Searches for high frequency gravitational waves using cavities based on the Gertsenshtein effect were recently proposed, building off existing axion dark matter experiments. In particular, the sensitivity of axion dark matter experiments using metamaterial plasmas (tunable plasma haloscopes) to gravitational waves has not been explored in detail. Here we perform a full analysis of gravitational wave detection in plasma haloscopes, showing that the baseline design of experiments such as ALPHA is several orders of magnitude less sensitive than previously thought. We show how simple changes to the experiment can recover that sensitivity and lead to a powerful gravitational wave detector in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mn>10</mn><mi>–</mi><mn>50</mn><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><mi>GHz</mi></math> frequency range.

United States

Rodolfo Capdevilla

Graciela B. Gelmini

Jonah Hyman

Alexander J. Millar

Italy

Edoardo Vitagliano

Gravitational wave detection with plasma haloscopes

In high-energy collisions far above the electroweak scale, the effects of electroweak symmetry breaking are expected to become parametrically small <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>δ</mi><mo>∼</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>W</mi></mrow></msub><mo>/</mo><mi>E</mi></mrow></math>. This defines the extent to which the electroweak gauge symmetry is restored: (i) the physics of the transverse gauge bosons and fermions is described by a massless theory in the unbroken phase; (ii) the longitudinal gauge bosons behave like the Goldstone bosons and join the Higgs boson to restore the unbroken O(4) symmetry in the original Higgs sector. Using the unique feature of the radiation amplitude zeros in gauge theory, we propose to study the electroweak symmetry restoration quantitatively by examining the processes for the gauge boson pair production <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>γ</mi><mo>,</mo><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>Z</mi></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mi>H</mi></mrow></math> at the LHC and muon colliders.

Tao Han

Electroweak Symmetry Restoration and Radiation Amplitude Zeros

The use of experiments searching for light axion dark matter as high-frequency gravitational wave detectors has garnered increasing attention in recent years. We explore the capabilities of the Broadband Reflector Experiment for Axion Detection (BREAD) in probing the GW parameter space and study the directional dependence of its coverage. This detector can investigate frequencies ranging from 0.05 to 200 THz. We find that by employing single photon detectors, BREAD is sensitive to GWs with characteristic strains as low as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>21</mn></mrow></msup></math> at 0.1 THz and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup></math> at 200 THz with a year exposure time, making it competitive with other proposals operating at similar frequencies.

Roni Harnik

South Korea

China

Taegyun Kim

Germany

Tom Krokotsch

High-frequency gravitational wave detection by the BREAD experiment

Scalar leptoquarks (LQ) with masses between 2 TeV and 50 TeV are prime candidates to explain deviations between measurements and Standard-Model predictions in decay observables of $\textit{b}$-flavored hadrons (“flavor anomalies”). Explanations of low-energy data often involve $$ \mathcal{O} $$ (1) LQ-quark-lepton Yukawa couplings, especially when collider bounds enforce a large LQ mass. This calls for the calculation of radiative corrections involving these couplings. Studying such corrections to LQ-mediated $\textit{b}$ → $\textit{cτν}$ and $\textit{b}$ → $\textit{sℓ}$ $\textit{ℓ}$ amplitudes, we find that they can be absorbed into finite renormalizations of the LQ Yukawa couplings. If one wants to use Yukawa couplings extracted from low-energy data for the prediction of on-shell LQ decay rates, one must convert the low-energy couplings to their high-energy counterparts, which subsume the corrections to the on-shell LQ-quark-lepton vertex. We present compact formulae for these correction factors and find that in scenarios with $\textit{S}$ , $\textit{R}$ , or $\textit{S}$ LQ the high-energy coupling is always smaller than the low-energy one, which weakens the impact of collider data on the determination of the allowed parameter spaces. For the $\textit{R}$ scenario addressing $\textit{b}$ → $\textit{cτν}$, in which one of the two involved Yukawa coupling must be significantly larger than 1, we find this coupling reduced by 15% at high energy. If both $\textit{S}$ and $\textit{R}$ are present, the high-energy coupling can also be larger and the size of the correction is unbounded, because tree contribution and vertex corrections involve different couplings. We further present the conversion formula to the $$ \overline{\textrm{MS}} $$ scheme for the Yukawa couplings of the $\textit{S}$ scenario.

Innes Bigaran

Ulrich Nierste

Radiative corrections relating leptoquark-fermion couplings probed at low and high energy

Minimal dark matter models feature one neutral particle that serves as a thermal relic dark matter candidate, as well as quasidegenerate charged states with TeV masses. When the charged states are produced at colliders, they can decay into dark matter and a low-momentum (soft) charged particle, which is challenging to reconstruct at hadron colliders. We demonstrate that a 3 TeV muon collider is capable of detecting these soft tracks, enabling the discovery of thermal Higgsinos and similar dark matter candidates that constitute highly motivated scenarios for future collider searches.

