We study the phenomenology of choosing a minimal set of effective operators simultaneously generating the dark matter relic density and matter–antimatter asymmetry of the universe. Neutrino masses are obtained in a specific case of baryogenesis via leptogenesis. We find that only two new particles—a heavy unstable fermion and a light dark matter scalar—need to be included in addition to the Standard Model particle content.

Slovakia

Tomáš Blažek

Peter Maták

Ján Ramaj

Martina Sabová

Minimal effective theory for leptogenesis, dark matter, and neutrino masses

This Letter presents the first search for dark matter axions with mass in the ranges <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>76.56</mn></mrow></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>76.82</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">μ</mi><mi>eV</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>79.31</mn></mrow></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>79.53</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">μ</mi><mi>eV</mi></mrow></math> using a prototype setup for the MAgnetized Disk and Mirror Axion eXperiment (MADMAX). The experimental setup employs a dielectric haloscope consisting of three sapphire disks and a mirror to resonantly enhance the axion-induced microwave signal within the magnetic dipole field provided by the 1.6 T Morpurgo magnet at CERN. Over 14.5 days of data collection, no axion signal was detected. A 95% CL upper limit on the axion-photon coupling strength down to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">|</mo><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo stretchy="false">|</mo><mo>∼</mo><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> is set in the targeted mass ranges, surpassing previous constraints, assuming a local axion dark matter density <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ρ</mi><mi>a</mi></msub></math> of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0.3</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><msup><mrow><mi>cm</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math>. This study marks the first axion dark matter search using a dielectric haloscope.

Germany

B. Ary dos Santos Garcia

D. Bergermann

A. Caldwell

France

V. Dabhi

C. Diaconu

J. Diehl

G. Dvali

J. Egge

E. Garutti

S. Heyminck

F. Hubaut

A. Ivanov

J. Jochum

United States

S. Knirck

M. Kramer

D. Kreikemeyer-Lorenzo

C. Krieger

C. Lee

D. Leppla-Weber

X. Li

A. Lindner

B. Majorovits

J.P.A. Maldonado

A. Martini

A. Miyazaki

E. Öz

P. Pralavorio

G. Raffelt

Spain

J. Redondo

A. Ringwald

J. Schaffran

A. Schmidt

F. Steffen

C. Strandhagen

I. Usherov

H. Wang

G. Wieching

First Search for Axion Dark Matter with a MADMAX Prototype

The photon sphere defines the unstable circular orbit of photons in a black hole spacetime. Photons emitted by a source located inside the photon sphere can be gravitationally lensed by the black hole and have time delays when reaching the observer. These delays may lead to light echoes produced in the light curve if an accretion event in the vicinity of the horizon can be observed. In this work, we present fully analytical formulas with high accuracy to describe the change of the azimuthal angle and the travel time of those photons. By employing the analytical approaches, we find that the time delay between photons emitted from the interior of the photon sphere has a typical time scale of $$2(\pi - \phi _\textrm{S}) u_\textrm{m}$$ with $$\phi _\textrm{S}$$ and $$u_\textrm{m}$$ being respectively the azimuthal angle of the source and the impact parameter evaluated at the photon sphere, which can provide some clues on the future search for gravitational lensing signatures in the accretion inflow event.

China

Yuan-Xing Gao

Analytical description for light propagation with the source inside the black hole photon sphere

In this work we investigate the muon anomalous magnetic dipole moment <math altimg='si1.svg'><msub><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow></msub></math> in a model that extends the Standard Model with a scalar triplet and a lepton triplet. Different from previous studies, we find that there is still viable parameter space in this model to explain the discrepancy <math altimg='si2.svg'><mi mathvariant='normal'>&#916;</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msub><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow></msub><mo stretchy='false'>(</mo><mrow><mi mathvariant='normal'>Exp</mi></mrow><mo stretchy='false'>)</mo><mo linebreak='goodbreak' linebreakstyle='after'>&#8722;</mo><msub><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow></msub><mo stretchy='false'>(</mo><mrow><mi mathvariant='normal'>SM</mi></mrow><mo stretchy='false'>)</mo></math>. While being consistent with the current data of neutrino mass, electroweak precision measurements and the perturbativity of couplings, our model can provide new physics contribution <math altimg='si128.svg'><msubsup><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow><mrow><mtext mathvariant='normal'>NP</mtext></mrow></msubsup></math> to cover the central region of <math altimg='si18.svg'><mi mathvariant='normal'>&#916;</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>&#956;</mi></mrow></msub></math> with new scalar and lepton mass as low as around TeV. This mass scale is allowed by the current collider searches for doubly charged scalars and the lepton triplet, and they can be tested at future high energy and/or high luminosity colliders.

