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.

Within the framework of NRQCD, the photoproduction of doubly heavy baryons Ξ , Ξ , Ξ and their $\textit{P}$-wave excited states has been systematically investigated. The production mechanism is that a color anti-triplet or sextuplet diquark ⟨$\textit{QQ}$ ⟩ is first produced, and then evolved into a corresponding doubly heavy baryon $$ {\Xi}_{QQ^{\prime }} $$ via the subprocess $\textit{γ}$ + $\textit{γ}$ → ⟨$\textit{QQ}$ ⟩[$\textit{n}$] + $$ {\overline{Q}}^{\prime } $$ + $$ \overline{Q} $$ → $$ {\Xi}_{QQ^{\prime }} $$ + $$ {\overline{Q}}^{\prime } $$ + $$ \overline{Q} $$ . Here, $\textit{Q}$ denotes the heavy quark $\textit{b}$ or $\textit{c}$, [$\textit{n}$] is the color and spin quantum number of intermediate diquark, which can be $$ {\left[^3{S}_1\right]}_{\overline{\textbf{3}}/\textbf{6}} $$ and $$ {\left[^1{S}_0\right]}_{\overline{\textbf{3}}/\textbf{6}} $$ for $\textit{S}$-wave states, or $$ {\left[^1{P}_1\right]}_{\overline{\textbf{3}}/\textbf{6}} $$ and $$ {\left[^3{P}_J\right]}_{\overline{\textbf{3}}/\textbf{6}} $$ with $\textit{J}$ = 0, 1, 2 for $\textit{P}$-wave states. Predictions for the cross sections, differential distributions, and theoretical uncertainty have been analyzed. The results indicate that, at $$ \sqrt{s} $$ = 91 GeV, the contribution of photoproduction for $\textit{P}$-wave Ξ , Ξ , and Ξ is approximately 2$\textit{.}$19%, 4$\textit{.}$23%, 1$\textit{.}$26% of the contribution for $\textit{S}$-wave, respectively. As the collision energy increases, the contribution of $\textit{P}$-wave also increases. Assuming that the highly excited state can decay into ground state with 100% efficiency, the total produced events at CEPC and FCC-ee can be as high as $$ \mathcal{O}\left({10}^8\right) $$ , $$ \mathcal{O}\left({10}^7\right) $$ $\textit{,}$ and $$ \mathcal{O}\left({10}^5\right) $$ corresponding to Ξ , Ξ , and Ξ , respectively, which is very promising to be detected in future experiments.

Hong-Hao Ma

Juan-Juan Niu

Lei Guo

Further study on excited $$ {\Xi}_{QQ^{\prime }} $$ via photoproduction at CEPC and FCC-ee

Using data samples of 983.0 fb and 427.9 fb accumulated with the Belle and Belle II detectors operating at the KEKB and SuperKEKB asymmetric-energy $\textit{e}$ $\textit{e}$ colliders, singly Cabibbo-suppressed decays $$ {\Xi}_c^{+}\to p{K}_S^0 $$ , $$ {\Xi}_c^{+}\to \Lambda {\pi}^{+} $$ , and $$ {\Xi}_c^{+}\to {\Sigma}^0{\pi}^{+} $$ are observed for the first time. The ratios of branching fractions of $$ {\Xi}_c^{+}\to p{K}_S^0 $$ , $$ {\Xi}_c^{+}\to \Lambda {\pi}^{+} $$ , and $$ {\Xi}_c^{+}\to {\Sigma}^0{\pi}^{+} $$ relative to that of $$ {\Xi}_c^{+}\to {\Xi}^{-}{\pi}^{+}{\pi}^{+} $$ are measured to be

I. Adachi

L. Aggarwal

N. Akopov

M. Alhakami

A. Aloisio

N. Althubiti

N. Anh Ky

D. Asner

H. Atmacan

T. Aushev

V. Aushev

M. Aversano

R. Ayad

V. Babu

N. Baghel

S. Bahinipati

P. Bambade

Sw. Banerjee

M. Barrett

J. Baudot

A. Baur

A. Beaubien

J. Becker

J. Bennett

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

B. Bhuyan

D. Biswas

A. Bobrov

D. Bodrov

A. Bolz

A. Bondar

J. Borah

A. Boschetti

A. Bozek

P. Branchini

T. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

G. Casarosa

C. Cecchi

J. Cerasoli

M.C. Chang

R. Cheaib

P. Cheema

K. Chilikin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

L. Corona

E. Cruz-Burelo

S. Motte

G. Nardo

G. Pietro

R. Sangro

S. Dey

A. Canto

F. Capua

J. Dingfelder

Z. Doležal

I. Domínguez Jiménez

T. Dong

M. Dorigo

D. Dossett

K. Dugic

G. Dujany

P. Ecker

D. Epifanov

P. Feichtinger

T. Ferber

T. Fillinger

G. Finocchiaro

F. Forti

B. Fulsom

A. Gabrielli

M. Garcia-Hernandez

G. Gaudino

V. Gaur

A. Gaz

A. Gellrich

G. Ghevondyan

D. Ghosh

H. Ghumaryan

G. Giakoustidis

R. Giordano

Observations of the singly Cabibbo-suppressed decays $$ {\Xi}_c^{+}\to p{K}_S^0 $$ , $$ {\Xi}_c^{+}\to \Lambda {\pi}^{+} $$ , and $$ {\Xi}_c^{+}\to {\Sigma}^0{\pi}^{+} $$ at Belle and Belle II