Mirror World at the Large Hadron Collider

TL;DR

This paper explores how a mirror world could alter Higgs signals at the LHC, affecting production, decay, and dark matter candidates, with implications for new physics scales and experimental detection.

Contribution

It introduces the concept of a mirror world with Z_2 symmetry affecting Higgs phenomenology and dark matter, providing new insights into LHC signals and physics beyond the standard model.

Findings

Mirror world modifies Higgs production and decay rates at the LHC.

Constraints on Higgs masses differ from the standard model due to mirror symmetry.

Mirror quarks and leptons could serve as dark matter candidates.

Abstract

A mirror world can modify in a striking way the LHC signals of the Higgs sector. An exact or approximate Z_2 symmetry between the mirror world and our world allows large mixing between the Higgs bosons of these worlds, leading to production rates and branching ratios for these states that are markedly different from the standard model and are characteristic of a mirror world. The constraints on these Higgs boson masses from precision electroweak data differ from the standard model bound, so that the new physics that cancels the quadratic divergence induced by the top quark may appear at a larger scale, possibly beyond the reach of the LHC. However, the scale of new physics needed to cancel the quadratic divergence induced by the Higgs boson is not significantly changed. With small breakings of the Z_2 parity, the lightest mirror quarks (and possibly charged mirror leptons) could be the dark matter in the universe, forming galactic halos that are stable to cooling. A possible signal from the relic radiation density of the mirror world is also discussed.