We explore the properties of vector dark matter (DM) particles that predominantly interact with Standard Model (SM) electroweak gauge bosons using an effective field theory approach. The study emphasizes effective contact interactions, invariant under the SM gauge group, between vector DM and SM-neutral electroweak gauge bosons. Focusing on interaction terms up to dimension-eight, we establish constraints on the model parameters based on the observed DM relic density and indirect detection signals. We also examine the prospects for dark matter-nucleon scattering in direct detection experiments. In addition, we analyze the sensitivity of low-energy LEP data to the pair production of light DM particles (with masses up to 80 GeV). Finally, we assess the potential of the proposed International Linear Collider to probe these effective operators through the detection of DM particles produced in association with mono-photons.

India

Hrishabh Bharadwaj

Exploring vector dark matter via effective interactions

We study the new $Z'$ boson as a portal for the production of Higgs bosons $h_0$ and $H_0$ predicted by the Bestest Little Higgs Model through Higgs-strahlung processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ . We focus on the resonant and nonresonant effects of the $Zh_0, ZH_0$ signals. In our analysis, we consider the center-of-mass energies of $\sqrt{s}=3, 4, 6, 10, 30$ TeV and integrated luminosities of ${\cal{L}}=2, 4, 6, 10, 30$ ${ {\rm{ab}}^{-1}}$ projected for a future muon collider. The possibility of performing precision measurements for Higgs bosons $h_0$ and $H_0$ is very promising for the future muon collider. Furthermore, our results may be useful to the High Energy Physics community. Complementarily, we generate and provide the Feynman rules necessary for studying processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ .

J.M. Martínez-Martínez

A. Gutiérrez-Rodríguez

E. Cruz-Albaro

M.A. Hernández-Ruíz

New $\textit{Z}$' boson of the bestest little Higgs model as a portal to signatures of Higgs bosons $\textit{h}$ $_{0}$ and $\textit{H}$ $_{0}$ at the future muon collider

In the framework of loop quantum cosmology, particularly within the quantum Oppenheimer–Snyder model, the semiclassical Ashtekar–Pawlowski–Singh (APS) metric is associated with a static, spherically symmetric black hole that incorporates quantum effects derived from the APS metric. This quantum-corrected black hole can be interpreted as a modified Schwarzschild black hole, where the Schwarzschild metric function is adjusted by an additional term proportional to $$\frac{M^{2}}{r^{4}}$$ , with $\textit{r}$ denoting the radial coordinate and $\textit{M}$, the black hole mass. In this study, we show that such a quantum-mechanically modified black hole can arise in the context of nonlinear electrodynamics with either electric or magnetic charge. This charged, quantum-corrected solution is then matched to a dust ball of constant mass $$M_{APS}$$ , governed by the APS metric, at a timelike thin-shell possessing nonzero mass $\textit{m}$ and electric charge $\textit{Q}$ or magnetic charge $\textit{P}$. Analytically, it is demonstrated that the thin-shell oscillates around an equilibrium radius $$r=R_{eq}$$ , which is expressed in terms of $$M_{APS}$$ , $\textit{m}$, and $\textit{Q}$ or $\textit{P}$.

Türkiye

S. Mazharimousavi

Charged quantum Oppenheimer–Snyder model

Previous computations of feebly interacting particle production have encountered issues with unphysical (negative) interaction rates at soft momenta. We address this problem by studying the production of Axion-Like Particles (ALPs) coupled to U(1)-gauge fields, employing the full form of 1PI-resummed gauge boson propagators. This approach avoids the need for matching or subtraction procedures. We find that the ALP production rate remains positive across all momentum scales and identify the dominant production mechanisms. At soft ALP momenta ($\textit{p}$ ≲ $\textit{g}$ $\textit{T}$), interactions involving two spacelike gauge bosons dominate the production rate, surpassing other channels by an order of magnitude. In particular, using the full gauge boson propagator suggests that at even softer momenta ($\textit{p}$ ≲ $\textit{g}$ $\textit{T}$), production involving two timelike gauge bosons becomes significant, potentially exceeding other contributions by another order of magnitude. We also find that a leading order accurate result for momenta $\textit{g}$ $\textit{T}$ ≲ $\textit{p}$ ≲ $\textit{g}$ $\textit{T}$ still requires extensions beyond the 1PI resummation. Using these insights, we update the thermal ALP abundance and refine the estimate of the average ALP momentum, providing important input for structure formation constraints on ALP dark matter in the keV mass range.

