Hidden and doubly heavy molecular states from interactions $$D^{()}_{(s)}{{\bar{D}}}^{()}_{s}$$/$$B^{()}_{(s)}{{\bar{B}}}^{()}_{s}$$ and $${D}^{()}_{(s)}D_{s}^{()}$$/$${B}^{()}_{(s)}B_{s}^{()}

• Published in: The European physical journal. C, Particles and fields Vol. 81; no. 8
• Main Authors: Ding, Zuo-Ming, Jiang, Han-Yu, Song, Dan, He, Jun
• Format: Journal Article
• Language: English
• Published: 01.08.2021
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-021-09534-6

Abstract In this work, we perform a systematical investigation about the possible hidden and doubly heavy molecular states with open and hidden strangeness from interactions of $$D^{(*)}{{\bar{D}}}^{(*)}_{s}$$ D ( ∗ ) D ¯ s ( ∗ ) / $$B^{(*)}{{\bar{B}}}^{(*)}_{s}$$ B ( ∗ ) B ¯ s ( ∗ ) , $${D}^{(*)}_{s}{{\bar{D}}}^{(*)}_{s}$$ D s ( ∗ ) D ¯ s ( ∗ ) / $${{B}}^{(*)}_{s}{{\bar{B}}}^{(*)}_{s}$$ B s ( ∗ ) B ¯ s ( ∗ ) , $${D}^{(*)}D_{s}^{(*)}$$ D ( ∗ ) D s ( ∗ ) / $${B}^{(*)}B_{s}^{(*)}$$ B ( ∗ ) B s ( ∗ ) , and $$D_{s}^{(*)}D_{s}^{(*)}$$ D s ( ∗ ) D s ( ∗ ) / $$B_{s}^{(*)}B_{s}^{(*)}$$ B s ( ∗ ) B s ( ∗ ) in a quasipotential Bethe-Salpeter equation approach. The interactions of the systems considered are described within the one-boson-exchange model, which includes exchanges of light mesons and $$J/\psi /\varUpsilon $$ J / ψ / Υ meson. Possible molecular states are searched for as poles of scattering amplitudes of the interactions considered. The results suggest that recently observed $$Z_{cs}(3985)$$ Z cs ( 3985 ) can be assigned as a molecular state of $$D^*{\bar{D}}_s+D{\bar{D}}^*_s$$ D ∗ D ¯ s + D D ¯ s ∗ , which is a partner of $$Z_c(3900)$$ Z c ( 3900 ) state as a $$D{\bar{D}}^*$$ D D ¯ ∗ molecular state. The calculation also favors the existence of hidden heavy states $$D_s{\bar{D}}_s/B_s{\bar{B}}_s$$ D s D ¯ s / B s B ¯ s with spin parity $$J^P=0^+$$ J P = 0 + , $$D_s{\bar{D}}^*_s/B_s{\bar{B}}^*_s$$ D s D ¯ s ∗ / B s B ¯ s ∗ with $$1^{+}$$ 1 + , and $$D^*_s{\bar{D}}^*_s/B^*_s{\bar{B}}^*_s$$ D s ∗ D ¯ s ∗ / B s ∗ B ¯ s ∗ with $$0^+$$ 0 + , $$1^+$$ 1 + , and $$2^+$$ 2 + . In the doubly heavy sector, the bound states can be found from the interactions $$(D^*D_s+DD^*_s)/(B^*B_s+BB^*_s)$$ ( D ∗ D s + D D s ∗ ) / ( B ∗ B s + B B s ∗ ) with $$1^+$$ 1 + , $$D_s{\bar{D}}_s^*/B_s{\bar{B}}_s^*$$ D s D ¯ s ∗ / B s B ¯ s ∗ with $$1^+$$ 1 + , $$D^*D^*_s/B^*B^*_s$$ D ∗ D s ∗ / B ∗ B s ∗ with $$1^+$$ 1 + and $$2^+$$ 2 + , and $$D^*_sD^*_s/B^*_sB^*_s$$ D s ∗ D s ∗ / B s ∗ B s ∗ with $$1^+$$ 1 + and $$2^+$$ 2 + . Some other interactions are also found attractive, but may be not strong enough to produce a bound state. The results in this work are helpful for understanding the $$Z_{cs}(3985)$$ Z cs ( 3985 ) , and future experimental search for the new molecular states.