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Showing papers on "Explicit symmetry breaking published in 2018"


Journal ArticleDOI
TL;DR: In this article, the authors present and analyze the interesting case where the pattern of explicit symmetry breaking naturally suppresses dark photon detection beyond the reach of current and future direct detection experiments.
Abstract: Dark matter could emerge along with the Higgs as a composite pseudo-Nambu-Goldstone boson $\chi$ with decay constant $f\sim \mathrm{TeV}$. This type of WIMP is especially compelling because its leading interaction with the Standard Model, the derivative Higgs portal, has the correct annihilation strength for thermal freeze-out if $m_\chi \sim O(100)$ GeV, but is negligible in direct detection experiments due to the very small momentum transfer. The explicit breaking of the shift symmetry which radiatively generates $m_\chi$, however, introduces non-derivative DM interactions. In existing realizations a marginal Higgs portal coupling $\lambda$ is generated with size comparable to the Higgs quartic, and thus well within reach of XENON1T. Here, we present and analyze the interesting case where the pattern of explicit symmetry breaking naturally suppresses $\lambda$ beyond the reach of current and future direct detection experiments. If the DM acquires mass from bottom quark loops, the bottom quark also mediates suppressed DM-nucleus scattering with cross sections that will be eventually probed by LZ. Alternatively, the DM can obtain mass from gauging its stabilizing $U(1)$ symmetry. No direct detection signal is expected even at future facilities, but the introduction of a dark photon $\gamma_D$ has a number of phenomenological implications which we study in detail, treating $m_{\gamma_D}$ as a free parameter. Complementary probes of the dark sector include indirect DM detection, DM self-interactions, and extra radiation, as well as collider experiments. We frame our discussion in an effective field theory, motivating our parameter choices with a detailed analysis of an $SO(7)/SO(6)$ composite Higgs model, which can yield either scenario at low energies.

51 citations


Journal ArticleDOI
TL;DR: By considering a solvable driven-dissipative quantum model, this article showed that continuous phase transitions in dissipative systems may occur without an accompanying symmetry breaking, as such, the...
Abstract: By considering a solvable driven-dissipative quantum model, we demonstrate that continuous phase transitions in dissipative systems may occur without an accompanying symmetry breaking. As such, the ...

46 citations


Journal ArticleDOI
TL;DR: In this article, the authors present and analyze the interesting case where the pattern of explicit symmetry breaking naturally suppresses dark photon detection beyond the reach of current and future direct detection experiments.
Abstract: Dark matter could emerge along with the Higgs as a composite pseudo-Nambu-Goldstone boson $\chi$ with decay constant $f\sim \mathrm{TeV}$. This type of WIMP is especially compelling because its leading interaction with the Standard Model, the derivative Higgs portal, has the correct annihilation strength for thermal freeze-out if $m_\chi \sim O(100)$ GeV, but is negligible in direct detection experiments due to the very small momentum transfer. The explicit breaking of the shift symmetry which radiatively generates $m_\chi$, however, introduces non-derivative DM interactions. In existing realizations a marginal Higgs portal coupling $\lambda$ is generated with size comparable to the Higgs quartic, and thus well within reach of XENON1T. Here, we present and analyze the interesting case where the pattern of explicit symmetry breaking naturally suppresses $\lambda$ beyond the reach of current and future direct detection experiments. If the DM acquires mass from bottom quark loops, the bottom quark also mediates suppressed DM-nucleus scattering with cross sections that will be eventually probed by LZ. Alternatively, the DM can obtain mass from gauging its stabilizing $U(1)$ symmetry. No direct detection signal is expected even at future facilities, but the introduction of a dark photon $\gamma_D$ has a number of phenomenological implications which we study in detail, treating $m_{\gamma_D}$ as a free parameter. Complementary probes of the dark sector include indirect DM detection, DM self-interactions, and extra radiation, as well as collider experiments. We frame our discussion in an effective field theory, motivating our parameter choices with a detailed analysis of an $SO(7)/SO(6)$ composite Higgs model, which can yield either scenario at low energies.

27 citations


Journal ArticleDOI
TL;DR: In this article, the authors used the lowest-order constrained variational (LOCV) method using AV18 two-body interaction supplemented by UIX three-body force to study the equation of state of asymmetric nuclear matter at both zero and finite temperature.

23 citations


Journal ArticleDOI
TL;DR: In this paper, the authors consider a 3-3-1 model with right-handed neutrinos and three scalar triplets and consider different spontaneous symmetry breaking patterns seeking for a nonlinear realization of accidental symmetries of the model, which will produce physical Nambu-Goldstone (NG) bosons in the neutral scalar spectrum.
Abstract: In the framework of a 3-3-1 model with right-handed neutrinos and three scalar triplets we consider different spontaneous symmetry breaking patterns seeking for a non-linear realization of accidental symmetries of the model, which will produce physical Nambu–Goldstone (NG) bosons in the neutral scalar spectrum. We make a detailed study of the safety of the model concerning the NG boson emission in energy-loss processes which could affect the standard evolution of astrophysical objects. We consider the model with a $$\mathbb {Z}_2$$ symmetry, conventionally used in the literature, finding that in all of the symmetry breaking patterns the model is excluded. Additionally, looking for solutions for that problem, we introduce soft $$\mathbb {Z}_2$$ -breaking terms in the scalar potential in order to remove the extra accidental symmetries and at the same time maintain the model as simple as possible. We find that there is only one soft $$\mathbb {Z}_2$$ -breaking term that enables us to get rid of the problematic NG bosons.