Lei Cai

South Korea

Chengcheng Han

Shi-Ping He

Peiwen Wu

Hybrid Type-II and Type-III seesaw model for the muon <italic>g</italic>&#8239;&#8722;&#8239;2 anomaly

The symmetry can be broken at high temperature and then restored at low temperature, which is the so-called <italic>high temperature symmetry breaking</italic>. It often appears in some theories such as the high scale electroweak baryogenesis mechanism. In this paper, we probe the high temperature <math altimg='si1.svg'><msub><mrow><mi mathvariant='double-struck'>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math> symmetry breaking with gravitational waves (GWs) from the melting domain walls. We first introduce a scalar with <math altimg='si1.svg'><msub><mrow><mi mathvariant='double-struck'>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math> symmetry and a few singlet fermions that interact with scalar through a five-dimension operator. This leads to that the scalar potential has a non-zero minimum at high temperature. At the early stage, the scalar is pinned at symmetric phase due to the large Hubble fraction. When the scalar field's thermal mass becomes comparable to the Hubble parameter, it can quickly roll down to the minimum of potential. Then the <math altimg='si1.svg'><msub><mrow><mi mathvariant='double-struck'>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math> symmetry is spontaneously broken and the domain walls will form. With the decrease of temperature, <math altimg='si1.svg'><msub><mrow><mi mathvariant='double-struck'>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math> symmetry will be restored. We find that if domain walls are formed at <math altimg='si2.svg'><mi mathvariant='script'>O</mi><mo stretchy='false'>(</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup><mo stretchy='false'>)</mo><mspace width='0.25em' /><mtext>GeV</mtext></math>, the GW produced by the melting domain walls is expected to be observed by BBO, CE and ET. In addition, we also discuss the relationships between this scenario and NANOGrav signal.

Xiu-Fei Li

Probing the high temperature symmetry breaking with gravitational waves from domain walls

Particle azimuthal anisotropies inside jets, defined within the momentum plane perpendicular to the jet axis, carry the information of the QCD cascade process for jet formation. In this work, we propose to measure the medium-induced modifications of the elliptic anisotropy inside jets in relativistic heavy-ion collisions to provide novel insight into the jet quenching phenomenon. By simulating the jet propagation in the hot and dense nuclear medium with a Linear Boltzmann Transport model, we observe a de-correlation in the two-particle azimuthal angular distribution for inclusive jet production in AA collisions relative to that in <italic>pp</italic> collisions, which results in significant suppression of the in-jet elliptic anisotropy coefficient <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>. This phenomenon arises from the stochastic and strong interactions with the thermal QGP medium undergone by the jet particles. Furthermore, the nuclear modifications of the in-jet <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> are found to be sensitive to the medium properties in the model study, which provide a potential probe for the jet tomography of nuclear matter.

Meng-Quan Yang

Wei-Xi Kong

Peng Ru

Ben-Wei Zhang

Suppression of elliptic anisotropy inside jets: A new perspective for jet quenching

We investigate the volume and lifetime of the high-baryon-density matter created in heavy-ion collisions and estimate the optimal collision-energy range to realize the high-baryon-density region over a large space-time volume. We simulate central collisions of gold ions for the center-of-mass energy per nucleon pair <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>2.4</mn><mo>−</mo><mn>19.6</mn><mspace width="0.28em"></mspace><mi>GeV</mi></mrow></math> with a microscopic transport model JAM. We discover that the optimal range is around <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>3</mn><mo>−</mo><mn>5</mn><mspace width="0.28em"></mspace><mi>GeV</mi></mrow></math>, where a baryon density exceeding three times the normal nuclear density is realized with a substantially large space-time volume. Higher and lower energies are disfavored due to short lifetime and low density, respectively. We also point out that event-by-event fluctuations of the space-time density profile are large, indicating the importance of the event selection in the experimental analysis.

Japan

Hidetoshi Taya

Asanosuke Jinno

Masakiyo Kitazawa

Yasushi Nara

Optimal collision-energy range for realizing macroscopic high-baryon-density matter

We revisit birefringence effects associated with the evolution of the polarization of light as it propagates through axion dark matter or the background of a passing gravitational wave (GW). We demonstrate that this can be described by a unified formalism, highlighting a synergy between searches for axions and high-frequency GWs. We show that by exploiting this framework, the optical cavities used by the ALPS II experiment can potentially probe axion masses in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>∼</mo><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mi>–</mi><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></mrow></math>, offering competitive sensitivity with existing laboratory and astrophysical searches. Also building on this approach, we propose using these optical cavities to search for high-frequency GWs by measuring changes in the polarization of their circulating laser fields. This makes it a promising method for exploring, in the near future, GWs with frequencies above 100 MHz and strain sensitivities on the order of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>Hz</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></math>. Such sensitivity allows the exploration of currently unconstrained parameter space, complementing other high-frequency GW experiments. This work contributes to the growing community investigating novel approaches for high-frequency GW detection.

