<p>Although discovered more than sixty years ago, direct measurement of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>892</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>K</mi><mi>π</mi></math> branching fractions is a formidable challenge that has not been attempted. Typically they are assumed to obey the isospin limit in hundreds of particle data measurements. We show that an abundance of recent amplitude analyses and other data, however, enables recovery of the ratios <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>π</mi><mn>0</mn></msup><mo stretchy="false">)</mo><mo>/</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mn>0</mn></msup><mo stretchy="false">)</mo><mo>/</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo stretchy="false">)</mo></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>5</mn><mo>%</mo></math> precision.</p>

France

Vladimir V. Gligorov

United States

Dean J. Robinson

Precise <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>892</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>K</mi><mi>π</mi></math> branching fractions

<p>The BESIII Collaboration has recently observed a resonant structure <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4500</mn><mo stretchy="false">)</mo></math> in <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>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math>, whose origin remains unresolved. In this study, we analyze the cross section line shape of <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>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math> by taking into account the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>4415</mn><mo stretchy="false">)</mo></math> state and intermediate charmed meson loops. By treating <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>4415</mn><mo stretchy="false">)</mo></math> as both a pure <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave state and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>−</mo><mi>D</mi></math> mixed states, and introducing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>Z</mi><mrow><mi>c</mi><mi>s</mi></mrow><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msubsup></math> resonance, we find that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4500</mn><mo stretchy="false">)</mo></math> peak at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>4.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> arises from the triangle singularity mechanism in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>Z</mi><mrow><mi>c</mi><mi>s</mi></mrow><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msubsup></math>-mediated rescattering processes, supporting its interpretation as a threshold effect rather than a conventional resonance.</p>

China

Xiao-Yun Wang

Liu-Lin Wang

Xiao-Hai Liu

Qiang Zhao

Threshold effects as the origin of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4500</mn><mo stretchy="false">)</mo></math> observed in <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>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math>

We present a measurement of the time-dependent $\textit{CP}$ asymmetry in $${B}^{0}\to {K}_{\text{S}}^{0}{\pi }^{+}{\pi }^{-}\gamma $$ decays using a data set of 365 fb recorded by the Belle II experiment and the final data set of 711 fb recorded by the Belle experiment at the Υ(4S) resonance. The direct and mixing-induced time-dependent $\textit{CP}$ violation parameters $\textit{C}$ and $\textit{S}$ are determined along with two additional quantities, $\textit{S}$ and $\textit{S}$ , defined in the two halves of the $${m}^{2}\left({K}_{\text{S}}^{0}{\pi }^{+}\right)-{m}^{2}\left({K}_{\text{S}}^{0}{\pi }^{-}\right)$$ plane. The measured values are $\textit{C}$ = $\textit{−}$0$\textit{.}$17 $\textit{±}$ 0$\textit{.}$09 $\textit{±}$ 0$\textit{.}$04, $\textit{S}$ = $\textit{−}$0$\textit{.}$29 $\textit{±}$ 0$\textit{.}$11 $\textit{±}$ 0$\textit{.}$05, $\textit{S}$ = −0$\textit{.}$57 $\textit{±}$ 0$\textit{.}$23 $\textit{±}$ 0$\textit{.}$10 and $\textit{S}$ = 0$\textit{.}$31 $\textit{±}$ 0$\textit{.}$24 $\textit{±}$ 0$\textit{.}$05, where the first uncertainty is statistical and the second systematic.

M. Abumusabh

I. Adachi

L. Aggarwal

H. Ahmed

Y. Ahn

H. Aihara

N. Akopov

S. Alghamdi

M. Alhakami

K. Amos

N. Anh Ky

D. Asner

H. Atmacan

T. Aushev

R. Ayad

V. Babu

S. Bahinipati

P. Bambade

Sw. Banerjee

M. Barrett

M. Bartl

J. Baudot

A. Beaubien

F. Becherer

J. Becker

J. Bennett

V. Bertacchi

E. Bertholet

M. Bessner

S. Bettarini

V. Bhardwaj

B. Bhuyan

F. Bianchi

T. Bilka

D. Biswas

A. Bobrov

D. Bodrov

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

R. Briere

T. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

G. Casarosa

C. Cecchi

P. Cheema

C. Chen

L. Chen

C. Cheshta

H. Chetri

J. Chin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

J. Colorado-Caicedo

L. Corona

J. Cui

E. Cruz-Burelo

S. Motte

G. Nardo

G. Pietro

R. Sangro

M. Destefanis

A. Canto

Z. Doležal

I. Domínguez Jiménez

T. Dong

X. Dong

M. Dorigo

G. Dujany

P. Ecker

J. Eppelt

R. Farkas

P. Feichtinger

T. Ferber

T. Fillinger

C. Finck

G. Finocchiaro

F. Forti

B. Fulsom

A. Gale

M. Garcia-Hernandez

R. Garg

G. Gaudino

V. Gaur

V. Gautam

A. Gaz

A. Gellrich

G. Ghevondyan

D. Ghosh

H. Ghumaryan

G. Giakoustidis

Measurement of time-dependent $\textit{CP}$ asymmetries in $${B}^{0}\to {K}_{\text{S}}^{0}{\pi }^{+}{\pi }^{-}\gamma $$ decays at Belle and Belle II

The top-quark Yukawa coupling is extracted from the distribution of the top-quark pair ( $$ t\overline{t} $$ ) invariant mass in proton-proton collisions using 140 fb of data at $$ \sqrt{s}=13 $$ TeV collected in 2015–2018 by the ATLAS experiment at the Large Hadron Collider. In the region near the production threshold, the $$ t\overline{t} $$ invariant mass spectrum is sensitive to electroweak virtual corrections, including contributions from Higgs boson exchange, thereby providing sensitivity to the top-quark Yukawa coupling. This is the first measurement in ATLAS that aims to obtain this coupling exploiting this approach. The $$ t\overline{t} $$ system is reconstructed in the single-lepton final state, requiring exactly one isolated electron or muon and at least four jets with at least two identified as originating from $\textit{b}$-quarks. The measured Yukawa coupling is found to be in good agreement with the Standard Model prediction. An upper limit on the top-quark Yukawa coupling strength of $\textit{Y}$ $\textit{<}$ 2$\textit{.}$1 relative to the Standard Model prediction is observed at 95% confidence level, consistent with the expected sensitivity.

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

Italy

United Kingdom

B. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

Spain

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

Sweden

T. Åkesson

A. Akimov

Japan

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G. Albouy

S. Alderweireldt

Z. Alegria

M. Aleksa

I. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

Saudi Arabia

H. Ali

S. Ali

S. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B. Allbrooke

D. Allen

J. Allen

P. Allport

A. Aloisio

Argentina

F. Alonso

Measurement of the top-quark Yukawa coupling from $$ t\overline{t} $$ production in the lepton+jets final state using $\textit{pp}$ collisions at $$ \sqrt{s}=13 $$ TeV with the ATLAS detector