Millicharged particles are well-motivated dark matter candidates arising in many extensions of the standard model. We show that, despite their tiny coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>e</mi><mi>m</mi></msub></math> to photons, millicharged dark matter (mDM) in the Earth’s geomagnetic field can generate a quasistatic, monochromatic magnetic signal with angular frequency twice the mDM mass. Using null results from the SuperMAG and SNIPE Hunt collaborations, we constrain the effective charge of bosonic mDM in the mass range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>18</mn></mrow></msup><mo>−</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math>. The resulting upper bounds exceed stellar cooling constraints by over 13 orders of magnitude, demonstrating the power of this method.

China

Ariel Arza

Yuanlin Gong

Jing Shu

Lei Wu

Qiang Yuan

Bin Zhu

Geomagnetic Constraints on Millicharged Dark Matter

This Letter reports the first calculation of the gravitational form factors (GFFs) of the scalar glueball, performed via lattice field theory in Yang-Mills theory at a single lattice spacing. The glueball GFFs are compared with those of other hadrons as determined in previous lattice calculations, providing strong indications that glueballs have a different gluonic structure than typical hadronic states. A mass radius of 0.263(31) fm is predicted, supporting previous suggestions that the scalar glueball is significantly smaller than other hadrons.

United States

Ryan Abbott

Daniel C. Hackett

Dimitra A. Pefkou

Switzerland

Fernando Romero-López

Phiala E. Shanahan

Lattice Evidence That Scalar Glueballs are Small

Using proton-proton collision data collected by the CMS experiment at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math> in 2016–2018, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>140</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>, the first full reconstruction of the three vector <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> meson states, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msubsup></mrow></math>, is performed. The mass differences between the excited mesons and their corresponding ground states are measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mi>m</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msup><mo stretchy="false">)</mo></mrow><mo>−</mo><mrow><mi>m</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">)</mo></mrow><mo>=</mo><mn>45.277</mn><mo>±</mo><mn>0.039</mn><mo>±</mo><mn>0.027</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mi>m</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo stretchy="false">)</mo></mrow><mo>−</mo><mrow><mi>m</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">)</mo></mrow><mo>=</mo><mn>45.471</mn><mo>±</mo><mn>0.056</mn><mo>±</mo><mn>0.028</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mi>m</mi><mo stretchy="false">(</mo><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msubsup><mo stretchy="false">)</mo></mrow><mo>−</mo><mrow><mi>m</mi><mo stretchy="false">(</mo><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">)</mo></mrow><mo>=</mo><mn>49.407</mn><mo>±</mo><mn>0.132</mn><mo>±</mo><mn>0.041</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math>, where the first uncertainties are statistical and the second are systematic. These results improve on the precision of previous measurements by an order of magnitude.

Armenia

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

M. Dragicevic

C. Giordano

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

M. Matthewman

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Shooshtari

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

H. Kwon

D. Ocampo Henao

T. Van Laer

P. Van Mechelen

J. Bierkens

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

Y. Hong

P. Kashko

S. Lowette

I. Makarenko

D. Müller

J. Song

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

A.K. Das

I. De Bruyn

G. De Lentdecker

H. Evard

L. Favart

P. Gianneios

A. Khalilzadeh

F.A. Khan

A. Malara

M.A. Shahzad

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

F. Zhang

M. De Coen

D. Dobur

G. Gokbulut

J. Knolle

L. Lambrecht

D. Marckx

K. Skovpen

N. Van Den Bossche

J. van der Linden

J. Vandenbroeck

L. Wezenbeek

S. Bein

A. Benecke

A. Bethani

G. Bruno

A. Cappati

J. De Favereau De Jeneret

C. Delaere

A. Giammanco

A.O. Guzel

V. Lemaitre

J. Lidrych

P. Malek

P. Mastrapasqua

S. Turkcapar

Brazil

G.A. Alves

M. Barroso Ferreira Filho

E. Coelho

C. Hensel

T. Menezes De Oliveira

C. Mora Herrera

P. Rebello Teles

M. Soeiro

E.J. Tonelli Manganote

A. Vilela Pereira

W.L. Aldá Júnior

H. Brandao Malbouisson

First Exclusive Reconstruction of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>B</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msubsup></mrow></math> Mesons and Precise Measurement of Their Masses

Extracting continuum properties of quantum field theories from discretized spacetime is challenging due to lattice artifacts. Renormalization-group (RG)-improved lattice actions can preserve continuum properties, but are in general difficult to parameterize. Machine learning (ML) with gauge-equivariant convolutional neural networks provides a way to efficiently describe such actions. We test a machine-learned RG-improved lattice gauge action, the classically perfect fixed-point (FP) action, for four-dimensional SU(3) gauge theory through Monte Carlo simulations. We establish that the gradient flow of the FP action is free of tree-level discretization effects to all orders in the lattice spacing, making it classically perfect. This allows us to test the quality of improvement of the FP action, without introducing additional artifacts. We find that discretization effects in gradient-flow observables are highly suppressed and less than 1% up to lattice spacings of 0.14 fm, allowing continuum physics to be extracted from coarse lattices. The quality of improvement achieved motivates the use of the FP action in future gauge theory studies. The advantages of ML-based parameterizations also highlight the possibility of realizing quantum perfect actions in lattice gauge theory.

