<p>The recent result of the Fermilab Muon g-2 experiment is still in conflict with the standard model (SM) prediction if dispersive methods are used as input for the hadronic vacuum polarization. We seek models where the same set of mediators around the weak scale or above contribute to neutrino masses and to the muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math> through a chiral enhanced contribution. As family lepton number violation is inherent to the former, non-negligible charged lepton flavor violation will be induced. We arrive at the following field content additional to the SM: one Higgs doublet, one singly charged scalar, and one right-handed neutrino. Neutrino masses will be generated by a combination of mechanisms: the tree-level seesaw, Zee mechanism, and Grimus-Neufeld mechanism, while lepton flavor violation will be minimized by considering Yukawa-aligned Higgs doublets. The setting is flexible enough to account for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>g</mi><mo>−</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>μ</mi></msub></math>, the Cabibbo angle anomaly, and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> mass deviation, while avoiding dangerous charged lepton flavor violation.</p>

Brazil

R.E.A. Bringas

A.L. Cherchiglia

G. De Conto

C.C. Nishi

Aligned Zee-Grimus-Neufeld model for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>g</mi><mo>−</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>μ</mi></msub></math>

Using a sample of (2$\textit{.}$712 ± 0$\textit{.}$014) × 10 $\textit{ψ}$(3686) events collected with the BESIII detector at the electron positron collider BEPCII, the decay $\textit{ψ}$(3686) → $$ {\Xi}^{-}{K}_S^0{\overline{\varOmega}}^{+} $$ + $\textit{c.c.}$ is observed for the first time, which has a significance of 5.9 standard deviations. The branching fraction of this decay is measured to be (2$\textit{.}$91 ± 0$\textit{.}$47 ± 0$\textit{.}$33) × 10 , where the first and second uncertainties are statistical and systematic, respectively. The ratio between $$ {\mathcal{B}}_{\psi (3686)\to {\varXi}^{-}{K}_S^0{\overline{\varOmega}}^{+}+c.c} $$ and $$ {\mathcal{B}}_{\psi (3686)\to {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0+c.c} $$ is determined to be 1$\textit{.}$05 ± 0$\textit{.}$23 ± 0$\textit{.}$14, which deviates from the isospin symmetry conservation predicted value of 0.5 by 2$\textit{.}$1$\textit{σ}$.

China

M. Ablikim

Russia

M. Achasov

Sweden

P. Adlarson

X. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

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. Briere

A. Brueggemann

H. Cai

M. Cai

X. Cai

A. Calcaterra

G. Cao

N. Cao

Türkiye

S. Cetin

X. Chai

J. Chang

G. Che

Y. Che

G. Chelkov

C. Chen

Chao Chen

G. Chen

H. Chen

M. Chen

S. Chen

T. Chen

X. Chen

Y. Chen

Z. Chen

South Korea

S. Choi

X. Chu

G. Cibinetto

F. Cossio

J. Cui

H. Dai

J. Dai

A. Dbeyssi

R. Boer

D. Dedovich

C. Deng

Z. Deng

A. Denig

I. Denysenko

M. Destefanis

F. Mori

B. Ding

X. Ding

Y. Ding

J. Dong

L. Dong

M. Dong

X. Dong

M. Du

S. Du

Y. Duan

Z. Duan

P. Egorov

G. Fan

J. Fan

Y. Fan

J. Fang

S. Fang

W. Fang

Y. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C. Feng

J. Feng

Y. Feng

M. Fritsch

C. Fu

J. Fu

Observation of $\textit{ψ}$(3686) $\textit{→}$ $$ {\Xi}^{-}{K}_S^0{\overline{\varOmega}}^{+} $$ + c.c.

