Calculations truncated at a fixed order in perturbation theory are accompanied by an associated theoretical uncertainty, which encodes the missing higher orders (MHOU). This is typically estimated by a scale variation procedure, which has well-known shortcomings. In this work, we propose a simple prescription to directly encode the missing higher order terms using theory nuisance parameters (TNPs) and estimate the uncertainty by their variation. We study multiple processes relevant for Large Hadron Collider physics at next-to-leading and next-to-next-to-leading order in perturbation theory, obtaining MHOU estimates for differential observables in each case. In cases where scale variations are well-behaved we are able to replicate their effects using TNPs, while we find significant improvement in cases where scale variation typically underestimates the uncertainty.

United Kingdom

Matthew A. Lim

Poland

Rene Poncelet

Robust estimates of theoretical uncertainties at fixed-order in perturbation theory

The flavor-changing neutral current semileptonic decays of <italic>B</italic> mesons provide an excellent platform for indirectly probing New Physics (NP) beyond the Standard Model (SM). Recent measurements of lepton flavor universality (LFU) ratios such as <italic>R<inf>K</inf></italic>, <math altimg='si22.svg'><msub><mi>R</mi><msup><mi>K</mi><mo>*</mo></msup></msub></math>, and <italic>R<inf>&#981;</inf></italic> are consistent with SM predictions, thereby reducing earlier hints of LFU violation. Nevertheless, notable tensions persist in individual branching fractions&#8212;for instance <math altimg='si38.svg'><mrow><mi mathvariant='script'>B</mi><mo>(</mo><msup><mi>B</mi><mo>+</mo></msup><mo>&#8594;</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup><mo>)</mo></mrow></math> and <math altimg='si50.svg'><mrow><mi mathvariant='script'>B</mi><mo>(</mo><msup><mi>B</mi><mo>+</mo></msup><mo>&#8594;</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup><mo>)</mo></mrow></math>, which deviate at the 4 <italic>&#963;</italic>&#8211;5 <italic>&#963;</italic> level in the low- <italic>q</italic> 2 region ([1.1,6] GeV 2). Similarly, the angular observable <math altimg='si10.svg'><msubsup><mi>P</mi><mn>5</mn><mo>&#8242;</mo></msubsup></math> in <math altimg='si8.svg'><mrow><mi>B</mi><mo>&#8594;</mo><msup><mi>K</mi><mo>*</mo></msup><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup></mrow></math> shows a 3.3 <italic>&#963;</italic> deviation, while <math altimg='si128.svg'><mrow><mi mathvariant='script'>B</mi><mo>(</mo><msub><mi>B</mi><mi>s</mi></msub><mo>&#8594;</mo><mi>&#981;</mi><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup><mo>)</mo></mrow></math> departs from the SM by 3.6 <italic>&#963;</italic>. Although such discrepancies could in principle originate from underestimated hadronic effects, they may also indicate possible NP contributions. In this work, we perform a global fit to the latest <math altimg='si16.svg'><mrow><mi>b</mi><mo>&#8594;</mo><mi>s</mi><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math> data within the framework of dimension-6 SMEFT operators. Our analysis systematically incorporates hadronic uncertainties from form factors, non-factorizable corrections, and input parameters, thereby providing a balanced assessment of the NP interpretation. We allow for NP contributions not only in <math altimg='si129.svg'><mrow><mi>b</mi><mo>&#8594;</mo><mi>s</mi><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup></mrow></math> transitions but also in <math altimg='si130.svg'><mrow><mi>b</mi><mo>&#8594;</mo><mi>s</mi><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup></mrow></math> channels, thus testing both lepton flavor universal (LFU) and lepton flavor universality violating (LFUV) NP scenarios. The interplay between these possibilities yields distinctive signatures in branching fractions, angular observables, and &#916;-observables, offering a comprehensive view of the current flavor anomalies.

