical photon counting
methods, provide accurate measurements of the decay length cτ over a large range of
30 µm − 40 m to better than 10%. Such data would allow one to extract the scale √ F
with an accuracy of ∼ 5%. Together with a knowledge of the SUSY particle spectrum,
a determination of the other fundamental GMSB parameters is feasible with
high precision: at the level of per mil for Λ and N mess and per cent for tanβ and M mess .
Other scenarios with a slepton as NLSP have also been studied [29], e.g. ˜τ 1 decaying
to ˜τ 1 → τ ˜G, producing long-lived, heavy particles or τ pairs, possibly coming from
secondary decay vertices.