Federico Meloni

Spain

Jose Zurita

Discovering Electroweak Interacting Dark Matter at Muon Colliders Using Soft Tracks

Collinear emission of $\textit{W}$ bosons off a high-energy muon induces a large muon-neutrino component among the Parton Distribution Functions (PDFs) of a muon. In this paper we study the phenomenology related to the $\textit{ν}$ PDF at future high-energy muon colliders. We examine total rates and differential distributions of the $$ e{\overline{\nu}}_e $$ and $\textit{Wγ}$ production processes, which receive a large, and often dominant, contribution from this PDF, allowing for a detailed experimental study. As a demonstration of the impact the $\textit{ν}$ PDF could have for searches of new physics, we study the charged-current pair production of a couple of heavy states, components of a SU(2) doublet. In both $$ e{\overline{\nu}}_e $$ production and charged-current pair production of heavy states, we compare results obtained using PDFs with those of a fixed-order simulation.

Francesco Garosi

David Marzocca

Switzerland

Austria

Bernd Stechauner

Testing the neutrino content of the muon at muon colliders

The Higgs boson was the last fundamental piece of the Standard Model to be experimentally confirmed. LHC is embarked in a quest to probe the possibility that this particle provides a portal to new physics. One front of this quest consists in measuring the interactions of the Higgs with itself and with other SM particles to a high precision. In a more exotic front, the LHC is searching for the possibility that a pair of Higgses (HH) is the evidence of a new resonance. Such resonances are predicted in models with extended Higgs sectors, extra dimensions, and in models with exotic bound states. In this paper we show how scalar quirks in Folded Supersymmetry can give rise to HH resonances. We point out a viable sector of the parameter space in which HH is the dominant decay channel for these squirkonium bound states. We found that future runs of the LHC could discover HH resonances in the range of 0.5–1.6 TeV under reasonable assumptions. Furthermore, for a given mass and width of the HH signal, the model predicts the branching ratio of the subsequent decay modes of the heavy resonance. Finding the extra decay modes in the predicted pattern can serve as a smoking gun to confirm the model.

Brazil

Mario Barela

Di-Higgs signatures in neutral naturalness

CERN

Carlotta Accettura

United Kingdom

Dean Adams

Rohit Agarwal

Claudia Ahdida

Chiara Aimè

Nicola Amapane

David Amorim

Paolo Andreetto

Fabio Anulli

Robert Appleby

Artur Apresyan

Aram Apyan

France

Sergey Arsenyev

Pouya Asadi

Egypt

Mohammed Mahmoud

Aleksandr Azatov

John Back

Lorenzo Balconi

Laura Bandiera

Roger Barlow

Nazar Bartosik

Emanuela Barzi

Fabian Batsch

Matteo Bauce

J. Berg

Andrea Bersani

Alessandro Bertarelli

Alessandro Bertolin

Kevin Black

Fulvio Boattini

Alex Bogacz

Maurizio Bonesini

Bernardo Bordini

Salvatore Bottaro

Luca Bottura

Alessandro Braghieri

Marco Breschi

Natalie Bruhwiler

Xavier Buffat

Laura Buonincontri

Philip Burrows

Graeme Burt

Dario Buttazzo

Barbara Caiffi

Marco Calviani

Simone Calzaferri

Daniele Calzolari

Christian Carli

Fausto Casaburo

Massimo Casarsa

Luca Castelli

Maria Catanesi

Lorenzo Cavallucci

Gianluca Cavoto

Francesco Celiberto

Luigi Celona

Alessandro Cerri

Gianmario Cesarini

Cari Cesarotti

Portugal

Grigorios Chachamis

Antoine Chance

Siyu Chen

Yang-Ting Chien

Mauro Chiesa

Anna Colaleo

Francesco Collamati

Gianmaria Collazuol

Marco Costa

Nathaniel Craig

Camilla Curatolo

Canada

David Curtin

Giacomo Molin

Magnus Dam

Heiko Damerau

Sridhara Dasu

Jorge Blas

Stefania Curtis

Ernesto Matteis

Stefania Rosa

Jean-Pierre Delahaye

Dmitri Denisov

Türkiye

Haluk Denizli

Christopher Densham

Radovan Dermisek

Luca Luzio

Elisa Meco

Biagio Micco

Keith Dienes

Eleonora Diociaiuti

Tommaso Dorigo

Alexey Dudarev

Robert Edgecock

Filippo Errico

Marco Fabbrichesi

Stefania Farinon

Anna Ferrari

Jose Somoza

Netherlands

Frank Filthaut

Davide Fiorina

Erratum: Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.

Towards a muon collider

We comprehensively study all viable new-physics scenarios that resolve the muon (g − 2) μ anomaly with only Standard Model singlet particles coupled to muons via renormalizable interactions. Since such models are only viable in the MeV–TeV mass range and require sizable muon couplings, they predict abundant accelerator production through the same interaction that resolves the anomaly. We find that a combination of fixed-target (NA64μ, M 3), B-factory (BABAR, Belle II), and collider (LHC, muon collider) searches can cover nearly all viable singlets scenarios, independently of their decay modes. In particular, future muon collider searches offer the only certain test of singlets above the GeV scale, covering all higher masses up to the TeV-scale unitarity limit for these models. Intriguingly, we find that <math> <mi>O</mi> <mfenced> <mrow> <mn>100</mn> <mspace width="0.25em"></mspace> <mi>GeV</mi> </mrow> </mfenced> </math> $$ \mathcal{O}\left(100\ \mathrm{GeV}\right) $$ muon colliders may yield better coverage for GeV-scale singlets compared to TeV-scale concepts, which has important implications for the starting center-of-mass energy of a staged muon collider program.

Yonatan Kahn

Gordan Krnjaic

Systematically testing singlet models for (g − 2) μ