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Abstract

Profiling the Higgs boson requires the study of its non-standard decay
modes. In this work we discuss the prospects of the Large Hadron
electron Collider (LHeC) to detect scalar particles with masses ,greater
than or similar to 10 GeV produced from decays of the Standard Model
(SM) Higgs boson. These scalar particles decay mainly to bottom pairs,
and in a vast portion of the allowed parameter space they acquire a
macroscopic lifetime, hence giving rise to displaced hadronic vertices.
The LHeC provides a very clean environment that allows for easy
identification of these final states, in contrast to hadronic colliders
where the overwhelming backgrounds and high pile-up render such searches
incredibly challenging. We find that the LHeC provides a unique window
of opportunity to detect scalar particles with masses between 10 and 30
GeV. In the Higgs Portal scenarios we can test the mixing angle squared,
sin(2)alpha, as low as 10(-5)-10(-7), with the exact value depending on
the vacuum expectation value of the new scalar.Our results are also
presented in a model-independent fashion in the lifetime-branching ratio
and mass-branching ratio planes. We have found that exotic branching
ratios of the Higgs boson at the sub-percent level can be probed, for
the scalar decay length in the range 10(-4) m less than or similar to c
tau less than or similar to 10(-1) m. The expected coverage of the
parameter space largely exceeds the published sensitivity of the
indirect reach at the high-luminosity Large Hadron Collider via the
invisible Higgs branching ratio.