Vacuum Stability and Two Loop Threshold Corrections to the Higgs Quartic Coupling

Abstract The superpotential in four-dimensional heterotic effective theories contains terms arising from holomorphic Chern-Simons invariants associated to the gauge and tangent bundles of the compactification geometry. These effects are crucial for a number of key features of the theory, including vacuum stability and moduli stabilization. Despite their importance, few tools exist in the literature to compute such effects in a given heterotic vacuum. In this work we present new techniques to explicitly determine holomorphic Chern-Simons invariants in heterotic string compactifications. The key technical ingredient in our computations are real bundle morphisms between the gauge and tangent bundles. We find that there are large classes of examples, beyond the standard embedding, where the Chern-Simons superpotential vanishes. We also provide explicit examples for non-flat bundles where it is non-vanishing and non-integer quantized, generalizing previous results for Wilson lines.

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ANEC in λϕ4 theory

Journal of High Energy Physics ◽

10.1007/jhep01(2021)132 ◽

2021 ◽

Vol 2021 (1) ◽

Author(s):

Teresa Bautista ◽

Lorenzo Casarin ◽

Hadi Godazgar

Keyword(s):

Critical Points ◽

Energy Condition ◽

Null Energy Condition ◽

Renormalisation Group ◽

Quartic Coupling ◽

Third Order ◽

Expectation Value ◽

Scalar State

Abstract Motivated by the goal of applying the average null energy condition (ANEC) to renormalisation group flows, we calculate in λϕ4 theory the expectation value of the ANEC operator in a particular scalar state perturbatively up to third order in the quartic coupling and verify the expected CFT answer. The work provides the technical tools for studying the expectation value of the ANEC operator in more interesting states, for example tensorial states relevant to the Hofman-Maldacena collider bounds, away from critical points.

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Vacuum stability and symmetry breaking in left-right symmetric model

Journal of High Energy Physics ◽

10.1007/jhep12(2019)137 ◽

2019 ◽

Vol 2019 (12) ◽

Cited By ~ 2

Author(s):

Garv Chauhan

Keyword(s):

Symmetry Breaking ◽

Symmetric Model ◽

Vacuum Stability

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Weak cosmic censorship with self-interacting scalar and bound on charge to mass ratio

Journal of High Energy Physics ◽

10.1007/jhep03(2021)045 ◽

2021 ◽

Vol 2021 (3) ◽

Author(s):

Yan Song ◽

Tong-Tong Hu ◽

Yong-Qiang Wang

Keyword(s):

Scalar Field ◽

Scalar Fields ◽

Cosmic Censorship ◽

Mass Ratio ◽

Quartic Coupling ◽

Scalar Theory ◽

Free Scalar ◽

The One ◽

Nonzero Scalar ◽

Large Charge

Abstract We study the model of four-dimensional Einstein-Maxwell-Λ theory minimally coupled to a massive charged self-interacting scalar field, parameterized by the quartic and hexic couplings, labelled by λ and β, respectively. In the absence of scalar field, there is a class of counterexamples to cosmic censorship. Moreover, we investigate the full nonlinear solution with nonzero scalar field included, and argue that these counterexamples can be removed by assuming charged self-interacting scalar field with sufficiently large charge not lower than a certain bound. In particular, this bound on charge required to preserve cosmic censorship is no longer precisely the weak gravity bound for the free scalar theory. For the quartic coupling, for λ < 0 the bound is below the one for the free scalar fields, whereas for λ > 0 it is above. Meanwhile, for the hexic coupling the bound is always above the one for the free scalar fields, irrespective of the sign of β.

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Neutrino masses, vacuum stability and quantum gravity prediction for the mass of the top quark

Journal of High Energy Physics ◽

10.1007/jhep01(2021)180 ◽

2021 ◽

Vol 2021 (1) ◽

Author(s):

Guillem Domènech ◽

Mark Goodsell ◽

Christof Wetterich

Keyword(s):

Quantum Gravity ◽

Top Quark ◽

Quark Mass ◽

Scalar Potential ◽

Planck Scale ◽

Neutrino Masses ◽

Top Quark Mass ◽

Vacuum Stability ◽

Intermediate Scale ◽

Yukawa Couplings

Abstract A general prediction from asymptotically safe quantum gravity is the approximate vanishing of all quartic scalar couplings at the UV fixed point beyond the Planck scale. A vanishing Higgs doublet quartic coupling near the Planck scale translates into a prediction for the ratio between the mass of the Higgs boson MH and the top quark Mt. If only the standard model particles contribute to the running of couplings below the Planck mass, the observed MH∼ 125 GeV results in the prediction for the top quark mass Mt∼ 171 GeV, in agreement with recent measurements. In this work, we study how the asymptotic safety prediction for the top quark mass is affected by possible physics at an intermediate scale. We investigate the effect of an SU(2) triplet scalar and right-handed neutrinos, needed to explain the tiny mass of left-handed neutrinos. For pure seesaw II, with no or very heavy right handed neutrinos, the top mass can increase to Mt ∼ 172.5 GeV for a triplet mass of M∆ ∼ 108GeV. Right handed neutrino masses at an intermediate scale increase the uncertainty of the predictions of Mt due to unknown Yukawa couplings of the right-handed neutrinos and a cubic interaction in the scalar potential. For an appropriate range of Yukawa couplings there is no longer an issue of vacuum stability.

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