20 citations


Journal ArticleDOI
TL;DR: In this article, the Kane-Mele model with the corresponding spin-triplet $f$-wave superconducting pairings becomes a full-gap topological superconductor possessing the time-reversal symmetry.
Abstract: We present an exactly solvable model of a spin-triplet $f$-wave topological superconductor on the honeycomb lattice in the presence of the Hubbard interaction for arbitrary interaction strength. First we show that the Kane-Mele model with the corresponding spin-triplet $f$-wave superconducting pairings becomes a full-gap topological superconductor possessing the time-reversal symmetry. We then introduce the Hubbard interaction. The exactly solvable condition is found to be the emergence of perfect flat bands at zero energy. They generate infinitely many conserved quantities. It is intriguing that the Hubbard interaction breaks the time-reversal symmetry spontaneously. As a result, the system turns into a trivial superconductor. We demonstrate this topological property based on the topological number and by analyzing the edge state in nanoribbon geometry.

16 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory, and that the anomalous dimension of the gluon field strength tensor squared (G^2$) that represents the quantum trace anomaly should be
Abstract: It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension ($\gamma _{G^2}$) of the gluon field strength tensor squared ($G^2$) that represents the quantum trace anomaly should be $\textbf 0<\gamma _{G^{2}}<3$.

16 citations


Journal ArticleDOI
TL;DR: The paradox of a free falling radiating charged particle in a gravitational field is a well-known fascinating conceptual challenge that involves classical electrodynamics and general relativity (GR) as mentioned in this paper.
Abstract: The paradox of a free falling radiating charged particle in a gravitational field is a well-known fascinating conceptual challenge that involves classical electrodynamics and general relativity (GR...

9 citations


Journal ArticleDOI
TL;DR: In this article, it was shown by an explicit example that symmetric Dirichlet boundary conditions do not necessarily imply the symmetry of the surface, and a symmetry result for a subclass of willmore surfaces of revolution satisfying symmetric boundary data was shown.
Abstract: In this paper, we prove explicit formulas for all Willmore surfaces of revolution and demonstrate their use in the discussion of the associated Dirichlet boundary value problems. It is shown by an explicit example that symmetric Dirichlet boundary conditions do in general not entail the symmetry of the surface. In addition, we prove a symmetry result for a subclass of Willmore surfaces satisfying symmetric Dirichlet boundary data.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the authors design and analyze theoretically photometamaterials with each meta-atom containing both photodiode and light-emitting diode, and demonstrate that inversion symmetry breaking occurs upon a certain threshold magnitude of the incident wave intensity, resulting in an abrupt emergence of second-harmonic generation, which was not originally available, as well as in the reduced thirdharmonic signal.
Abstract: We design and analyze theoretically photometamaterials with each meta-atom containing both photodiode and light-emitting diode. Illumination of the photodiode by the light-emitting diode gives rise to an additional optical feedback within each unit cell, which strongly affects resonant properties and nonlinear response of the meta-atom. In particular, we demonstrate that inversion symmetry breaking occurs upon a certain threshold magnitude of the incident wave intensity resulting in an abrupt emergence of second-harmonic generation, which was not originally available, as well as in the reduced third-harmonic signal.

6 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explore the model building and phenomenology of flavored gauge-mediation models of supersymmetry breaking in which the electroweak Higgs doublets and the $SU(2)$ messenger doublets are connected by a discrete non-Abelian symmetry.
Abstract: We explore the model building and phenomenology of flavored gauge-mediation models of supersymmetry breaking in which the electroweak Higgs doublets and the $SU(2)$ messenger doublets are connected by a discrete non-Abelian symmetry The embedding of the Higgs and messenger fields into representations of this non-Abelian Higgs-messenger symmetry results in specific relations between the Standard Model Yukawa couplings and the messenger-matter Yukawa interactions Taking the concrete example of an ${\mathcal{S}}_{3}$ Higgs-messenger symmetry, we demonstrate that, while the minimal implementation of this scenario suffers from a severe $\ensuremath{\mu}/{B}_{\ensuremath{\mu}}$ problem that is well known from ordinary gauge mediation, expanding the Higgs-messenger field content allows for the possibility that $\ensuremath{\mu}$ and ${B}_{\ensuremath{\mu}}$ can be separately tuned, allowing for the possibility of phenomenologically viable models of the soft supersymmetry-breaking terms We construct toy examples of this type that are consistent with the observed 125 GeV Higgs boson mass