Camilo García-Cely

Luca Marsili

Andreas Ringwald

Aaron D. Spector

Polarimetric searches for axion dark matter and high-frequency gravitational waves using optical cavities

Atmospheric neutrino oscillations are important to the study of neutrino properties, including the neutrino mass ordering problem. A good capability to identify neutrinos’ flavor and neutrinos against antineutrinos is crucial in such measurements. In this paper, we present a machine-learning-based approach for identifying atmospheric neutrino events in a large homogeneous liquid scintillator detector. This method identifies features of photomultiplier tube waveforms that reflect event topologies and uses them as input to machine learning models. In addition, neutron-capture information is utilized to achieve neutrino vs antineutrino discrimination. Preliminary performances based on Monte Carlo simulations are presented, which demonstrate such a detector’s potential in future measurements of atmospheric neutrinos such as the one planned for the JUNO experiment.

Jiaxi Liu

Fanrui Zeng

Hongyue Duyang

Wanlei Guo

Xinhai He

Teng Li

Zhen Liu

Wuming Luo

Wing Yan Ma

Xiaohan Tan

Liangjian Wen

Zekun Yang

Yongpeng Zhang

Neutrino type identification for atmospheric neutrinos in a large homogeneous liquid scintillation detector

We investigate the production of charged scalar boson pairs <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>H</mi><mo>−</mo></msup><msup><mi>H</mi><mo>+</mo></msup></math> via photon-photon fusion in proton-proton collisions at the High-Luminosity LHC (HL-LHC), High-Energy LHC (HE-LHC), and Future Circular hadron-hadron Collider (FCC-hh). The analysis is performed within the framework of the Two-Higgs-Doublet Model type-III, which predicts large branching ratios for the decay channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>H</mi><mo>±</mo></msup><mo stretchy="false">→</mo><msup><mi>τ</mi><mo>±</mo></msup><msub><mi>ν</mi><mi>τ</mi></msub></math>, the focus of this work. Motivated by the current excess of events in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mi mathvariant="script">R</mi></mrow><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">→</mo><msup><mi>H</mi><mo>±</mo></msup><mi>b</mi><mo stretchy="false">)</mo><mo>×</mo><mrow><mi mathvariant="script">B</mi><mi mathvariant="script">R</mi></mrow><mo stretchy="false">(</mo><msup><mi>H</mi><mo>±</mo></msup><mo stretchy="false">→</mo><mi>c</mi><mi>b</mi><mo stretchy="false">)</mo></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><msup><mi>H</mi><mo>±</mo></msup></msub><mo>=</mo><mn>130</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, we explore charged Higgs boson masses in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><msup><mi>H</mi><mo>±</mo></msup></msub><mo>=</mo><mn>100</mn><mi>–</mi><mn>150</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. Using benchmark points (BPs) consistent with current experimental constraints, we evaluate the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mi>H</mi><mo>−</mo></msup><msup><mi>H</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>τ</mi><msub><mi>ν</mi><mi>τ</mi></msub><mi>τ</mi><msub><mi>ν</mi><mi>τ</mi></msub><mo stretchy="false">→</mo><mi>e</mi><mi>μ</mi><mo>+</mo><msub><menclose notation="updiagonalstrike"><mi>E</mi></menclose><mi>T</mi></msub></math> and find signal significances <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≳</mo><mn>5</mn><mi>σ</mi></math> across the entire mass range. For the most favored BP with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><msup><mi>H</mi><mo>±</mo></msup></msub><mo>=</mo><mn>130</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, we predict significances of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>σ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>8</mn><mi>σ</mi></math> with integrated luminosities of 3000, 2300, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>300</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> at center-of-mass energies of 14 TeV (HL-LHC), 27 TeV (HE-LHC), and 100 TeV (FCC-hh), respectively.

Mexico

M.A. Arroyo-Ureña

O. Félix-Beltrán

J. Hernández-Sánchez

C.G. Honorato

T.A. Valencia-Pérez

Prospects for observing novel photon-induced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>H</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>H</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> production at the high luminosity LHC