- The paper introduces the Twin Higgs mechanism to cancel Higgs mass divergences via a dark sector, addressing the little hierarchy problem.
- It details collider phenomenology by proposing that twin glueballs and exotic Higgs portal decays yield displaced vertex signatures at the LHC.
- The work outlines experimental strategies leveraging non-colored twin particles, redefining search directions for naturalness in particle physics.
Analysis of "Naturalness in the Dark at the LHC"
The paper "Naturalness in the Dark at the LHC" revisits the concept of the Twin Higgs mechanism as a proposed solution to the little hierarchy problem, emphasizing its implications for collider physics, principally at the LHC. The authors, Nathaniel Craig, Andrey Katz, Matt Strassler, and Raman Sundrum, present a thorough investigation of a "dark naturalness" framework, wherein the light hierarchy problem is addressed through uncolored particles and mirror symmetries.
Key Points
The primary focus is on the Twin Higgs model which introduces the notion of a "dark" solution, where a discrete symmetry ensures cancellation of divergences typically requiring new particles around the TeV scale. This model opposes the conventional colored top partners approach.
- Twin Higgs Mechanism: Central to the Twin Higgs setup is the existence of twin particles, neutral under the Standard Model (SM) gauge group, facilitating cancellations of radiative corrections to the Higgs mass. This includes the twin top quark, whose contribution to the Higgs mass divergence cancels with that of the SM top quark due to discrete symmetry.
- Collider Phenomenology: The authors elaborate on the collider signatures of such a dark sector, focusing on Hidden Valley dynamics. The presence of twin QCD is inevitable, and its low confinement scale introduces long-lived exotic particle signatures. Twin glueballs and other hidden sector hadrons could manifest through Higgs portal interactions.
- Higgs Portal: By exploiting Higgs mixing, the model predicts novel and observable signals at colliders. Exotic decays of the Higgs into twin hadrons, particularly the twin glueballs, are proposed as promising LHC search targets. In parts of the parameter space, these decays can produce visible signatures characterized by displaced vertices.
Implications and Prospects
Implications for LHC Searches: The observations made in this paper suggest specific strategies for LHC experimental searches. With twin glueballs potentially having long-lived decays, existing detectors’ capabilities could be exploited to observe these events through displaced vertex searches, thus offering a new avenue for understanding whether the Higgs sector could conceal a twin sector.
Naturalness and Phenomenological Viability: This model provides an alternative pathway toward naturalness while maintaining LHC accessibility, calculated based on current precision measurements and theoretically favored parameter spaces. It challenges the current paradigm where supersymmetric spectra or composite states at the TeV-scale were conventionally expected.
Future Directions: Given that this model allows for new experimental search strategies, future collider experiments may be optimized to explore the Higgs decays into the hidden sector states proposed by this dark naturalness model. Upgrades to detector capabilities, particularly for detecting soft or displaced tracks, would prove valuable in validating or constraining Twin Higgs models.
In conclusion, the paper "Naturalness in the Dark at the LHC" offers a comprehensive framework that redefines the little hierarchy problem’s solution through uncolored dark sectors, repositioning the collider physics community to look beyond the conventional search paradigms. By extending experimental searches to account for hidden sector dynamics, this approach broadens the potential for discovering new physics in the Higgs domain, awaiting validation or refutation by current and future collider experiments.