Italy

Germany

Mathias Becker

Julia Harz

Enrico Morgante

Cristina Puchades-Ibáñez

Pedro Schwaller

ALP production from abelian gauge bosons: beyond hard thermal loops

We present the first complete two-loop calculation of the electric dipole moment of the electron, as well as the rates of the lepton-flavor violating decays $\textit{μ}$ → $\textit{e}$ + $\textit{γ}$ and $\textit{τ}$ → $\textit{e/μ}$ + $\textit{γ}$, in the unconstrained two-Higgs doublet model. We include the most general Yukawa interactions of the Higgs doublets with the Standard Model fermions up to quadratic order, and allow for generic phases in the Higgs potential. A python implementation of our results is provided via a public git repository.

United States

Wolfgang Altmannshofer

Benoît Assi

Joachim Brod

Nick Hamer

Indonesia

J. Julio

Thailand

Patipan Uttayarat

Daniil Volkov

Electron EDM and Γ($\textit{μ → eγ}$) in the 2HDM

In this paper, we construct the path integral for infinite and semi-infinite scalar worldlines. We show that, at the asymptotic endpoints, on-shell physical states can be generated by inserting vertex operators at infinity. This procedure implements automatically the LSZ reduction, thus leading to a direct worldline representation of scattering amplitudes. To obtain it, we introduce generalized vertex operators, to be viewed as the gluing of entire tree subdiagrams to a given worldline. We demonstrate that the subdiagrams themselves are given, via a recursive relation, by correlation functions on the semi-infinite line. In this sense, the approach we take is fully first-quantized, in that it does not need any field theoretic quantity as input. We envisage that, when suitably extended to gauge theories, it could provide useful insights in addressing current research issues, such as color-kinematics duality.

Roberto Bonezzi

Maria Kallimani

Worldline geometries for scattering amplitudes

We study a two-matrix toy model with a BFSS-like interaction term using the collective field formalism. The main technical simplification is obtained by gauge-fixing first, and integrating out the off-diagonal elements, before changing to the collective field variable. We show that the resulting (2 + 1)-dimensional collective field action has novel features with respect to non-locality, and that we need to add a mass term to get a time-local potential. As is expected, one recovers the single matrix quantum mechanical collective field Hamiltonian in the proper limit.

not found

Suddhasattwa Brahma

Canada

Robert Brandenberger

Keshav Dasgupta

Yue Lei

Julia Pasiecznik

Collective field theory of gauged multi-matrix models: integrating out off-diagonal strings

The spectrum and dynamics of near-extremal black holes is strongly modified by quantum effects at low temperatures. When the extremal limit does not preserve any supersymmetry, the density of states goes to zero at extremality and no extremal black holes remain. However, when the extremal limit is supersymmetric, a large microscopic degeneracy survives and there is a gap to the first excited black hole visible from gravity. In this article we study large $\textit{N}$ quantum mechanical models where supersymmetry is explicitly broken, allowing us to interpolate between these two qualitatively different pictures. We propose and analyze deformations of $$ \mathcal{N} $$ = 2 SYK models with such a pattern of (super) symmetry breaking which violate the U(1) $\textit{R}$-symmetry. These models feature a lifting of the BPS degeneracy and a closing of the spectral gap, and we further show that the large $\textit{N}$ soft effective action is given by a modification of the $$ \mathcal{N} $$ = 2 Schwarzian theory in which the U(1) mode becomes massive.

Matthew Heydeman

Yifei Liu

Gustavo Turiaci

Supersymmetry breaking in SYK and the black hole spectrum

We explore various field theory aspects of integrable $\textit{η}$-deformed geometry in type IIB supergravity by employing several holographic probes. These include the computation of holographic timelike entanglement entropy and estimation of various other field theory observables for example, the flow central charge and the quantum complexity. We also discuss the associated brane set up and compute Page charges. We further use them to calculate the coupling constant in the dual QFTs considering both small and large deformation limits.

Dibakar Roychowdhury

Field theory aspects of $\textit{η}$-deformed superstring background

In this work, we have studied the mass accretion mechanism of a 4-dimensional black hole in the Bumblebee gravity framework. We work with three well-known red-shift parameterizations of dark energy EoS, namely, Linear, Chevallier–Polarski–Lindler (CPL), and Jassal–Bagla–Padmanabhan (JBP) parameterization. First, we discussed the fundamentals of Bumblebee gravity theory, specifically the basic field equations, and then went on to discuss the three dark energy models and their respective equations of state, energy density equations, and associated Hubble parameter equations. Next, the free parameters for the Bumblebee theory of gravity are constrained using the MCMC analysis. After determining the necessary parameters, we initiated the mass accretion procedure. We derived the mass equation for the models using the redshift function and then graphically depicted how the black hole’s mass changed with redshift. The accretion of all the dark energy candidates discussed above led us to the final conclusion that the mass of a 4-dimensional Bumblebee Black Hole will progressively rise in accordance with the universe’s evolution.

Anuka Basak

Ujjal Debnath

Accretion of dark energy onto black hole in Bumblebee field