Abstract
Within the chiral unitary approach, the axial-vector resonance $K_1(1270)$ has been predicted to manifest a two-pole nature. The lowest pole has a mass of 1195 Mev and a width of 246 Mev and couples mostly to $K^*\pi$, and the highest pole has a mass of 1284 Mev and a width of 146 Mev and couples mostly to $\rho K$. We analyze theoretically how this double-pole structure can show up in the $D^0\to \pi^+ VP$ decays by looking at the vector-pseudoscalar ($VP$) invariant mass distribution for different $VP$ channels, exploiting the fact that each pole couples differently to different $VP$ pairs. We find that the final $\bar K^*\pi$ and $\rho \bar K$ channels are sensible to the different poles of the $K_1(1270)$ resonance and hence are suitable reactions to analyze experimentally the double pole nature of this resonance.
Highlights
The standard quark model picture, with baryons of three quarks and mesons made of quark and antiquark, has an undeniable value, putting some order in the large amount of mesons and baryons [1,2,3,4,5]
For the sake of completeness, we briefly summarize the chiral unitary approach for the vectorpseudoscalar interaction in s-wave [9,14], where most of the low lying axial-vector resonances are obtained dynamically without the need to include them as explicit degrees of freedom
We have studied theoretically the suitability of the D0 → πþVP decay to check the double-pole nature of the K1ð1270Þ resonance predicted by the chiral unitary approach
Summary
The standard quark model picture, with baryons of three quarks and mesons made of quark and antiquark, has an undeniable value, putting some order in the large amount of mesons and baryons [1,2,3,4,5]. One of the novel things of the work of [9] is that two states appeared related to K1ð1270Þ, which coupled differently to the different channels These states were further studied in [14] in connection with experimental information which provided support for two states, one with 1195 MeV, coupling mostly to KÃπ, and another one with 1284 MeV, coupling mostly to ρK. With data piling up on weak meson decays at present hadron facilities, it becomes convenient to exploit the potential of such reactions to provide information on the nature of the axial-vector states. Work along these lines for other kind of hadrons in the final state from weak decays of B, D, Λb, Λc hadrons has been summarized in [15]. We use the results to encourage the experimental community to do a thorough investigation of this problem which can lead to the clear observation of the two K1ð1270Þ states and important information concerning their nature, and that of the axial-vector mesons by extension
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