In gravitational lensing under the weak-field approximation, the usual viewpoint is that light bending measures how a ray deviates from a straight line in Euclidean space. In this work, we take the opposite perspective: we ask how a straight line bends in a curved space, such as optical geometry–that is, how it deviates from geodesics. Using the Gauss–Bonnet theorem, we show that, at leading order, the deflection angle can be written as the integral of the geodesic curvature of a straight line in curved space. This reformulation emphasizes the global, coordinate-independent nature of the deflection angle and provides a complementary way of understanding the classical Gibbons–Werner method. To illustrate the idea, we apply it to three familiar spacetimes–Schwarzschild, Reissner–Nordström, and Kerr–and recover the well-known results. Furthermore, we extend the method to massive particles using the Jacobi metric, and illustrate it with the Reissner–Nordström spacetime.

China

Zonghai Li

Xiao-Jun Gao

The bending of a straight line

This study examines the $ h\to Z\gamma $ and $ h\to\gamma\gamma $ decays in the flavor-gauged two Higgs doublet model (FG2HDM), which augments the Standard Model (SM) with an additional scalar doublet, a singlet, and a $ U(1)' $ flavor gauge symmetry. Beyond the SM spectrum, FG2HDM predicts five additional physical scalars and a new neutral gauge boson, $ Z' $ . We demonstrate that while both decay channels are sensitive to charged Higgs loops, $ h \to Z\gamma $ is uniquely modified by fermion-antifermion-$\textit{Z}$ ( $ f\bar{f}Z $ ) vertex corrections. These vertex corrections further impact top-quark observables and the flavor-changing neutral current (FCNC) process $ b\to s\ell^+\ell^- $ . Our analysis identifies a viable parameter space ( $ m_{H^\pm} \gt 200 $ GeV and $ \lambda_{hH^+H^-} \lt 0 $ ) consistent with current $ 1\sigma $ experimental limits, where the signal strength $ \mu_{\gamma\gamma} $ remains the primary constraint on scalar sector parameters. Regarding the $ f\bar{f}Z $ couplings, we delineate the allowed regions in the $ \mathcal{Q}_{tL} $ - $ \mathcal{Q}_{tR} $ plane by evaluating the leading top-quark contributions, revealing that $ b\to s\ell^+\ell^- $ imposes the most stringent bounds. Finally, we highlight that the $ 14\% $ projected precision for $ \mu_{Z\gamma} $ at the High-Luminosity LHC (HL-LHC) will significantly enhance sensitivity to the FG2HDM.

Feng-Zhi Chen

Qiaoyi Wen

Fanrong Xu

Higgs decays to $\textit{Z}$ $\textit{γ}$ and $\textit{γ}$ $\textit{γ}$ in the flavor-gauged two Higgs doublet model * Supported by NSFC (12475095, U1932104), the Fundamental Research Funds for the Central Universities (11623330) and the 2024 Guangzhou Basic and Applied Basic Research Scheme Project for Maiden Voyage (2024A04J4190)

A new measurement of the $^{65}$Cu($\textit{γ}$, $\textit{n}$)$^{64}$Cu photoneutron cross section is performed using quasi-monoenergetic, tunable $\textit{γ}$-ray beams produced at the Shanghai Laser Electron Gamma Source (SLEGS). The energy spectrum of the SLEGS $\textit{γ}$-ray beams incident on the isotopically enriched $^{65}$Cu target is monitored using a BGO detector, while the photoneutron yields are determined with a moderated $^{3}$He detection array with high and flat efficiency. Within the energy range of $10.1 \le E_\gamma \le 17.6$ MeV, the measured $\sigma(E_\gamma)$ data have an uncertainty of $\lesssim 4$ %, and a pronounced giant-dipole peak is observed at $E_\gamma \simeq 16.65$ MeV with a maximal cross section of $\sigma_{\text{max}} \simeq 137$ mb. These photoneutron data are compared with previous experimental results and are employed to extract the $\textit{γ}$-ray strength function of $^{65}$Cu above the neutron threshold. Furthermore, we calculate the radiative neutron capture cross sections and astrophysical reaction rates for $^{64}$Cu, which is a short-lived intermediate nucleus whose reaction rate controls the local abundance distribution in the weak $\textit{s}$-process. It is found that the calculated $^{64}$Cu($\textit{n,}$ $\textit{γ}$)$^{65}$Cu data have an overall agreement with ENDF/B-VIII.0, JEFF-3.3, and TENDL-2023 evaluations, and the corresponding astrophysical reaction rates are consistent with those reported in the JINA REACLIB database.

