A study of the charmless baryonic decays $$ {B}_{(s)}^0\to {K}^0p\overline{p} $$ is presented, where $$ {B}_{(s)}^0 $$ denotes either a $\textit{B}$ or a $$ {B}_s^0 $$ meson. The analysis is based on 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 decay $$ {B}_s^0\to {K}^0p\overline{p} $$ is observed for the first time, with a measured branching fraction of (9$\textit{.}$14 $\textit{±}$ 1$\textit{.}$69 $\textit{±}$ 0$\textit{.}$90 $\textit{±}$ 0$\textit{.}$33 $\textit{±}$ 0$\textit{.}$20) $\textit{×}$ 10 and a significance of 5.6$\textit{σ}$. The uncertainties respectively account for statistical and systematic contributions, the precision of the branching fraction of the normalisation channel $\textit{B}$ $\textit{→ K}$ $\textit{π}$ $\textit{π}$ and the fragmentation fraction ratio $\textit{f}$ $\textit{/f}$ . The branching fraction determined for $$ {B}^0\to {K}^0p\overline{p} $$ is (2$\textit{.}$82 $\textit{±}$ 0$\textit{.}$08 $\textit{±}$ 0$\textit{.}$12 $\textit{±}$ 0$\textit{.}$10) $\textit{×}$ 10 , which is the most precise measurement 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

F. Alessio

Z. Aliouche

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

China

L. An

L. Anderlini

M. Andersson

A. Andreianov

P. Andreola

M. Andreotti

D. Andreou

A. Anelli

D. Ao

F. Archilli

M. Argenton

Costa Rica

S. Arguedas Cuendis

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

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

T. Blake

F. Blanc

J. Blank

S. Blusk

V. Bocharnikov

Observation of the decay $$ {B}_s^0\to {K}^0p\overline{p} $$ and measurement of the $$ {B}_{(s)}^0\to {K}^0p\overline{p} $$ branching fractions

<p>By analyzing <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 with the BESIII detector operating at the BEPCII collider, the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>0</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><mn>3</mn><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>∓</mo></mrow></msup></mrow></math> are observed for the first time with statistical significances greater than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>10</mn><mi>σ</mi></math>. The branching fractions of these decays are determined to be <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><mn>3</mn><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>∓</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>7.95</mn><mo>±</mo><mn>0.50</mn><mo>±</mo><mn>0.65</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</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><mn>3</mn><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>∓</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.62</mn><mo>±</mo><mn>0.08</mn><mo>±</mo><mn>0.19</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, and <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><mn>3</mn><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>∓</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.72</mn><mo>±</mo><mn>0.07</mn><mo>±</mo><mn>0.15</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, where the first uncertainties are statistical and the second systematic.</p>

M. Ablikim

Russia

M.N. Achasov

X.C. Ai

R. Aliberti

A. Amoroso

Q. An

Y. Bai

JINR

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.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

G.R. Che

Y.Z. Che

G. Chelkov

C. Chen

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

Z.H. Duan

Observation 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><mn>3</mn><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>±</mo></msup><msup><mi>π</mi><mo>∓</mo></msup></math>