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arXiv · 1809.07327

Boosting the $H\to$ invisibles searches with $Z$ boson polarization

Dorival Goncalves·Junya Nakamura
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Abstract

It is argued that, in $H \to $ invisibles searches with $Z(\ell\ell)H$ associated production at the LHC, the signal efficiency can be sensibly improved via a detailed study of the $Z$ boson polarization, discriminating between the signal and the dominant-irreducible $Z(\ell\ell)Z(\nu\nu)$ background. We first present a comprehensive polarization study, obtaining the complete set of angular coefficients $A_i$ in the Collins-Soper reference frame and identifying the dominant phenomenological effects. Then, we show the results for a realistic Monte Carlo study to $H\to$ invisibles, taking the polarization analysis into account. We obtain about $20\%$ improvement in the upper bound for the branching ratio of the Higgs boson to invisible particles, assuming $300\ \mathrm{fb}^{-1}$ of data at the 13 TeV LHC.

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Dorival Goncalves, Junya Nakamura. 2018-09-19. Boosting the $H\to$ invisibles searches with $Z$ boson polarization. https://doi.org/10.1103/physrevd.99.055021

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