Yu-Long Shen

Zi-Rui Hao

Qian-kun Sun

Hong-Wei Wang

Long-Xiang Liu

Hang-Hua Xu

Yue Zhang

Sheng Jin

Kai-Jie Chen

Meng-Die Zhou

Zhen-Wei Wang

Meng-Ke Xu

Xiang-Fei Wang

Chang Yang

Pu Jiao

Chun-Wang Ma

Gong-Tao Fan

Zhi-Cai Li

Wen Luo

Photoneutron cross section measurements on $^{65}$Cu: toward understanding ($\textit{n,}$ $\textit{γ}$) cross sections relevant to weak $\textit{s}$-process nucleosynthesis * This work was supported by the National Key Research and Development Program (2023YFA1606901), and the National Natural Science Foundation of China (12575133, 12505144)

The processes of $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ and $ K^- p \to \pi^0 \Lambda(1405) $ are studied within the effective Lagrangian approach. In addition to the “background” contribution from the $\textit{u}$-channel nucleon pole term, the contribution from the $ \Sigma(1660) $ resonance with spin-parity $ J^P=1/2^+ $ is also considered. For the $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ reaction, we perform a calculation for the total and differential cross sections by considering the contribution from the $ \Sigma(1660) $ intermediate resonance decaying into $ \pi^0 \Lambda(1405) $ with $ \Lambda(1405) $ decaying into $ \pi^0 \Sigma^0 $ . With our model parameters, the available experimental data on both the $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ and $ K^- p \to \pi^0 \Lambda(1405) $ reactions can be fairly well reproduced. It is shown that the contribution from the $ \Sigma(1660) $ resonance is necessary, and that these experimental measurements could be used to determine some properties of the $ \Sigma(1660) $ resonance.

Xing-Yi Ji

Si-Wei Liu

Wen-Tao Lyu

De-Min Li

En Wang

Ju-Jun Xie

Role of Σ(1660) in the $\textit{K}$ $^{−}$ $\textit{p}$ → $\textit{π}$ $^{0}$ $\textit{π}$ $^{0}$Σ$^{0}$ reaction * Supported by the National Key R&D Program of China (2023YFA1606703, 2024YFE0105200), the National Natural Science Foundation of China (12435007, 12475086, 12192263, 12361141819, 1252200936), the Natural Science Foundation of Henan (232300421140, 252300423951) and the Zhengzhou University Young Student Basic Research Projects (PhD students) (ZDBJ202522)

This study investigates the ultraviolet realization of semileptonic four-fermion operator $ O_{ledq}^{\alpha \beta 11} $ that incorporates Majorana dark matter (DM) in both lepton-flavor-conserving (LFC) and lepton-flavor-violating (LFV) scenarios at the one-loop level via box diagram, thereby effectively alleviating the lower bounds on the new physics scale. In addition, we investigate the interplay between model-independent constraints on the Wilson coefficients and DM direct detection, relic density, and collider searches in the context of fermion portal DM model with two mediators. We found that both the projected future constraint on the LFC Wilson coefficient $ C_{ledq}^{2211}/\Lambda^2 \lt $ $ (12.3\; \text{TeV})^{-2} $ from the measurements of neutrino non-standard interaction in the next-generation neutrino oscillation experiments, and the LFV constraint $ C_{ledq}^{1211}/\Lambda^2 \lt \left(2.2\times 10^3\; \text{TeV} \right)^{-2} $ from ongoing charged-lepton-flavor-violation searches, provide a complementary exploration of the parameter space encompassing the DM and scalar masses. With a colored mediator mass of approximately $ 2\; \text{TeV} $ , the sensitivity of the indirect constraints on the four-fermion operator can surpass those of collider searches and DM direct detection, in scenarios where the masses of the DM and scalar are close. By ensuring the correct DM relic density, however, we find that the collider searches and DM direct detection are more sensitive to the electroweak-scale DM and scalar than indirect constraints.

Yuxuan He

Gang Li

Jia Liu

Xiao-Ping Wang

Xiang Zhao

Lepton flavor of four-fermion operator and fermion portal dark matter * Gang Li and Xiang Zhao are supported by the National Natural Science Foundation of China (12347105, 12505127), the Guangdong Basic and Applied Basic Research Foundation (2024A1515012668). The work of Jia Liu is supported by the National Science Foundation of China (12235001, 12475103) and State Key Laboratory of Nuclear Physics and Technology (NPT2025ZX11). The work of Xiao-Ping Wang is supported by National Science Foundation of China (12375095) and the Fundamental Research Funds for the Central Universities

Using a sample of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">(</mo><mn>2712.4</mn><mo>±</mo><mn>14.3</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></mrow></math> events collected by the BESIII detector at the BEPCII collider, we measure the branching fractions of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi><mo>,</mo><mi>ϕ</mi><mi>ϕ</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2). The obtained branching fractions are <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>0</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>7.40</mn><mo>±</mo><mn>0.23</mn><mo>±</mo><mn>0.55</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mn>3.33</mn><mo>±</mo><mn>0.14</mn><mo>±</mo><mn>0.25</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>5.46</mn><mo>±</mo><mn>0.17</mn><mo>±</mo><mn>0.40</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>0</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.96</mn><mo>±</mo><mspace linebreak="goodbreak"></mspace><mn>0.23</mn><mo>±</mo><mn>0.29</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><msup><mi>η</mi><mo>′</mo></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>0.69</mn><mo>±</mo><mn>0.10</mn><mo>±</mo><mn>0.08</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><msup><mi>η</mi><mo>′</mo></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>0.65</mn><mo>±</mo><mn>0.09</mn><mo>±</mo><mspace linebreak="goodbreak"></mspace><mn>0.07</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.23</mn><mo>±</mo><mn>0.08</mn><mo>±</mo><mn>0.10</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.00</mn><mo>±</mo><mspace linebreak="goodbreak"></mspace><mn>0.07</mn><mo>±</mo><mn>0.07</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.82</mn><mo>±</mo><mn>0.09</mn><mo>±</mo><mn>0.14</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math> is not from the decay of a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi></math> meson, the first uncertainties are statistical and the second systematic. The branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi></math> are measured with precision improved by factors of 1.5–1.9, and those of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><msup><mi>η</mi><mo>′</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi></math> are measured for the first time.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

