The $$P_{cs}(4459)$$ pentaquark from a combined effective field theory and phenomenological perspective
Abstract The observation of the $$P_{cs}(4459)$$ P cs ( 4459 ) by the LHCb collaboration adds a new member to the set of known hidden-charm pentaquarks, which includes the $$P_c(4312)$$ P c ( 4312 ) , $$P_c(4440)$$ P c ( 4440 ) and $$P_c(4457)$$ P c ( 4457 ) . The $$P_{cs}(4459)$$ P cs ( 4459 ) is e...
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Published in | The European physical journal. C, Particles and fields Vol. 81; no. 7 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Springer Verlag (Germany)
01.07.2021
|
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
The observation of the
$$P_{cs}(4459)$$
P
cs
(
4459
)
by the LHCb collaboration adds a new member to the set of known hidden-charm pentaquarks, which includes the
$$P_c(4312)$$
P
c
(
4312
)
,
$$P_c(4440)$$
P
c
(
4440
)
and
$$P_c(4457)$$
P
c
(
4457
)
. The
$$P_{cs}(4459)$$
P
cs
(
4459
)
is expected to have the light-quark content of a
$$\Lambda $$
Λ
baryon (
$$I=0$$
I
=
0
,
$$S=-1$$
S
=
-
1
), but its spin is unknown. Its closeness to the
$${\bar{D}}^* \Xi _c$$
D
¯
∗
Ξ
c
threshold –
$$4478\,{\mathrm{MeV}}$$
4478
MeV
in the isospin-symmetric limit – suggests the molecular hypothesis as a plausible explanation for the
$$P_{cs}(4459)$$
P
cs
(
4459
)
. While in the absence of coupled-channel dynamics heavy-quark spin symmetry predicts the two spin-states of the
$${\bar{D}}^* \Xi _c$$
D
¯
∗
Ξ
c
to be degenerate, power counting arguments indicate that the coupling with the nearby
$${\bar{D}} \Xi _c'$$
D
¯
Ξ
c
′
and
$${\bar{D}} \Xi _c^*$$
D
¯
Ξ
c
∗
channels might be a leading order effect. This generates a hyperfine splitting in which the
$$J=\tfrac{3}{2}$$
J
=
3
2
$${\bar{D}}^* \Xi _c$$
D
¯
∗
Ξ
c
pentaquark will be lighter than the
$$J=\tfrac{1}{2}$$
J
=
1
2
configuration, which we estimate to be of the order of
$$5-15\,{\mathrm{MeV}}$$
5
-
15
MeV
. We also point out an accidental symmetry between the
$$P_{cs}(4459)$$
P
cs
(
4459
)
and
$$P_c(4440/4457)$$
P
c
(
4440
/
4457
)
potentials. Finally, we argue that the spectroscopy and the
$$J/\psi \Lambda $$
J
/
ψ
Λ
decays of the
$$P_{cs}(4459)$$
P
cs
(
4459
)
might suggest a marginal preference for
$$J = \tfrac{3}{2}$$
J
=
3
2
over
$$J = \tfrac{1}{2}$$
J
=
1
2
. |
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ISSN: | 1434-6044 1434-6052 |
DOI: | 10.1140/epjc/s10052-021-09416-x |