India

Md Isha Ali

Utpal Chattopadhyay

Dilip Kumar Ghosh

N. Rajeev

Constraints on lepton flavor universal and non-universal new physics in <math altimg='si127.svg'><mrow><mi>b</mi><mspace width='0.16em' /><mo>&#8594;</mo><mspace width='0.16em' /><mi>s</mi><mspace width='0.16em' /><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math> decays: A global SMEFT survey

High-energy muon beam dump experiments are powerful probes of new physics models beyond the Standard Model, particularly those involving flavor-dependent interactions. We demonstrate the potential of muon beam dump by placing strong constraints on three new physics models utilizing data from the recent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>NA</mi><mrow><mn>64</mn><mi>μ</mi></mrow></mrow></math> experiment: (1) axions coupling to photons, (2) axions coupling to muons, and (3) a dark sector mediated by a massless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math> gauge boson. The new particles can be identified from the significant missing energy as the invisible channel, or the distinct energy deposition signature as the visible channel. We find that the current <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>NA</mi><mrow><mn>64</mn><mi>μ</mi></mrow></mrow></math> data do not yet probe new parameter region on axion-photon coupling, while excluding new parameter space for the axion-muon coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>μ</mi><mi>μ</mi></mrow></msub><mo>≳</mo><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mrow><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> and the axion mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><mn>0.2</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. For the dark sector, the current data provide stringent constraints that surpass existing ones by nearly one order of magnitude. The data from the 2023 <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>NA</mi><mrow><mn>64</mn><mi>μ</mi></mrow></mrow></math> run, once available, will be capable of excluding new axion-photon coupling parameter space and probing the flavor structure of new physics, with more sensitivity advancement expected in near future runs.

China

Haotian Li

Zuowei Liu

Ningqiang Song

Probing axion and flavored new physics with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>NA</mi><mrow><mn>64</mn><mi>μ</mi></mrow></mrow></math> experiment

We study the sensitivity of COHERENT-like experiments to non-standard contributions within the so-called $\textit{ν}$WEFT framework. The latter is the most general low-energy effective field theory that includes not only the light SM fields but also additional right-handed Dirac neutrinos. Our analysis includes for the first time flavor-general New Physics effects in neutrino production (pion and muon decays) and neutrino detection (through Coherent Elastic Neutrino-Nucleus Scattering). Despite the generality, the results can be written in compact form and are easy to implement in existing or future analyses using effective nuclear charges. We use current COHERENT data to set constraints on the corresponding effective operators, and we estimate the sensitivity of future measurements.

Germany

Víctor Bresó-Pla

Spain

Sergio Cruz-Alzaga

Martín González-Alonso

Suraj Prakash

EFT analysis of new physics at COHERENT with Dirac neutrinos

We present a novel application of a qubit-coupled phonon detector to search for new physics, e.g., ultralight dark matter (DM) and high-frequency gravitational waves. The detector, motivated by recent advances in quantum acoustics, is composed of superconducting transmon qubits coupled to high-overtone bulk acoustic resonators (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>h</mi><mi>BARs</mi></mrow></math>) and operates in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mtext> </mtext><mi>GHz</mi><mo>−</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi>GHz</mi></mrow></math> frequency range. New physics can excite <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">μ</mi><mi>eV</mi><mo stretchy="false">)</mo></math> phonons within the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>BAR</mi></math>, which are then converted to qubit excitations via a transducer. We detail the design, operation, backgrounds, and expected sensitivity of a prototype detector, as well as a next-generation detector optimized for new physics signals. We find that a future detector can complement current haloscope experiments in the search for both dark photon DM and high-frequency gravitational waves. Lastly, we comment on such a detector’s ability to operate as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">μ</mi><mi>eV</mi><mo stretchy="false">)</mo></mrow></math> athermal phonon sensor for sub-GeV DM detection.

