We perform a model-independent study of new physics effects in the Higgs decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mo stretchy="false">→</mo><mi mathvariant="normal">ϒ</mi><mi>γ</mi></math>, focusing on scenarios that spoil the accidental cancellation between the direct and indirect amplitudes. After imposing all existing constraints from Higgs production and decay measurements, we find that a wrong-sign <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> coupling is the only viable scenario capable of enhancing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mo stretchy="false">→</mo><mi mathvariant="normal">ϒ</mi><mi>γ</mi></math> decay width by nearly 2 orders of magnitude. Therefore, an observation of a significantly enhanced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mo stretchy="false">→</mo><mi mathvariant="normal">ϒ</mi><mi>γ</mi></math> rate at the LHC or future colliders would provide unambiguous evidence for a wrong-sign <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> coupling, directly pointing to the presence of an extended Higgs sector.

India

Portugal

Aditya Batra

South Korea

Sanjoy Mandal

Rahul Srivastava

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mo stretchy="false">→</mo><mi mathvariant="normal">ϒ</mi><mi>γ</mi></math> decay: Smoking gun signature of a wrong-sign <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> coupling

In Friedmann cosmology with Einstein–Cartan torsion, the homogeneous torsion mode compatible with a separately conserved matter sector scales as $$\Phi \propto a^{-3}$$ and enters the Friedmann constraint as a stiff component of negative energy density, $$-3\Phi ^{2}\propto a^{-6}$$ . It has recently been claimed that this mode rescues the Hubble radius as an infrared cutoff for holographic dark energy, producing late-time acceleration and a phantom-divide crossing of possible relevance to DESI. We show that it cannot. With the Hubble cutoff the holographic density drops out of the deceleration parameter, and the only accelerating regime is the transient window $$\bar{a}\le a<4^{1/3}\bar{a}$$ around the torsion bounce at $$H(\bar{a})=0$$ ; placing that window at observable redshifts would force the Hubble rate to vanish in our recent past, against the measured expansion history. Requiring a viable history yields nested upper bounds on $$\Omega _{\Phi }\equiv (\Phi _{0}/H_{0})^{2}$$ : fitting the official DESI DR2 BAO likelihood gives $$\Omega _{\Phi }<8.7\times 10^{-4}$$ ( $$95\%$$ CL), the existence of a spectroscopically confirmed galaxy at $$z=14.32$$ gives $$8.4\times 10^{-5}$$ , the CMB gives $$3.1\times 10^{-10}$$ , and Big Bang nucleosynthesis gives $$5\times 10^{-24}$$ . Today’s imprint on the dark energy equation of state, $$|1+\omega _{0}|\le 2\Omega _{\Phi }/\Omega _{\Lambda }$$ , falls short of the DESI preference by two orders of magnitude at best and twenty-two at worst, and on the phantom side. In the Granda–Oliveros cutoff, torsion deepens rather than prevents the big-rip singularity. An appendix derives the Friedmann pair from the Einstein–Cartan field equations and shows that the $$a^{-3}$$ scaling is the kinematics of a diluting spin fluid; escaping the no-go requires breaking exactly that.

Chile

Fernando Izaurieta

Samuel Lepe

Cristian Quinzacara

No late-time role for adiabatic torsion: a no-go result for Hubble-cutoff holographic dark energy in Einstein–Cartan cosmology

We present the design and the sensitivity reach of the qubit-based light dark matter detection experiment. We propose the novel two-chip design to reduce signal dissipation, with quantum parity measurement to enhance single-phonon detection sensitivity. We demonstrate the performance of the detector with full phonon and quasiparticle simulations. The experiment is projected to detect <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≳</mo><mn>30</mn><mtext> </mtext><mtext> </mtext><mi>meV</mi></math> energy deposition with nearly 100% efficiency and high energy resolution. The sensitivity to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>χ</mi></msub><mo>≳</mo><mn>0.01</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> dark matter scattering cross section is expected to be advanced by orders of magnitude for both light and heavy mediators, and similar improvements will be achieved for axion and dark photon absorption in the 0.04–0.2 eV mass range.