Kieran Holland

Andreas Ipp

David I. Müller

Urs Wenger

Machine-Learned Renormalization-Group-Improved Gauge Actions and Classically Perfect Gradient Flows

We propose a probabilistic construction of imaginary Liouville field theory based on a real (noncompactified) Gaussian free field. We argue that our theory represents the first explicit Lagrangian field theory that generates the imaginary Dorn, Otto, Zamolodchikov, and Zamolodchikov (DOZZ) constants without requiring a neutrality constraint. The validity of our theory is backed up by exact results on the behavior of the imaginary multiplicative chaos on a circle, and by numerical simulations on the theory on the sphere. In particular, the three point functions of the theory that are in a very good agreement with the imaginary DOZZ constant.

France

Romain Usciati

Colin Guillarmou

Remi Rhodes

Raoul Santachiara

Probabilistic Construction of Noncompactified Imaginary Liouville Field Theory

We propose a mechanism for the generation of magnetic fields on cosmological scales that is operative after recombination. An essential ingredient is an instability (of parametric resonance type) of the electromagnetic field driven by an oscillating pseudoscalar dark-matter field, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>ϕ</mi></mrow></math>, that is coupled to the electromagnetic field tensor via a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>ϕ</mi><mi>F</mi><mo>∧</mo><mi>F</mi></mrow></math> term in the Lagrangian of axion electrodynamics. We find that magnetic fields larger than the observational lower bounds can be generated soon after recombination on scales of 1 Mpc.

Canada

Robert Brandenberger

Jürg Fröhlich

South Korea

Hao Jiao

Cosmological Magnetic Fields from Ultralight Dark Matter

We numerically construct asymptotically global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>AdS</mi><mn>3</mn></msub><mo>×</mo><msup><mi mathvariant="normal">S</mi><mn>3</mn></msup><mo>×</mo><msup><mi mathvariant="normal">T</mi><mn>4</mn></msup></math> black holes in type IIB supergravity, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="double-struck">R</mi><mi>t</mi></msub><mo>×</mo><mrow><mi>SO</mi></mrow><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo><mo>×</mo><mrow><mi>SO</mi></mrow><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>1</mn><msup><mo stretchy="false">)</mo><mn>4</mn></msup></math> symmetry, localized on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">S</mi><mn>3</mn></msup></math> and translationally invariant along the torus. These solutions, with horizons whose spatial cross sections have <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">S</mi><mn>4</mn></msup><mo>×</mo><msup><mi mathvariant="normal">T</mi><mn>4</mn></msup></math> topology, dominate the microcanonical ensemble at low energies. At higher energies, a first-order phase transition occurs to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>BTZ</mi><mo>×</mo><msup><mi mathvariant="normal">S</mi><mn>3</mn></msup><mo>×</mo><msup><mi mathvariant="normal">T</mi><mn>4</mn></msup></math> black holes—possessing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="double-struck">R</mi><mi>t</mi></msub><mo>×</mo><mrow><mi>SO</mi></mrow><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo><mo>×</mo><mrow><mi>SO</mi></mrow><mo stretchy="false">(</mo><mn>4</mn><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>1</mn><msup><mo stretchy="false">)</mo><mn>4</mn></msup></math> symmetry and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">S</mi><mn>1</mn></msup><mo>×</mo><msup><mi mathvariant="normal">S</mi><mn>3</mn></msup><mo>×</mo><msup><mi mathvariant="normal">T</mi><mn>4</mn></msup></math> horizon topology. By the AdS/CFT correspondence, this transition reflects the spontaneous breaking of the SO(4) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi></math> symmetry of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>D</mi><mn>1</mn><mtext>−</mtext><mi>D</mi><mn>5</mn></mrow></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CFT</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> to SO(3). We also compute the expectation value of the scalar operator with lowest conformal dimension in the low-energy phase. Our SO(3)-localized black holes—together with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>1</mn><msup><mrow><mo stretchy="false">)</mo></mrow><mn>2</mn></msup></mrow></math>-localized solutions of Bena et al. [<a href="http://dx.doi.org/10.1007/JHEP10(2025)165">J. High Energy Phys. 10 (2025) 165</a>.]—point to a rich landscape of novel black holes that may approach the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>CFT</mi><mn>2</mn></msub></math> “sparseness bootstrap condition,” and shed light on how macroscopic entanglement in thermal phases encodes microscopic structure via internal directions.