United States

Ryan Linehan

Tanner Trickle

Christopher R. Conner

Sohitri Ghosh

Tongyan Lin

Austria

Mukul Sholapurkar

Andrew N. Cleland

Listening for new physics with quantum acoustics

NuMI Off-axis <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>e</mi></msub></math> Appearance (NOvA) experiment is an ongoing long-baseline neutrino oscillation experiment. The primary channels of interest are the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>e</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>e</mi></msub></math> appearance, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>μ</mi></msub></math> disappearance channels analyzed in the energy window <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>&lt;</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>&lt;</mo><mn>4</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. However, NOvA far detector sees nontrivial high-energy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>e</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>e</mi></msub></math> events in the energy range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>&lt;</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>&lt;</mo><mn>20</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. These high-energy events provide us with an opportunity to investigate the subleading new physics scenarios. In this context, we study the sensitivity of the NOvA experiment to constrain the nonstandard interaction (NSI) parameters and environmental decoherence parameters. We observe that by including high energy events (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>signal</mi><mo>+</mo><mtext>background</mtext></mrow></math>) the degeneracy around <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ε</mi><mrow><mi>e</mi><mi>τ</mi></mrow></msub><mo>∼</mo><mn>1.6</mn></math> can be removed throughout the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>e</mi><mi>τ</mi></mrow></msub></math> range. Further, we examine the role of signal versus beam background events in removing this degeneracy. In addition, we constrain the decoherence parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Γ</mi></math> considering events from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1</mn><mo>&lt;</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>ν</mi></mrow></msub><mo>&lt;</mo><mn>20</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>. Later, assuming the presence of decoherence in nature we obtain the allowed regions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>θ</mi><mn>23</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math> plane.

Chinmay Bera

K.N. Deepthi

Probing new physics scenarios using high energy events at the NOvA far detector

Based on available experimental results on $ \chi _{cJ}(J=0,1,2) $ decays, we investigated the $ \chi_{cJ}\to PP $ , $ VV $ , $ PV $ , and $ PT $ decays using the $\textit{SU}$(3) flavor symmetry/breaking approach, where $\textit{P}$, $\textit{V}$, and $\textit{T}$ denote light pseudoscalar, vector, and tensor mesons, respectively. With the decay amplitude relations determined by $\textit{SU}$(3) flavor symmetry/breaking, we present the branching ratios for all $ \chi_{cJ}\to PP $ and $ \chi_{cJ}\to VV $ modes, including those without experimental data. While theoretical considerations strongly suppress or even forbid most $ \chi_{cJ}\to PV $ and $ PT $ decays, we also provide quantitative predictions constrained by existing experimental data. Our results are expected to be accessible in future experiments at BESIII and the planned Super Tau-Charm Facility.

Bo Lan

Qin-Ze Song

Jin-Huan Sheng

Yi Qiao

Ru-Min Wang

Study of χ$_{cJ}$ ($\textit{J}$ = 0,1,2) decays to light meson pairs based on $\textit{SU}$(3) flavor symmetry/breaking analysis * Supported by the National Natural Science Foundation of China (12175088, 12305100, 12365014) and Graduate Innovation Fund Project of Jiangxi Provincial Department of Education (YJS2024091)

Based on a sample of $2.7\times10^{9}$ $\psi(3686)$ events collected by the BESIII detector operating at the BEPCII collider, the decay $\psi(3686)\to\gamma\chi_{cJ}, \chi_{cJ}\to\eta\eta\eta^{\prime}$ is analyzed. The decay modes $\chi_{c1}$ and $\chi_{c2}\to\eta\eta\eta^{\prime}$ are observed for the first time, and their corresponding branching fractions are determined to be ${\cal{B}}(\chi_{c1}\to\eta\eta\eta^{\prime}) = $ $ (1.40\, \pm 0.13\, (\text{stat.}) \pm 0.09\, (\text{sys.})) \times 10^{-4}$ and ${\cal{B}}(\chi_{c2}\to\eta\eta\eta^{\prime}) = (4.18\, \pm 0.84\, (\text{stat.}) \pm 0.48\, (\text{sys.})) \times 10^{-5}$ . An upper limit on the branching fraction of $\chi_{c0}\to\eta\eta\eta^{\prime}$ is set as $2.59 \times 10^{-5}$ at a 90% confidence level (CL). A partial wave analysis (PWA) of the decay $\chi_{c1}\to\eta\eta\eta^{\prime}$ is performed to search for the $1^{-+}$ exotic state $\eta_1(1855)$ . The PWA result indicates that the structure in the $\eta\eta^{\prime}$ mass spectrum is attributed to $f_0(1500)$ , while in the $\eta\eta$ mass spectrum, it is attributed to the $0^{++}$ phase space. The upper limit of ${\cal{B}}(\chi_{c1}\to\eta_{1}(1855)\eta) \cdot {\cal{B}}(\eta_{1}(1855)\to\eta\eta^{\prime}) \lt $ $ 9.79 \times 10^{-5}$ is set based on the PWA at 90% CL.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

