Traditional direct detection experiments lack the sensitivity to probe the sub-GeV dark matter(DM), primarily due to the low energy of the expected nuclear recoils. In this work, we investigate cosmic-ray (CR) upscattering as a mechanism to accelerate DM particles to detectable velocities in underground experiments. By analyzing four models of DM-nucleon interactions – namely scalar, vector, pseudoscalar, and axial-vector mediators – we derive constraints on the coupling parameters using data from the LZ, XENON, and Borexino experiments, covering mediator mass from $$10^{-6}$$ to 1 GeV. As the mediator mass varies, the shift in dominance between momentum transfer and mediator mass leads to a turnover in the constraints around $$10^{-2}$$ – $$10^{-3}~\textrm{GeV}$$ . Our results extend the reach of direct detection into the sub-GeV window and clarify the critical role of momentum dependence in light-mediator scenarios.

China

Yang Yu

Guan-Sen Wang

Bo Zhang

Tian-Peng Tang

Bing-Yu Su

Lei Feng

New constraints on cosmic-ray boosted sub-Gev dark matter via light mediators

Axions and axion-like particles generically appear in extensions of the Standard Model. While many searches assume only a single axion species, there may exist a whole spectrum of multiple such fields. We develop general formulas for axion-photon oscillations in the presence of multiple axions and analyze the implications for experimental searches, including light-shining-through-a-wall experiments, helioscopes and haloscopes. We demonstrate that axion multiplicity can qualitatively alter observational signatures, particularly through coherence and interference effects. Multiple axions can not only enhance signals compared to single axion scenarios, but also suppress them. We show that variations of experimental parameters and searches allow identifying contributions of multiple axions and obtaining information about their properties.

United Kingdom

Arturo Giorgi

Germany

Joerg Jaeckel

France

Sebastian Monath

Japan

Volodymyr Takhistov

Multiple axions in laboratory experiments

<p>We search for the reaction channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>η</mi><mi>η</mi><mi>J</mi><mo>/</mo><mi>ψ</mi></math> in a data sample with center-of-mass energies from 4.226 to 4.950 GeV that was collected by the BESIII detector operating at the Beijing Electron Positron Collider (BEPCII). The data analysis is performed with two different reconstruction methods, exclusive and semi-inclusive, enabling a comparison and combination of the results. Only at a few energy points is a nonzero cross section observed with a statistical significance of more than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>σ</mi></math> using one of the methods. Therefore, the corresponding upper limits of the cross section at the 90% confidence level are determined. The energy-dependent results show clear deviations from the line shape expected from three-body phase space alone. Since the statistical significance for almost all center-of-mass energies is low, the upper limits for the reaction channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>η</mi><mi>η</mi><mi>J</mi><mo>/</mo><mi>ψ</mi></math> also serve as limits for the existence of a possible isospin partner to the charmonium-like isospin triplet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi mathvariant="normal">c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> which decays to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>η</mi></math>.</p>

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Search for the reaction channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>η</mi><mi>η</mi><mi>J</mi><mo>/</mo><mi>ψ</mi></math> and the isospin partner of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> at center-of-mass energies <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>4.226</mn><mtext> </mtext><mi>−</mi><mtext> </mtext><mn>4.950</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>

The new measurement of the $$K^+\rightarrow \pi ^+\nu \bar{\nu }$$ branching ratio by the NA62 collaboration represents an important milestone in precision flavour physics. Under different flavour assumptions on beyond the standard model physics, this decay mode can be related to many other observables with underlying flavour-changing currents, such as $$B\rightarrow K\nu \bar{\nu }$$ or $$B_s\rightarrow \mu \mu $$ , effectively providing an additional handle in our exploration of flavour-violating new physics effects. We study the impact of this new result, under the hypotheses that deviations from the standard model arise from modified $\textit{Z}$ couplings, or from effects in semileptonic interactions. Finally, we review the implications of our scenarios for the yet to be measured partner mode $$K_L\rightarrow \pi ^0\nu \bar{\nu }$$ .

Lukas Allwicher

Marzia Bordone

Implications of $$K\rightarrow \pi \nu \bar{\nu }$$ for new physics in $\textit{B}$ decays

The penguin loop-suppressed $\textit{B}$ → $\textit{ϕK}$ decays are highly sensitive to contributions of hypothetical heavy new particles. Particularly interesting probes for testing the Standard Model and revealing such phenomena are provided by CP violation in the $${B}_{d}^{0}\to \phi {K}_{S}$$ decay. Standard-Model estimates for the corresponding CP-violating observables are theoretically limited by doubly Cabibbo-suppressed penguin contributions. We study these effects using a factorization approach, and provide predictions for CP asymmetries, to be contrasted with future measurements. To gain additional insight into these hadronic effects, we propose the $${B}_{s}^{0}\to \phi {K}_{S}$$ decay as a new channel. We predict the observables for this decay for which currently no measurements exist. By comparing $${B}_{d}^{0}\to \phi {K}_{S}$$ and $\textit{B}$ → $\textit{ϕK}$ , we further derive state-of-the-art constraints on isospin observables within the Standard Model. The same framework enables probing of possible New-Physics contributions, including general effects and those with non-trivial isospin structure. Interesting prospects arise for the high-precision era of flavour physics ahead.

Netherlands

Robert Fleischer

Jelle Groot

K. Vos

CP violation in $\textit{B}$ ($\textit{s}$) $\textit{→ ϕK}$ decays: Standard Model benchmarks and isospin-breaking New Physics

Final states comprising two or more top quarks are important search channels at the Large Hadron Collider for scalar particles predicted in models of physics beyond the Standard Model. While the di-top final state profits from a higher signal cross section, it can be subject to intricate interference patterns. Besides the interference with the large QCD background, in case of the presence of more than one high-mass scalar also large signal–signal interference contributions can occur. We show that in such scenarios it is crucial to account for loop-level mixing for obtaining accurate exclusion bounds. We demonstrate how the interference patterns can obscure the interpretation of possible deviations from the Standard Model expectations. We show that the four-top final state, while giving rise to a smaller signal cross section, provides important complementary information due to its much smaller signal–background interference contributions. Thus, the results obtained from the four-top final state can be instrumental for pinpointing the underlying new physics scenario.