We investigate how the solution to the strong CP problem and the explanation for the observed fermion mass hierarchies can be intrinsically related. Specifically, we explore the Nelson-Barr mechanism and identify its “seesaw limit”, where light quark masses are suppressed by large CP-violating terms. Upon adding three (two) vector-like quarks that mix with the down-type (up-type) quark sector of the Standard Model, we demonstrate how the lack of CP violation in the strong sector and the observed quark mass hierarchy can be simultaneously achieved.

A.G. Dias

Spain

J. Leite

Seesaw limit of the Nelson-Barr mechanism

Using (27.12 ± 0.14) × 108 ψ(3686) events collected with the BESIII detector at BEPCII, the decay of ψ(3686) →   <math> <msup> <mi>Ω</mi> <mo>−</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> <msup> <mover> <mi>Ξ</mi> <mo>¯</mo> </mover> <mn>0</mn> </msup> </math>  $$ {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0 $$  + c.c. is observed for the first time. The branching fraction of this decay is measured to be   <math> <msub> <mi>B</mi> <mrow> <mi>ψ</mi> <mfenced> <mn>3686</mn> </mfenced> <mo>→</mo> <msup> <mi>Ω</mi> <mo>−</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> <msup> <mover> <mi>Ξ</mi> <mo>¯</mo> </mover> <mn>0</mn> </msup> <mo>+</mo> <mi>c</mi> <mo>.</mo> <mi>c</mi> <mo>.</mo> </mrow> </msub> </math>  $$ {\mathcal{B}}_{\psi (3686)\to {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0+\textrm{c}.\textrm{c}.} $$  = (2.78 ± 0.40 ± 0.18) × 10 −6, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

O. Afedulidis

JINR

I. Balossino

Y. Fu

H. Gao

X. Gao

Observation of ψ(3686) →   <math> <msup> <mi>Ω</mi> <mo>−</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> <msup> <mover> <mi>Ξ</mi> <mo>¯</mo> </mover> <mn>0</mn> </msup> </math>  $$ {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0 $$  + c.c.

Using (10087 ± 44) × 106 J/ψ events collected with the BESIII detector at the BEPCII e + e  −  storage ring at the center-of-mass energy of   <math> <msqrt> <mi>s</mi> </msqrt> </math>  $$ \sqrt{s} $$  = 3.097 GeV, we present a search for the rare semi-muonic charmonium decay J/ψ → D − μ + ν  μ  + c.c.. Since no significant signal is observed, we set an upper limit of the branching fraction to be   <math> <mi>B</mi> </math>  $$ \mathcal{B} $$  (J/ψ → D − μ + ν  μ  + c.c.) &lt; 5.6 × 10 −7 at 90% confidence level. This is the first search for the weak decay of charmonium with a muon in the final state.

M. An

T. Chang

W. Chang

W. Cheng

S. Coen

United Kingdom

K Fischer

C. Fritzsch

Y. Gao

S. Garbolino

I. Garzia

P. Ge

Search for the semi-muonic charmonium decay J/ψ → D  −  μ + ν  μ  + c.c.

Using e + e  −  collision datasets corresponding to a total integrated luminosity of 21.7 fb −1 collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 4.009 GeV to 4.951 GeV, the energy-dependent cross sections of   <math> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>−</mo> </msup> <mo>→</mo> <mi>p</mi> <msup> <mi>K</mi> <mo>−</mo> </msup> <mover> <mi>Λ</mi> <mo>¯</mo> </mover> <mo>+</mo> <mi>c</mi> <mo>.</mo> <mi>c</mi> <mo>.</mo> </math>  $$ {e}^{+}{e}^{-}\to p{K}^{-}\overline{\Lambda}+c.c. $$  are measured for the first time. By fitting these energy-dependent cross sections, we search for the excited ψ states ψ(4160) and ψ(4415), and the vector charmonium-like states ψ(4230), ψ(4360), and ψ(4660). No evidence for these is observed and the upper limits on the branching fractions of these states decaying into   <math> <mi>p</mi> <msup> <mi>K</mi> <mo>−</mo> </msup> <mover> <mi>Λ</mi> <mo>¯</mo> </mover> <mo>+</mo> <mi>c</mi> <mo>.</mo> <mi>c</mi> <mo>.</mo> </math>  $$ p{K}^{-}\overline{\Lambda}+c.c. $$  are set at the 90% confidence level.

