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We recall that the chiral unitary approach for the interaction of pseudoscalar mesons with the baryons of the decuplet predicts two states for the Ξ(1820) resonance, one with a narrow width and the other one with a large width. We contrast this fact with the recent BESIII measurement of the K−Λ mass distribution in the ψ(3686) decay to K−ΛΞ¯+, which demands a width much larger than the average of the PDG, and show how the consideration of the two Ξ(1820) states provides a natural explanation to the experimental data.

Abstract Starting from the molecular picture for the $$D_{s1}(2460)$$ D s 1 ( 2460 ) and $$D_{s1}(2536)$$ D s 1 ( 2536 ) resonances, which are dynamically generated by the interaction of coupled channels, the most important of which are the $$D^*K$$ D ∗ K for the $$D_{s1}(2460)$$ D s 1 ( 2460 ) and $$DK^*$$ D K ∗ for the $$D_{s1}(2536)$$ D s 1 ( 2536 ) , we evaluate the ratio of decay widths for the $$\bar{B}_s^0 \rightarrow D_{s1}(2460)^+ K^-$$ B ¯ s 0 → D s 1 ( 2460 ) + K - and $$\bar{B}_s^0 \rightarrow D_{s1}(2536)^+ K^-$$ B ¯ s 0 → D s 1 ( 2536 ) + K - decays, the latter of which has been recently investigated by the LHCb collaboration, and we obtain a ratio of the order of unity. The present results should provide an incentive for the related decay into the $$D_{s1}(2460)$$ D s 1 ( 2460 ) resonance to be performed, which would provide valuable information on the nature of these two resonances.

We have a look at the Pcs states generated from the interaction of D¯(⁎)Ξc(′⁎) coupled channels. We consider the blocks of pseudoscalar-baryon (12+,32+) and vector-baryon (12+,32+), and find 10 resonant states coupling mostly to D¯Ξc,D¯⁎Ξc,D¯Ξc′,D¯⁎Ξc′,D¯Ξc⁎ and D¯⁎Ξc⁎. A novel aspect of the work is the realization that the D¯Ξc,D¯sΛc or D¯⁎Ξc,D¯s⁎Λc channels, with a strong transition potential, collaborate to produce a larger attraction than the corresponding states D¯Σc,D¯Λc or D¯⁎Σc,D¯⁎Λc appearing in the generation of the strangenessless Pc states, since in the latter case the transition potential between those channels is zero. The extra attraction obtained in the D¯Ξc,D¯⁎Ξc pairs preclude the association of these channels to the Pcs(4338) and Pcs(4459) states respectively. Then we find a natural association of the Pcs(4338) state coupling mostly to D¯⁎Ξc while the Pcs(4459) is associated to the state found that couples mostly to D¯Ξc′. Four more states appear, like in other molecular pictures, and some of the states are degenerate in spin. Counting different spin states we find 10 states, which we hope can be observed in the near future.

This paper presents the thermo-hydraulic performance of printed circuit heat exchangers (PCHEs) with cambered NACA four-digit airfoil fins (AFFs) used as the condenser in supercritical CO2 Brayton power cycle. Results show that the NACA8515 AFFs with consistent and reverse layout applied to a PCHE may averagely improve the transferred heat per unit area by 28% and 11% accompanying with increase of the pressure loss by 150% and 22%, respectively, compared to the PCHE with symmetrical AFFs. Based on the flow streamlines, the reverse and tangent fin layout with angled inlet manifold is proposed which can improve the overall performance effectively. The AFFs with cambers of 8.0%, 14.4%, 25.0% and 43.3% used in PCHEs are studied, and the Nusselt number can be averagely improved by 42%, 54%, 75% and 66%, besides the Darcy friction factor averagely increases 125%, 460%, 980% and 890%, respectively. Meanwhile, the overall performance has a maximum improvement of 39% at lower Reynolds number. In order to demonstrate the advantage of cambered AFFs more effectively, the PCHE with non-uniform layout of AFFs is proposed, and the overall performance of a typical case can be improved by 46% maximally and 25% averagely in the applicable range. [ABSTRACT FROM AUTHOR]