O. Bakina

Y. Ban

H.R. Bao

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

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

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 $\textit{η}$ $_{1}$(1855) in $\textit{χ}$ $\textit{cJ}$ → $\textit{ηηη}$′ decays * Supported in part by National Key R&D Program of China (2023YFA1606000, 2023YFA1606704); National Natural Science Foundation of China (NSFC) (11635010, 11935015, 11935016, 11935018, 12025502, 12035009, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; CAS (YSBR-101); 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; Agencia Nacional de Investigación y Desarrollo de Chile (ANID), Chile (ANID PIA/APOYO AFB230003); German Research Foundation DFG (FOR5327); Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299); Ministry of Development of Turkey (DPT2006K-120470); National Research Foundation of Korea ( NRF-2022R1A2C1092335); National Science and Technology fund of Mongolia; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources Institutional Development, Research and Innovation of Thailand ( B50G670107); Polish National Science Centre (2024/53/B/ST2/00975); Swedish Research Council (2019.04595); U. S. Department of Energy (DE-FG02-05ER41374)

A complete assessment of any dark matter model requires confronting its low-energy phenomenology with its high-scale theoretical viability. We undertake such a dual analysis for a class of two-component scalar dark matter models stabilized by $$\mathbb {Z}_{2n}$$ symmetries, specifically the $$\mathbb {Z}_4$$ , $$\mathbb {Z}_6(23)$$ , and $$\mathbb {Z}_6(13)$$ frameworks. Each model is tested against the latest observational data, including the Planck relic abundance and stringent direct detection limits from the LUX-ZEPLIN (LZ) experiment. Simultaneously, we evaluate their theoretical integrity up to the GUT and Planck scales by enforcing vacuum stability and perturbative unitarity with one-loop Renormalization Group Equations. This combined approach reveals a rich and varied landscape of possibilities. We demonstrate that the $$\mathbb {Z}_4$$ model offers a broadly viable parameter space sustained by efficient semi-annihilation. In stark contrast, the $$\mathbb {Z}_6(13)$$ scenario is shown to be highly fine-tuned, with solutions confined to the Higgs resonance. Our most significant finding concerns the $$\mathbb {Z}_6(23)$$ model: we show that an apparent conflict between experimental data and high-scale consistency is resolved when the model is viewed as an effective field theory, yielding a concrete prediction for new physics at or below the $$10^6$$ GeV scale. This work provides a definitive guide to the viability of these $$\mathbb {Z}_{2n}$$ scenarios and serves as a compelling demonstration of how high-energy consistency checks can yield crucial insights into the nature of dark matter.

Brazil

J. Carvalho-Corrêa

I. Pereira

B. Sánchez-Vega

A. Viglioni

Theoretical and experimental constraints on $$\mathbb {Z}_{2n}$$ multi-component dark matter models

If sub-GeV dark matter (DM) annihilates into charged particles such as $$e^+ e^-$$ , $$\mu ^+ \mu ^-$$ , or $$\pi ^+ \pi ^-$$ , it generates an additional source of electrons and positrons in the cosmic ray (CR) population within our Milky Way. During propagation, these secondary electrons and positrons undergo reacceleration processes, boosting their energies to the GeV scale. Observatories like AMS-02 can detect these high-energy particles, enabling constraints on the properties of sub-GeV DM. By analyzing AMS-02 electron and positron data, the 95% upper limits on the DM annihilation cross-section have been established in the range of $$10^{-28}$$ to $$10^{-27}$$ cm $$^3\,$$ s $$^{-1}$$ , corresponding to DM masses ranging from 100 MeV to 1 GeV. Meanwhile, MeV telescopes will provide complementary constraints on DM properties by detecting photon emissions from such annihilation processes. Notably, the sensitivity of future MeV gamma-ray observatories is projected to approach or match the constraints derived from CR data.