Flavor decomposition of electromagnetic multipole moments in [q1q2][q¯3c¯] tetraquarks: Light-quark analogs of Tcs1(2900)0 with JP=1+

We present a systematic study of the magnetic dipole and electric quadrupole moments of compact [ q 1 q 2 ] [ q ¯ 3 c ¯ ] tetraquark states with quantum numbers J P = 1 + , in the diquark–antidiquark picture and within the light-cone QCD sum rule framework. By performing a flavor decomposition across all admissible u / d configurations, we show that the charm-quark contribution to the electromagnetic moments vanishes algebraically at the operator level – a structural feature of the specific spin organization adopted here, in which the heavy antiquark resides in a pseudoscalar antidiquark, distinct from the dynamical 1/ m c suppression operative in alternative compact constructions and in hadronic molecules. The magnetic moments follow a coherent light-flavor pattern – positive for uu -, negative for dd -, and suppressed for mixed-flavor diquarks – and the quadrupole moments are non-zero throughout, corresponding, in the customary geometrical interpretation, to intrinsically deformed charge distributions. We further identify the dimensionless multipole ratio D / μ as a structural observable, independent of the normalization of the interpolating current, which probes the relative geometry of the spin-current and charge distributions complementary to the absolute moments. Taken together, the algebraic decoupling of the charm contribution and the operator-level distinction it implies among different singly-heavy tetraquark architectures constitute methodological signatures that discriminate among the corresponding internal organizations and, to the extent that a physical candidate is dominated by one of them, among compact and molecular interpretations.