We present the phenomenology of the charged Higgs boson $\textit{H}$ appearing in a fermionic dark matter model mediated by an additional scalar doublet. In order to couple the dark matter fermion to the scalar doublet, we introduce a U(1) gauge symmetry, which is spontaneously broken at electroweak symmetry breaking, resulting in a massive $\textit{Z′}$ gauge boson. Since $\textit{Z′}$ is generically light, the model is subject to strong constraints from electroweak precision observables. As a result, the charged Higgs boson mass allowed by current experimental bounds is typically light in this model, 110 GeV $\textit{<}$ $$ {m}_{H^{\pm }} $$ $\textit{<}$ 170 GeV. Such a light charged Higgs boson will be produced mainly through top-quark decays at the LHC. Additionally, depending on the mass of the additional neutral Higgs boson $\textit{h}$ and the dark gauge boson $\textit{Z′}$, the direct production channels $\textit{pp}$ → $\textit{H}$ $\textit{Z′}$ and $\textit{pp}$ → $\textit{H}$ $\textit{h}$ can become sizable. We investigate the corresponding signal processes at the LHC to assess the discovery potential for $\textit{H}$ . Current ATLAS and CMS searches for light charged Higgs bosons already impose further constraints on the model. We also discuss the implications of dark matter in relation to the charged Higgs boson phenomenology.

South Korea

Kyu Bae

Jinn-Ouk Gong

Dong-Won Jung

Kang Lee

Chaehyun Yu

Chan Park

Charged Higgs boson phenomenology in the dark $\textit{Z}$ mediated fermionic dark matter model

The Lee–Wick pseudo-quantum electrodynamics in the presence of a Chern–Simons term is studied in this paper. The paper starts with a non-local lagrangian density that sets the pseudo-Lee–Wick electrodynamics defined on a $$1+2$$ space-time added to a non-local Chern–Simons topological term. Thus, we obtain the Lee–Wick–Chern–Simons pseudo-electrodynamics as a most complete gauge invariant model that provides a light mass associated with the Chern–Simons parameter, and also includes a Lee–Wick heavy mass. We investigate classical aspects as the potential energy for the interaction of static charges through the gauge propagator. The causality of theory is discussed through the retarded Green function in the coordinate space. The gauge field of the Lee–Wick–Chern–Simons pseudo-electrodynamics is minimally coupled to the fermions sector that includes new degree of freedoms, as a Lee–Wick heavy fermion partner of the electron. The perturbative approach for the theory is presented via effective action in which we obtain the Ward identities. We study the quantum corrections at one loop, as the electron self-energy, the vacuum polarization, and the 3-vertex. We show that the Lee–Wick mass has a fundamental role in these results, where it works like a natural regulator of the ultraviolet divergences. The $$g-2$$ factor for the electron is obtained as function of the LW mass, and of the CS parameter. Through the optical theorem, the Lee–Wick–Chern–Simons pseudo-electrodynamics is unitary at the tree level.

Brazil

M. Neves

The Lee–Wick–Chern–Simons pseudo-quantum electrodynamics

We accomplish the Batalin-Fradkin-Vilkovisky (BFV) quantization of the Christ-Lee model in both polar and Cartesian coordinates. We construct the BRST charge along with gauge-fixing function and obtain the BRST invariant effective action. We also procure the finite field-dependent BRST (FFBRST) symmetries of the model. Finally, we obtain a generalized action of the model with finite field-dependent parameter. Thus, we bridge the BFV-BRST gauge-fixed action and the gauge-invariant classical action of the model using FFBRST transformations.

India

Ansha S. Nair

R. Kumar

Saurabh Gupta

BFV quantization and FFBRST of Christ-Lee model

<list id='lst0001'><list-item id='lstitem0001'><label>&#8226;</label><para id='p0001'>We investigate a classical model of coupled harmonic oscillators (CHO) as the classical counterpart of the Lee model. In this classical model, the divergence of the fundamental frequency and its renormalization precisely reproduce the divergence and renormalization of the physical mass of the particle, revealing that mass divergence in the Lee model is not solely a quantum phenomenon.</para></list-item><list-item id='lstitem0002'><label>&#8226;</label><para id='p0002'>We derive the necessary conditions that any renormalization must satisfy for the two-oscillator system corresponding to the single-mode Lee model.</para></list-item><list-item id='lstitem0003'><label>&#8226;</label><para id='p0003'>We examine the classical analog of the <italic>N</italic>-<italic>&#952;</italic> scattering process in the Lee model and demonstrate that the cutoff-dependent behavior of the scattering strength parallels the quantum scenario, indicating that the suppression of scattering also has a classical origin.</para></list-item></list>

China

Kang Xu

C.P. Sun

Classical analog of the T. D. Lee model for renormalization

<p>Using the recent six loop renormalization group functions for Lee-Yang and percolation theory constructed by Schnetz from a scalar cubic Lagrangian, we deduce the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ε</mi></math> expansion of the critical exponents for both cases. Estimates for the exponents in three, four, and five dimensions are extracted using two-sided Padé approximants and shown to be compatible with values from other approaches.</p>