Dissertation
01 Jan 2018
TL;DR: In this paper, the authors study the persistence of stationary motion under explicit symmetry breaking perturbations in Hamiltonian systems and give a lower bound for the number of orbits of equilibria and orbits of relative equilibrium which persist after a small perturbation in terms of the Lyusternik-Schnirelmann category of the group orbit.
Abstract: The central topic of this thesis is the study of persistence of stationary motion under explicit symmetry breaking perturbations in Hamiltonian systems. Explicit symmetry breaking occurs when a dynamical system having a certain symmetry group is perturbed in a way that the perturbation preserves only some symmetries of the original system. We give a geometric approach to study this phenomenon in the setting of equivariant Hamiltonian systems. A lower bound for the number of orbits of equilibria and orbits of relative equilibria which persist after a small perturbation is given. This bound is given in terms of the equivariant Lyusternik-Schnirelmann category of the group orbit. We also find a localization formula for this category in terms of the closed orbit-type strata. We show that this formula holds for topological spaces admitting a particular cover, made of tubular neighbourhoods of their minimal orbit-type strata. Finally we propose a construction of symplectic slices for subgroup actions.

Journal ArticleDOI
TL;DR: In this article, the existence of kink soliton configurations in interacting scalar field theories containing two fields without $SO(2)$ invariance is studied. But the authors focus on the Montonen-Sarker-Trullinger-Bishop model.
Abstract: In this article, we study kink soliton configurations in interacting scalar field theories containing two fields without $SO(2)$ invariance. We study a class of such theories, the well-known Montonen-Sarker-Trullinger-Bishop model is one of them. These models are interesting since the $U(1)$ current is not conserved in them due to the presence of explicit symmetry breaking terms in the action. The existence of kink soliton configurations is shown in terms of a system of first-order ordinary differential equations. Although $U(1)$ current in these models are non-conserved, our approach is general enough to study soliton configurations in a generic two interacting scalar field theory. We also discuss other benefits of this approach.

Journal ArticleDOI
TL;DR: In this article, a minimal model where the Higgs boson arises as an elementary pseudo-Nambu-Goldstone boson was considered and the model is based on an extended scalar sector with global SO(5)/SO(4) symmetry.
Abstract: We consider a minimal model where the Higgs boson arises as an elementary pseudo-Nambu-Goldstone boson. The model is based on an extended scalar sector with global SO(5)/SO(4) symmetry. To achieve the correct electroweak symmetry breaking pattern, the model is augmented either with an explicit symmetry breaking term or an extra singlet scalar field. We consider separately both of these possibili- ties. We fit the model with the known particle spectrum at the electroweak scale and extrapolate to high energies using renormalization group. We find that the model can remain stable and perturbative up to the Planck scale provided that the heavy beyond Standard Model scalar states have masses in a narrow interval around 3 TeV.

Journal ArticleDOI
TL;DR: Based on the Curie symmetry principle, connecting between causality and symmetry, the authors formulate the intuitive but formal selection rules and apply to determine the excitable resonant modes of a photonic crystal defect cavity, which is an important element for plasmonic applications.
Abstract: Symmetry, which defines invariant properties under a group of transformations, provides a frame of generalization uncovering regularities from given quantitative descriptions. Based on the Curie’s symmetry principle, connecting between causality and symmetry, we formulate the intuitive but formal selection rules and apply to determine the excitable resonant modes of a photonic crystal defect cavity, which is an important element for plasmonic applications. Quantitative agreement with the numerical simulations demonstrates the effectiveness of the fundamental principle in finding the critical symmetry conditions for the available localized defect states within photonic crystals. Moreover, the principle facilitates analysis of the higher-order or even forbidden modes in the asymmetric excitation configurations regarding the polarizations or positions of the light source, which typically require heavy computations. Our results may be extended similarly to develop the qualitative selection rules in other physical systems with a geometric symmetry.

Journal ArticleDOI
TL;DR: In this article, the properties of a 3D dipolar Bose-Einstein condensate in a double-well potential (DWP) were investigated and symmetry breaking and tunneling dynamics phenomena were demonstrated.
Abstract: We investigate the properties of a three-dimensional (3D) dipolar Bose–Einstein condensate (BEC) in a double-well potential (DWP). Symmetry breaking and tunneling dynamics phenomena are demonstrate...

Posted ContentDOI
TL;DR: In this article, the effects arising from manifestly broken time-reversal symmetry are investigated using time-dependent perturbation theory in a simple model, where the forward time and the backward time Hamiltonians are taken to be different and hence the forward and backward amplitudes become unsymmetrical and are not complex conjugates of each other.
Abstract: Quantum effects arising from manifestly broken time-reversal symmetry are investigated using time-dependent perturbation theory in a simple model. The forward time and the backward time Hamiltonians are taken to be different and hence the forward and backward amplitudes become unsymmetrical and are not complex conjugates of each other. The effects vanish when the symmetry breaking term is absent and ordinary quantum mechanical results such as Fermi Golden rule are recovered.