A search for the decay $\textit{B}$ $\textit{→ ϕϕ}$ is made using $\textit{pp}$ collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb . No significant signal is observed, and an upper limit on the branching fraction of 1$\textit{.}$3 (1$\textit{.}$4) × 10 at 90 (95)% confidence level is set. This result supersedes the previous LHCb study and improves the upper limit by a factor of two.

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

Search for the decay $\textit{B}$

The first measurement at midrapidity (|$\textit{y}$|$\textit{ <}$ 0$\textit{.}$5) of the production yield of the strange-charm baryons $${\Xi }_{\text{c}}^{+}$$ and $${\Xi }_{\text{c}}^{0}$$ as a function of transverse momentum ($\textit{p}$ ) in different charged-particle multiplicity classes in proton-proton collisions at $$\sqrt{s}=13$$ TeV with the ALICE experiment at the LHC is reported. The $${\Xi }_{\text{c}}^{+}$$ baryon is reconstructed via the $${\Xi }_{\text{c}}^{+}\to {\Xi }^{-}{\pi }^{+}{\pi }^{+}$$ decay channel in the range 4 $\textit{< p}$ $\textit{<}$ 12 GeV$\textit{/c}$, while the $${\Xi }_{\text{c}}^{0}$$ baryon is reconstructed via both the $${\Xi}_{\text{c}}^{0}\to {\Xi}^{-}{\pi }^{+}$$ and $${\Xi}_{\text{c}}^{0}\to {\Xi}^{-}{\text{e}}^{+}{\nu }_{\text{e}}$$ decay channels in the range 2 $\textit{< p}$ $\textit{<}$ 12 GeV$\textit{/c}$. The baryon-to-meson $$\left({\Xi}_{\text{c}}^{0,+}/{\text{D}}^{0}\right)$$ and the baryon-to-baryon $$\left({\Xi}_{\text{c}}^{0,+}/{\Lambda}_{\text{c}}^{+}\right)$$ production yield ratios show no significant dependence on multiplicity. In addition, the observed yield ratios are not described by theoretical predictions that model charm-quark fragmentation based on measurements at e e and e p colliders, indicating differences in the charm-baryon production mechanism in pp collisions. A comparison with different event generators and tunings, including different modelling of the hadronisation process, is also discussed. Moreover, the branching-fraction ratio of $${\text{BR}}\left({\Xi}_{\text{c}}^{0}\to {\Xi }^{-}{\text{e}}^{+}{\nu }_{\text{e}}\right)/{\text{BR}}\left({\Xi}_{\text{c}}^{0}\to {\Xi }^{-}{\pi }^{+}\right)$$ is measured as 0.825 ± 0.094 (stat.) ± 0.081 (syst.). This value supersedes the previous ALICE measurement, improving the statistical precision by a factor of 1.6.

I. Abualrob

S. Acharya

G. Aglieri Rinella

L. Aglietta

M. Agnello

N. Agrawal

India

Z. Ahammed

S. Ahmad

Slovakia

I. Ahuja

Indonesia

ZUL. Akbar

A. Akindinov

V. Akishina

M. Al-Turany

D. Aleksandrov

B. Alessandro

H. Alfanda

Mexico

R. Alfaro Molina

B. Ali

A. Alici

South Korea

A. Alkin

Norway

J. Alme

G. Alocco

T. Alt

A. Altamura

I. Altsybeev

Romania

C. Andrei

N. Andreou

A. Andronic

E. Andronov

V. Anguelov

F. Antinori

P. Antonioli

N. Apadula

H. Appelshäuser

S. Arcelli

R. Arnaldi

J. Arneiro

I. Arsene

M. Arslandok

A. Augustinus

R. Averbeck

M. Azmi

Japan

H. Baba

A. Babu

A. Badalà

J. Bae

Y. Bae

Y. Baek

X. Bai

R. Bailhache

Y. Bailung

R. Bala

A. Baldisseri

B. Balis

S. Bangalia

Z. Banoo

V. Barbasova

F. Barile

L. Barioglio

Greece

M. Barlou

B. Barman

Hungary

G. Barnaföldi

L. Barnby

E. Barreau

V. Barret

L. Barreto

K. Barth

E. Bartsch

N. Bastid

G. Batigne

D. Battistini

B. Batyunya

Multiplicity dependence of $${\Xi }_{\text{c}}^{+}$$ and $${\Xi }_{\text{c}}^{0}$$ production in pp collisions at $$\sqrt{s}=13$$ TeV