https://doi.org/10.1140/epjc/s10052-016-3977-0
Regular Article - Theoretical Physics
Stop decay with LSP gravitino in the final state: 
Facultad de Ciencias Físico-Matemáticas, BUAP, Apdo. Postal 1364, C.P. 72000, Puebla, PUE, Mexico
* e-mail: bryanlarios@gmail.com
Received:
13
October
2015
Accepted:
25
February
2016
Published online:
18
March
2016
In MSSM scenarios where the gravitino is the lightest supersymmetric particle (LSP), and therefore a viable dark matter candidate, the stop 
could be the next-to-lightest superpartner (NLSP). For a mass spectrum satisfying 
, the stop decay is dominated by the 3-body mode 
. We calculate the stop lifetime, including the full contributions from top, sbottom, and chargino as intermediate states. We also evaluate the stop lifetime for the case when the gravitino can be approximated by the goldstino state. Our analytical results are conveniently expressed using an expansion in terms of the intermediate state mass, which helps to identify the massless limit. In the region of low gravitino mass (
) the results obtained using the gravitino and goldstino cases turns out to be similar, as expected. However, for higher gravitino masses 
the results for the lifetime could show a difference of O(100) %.
© The Author(s), 2016
