Abstract
A
bstract
We calculate the electromagnetic multipole moments of the Σ-type strange hidden-charm pentaquarks
$$ {P}_{\psi s}^{\Sigma} $$
P
ψs
Σ
— which form an isospin triplet with three distinct charge states (Σ
+
, Σ
0
, Σ
−
) offering independently measurable electromagnetic properties — using QCD light-cone sum rules, employing six interpolating currents for the spin-
$$ \frac{1}{2} $$
1
2
channel and seven for the spin-
$$ \frac{3}{2} $$
3
2
channel, each built from diquark-diquark-antiquark operators with scalar or axial-vector diquark content. We compute the magnetic dipole moment
μ
for all channels and, for spin-
$$ \frac{3}{2} $$
3
2
, the electric quadrupole
$$ \mathcal{Q} $$
Q
and magnetic octupole
$$ \mathcal{O} $$
O
moments, the latter two for the first time for this system, and provide the first systematic quark-flavor decomposition of all three multipole moments for
$$ {P}_{\psi s}^{\Sigma} $$
P
ψs
Σ
. The results show a systematic dependence on the diquark spin. Scalar diquark currents yield charm-sector-dominated, flavor-insensitive moments (
μ
∈ [−1.92, −1.21]
μ
N
for spin-
$$ \frac{1}{2} $$
1
2
and |
μ
| ≲ 1.2
μ
N
for spin-
$$ \frac{3}{2} $$
3
2
), consistent with the heavy-quark spin symmetry limit. Axial-vector diquark currents produce larger, flavor-sensitive moments with sign reversals governed by the
e
u
/
e
d
= –2 charge ratio. For
$$ \mathcal{Q} $$
Q
, scalar-diquark currents give oblate deformations (
Q
0
≈ –2.0 × 10
−2
fm
2
) dominated by the charm sector, while two-axial-vector-diquark currents predict prolate values up to
Q
0
= +8.0 × 10
−2
fm
2
, with a sign reversal for
$$ \left[ su\right]\left[ uc\right]\overline{c} $$
su
uc
c
¯
in two currents. Currents with scalar antiquark coupling yield a topology-independent octupole value
$$ \mathcal{O} $$
O
≈ –0.25 × 10
−3
fm
3
, which may serve as a lattice QCD benchmark. Comparison with constituent quark model predictions identifies four qualitative discriminants: |
μ
| ≳ 3
μ
N
in the spin-
$$ \frac{1}{2} $$
1
2
sector; the sign of
μ
for the
$$ \left[ su\right]\left[ uc\right]\overline{c} $$
su
uc
c
¯
state in the spin-
$$ \frac{3}{2} $$
3
2
sector; a non-zero
$$ \mathcal{Q} $$
Q
, which vanishes in the
S
-wave molecular approximation; and the sign correlation between
$$ \mathcal{Q} $$
Q
and
$$ \mathcal{O} $$
O
, which probes the 1/
m
q
mass weighting of the magnetization distribution.