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Title: 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.
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1550-7998; arXiv eprint number arXiv:1308.0320
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles, Fields, Gravitation and Cosmology; Journal Volume: 88; Journal Issue: 11
American Physical Society (APS)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States