The
Λ
+
c
K
−
mass spectrum is studied with a data sample of
p
p
collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of
5.6
 
 
fb
−
1
collected by the LHCb experiment. Three
Ξ
0
c
states are observed with a large significance and their masses and natural widths are measured to be
m
[
Ξ
c
(
2923
)
0
]
=
2923.04
±
0.25
±
0.20
±
0.14
 
 
MeV
,
Γ
[
Ξ
c
(
2923
)
0
]
=
7.1
±
0.8
±
1.8
 
 
MeV
,
m
[
Ξ
c
(
2939
)
0
]
=
2938.55
±
0.21
±
0.17
±
0.14
 
 
MeV
,
Γ
[
Ξ
c
(
2939
)
0
]
=
10.2
±
0.8
±
1.1
 
 
MeV
,
m
[
Ξ
c
(
2965
)
0
]
=
2964.88
±
0.26
±
0.14
±
0.14
 
 
MeV
,
Γ
[
Ξ
c
(
2965
)
0
]
=
14.1
±
0.9
±
1.3
 
 
MeV
, where the uncertainties are statistical, systematic, and due to the limited knowledge of the
Λ
+
c
mass. The
Ξ
c
(
2923
)
0
and
Ξ
c
(
2939
)
0
baryons are new states. The
Ξ
c
(
2965
)
0
state is in the vicinity of the known
Ξ
c
(
2970
)
0
baryon; however, their masses and natural widths differ significantly.