Boosted di-boson from a mixed heavy stop
The lighter mass eigenstate ($$\widetilde{t}_1$$) of the two top squarks, the scalar superpartners of the top quark, is extremely difficult to discover if it is almost degenerate with the lightest neutralino ($$\widetilde{\chi}_1^0$$), the lightest and stable supersymmetric particle in the R-parity conserving supersymmetry. The current experimental bound on $$\widetilde{t}_1$$ mass in this scenario stands only around 200 GeV. For such a light $$\widetilde{t}_1$$, the heavier top squark ($$\widetilde{t}_2$$) can also be around the TeV scale. Moreover, the high value of the higgs ($$h$$) mass prefers the left and right handed top squarks to be highly mixed allowing the possibility of a considerable branching ratio for $$\widetilde{t}_2 \to \widetilde{t}_1 h$$ and $$\widetilde{t}_2 \to \widetilde{t}_1 Z$$. In this paper, we explore the above possibility together with the pair production of $$\widetilde{t}_2$$ $$\widetilde{t}_2^*$$ giving rise to the spectacular di-boson + missing transverse energy final state. For an approximately 1 TeV $$\widetilde{t}_2$$ and a few hundred GeV $$\widetilde{t}_1$$ the final state particles can be moderately boosted which encourages us to propose a novel search strategy employing the jet substructure technique to tag the boosted $$h$$ and $$Z$$. The reconstruction of the $$h$$ and $$Z$$ momenta also allows us to construct the stransverse mass $$M_{T2}$$ providing an additional efficient handle to fight the backgrounds. We show that a 4--5$$\sigma$$ signal can be observed at the 14 TeV LHC for $$\sim$$ 1 TeV $$\widetilde{t}_2$$ with 100 fb$$^{-1}$$ integrated luminosity.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1155845
- Report Number(s):
- FERMILAB-PUB-13-306-T; arXiv eprint number arXiv:1308.0320
- Journal Information:
- Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 88, Issue 11; ISSN 1550-7998
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
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