https://doi.org/10.1140/epjc/s10052-018-6331-x
Regular Article - Theoretical Physics
Flavour-violating decays of mixed top-charm squarks at the LHC
1
Theory Center, IPNS, KEK, Tsukuba, Ibaraki, 305-0801, Japan
2
Sorbonne Université, CNRS, Laboratoire de Physique Théorique et Hautes Energies, LPTHE, 75005, Paris, France
3
Institut Universitaire de France, 103 boulevard Saint-Michel, 75005, Paris, France
4
Univ. Grenoble Alpes, USMB, CNRS, LAPTh, 74000, Annecy, France
5
The Graduate University of Advanced Studies (Sokendai), Tsukuba, Ibaraki, 305-0801, Japan
6
Kavli IPMU (WPI), University of Tokyo, Kashiwa, Chiba, 277-8583, Japan
7
CERN, Experimental Physics Department, 1211, Geneva 23, Switzerland
8
INFN, Sezione di Pavia, Via Bassi 6, 27100, Pavia, Italy
* e-mail: amit@post.kek.jp
Received:
28
August
2018
Accepted:
10
October
2018
Published online:
20
October
2018
We explore signatures related to squark decays in the framework of non-minimally flavour-violating supersymmetry. We consider a simplified model where the lightest squark consists of an admixture of charm and top flavour. By recasting the existing LHC searches for top and charm squarks, we show that the limits on squark masses from these analyses are significantly weakened when the top-charm mixing is sizeable. We propose a dedicated search for squarks based on the 
final state which enhances the experimental sensitivity for the case of high mixing, and we map its expected reach for the forthcoming runs of the LHC. We emphasize the role of analyses requiring a jet tagged as produced by the fragmentation of a charm quark in understanding the squark mixing pattern, thus providing a novel handle on new physics. Our results show that, in order to achieve full coverage of the parameter space of supersymmetric models, it is necessary to extend current experimental search programmes with analyses specifically targeting the cases where the lightest top-partner is a mixed state.
© The Author(s), 2018
