Criteria for Natural Hierarchies

Abstract

With the discovery of a particle that seems rather consistent with the minimal Standard Model Higgs boson, attention turns to questions of naturalness, fine-tuning, and what they imply for physics beyond the Standard Model and its discovery prospects at run II of the LHC. In this article we revisit the issue of naturalness, discussing some implicit assumptions that underly some of the most common statements, which tend to assign physical significance to certain regularization procedures. Vague arguments concerning fine-tuning can lead to conclusions that are too strong and perhaps not as generic as one would hope. Instead, we explore a more pragmatic definition of the hierarchy problem that does not rely on peeking beyond the murky boundaries of quantum field theory: we investigate the fine-tuning of the electroweak scale associated with thresholds from heavy particles, which is both calculable and dependent on the nature of the would-be ultraviolet completion of the Standard Model. We discuss different manifestations of new high-energy scales that are favored by experimental hints for new physics with an eye toward making use of fine-tuning in order to determine natural regions of the new physics parameter spaces.

v2: corrected discussion of gravitational corrections to include an important contribution previously neglected

References in corpus (5)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• A solution to the hierarchy problem from an almost decoupled hidden sector within a classically scale invariant theory
• Neutrino mass in radiatively-broken scale-invariant models
• Expectations for LHC from Naturalness: Modified vs. SM Higgs Sector

Cited by in corpus (13)

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• Massive neutrinos and invisible axion minimally connected
• A Composite Axion from a Supersymmetric Product Group
• The Higgsino-Singlino World at the Large Hadron Collider
• Comments on the Hierarchy Problem in Effective Theories
• Guises and Disguises of Quadratic Divergences
• The Hierarchy Problem: From the Fundamentals to the Frontiers
• Pure leptonic proposal to $W^{+}{W}^{-}$ excess and neutrino mass generation
• Top 2014: Theory Summary
• Softening Higgs Naturalness - an EFT Analysis