J. Bloms

Yang Gao

Measurement of   <math> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>−</mo> </msup> <mo>→</mo> <mi>p</mi> <msup> <mi>K</mi> <mo>−</mo> </msup> <mover> <mi>Λ</mi> <mo>¯</mo> </mover> <mo>+</mo> <mi>c</mi> <mo>.</mo> <mi>c</mi> <mo>.</mo> </math>  $$ {e}^{+}{e}^{-}\to p{K}^{-}\overline{\Lambda}+c.c. $$  cross sections between 4.009 GeV and 4.951 GeV

The light axial vector mesons can couple to <math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>*</mo></mrow></msup><mover><mrow><mi>K</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>+</mo><mi>c</mi><mo>.</mo><mi>c</mi><mo>.</mo></mrow></math> in an <math><mi>S</mi></math> wave at the tree level. Because of the near-threshold <math><mi>S</mi></math>-wave interactions, the couplings can be affected by the final state interactions. It is of peculiar interest that the pion exchange between <math><msup><mi>K</mi><mo>*</mo></msup><mover><mi>K</mi><mo>¯</mo></mover><mo>+</mo><mi>c</mi><mo>.</mo><mi>c</mi><mo>.</mo></math> can go through a triangle diagram which is within the kinematics of the triangle singularity. This mechanism will introduce energy dependence and a <math><mi>D</mi></math>-wave amplitude to the vertex couplings. Hence, it should be necessary to investigate the role played by the <math><msup><mi>K</mi><mo>*</mo></msup><mover><mi>K</mi><mo>¯</mo></mover><mo>+</mo><mi>c</mi><mo>.</mo><mi>c</mi><mo>.</mo></math> threshold in order to have a better understanding of the light axial vector spectrum.

Meng-Chuan Du

Yin Cheng

Qiang Zhao

Vertex corrections due to the triangle singularity mechanism in the light axial vector meson couplings to <math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>*</mo></mrow></msup><mover><mrow><mi>K</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>+</mo></mrow></math>c.c.

By analyzing 4.48 × 108 ψ(3686) events collected with the BESIII detector, we observe the decays χ  cJ  →   <math> <msubsup> <mi>nK</mi> <mi>S</mi> <mn>0</mn> </msubsup> <mover> <mi>Λ</mi> <mo>¯</mo> </mover> </math>  $$ {nK}_S^0\overline{\Lambda} $$  + c.c. (J = 0, 1, 2) for the first time, via the radiative transition ψ(3686) → γχ  cJ . The branching fractions are determined to be (6.65 ± 0.26stat ± 0.41syst) × 10 −4, (1.66 ± 0.12stat ± 0.12syst) × 10 −4, and (3.58 ± 0.16stat ± 0.23syst) × 10 −4 for J = 0, 1, and 2, respectively.

S. Ahmed

M. Albrecht

X. Bai

R. Baldini Ferroli

D. Chen

X. Cui

X. Dai

C. Dong

C. Geng

E. Gersabeck

A. Gilman

K. Goetzen

L. Gong

W. Gong

W. Gradl

M. Greco

L. Gu

M. Gu

Y. Gu

C. Guan

A. Guo

L. Guo

R. Guo

Y. Guo

A. Guskov

T. Han

W. Han

Observation of the decays χ cJ →   <math> <msubsup> <mi>nK</mi> <mi>S</mi> <mn>0</mn> </msubsup> <mover> <mi>Λ</mi> <mo>¯</mo> </mover> </math>  $$ {\mathrm{nK}}_{\mathrm{S}}^0\overline{\Lambda} $$  + c.c.