United Kingdom

Óscar J.C. Dias

Jorge E. Santos

Localized <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>×</mo></mrow><msup><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>×</mo><mtext> </mtext><msup><mrow><mi mathvariant="normal">T</mi></mrow><mrow><mn>4</mn></mrow></msup></mrow></math> Black Holes

In quantum systems, purification can map mixed states into pure states and a nonunitary evolution into a unitary one by enlarging the Hilbert space. We establish a connection between the complexities of mixed quantum states and their purification, proposing new inequalities among these complexities. By examining single qubits, two-qubit Werner states, eight-dimensional Gaussian random unitary ensembles, and infinite-dimensional systems, we demonstrate how these relationships manifest across a broad class of systems. We find that the spread complexity of purification of a vacuum state evolving into a thermal state equals the average number of Rindler particles. This complexity is also shown to adhere to the Lloyd-like bound, indicating a further relation to the quantum speed limit. Finally, using mutual Krylov complexity, we observe subadditivity of the Krylov complexities, which contrasts with known results from holographic volume complexity. We put forward Krylov mutual complexity as a diagnosis of a potential gravity dual of Krylov complexities.

Germany

Rathindra Nath Das

Japan

Takato Mori

Krylov Complexity of Purification

We provide evidence that three-party entanglement signals in holography obey a relation that is not satisfied by generalized Greenberger-Horne-Zeilinger (GHZ) states. Using proposed holographic duals for these entanglement signals, we provide a geometric argument establishing this relation. This is the first known inequality on the structure of pure three-party holographic states, and shows that time-symmetric holographic states can never have purely GHZ-like entanglement. We also discuss similar relations for four parties.

Vijay Balasubramanian

Monica Jinwoo Kang

Charlie Cummings

Chitraang Murdia

Simon F. Ross

Purely Greenberger-Horne-Zeilinger–like Entanglement is Forbidden in Holography

The LEGEND Collaboration is searching for neutrinoless double-beta (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math>) decay by operating high-purity germanium detectors enriched in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ge</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>76</mn></mrow></mmultiscripts></mrow></math> in a low-background liquid argon environment. Building on key technological innovations from the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math> decay search based on 61.0 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msubsup><mrow><mn>0.5</mn></mrow><mrow><mo>−</mo><mn>0.2</mn></mrow><mrow><mo>+</mo><mn>0.3</mn></mrow></msubsup><mtext> </mtext><mtext> </mtext></mrow><mi>cts</mi><mo>/</mo><mo stretchy="false">(</mo><mi>keV</mi><mtext> </mtext><mi>ton</mi><mtext> </mtext><mi>yr</mi><mo stretchy="false">)</mo></mrow></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math> decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.8</mn><mo>×</mo><mrow><msup><mn>10</mn><mn>26</mn></msup><mtext> </mtext><mtext> </mtext><mi>yr</mi></mrow></math> on the half-life of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math> decay, reveals no evidence for a signal and sets a new observed lower limit at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>T</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow><mrow><mn>0</mn><mi>ν</mi></mrow></msubsup><mo>&gt;</mo><mn>1.9</mn><mo>×</mo><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>26</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>yr</mi></mrow></mrow></math> (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>β</mi><mi>β</mi></mrow></msub><mo>&lt;</mo><mn>75</mn><mi>–</mi><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>meV</mi></mrow></math>, depending on the adopted nuclear matrix element.

H. Acharya

N. Ackermann

M. Agostini

A. Alexander

C. Andreoiu

G.R. Araujo

F.T. Avignone

M. Babicz

W. Bae

Russia

A.M. Bakalyarov

Italy

M. Balata

A.S. Barabash

P.S. Barbeau

C.J. Barton

L. Baudis

C. Bauer

E. Bernieri

L. Bezrukov

K.H. Bhimani

V. Biancacci

E. Blalock

S.J. Borden

G. Borghi

F. Borra

B. Bos

A. Boston

V. Bothe

R. Bouabid

R. Brugnera

N. Burlac

M. Busch

S. Calgaro

L. Canonica

S. Capra

M. Carminati

R.M.D. Carney

First Results on the Search for Lepton Number Violating Neutrinoless Double-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>β</mi></math> Decay with the LEGEND-200 Experiment