China

Xuegang Li

Yuxiang Liu

Jing Shu

Ningqiang Song

Yidong Song

Junhua Wang

Yue-Liang Wu

Tiantian Zhang

Yu-Feng Zhou

Novel light dark matter detection with a quantum parity detector using qubit arrays

This paper investigates how to extract energy from a non-Kerr rotating spacetime with an anomalous quadrupole moment via the Comisso–Asenjo magnetic reconnection mechanism. Unlike many other rotating spacetimes, this spacetime possesses closed timelike curves, and the corresponding spacetime regions must be excluded when extracting energy. After introducing the event horizon, ergosphere, and closed timelike curves of this spacetime, we deeply analyze the energy per unit enthalpy at infinity for accelerated and decelerated plasmas, the allowed region for energy extraction, and the power and efficiency of energy extraction. The results show that energy extraction is possible for both positive and negative anomalous quadrupole moments, but a positive and small anomalous quadrupole moment corresponds to higher power and efficiency of energy extraction.

Ke Wang

Xiao-Xiong Zeng

Extracting energy from a non-Kerr rotating spacetime with an anomalous quadrupole moment via magnetic reconnection

We investigate the holographic superfluid dynamics subjected to external rotation on a spherical geometry. Through a linear perturbation analysis, we identify several dynamically unstable phases in the phase diagram, each characterized by distinct unstable modes. Employing fully nonlinear numerical simulations, we further demonstrate that these unstable modes generically drive the system into vortex–antivortex configurations with definite winding numbers, determined by the symmetry of the corresponding unstable modes.

Chang-Xu Yan

Hao-Ran Chang

Meng Gao

Yu Tian

Hongbao Zhang

Formation of holographic vortex in a rotating shell-shaped superfluid

We compute the vacuum expectation value of the stress-energy tensor of a scalar field on a product spacetime composed of an FLRW background times a compact dimension (ℳ × 𝒮 ), where the size of the latter is allowed to vary with time. We modify the standard adiabatic regularization prescription to obtain analytic expressions for both $\textit{d}$ = 3 and $\textit{d}$ = 4. In the massless and conformally coupled limit, the leading order time-dependent results are consistent with known time-independent Casimir contributions. Furthermore, in this limit, the higher-order time-dependent corrections, when the FLRW and compact-dimension scale factors coincide, match known results for (1 + $\textit{d}$)-dimensional FLRW spacetime.

United States

Anamitra Paul

Sonia Paban

Stress-energy tensor of a scalar field on a product spacetime with a time-dependent compact dimension

We investigate the strong gravitational lensing and shadow of a Schwarzschild–MOG black hole in a homogeneous plasma, adopting the constant-coupling, static branch of scalar–tensor–vector gravity. Analytical expressions for the strong-deflection limit coefficients <math altimg='si1.svg'><mover><mrow><mi>a</mi></mrow><mo stretchy='true'>&#8254;</mo></mover></math> and <math altimg='si2.svg'><mover><mrow><mi>b</mi></mrow><mo stretchy='true'>&#8254;</mo></mover></math>, as well as the deflection angle <italic>&#945;<inf>p</inf></italic>( <italic>b</italic>), are obtained. The deflection angle increases with the MOG parameter but decreases in the presence of plasma. Numerical estimation of the lensing observables, including the angular position <italic>&#952;</italic> <inf>&#8734;</inf>, angular image separation <math altimg='si4.svg'><mover><mrow><mi>s</mi></mrow><mo stretchy='true'>&#8254;</mo></mover></math>, flux ratio <math altimg='si5.svg'><mi mathvariant='script'>R</mi></math>, and leading order time delay between the first and second relativistic images <math altimg='si6.svg'><mrow><mstyle mathvariant='normal'><mi>&#916;</mi></mstyle><msubsup><mi>T</mi><mrow><mn>21</mn></mrow><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow></msubsup></mrow></math>, is carried out by modeling the supermassive compact object Sgr A*. It is observed that <italic>&#952;</italic> <inf>&#8734;</inf> and leading-order time delay increase with the MOG parameter <italic>&#945;</italic> at fixed source mass <italic>M</italic>, but decrease at fixed asymptotic metric mass <math altimg='si13.svg'><mrow><msub><mi>M</mi><mtext>ADM</mtext></msub><mo linebreak='goodbreak'>=</mo><mrow><mo>(</mo><mn>1</mn><mo linebreak='badbreak'>+</mo><mi>&#945;</mi><mo>)</mo></mrow><mi>M</mi></mrow></math>. Their increase with the plasma parameter <italic>&#963;</italic> persists under both mass conventions, whereas the flux ratio decreases with increasing values of both the MOG and plasma parameters. We also investigate black hole shadows and find that the shadow radius increases in the presence of homogeneous plasma. This comparison separates mass-scale contributions from the geometrical deformation of the Reissner&#8211;Nordstr&#246;m-type background. The results provide a theoretical benchmark for dispersive strong-field lensing rather than a direct model of the observed Sgr A* emission.

