6533b7d5fe1ef96bd1264802

RESEARCH PRODUCT

The Z(3985) as a threshold effect from the D¯s⁎D+D¯sD⁎ interaction

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Abstract We study the e + e − → K + ( D s ⁎ − D 0 + D s − D ⁎ 0 ) reaction recently measured at BESIII, from where a new Z c s state has been reported. We study the interaction of D ¯ s D ⁎ with the coupled channels J / ψ K − , K ⁎ − η c , D s − D ⁎ 0 , D s ⁎ − D 0 by means of an extension to the charm sector of the local hidden gauge approach. We find that the D s − D ⁎ 0 + D s ⁎ − D 0 combination couples to J / ψ K − and K ⁎ − η c , but the D s − D ⁎ 0 − D s ⁎ − D 0 combination does not. The coupled channels help to build up strength in the D s − D ⁎ 0 + D s ⁎ − D 0 diagonal scattering matrix close to threshold and, although the interaction is not strong enough to produce a bound state or resonance, it is sufficient to produce a large accumulation of strength at the D ¯ s D ⁎ threshold in the e + e − → K + ( D s ⁎ − D 0 + D s − D ⁎ 0 ) reaction in agreement with experiment.