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.B. 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

T.T. 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.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.K. Chen

J.C. Cheng

L.N. Cheng

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

H.L. Dai

J.P. Dai

X.C. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denisenko

M. Destefanis

F. De Mori

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

X.L. Du

Y.Y. Duan

Z.H. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Y.T. Feng

M. Fritsch

Measurements of the branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><mi>ϕ</mi><mi>η</mi><mo>,</mo><mtext> </mtext><mi>ϕ</mi><mi>ϕ</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>η</mi></math>

Using a data sample of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2712.4</mn><mo>±</mo><mn>14.3</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> events collected with the BESIII detector operating at the BEPCII collider, we report the first observation of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mn>2</mn><msup><mi>K</mi><mo>+</mo></msup><mn>2</mn><msup><mi>K</mi><mo>−</mo></msup><mi>ω</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>ω</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2) via the radiative transitions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math>. The branching fractions of these decays are measured for the first time, and the statistical significance for each signal exceeds <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>10</mn><mi>σ</mi></math>.

X.L. Bao

W. Chen

J. Cheng

Measurements of the branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mn>2</mn><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mn>2</mn><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>ω</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mi>ω</mi></math> decays

The $\textit{μ}$-$\textit{e}$ conversion process is one of the most powerful ways to test lepton-flavor-violating (LFV) interactions involving charged leptons. The standard model with massive neutrinos predicts an extremely low rate for $\textit{μ}$-$\textit{e}$ conversion, making this process an excellent probe for testing LFV arising from new physics. Among many theoretical models that can induce LFV, the Supersymmetric model with R-parity violating interactions is one of the most studied for $\textit{μ}$-$\textit{e}$ conversion. In this work, we revisit trilinear $\textit{R}$-parity violating interactions for $\textit{μ}$-$\textit{e}$ conversion, considering renormalization group (RG) running effects from high to low energy scales. The $\textit{μ}$-$\textit{e}$ conversion, $\textit{μ}$ → $\textit{eγ}$, and $\textit{μ}$ → $\textit{eee}$ experimental data are compared to give upper limits on the relevant 15 combinations of the trilinear $\textit{λ′}$ couplings and 6 combinations of the $\textit{λ}$ couplings, certain of which are underexplored in previous studies. We find that RG running effects influence the limits by no more than 30% in most cases, but can improve constraints by ~80% in certain combinations, which cannot be neglected. In the near future, COMET and Mu2e are expected to begin data-taking and aim to provide the most stringent constraints on $\textit{μ}$-$\textit{e}$ conversion. These next-generation $\textit{μ}$-$\textit{e}$ experiments have the ability to give much more comprehensive examinations on most trilinear coupling combinations than the $\textit{μ}$ → $\textit{eγ}$ and $\textit{μ}$ → 3$\textit{e}$ decay experiments. The $\textit{μ}$-$\textit{e}$ experiments will not only deepen our understanding of LFV but also provide a crucial way to examine the underlying new physics contributions.

Yu-Qi Xiao

Xiao-Gang He

Hong-Yi Niu

Rong-Rong Zhang

Revisiting $\textit{μ}$-$\textit{e}$ conversion in $\textit{R}$-parity violating SUSY

A search for dark matter particles produced in association with a Higgs boson decaying to a bottom quark-antiquark pair in proton-proton collisions 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> is presented. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>101</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The analysis is performed in exclusive categories targeting both Lorentz-boosted (merged) and resolved <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi></math> jet pair topologies, covering a wide range of Higgs boson transverse momentum. A statistical combination is made with a previous search using data collected in 2016 and corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>35.9</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The observed data agree with the standard model background predictions. Constraints are placed on models predicting new particles or interactions, such as those in the simplified frameworks of baryonic-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mi>HDM</mi><mo>+</mo><mi>a</mi></mrow></math>, where the latter is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the production cross section for these models. For the baryonic-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> model, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> boson masses below 2.25 TeV are excluded for a dark matter particle candidate mass of 1 GeV. In the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mi>HDM</mi><mo>+</mo><mi>a</mi></mrow></math> model, heavy pseudoscalar masses between 850 and 1300 GeV are excluded for a light pseudoscalar mass of 350 GeV.

Armenia

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

L. Benato

T. Bergauer

M. Dragicevic

C. Giordano

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

M. Matthewman

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

Search for dark matter produced in association with a Higgs boson decaying to bottom quarks in proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>