A time-integrated angular analysis of the decay $$ {B}_s^0\to J/\psi {\overline{K}}^{\ast }{(892)}^0 $$ , with $\textit{J}$/$\textit{ψ}$ → $\textit{μ}$ $\textit{μ}$ and $$ {\overline{K}}^{\ast }{(892)}^0\to {K}^{-}{\pi}^{+} $$ , is presented. The analysis employs a sample of proton-proton collision data collected by the LHCb experiment during 2015–2018 at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb . A simultaneous maximum-likelihood fit is performed to the angular distributions in bins of the $\textit{K}$ $\textit{π}$ mass. This fit yields measurements of the $\textit{CP}$-averaged polarisation fractions and $\textit{CP}$ asymmetries for the P-wave component of the $\textit{K}$ $\textit{π}$ system. The longitudinal and parallel polarisation fractions are determined to be $\textit{f}$ = 0.534 ± 0.012 ± 0.009 and $\textit{f}$ = 0.211 ± 0.014 ± 0.005, respectively, where the first uncertainty is statistical and the second is systematic. The $\textit{CP}$ asymmetries are measured with 3–7% precision and are found to be consistent with zero. These measurements, along with an updated determination of the branching fraction relative to the $\textit{B}$ → $\textit{J}$/$\textit{ψK}$ decay, are combined with previous LHCb results, providing the most precise values for these observables to date.

Netherlands

R. Aaij

United Kingdom

A. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A. Adefisoye

Spain

B. Adeva

M. Adinolfi

Sweden

P. Adlarson

France

C. Agapopoulou

C. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Italy

P. Albicocco

Germany

J. Albrecht

Lithuania

R. Aleksiejunas

F. Alessio

Z. Aliouche

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

China

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

F. Archilli

Z Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J. Back

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I. Barbosa

R. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

Poland

S. Bashir

B. Batsukh

P. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I. Bediaga

N. Behling

S. Belin

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

C. Betancourt

F. Betti

J. Bex

Ia. Bezshyiko

Ukraine

O. Bezshyyko

J. Bhom

M. Bieker

N. Biesuz

P. Billoir

A. Biolchini

M. Birch

F. Bishop

A. Bitadze

A. Bizzeti

Canada

T. Blake

F. Blanc

J. Blank

Updated measurement of $\textit{CP}$ violation and polarisation in $$ {B}_s^0\to J/\psi {\overline{K}}^{\ast }{(892)}^0 $$ decays

Branching fraction ratios between the decays $$ {B}_{(s)}^0\to J/\psi {\eta}^{\left(\prime \right)} $$ are measured using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb . The measured ratios of these branching fractions are

C. Arata

L. Arnone

Z. Baldwin

A. Bellavista

Improved measurement of $\textit{η/η′}$ mixing in $$ {B}_{(s)}^0\to J/\psi {\eta}^{\left(\prime \right)} $$ decays

By combining the effective Lagrangian and Bethe-Salpeter framework, we studied the mass spectra, wave functions, and strong decay widths of the two pentaquark states $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ reported by LHCb in 2019. Taking into account both the mass ordering and the decay widths, our results favor the interpretation of $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ as the isospin- $$\frac{1}{2}$$ $$\left[{\overline{D} }^{*}{\Sigma}_{c}\right]$$ molecular states with $\textit{J}$ configuration $${\left(\frac{3}{2}\right)}^{-}$$ and $${\left(\frac{1}{2}\right)}^{-}$$ , respectively. We first calculate the one-boson-exchange interaction kernel of $$\left[{\overline{D} }^{*}{\Sigma}_{c}\right]$$ in the isospin- $$\frac{1}{2}$$ configuration. Then we present the Bethe-Salpeter equation (BSE) and wave functions for the bound states of a vector meson and a $$\frac{1}{2}$$ baryon with $${J}^{P}=\frac{1}{2}^{-}$$ and $$\frac{3}{2}^{-}$$ . The obtained mass results for the $${\left(\frac{3}{2}\right)}^{-}$$ and $${\left(\frac{1}{2}\right)}^{-}$$ are 4.442 and 4.457 GeV, respectively. Combining the effective Lagrangians and the BS wave functions, we further calculate the strong decay channels $${\overline{D} }^{(*)0}{\Lambda}_{c}^{+}$$ , $\textit{J}$/$\textit{ψ}$($\textit{η}$ )$\textit{p}$, and $$\overline{D}{\Sigma }_{c}^{(*)}$$ for the two $${P}_{\psi }^{N}$$ states. In the favored $$\frac{3}{2}^{-}$$ and $$\frac{1}{2}^{-}$$ configuration, the obtained total widths are 21.8 MeV and 13.0 MeV, respectively, which are substantially consistent with the LHCb data. Our results suggest that $${\overline{D} }^{0}{\Lambda}_{c}^{+}$$ and $${\overline{D} }^{(*)0}{\Lambda}_{c}^{+}$$ are the dominant decay channels to detect $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ , respectively.

Qiang Li

Chao-Hsi Chang

Xin Tong

Xiao-Ze Tan

Tianhong Wang

Guo-Li Wang

Strong decays of $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ within the Bethe-Salpeter framework

Using (2712 ± 14) × 10 $\textit{ψ}$(3686) events collected with the BESIII detector, we perform the first amplitude analysis of the radiative decay $$ \psi (3686)\to \gamma {K}_S^0{K}_S^0 $$ within the mass region $$ {M}_{K_S^0{K}_S^0}&lt;2.8 $$ GeV/$\textit{c}$ . Employing a one-channel K-matrix approach for the description of the dynamics of the $$ {K}_S^0{K}_S^0 $$ system, the data sample is well described with four poles for the $\textit{f}$ -wave and three poles for the $\textit{f}$ -wave. The determined pole positions are consistent with those of well-established resonance states. The observed $\textit{f}$ and $\textit{f}$ states are found to be in agreement with those produced in radiative $\textit{J/ψ}$ decays. The production behaviors of $\textit{f}$ and $\textit{f}$ poles in $$ \psi (3686)\to \gamma {K}_S^0{K}_S^0 $$ are qualified with their residues and the converted branching fractions. By comparing with $$ J/\psi \to \gamma {K}_S^0{K}_S^0 $$ decay, the ratios $$ \frac{\mathcal{B}\left(\psi (3686)\to \gamma {f}_{0,2}\right)}{\mathcal{B}\left(J/\psi \to \gamma {f}_{0,2}\right)} $$ are determined, which provides crucial experimental inputs on the internal structure of the $\textit{f}$ states, especially their potential mixing with glueball components.

M. Ablikim

Russia

M. Achasov

X. Ai

R. Aliberti

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. 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. Cottee-Meldrum

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

Amplitude analysis of $$ \psi (3686)\to \gamma {K}_S^0{K}_S^0 $$