Henning Bahl

Philipp Gadow

Romal Kumar

Krisztian Peters

Cyprus

Panagiotis Stylianou

Georg Weiglein

Complementarity of di-top and four-top searches in interpreting possible signals of new physics

The need to map parton-level processes to color-neutral hadrons in a way that respects quark-hadron duality arises in several areas of physics, including in the semileptonic decays of $\textit{B}$ mesons. Integrated over large regions of phase space, the quark-level and hadron-level quantities are expected to be equal. However, the breakdown of duality is manifest at low hadron-system invariant masses, where discrete resonances dominate. In practice, this means independent simulations of decays to low-lying resonances and to higher-mass hadronic systems must be merged into a coherent model. We present a novel method to combine these resonant and non-resonant components in simulations of inclusive $\textit{b}$ → $\textit{uℓν}$ decays that uses an optimal transport algorithm. The method currently used in measurements of inclusive semileptonic $\textit{B}$ decay branching fractions introduces unphysical features in kinematic spectra such as large discontinuities and negative yields. The optimal transport method solves both of these issues and can be easily implemented in experimental studies of $\textit{B}$ → $\textit{X}$ $\textit{ℓν}$ decays.

Canada

Philipp Horak

Robert Kowalewski

Tommy Martinov

Mapping quark-level kinematics to hadrons in a new hybrid model of semileptonic $\textit{B}$ meson decays

We study the weak magnetic and electric dipole moments of the $\textit{τ}$ lepton as precision tests of the Standard Model (SM) and probes of heavy New Physics (NP). We present an updated SM prediction for the $\textit{τ}$ weak magnetic dipole moment at one loop, including a careful assessment of theoretical uncertainties from electroweak scheme dependence. Working within the SM Effective Field Theory, we derive comprehensive current constraints on the $\textit{τ}$ dipole operators from a combination of observables: the $\textit{τ}$ weak and electromagnetic dipole moments, high-mass Drell-Yan tails at the LHC, $\textit{Z}$ partial decay widths, and the electron electric dipole moment. Finally, we assess the prospects of measuring the SM value of the $\textit{τ}$ weak magnetic moment at the FCC-$\textit{ee}$ Tera-$\textit{Z}$ run, and project the sensitivities of the leading observables to heavy NP at FCC-$\textit{ee}$ and HL-LHC, incorporating informed assumptions about improvements of systematic uncertainties. We find that the $\textit{τ}$ weak dipole moments are already among the leading probes of the $\textit{τ}$ dipole operators, and will become increasingly dominant at future colliders.

Slovenia

Nejc Košnik

Zachary Polonsky

Aleks Smolkovič

Current and future constraints on heavy New Physics from $\textit{τ}$ weak dipole moments

Anomalies in the non-leptonic $$\bar{B}^0\rightarrow D^{(*)+}K^{(*)-}$$ and $$\bar{B}^0_s\rightarrow D^{(*)+}_s\pi ^-$$ decays may be an indication of physics beyond the Standard Model, but the large deviations require strongly coupled new physics that should be visible at colliders. We explore three new directions that could lead to viable new physics models, performing a detailed collider study to examine the possible weakening of previously known constraints on additional $$SU(2)_L$$ doublets. Our results show that, despite the difficulty of probing $$t\bar{t}$$ final states, increasing the branching ratio to this decay mode does not significantly weaken the bounds on weak doublet scalars, as additionally existing charged Higgs searches are equally strong. Beyond this, we analyse a potentially large breakdown of QCD factorisation by including large-power corrections to $\textit{B}$ decays, and the effect of diluting collider searches with multi-scalar extensions. We find that these typical model-building routes for constructing a viable scenario remain constrained by collider measurements, indicating that these non-leptonic anomalies remain among the most puzzling discrepancies from the SM.

Jack Araz

Christoph Englert

Matthew Kirk

Gilberto Tetlalmatzi-Xolocotzi

New insights into the $$b\rightarrow c \bar{u}q$$ puzzle through Top–Bottom synergies

<p>We determine the future sensitivity of the TRIDENT neutrino telescope to dark matter annihilation in the Galactic Center. By applying the full detector design and assuming an Navarro-Frenk-White (NFW) halo profile, we show that TRIDENT will probe annihilation cross section down to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">⟨</mo><mi>σ</mi><mi>v</mi><mo stretchy="false">⟩</mo><mo>≈</mo><mn>5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>27</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mn>3</mn></msup><mtext> </mtext><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> for 10 TeV dark matter, falling below the thermal freeze-out benchmark. The analysis is carried out with all-flavor neutrino interactions, where we demonstrate that cascade events, primarily due to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mrow><mi>e</mi><mo>,</mo><mi>τ</mi></mrow></msub></math>, show greater sensitivity to a dark matter signal compared to the more commonly studied track events. Furthermore, we highlight the impact of a previously overlooked background, Galactic neutrinos produced from interactions between hadronic cosmic rays and interstellar gas. We find dark matter sensitivities are more strongly degraded in the high energy region above <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, with a maximal weakening of approximately a factor of 2. This effect remains smaller than the uncertainty associated with the dark matter density profile but can nonetheless mimic a positive annihilation signal. We contextualize these results with a concrete particle model and show that TRIDENT will be able to probe the most interesting untested parts of parameter space.</p>