United Kingdom

J.A. Gracey

Six loop critical exponent analysis for Lee-Yang and percolation theory

<p>We study the quantum chromodynamics (QCD) phase transitions in the complex chemical potential plane via the Dyson-Schwinger equation approach, incorporating a constant gluonic background field that represents the confining dynamics. We solve the quark gap equation and the background field equation self-consistently, which allows us to directly explore the confinement phase transition and furthermore, evaluate the impact of the back-coupling of confinement on chiral symmetry breaking. Moreover, within such a coupled framework toward the complex chemical potential region, we demonstrate the emergence of Roberge-Weiss (RW) symmetry and investigate the trajectory of Lee-Yang edge singularities (LYESs). Our analysis reveals that the LYESs scaling behavior is similar to our previous findings without the background field condensate. However, a significant difference from our earlier work is that the trajectory of LYESs terminates when the imaginary part of the singularity becomes <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><mn>3</mn><mi>π</mi><mi>T</mi></math>. We elaborate that this cutoff behavior is caused by the RW symmetry that is symmetric to the imaginary chemical potential <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Im</mi><mi>μ</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>3</mn><mi>π</mi><mi>T</mi></math>.</p>

Zi-yan Wan

Yi Lu

Fei Gao

Yu-xin Liu

Lee Yang edge singularities of QCD in association with the Roberge-Weiss and chiral phase transitions

We employ the Fuzzy Sphere regulator to study the 3D Lee-Yang CFT. The model is defined by deforming the Ising model on the Fuzzy Sphere via a purely imaginary longitudinal magnetic field. This model undergoes a quantum phase transition, whose critical point we determine and identify with the 3D Lee-Yang CFT. We show how to tune the model and find that the lowest-lying states of the Hamiltonian align well with the expected CFT spectrum. We discuss the Fuzzy Sphere estimates for the scaling dimension ∆ of the lowest primary operator. Finally, we interpret small deviations from the CFT expectations in terms of the leading irrelevant operators of the Lee-Yang CFT. We show that the Fuzzy Sphere calculations are compatible with the best five-loop $\textit{ϵ}$-expansion estimates.

Italy

Joan Miró

Switzerland

Olivier Delouche

Flowing from the Ising model on the fuzzy sphere to the 3D Lee-Yang CFT

The study of effective potential for the scalar Lee-Wick pseudo-electrodynamics in one-loop is presented in this letter. The planar and non-local Lee-Wick pseudo-electrodynamics is so coupled to a complex scalar field sector in <math altimg='si2.svg'><mrow><mn>1</mn><mo linebreak='goodbreak'>+</mo><mn>2</mn></mrow></math> dimensions, where we achieve the Lee-Wick pseudo-scalar electrodynamics. The effective action formalism is applied such that the quantum corrections are examined in one loop to the scalar effective potential as function of the classical field, of the Lee-Wick mass, and also of the coupling constants of this model. The instability of the effective potential is investigated due to Lee-Wick mass.

M.J. Neves

Effective potential of scalar Lee-Wick pseudo-electrodynamics

We study compact kinks in a modified Christ-Lee model where the potential is a non-analytic function at the minima. The model has two control parameters that determine the order of the potential and its overall shape. We consider cases in which the potential has a double well shape, a triple well shape, as well as cases with a false vacuum. Compact kink solutions and their internal modes are found for each of these cases. We also study the collision of such kinks and their dependence on the solitons velocity and on the potential parameters. Several interesting dynamical processes are reported, such as the formation of central oscillons for some high velocity collisions, absence of outgoing solitons in cases where the potential is given by piece-wise linear functions, and the decoupling of subkinks from the larger kink in cases with false vacuum, leading to the formation of false vacuum bubbles.

F. Hahne

R. Thibes

Compact kinks in a modified Christ-Lee model

In this study, we present several improvements of the non-relativistic Friedrichs-Lee model with multiple discrete and continuous states while retaining its solvability. Our findings establish a solid theoretical basis for the exploration of resonance phenomena in scenarios involving multiple interfering states across various channels. The scattering amplitudes associated with the continuum states naturally adhere to coupled-channel unitarity, rendering this framework particularly valuable for investigating hadronic resonant states appearing in multiple coupled channels. Moreover, this generalized framework exhibits a wide-range applicability, enabling investigations into resonance phenomena across diverse physical domains, including hadron physics, nuclear physics, optics, cold atom physics, etc.

Zhiguang Xiao

Zhi-Yong Zhou

On the generalized Friedrichs-Lee model with multiple discrete and continuous states * Supported by China National Natural Science Foundation (11975075, 12375132, 12375078, 11575177, 11947301, 12335002), also supported by the Fundamental Research Funds for the Central Universities