Rukkiyya V․ P․

Sini R․

Strong gravitational lensing and the shadow of a Schwarzschild MOG black hole in a homogeneous plasma

Within a well-motivated 3-Higgs doublet model, in which the extended dark sector accommodates CP violation, we analyse the electroweak phase transition (EWPT) at one- and two-loop order. We show the importance of higher loop calculations in EWPT analyses and identify the regions of the parameter space of our model where EWPT is of first order while in agreement with all theoretical and experimental bounds, including Dark Matter relic density and direct and indirect searches.

Finland

Ireland

Venus Keus

United Kingdom

Lucy Lewitt

Jasmine Thomson-Cooke

Electroweak phase transition enhanced by a CP-violating dark sector

This Letter presents a measurement of prompt charged-particle production in proton-oxygen interactions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><msub><mi>s</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>9.62</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> center-of-mass energy with the ATLAS detector, corresponding to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>634</mn><mtext> </mtext><mtext> </mtext><mi>μ</mi><mrow><msup><mrow><mi mathvariant="normal">b</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math> of integrated luminosity. A total of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>246</mn><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup></math> selected events have at least one track with transverse momentum <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub><mo>&gt;</mo><mn>500</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> and pseudorapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>η</mi><mo stretchy="false">|</mo><mo>&lt;</mo><mn>2.5</mn></math>. The measured fiducial proton-oxygen cross section is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>σ</mi><mrow><mi>fid</mi><mo>.</mo></mrow><mrow><mi>p</mi><mi mathvariant="normal">O</mi></mrow></msubsup><mo>=</mo><mn>396</mn><mo>±</mo><mn>6</mn><mo stretchy="false">(</mo><mrow><mi>exp</mi><mo>.</mo></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>9</mn><mo stretchy="false">(</mo><mrow><mi>lumi</mi><mo>.</mo></mrow><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><mi>mb</mi></math> and the extrapolated inelastic proton-air cross section is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>σ</mi><mrow><mi>inel</mi><mo>.</mo></mrow><mrow><mi>p</mi><mo>+</mo><mi>air</mi></mrow></msubsup><mo>=</mo><mn>406</mn><mo>±</mo><mn>6</mn><mo stretchy="false">(</mo><mrow><mi>exp</mi><mo>.</mo></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>9</mn><mo stretchy="false">(</mo><mrow><mi>lumi</mi><mo>.</mo></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>28</mn><mo stretchy="false">(</mo><mrow><mi>th</mi><mo>.</mo></mrow><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><mi>mb</mi></math>. Measurements of charged-particle multiplicity, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math> distributions are an order-of-magnitude more precise than differences between hadronic-interaction models. These results enable improved modeling of cosmic-ray air showers, which is important for astroparticle physics.