Using 10.1 × 109 J/ψ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy   <math> <msqrt> <mi>s</mi> </msqrt> </math>  $$ \sqrt{s} $$  = 3.097 GeV and collected with the BESIII detector, we present a search for the rare semi-leptonic decay J/ψ → D  −  e + ν  e  + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction ℬ(J/ψ → D − e + ν  e  + c. c.) &lt; 7.1 × 10−8 is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.

S. Gu

Search for the rare semi-leptonic decay J/ψ → D − e+ ν e + c.c.

Under the aegis of isospin conservation, the amplitudes in Born approximation, i.e., considering the only one-photon-exchange mechanism, of the decay  $$\psi \rightarrow \Lambda \overline{\Sigma }{}^0+\text {c.c.}$$  <math> <mrow> <mi>ψ</mi> <mo>→</mo> <mi>Λ</mi> <mover> <mi>Σ</mi> <mo>¯</mo> </mover> <msup> <mrow></mrow> <mn>0</mn> </msup> <mo>+</mo> <mtext>c.c.</mtext> </mrow> </math>  , where  $$\psi $$  <math> <mi>ψ</mi> </math>   is a vector charmonium, and of the reaction  $$e^+e^-\rightarrow \Lambda \overline{\Sigma }{}^0+\text {c.c.}$$  <math> <mrow> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>-</mo> </msup> <mo>→</mo> <mi>Λ</mi> <mover> <mi>Σ</mi> <mo>¯</mo> </mover> <msup> <mrow></mrow> <mn>0</mn> </msup> <mo>+</mo> <mtext>c.c.</mtext> </mrow> </math>   at the  $$\psi $$  <math> <mi>ψ</mi> </math>   mass, are parametrized by the same electromagnetic coupling. It follows that, the modulus of such a coupling can be extracted from the data on the two observables: the decay branching fraction and the annihilation cross section. By considering the first two vector charmonia,  $$J/\psi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> </mrow> </math>   and  $$\psi (2S)$$  <math> <mrow> <mi>ψ</mi> <mo>(</mo> <mn>2</mn> <mi>S</mi> <mo>)</mo> </mrow> </math>  , it is found that, especially in the case of  $$\psi (2S)$$  <math> <mrow> <mi>ψ</mi> <mo>(</mo> <mn>2</mn> <mi>S</mi> <mo>)</mo> </mrow> </math>  , there is a substantial discrepancy between the values of the modulus of the same electromagnetic coupling extracted from the branching ratio and the cross section. We propose, as a possible explanation for such a disagreement, the presence in the decay amplitude of isospin-violating contributions driven by two different mechanisms, that, however, appear to be more favored in the  $$\psi (2S)$$  <math> <mrow> <mi>ψ</mi> <mo>(</mo> <mn>2</mn> <mi>S</mi> <mo>)</mo> </mrow> </math>   than in the  $$J/\psi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> </mrow> </math>   decays.

Rinaldo Ferroli

Alessio Mangoni

Simone Pacetti

The cross section of  $$e^+e^-\rightarrow \Lambda \overline{\Sigma }{}^0+\text {c.c.}$$  <math> <mrow> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>-</mo> </msup> <mo>→</mo> <mi>Λ</mi> <mover> <mi>Σ</mi> <mo>¯</mo> </mover> <msup> <mrow></mrow> <mn>0</mn> </msup> <mo>+</mo> <mtext>c.c.</mtext> </mrow> </math>   as a litmus test of isospin violation in the decays of vector charmonia into  $$\Lambda \overline{\Sigma }{}^0+\text {c.c.}$$  <math> <mrow> <mi>Λ</mi> <mover> <mi>Σ</mi> <mo>¯</mo> </mover> <msup> <mrow></mrow> <mn>0</mn> </msup> <mo>+</mo> <mtext>c.c.</mtext> </mrow> </math>