Lowest-lying 1{2}^- and 3{2}^- ₐ resonances: from the strange to the bottom sectors

We present a detailed study of the lowest-lying 1{2}^- and 3{2}^- ₐ resonances both in the heavy quark (bottom and charm) and the strange sectors. We have paid special attention to the interplay between the constituent quark-model and chiral baryon-meson degrees of freedom, which are coupled using a unitarized scheme consistent with leading-order heavy quark symmetries. We show that the b (5912) JP=1/2^-, b (5920) JP=3/2^- and the c (2625) JP=3/2^-, and the (1520) JP=3/2^- admitting larger breaking corrections, are heavy-quark spin-flavor siblings. They can be seen as dressed quark-model states with ₐ^ (*) molecular components of the order of 30\%. The JP=1{2}^- c (2595) has, however, a higher molecular probability of at least 50\%, and even values greater than 70\% can be easily accommodated. This is because it is located almost on top of the threshold of the c pair, which largely influences its properties. Although the light degrees of freedom in this resonance would be coupled to spin-parity 1^- as in the b (5912), b (5920) and c (2625), the c (2595) should not be considered as a heavy-quark spin-flavor partner of the former ones. We also show that the (1405) chiral two-pole pattern does not have analogs in the 12^- charmed and bottomed sectors, because the ND^ (*) and NB^ (*) channels do not play for heavy quarks the decisive role that the N K does in the strange sector, and the notable influence of the bare quark-model states for the charm and bottom resonances. Finally, we predict the existence of two b (6070) and two c (2765) heavy-quark spin and flavor sibling odd parity states.