France

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N.J. Abicht

S.H. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Italy

B.S. Acharya

A. Ackermann

Switzerland

J. Ackerschott

C. Adam Bourdarios

Poland

L. Adamczyk

S.V. Addepalli

M.J. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A.A. Affolder

Y. Afik

Spain

M.N. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

A. Ahmad

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

Sweden

T.P.A. Åkesson

Japan

D. Akiyama

N.N. Akolkar

S. Aktas

G.L. Alberghi

Canada

J. Albert

U. Alberti

P. Albicocco

S. Alderweireldt

Z.L. Alegria

CERN

M. Aleksa

I.N. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

H.M.J. Ali

S. Ali

S.W. Alibocus

South Africa

M. Aliev

G. Alimonti

C. Allaire

B.M.M. Allbrooke

D.R. Allen

J.S. Allen

J.F. Allen

Australia

C.S. Alley

E.R. Almazan

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

A. Alvarez Fernandez

M. Alves Cardoso

M.G. Alviggi

M. Aly

Brazil

Y. Amaral Coutinho

C. Amelung

M. Amerl

T. Amezza

B. Amini

K. Amirie

A. Amirkhanov

D. Amperiadou

S. An

C. Anastopoulos

T. Andeen

J.K. Anders

A.C. Anderson

A. Andreazza

S. Angelidakis

A. Angerami

A.V. Anisenkov

A. Annovi

C. Antel

E. Antipov

M. Antonelli

F. Anulli

M. Aoki

T. Aoki

M.A. Aparo

L. Aperio Bella

M. Apicella

C. Appelt

A. Apyan

M. Arampatzi

Measurement of Charged-Particle Production in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><msub><mi>s</mi><mrow><mi>NN</mi></mrow></msub></msqrt><mo>=</mo><mn>9.62</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> Proton-Oxygen Collisions as a Probe of Cosmic-Ray Air Showers with the ATLAS Detector

A pseudoscalar resonance structure, denoted as the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math>, was recently discovered by the COMPASS Collaboration in the scattering reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>−</mo></msup><mo>+</mo><mi>p</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mo>−</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup><mo>+</mo><mi>p</mi></math>. If the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> is a genuine state, there are three observed pseudoscalar strange mesons, namely the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1460</mn><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1830</mn><mo stretchy="false">)</mo></math>, in the 1.0–2.0 GeV region. However, within the conventional quark model, only the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mrow><mmultiscripts><mrow><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mprescripts></mprescripts><none></none><mrow><mn>1</mn></mrow></mmultiscripts></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mrow><mmultiscripts><mrow><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mprescripts></mprescripts><none></none><mrow><mn>1</mn></mrow></mmultiscripts></mrow></math> strange meson states are expected in this energy region. Therefore, at least one of these states should be interpreted as an exotic candidate. In this work, we study the spectrum of strange mesons systematically, and find that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1460</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1830</mn><mo stretchy="false">)</mo></math> are good candidates of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mrow><mmultiscripts><mrow><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mprescripts></mprescripts><none></none><mrow><mn>1</mn></mrow></mmultiscripts></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mrow><mmultiscripts><mrow><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mprescripts></mprescripts><none></none><mrow><mn>1</mn></mrow></mmultiscripts></mrow></math> strange mesons, respectively. A further investigation of their strong decays also supports this assignment. Furthermore, we note that the production mechanism of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> is similar to that of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>π</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1600</mn><mo stretchy="false">)</mo></math>, which has been widely regarded as a hybrid meson candidate. We investigate the strong decays of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> within a constituent gluon model by treating it as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>0</mn><mo>−</mo></msup></math> strange hybrid meson and find that the results support the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> as a hybrid state. Finally, we identify several important decay modes of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> that may be used in future experiments to test whether it contains the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>n</mi><msub><mrow><mmultiscripts><mrow><mi>S</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>1</mn></mrow></mmultiscripts></mrow><mrow><mn>0</mn></mrow></msub></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>n</mi><mo>=</mo><mn>2</mn></math> and 3) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover></math> component. We also suggest BESIII to search for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> state through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>K</mi><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>K</mi><msubsup><mi>K</mi><mn>0</mn><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>1430</mn><mo stretchy="false">)</mo><mi>π</mi><mo stretchy="false">→</mo><mi>K</mi><mi>K</mi><mi>π</mi><mi>π</mi></math> process.

Bing Chen

Ri-Qing Qian

Xiang Liu

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">(</mo><mn>1690</mn><mo stretchy="false">)</mo></math> signal from COMPASS as a strange hybrid state