Testing the origin of the “$$f_1(1420)$$” with the $${\bar{K}} p \rightarrow \Lambda (\Sigma ) K{\bar{K}} \pi $$ reaction

Abstract

We study the $${\bar{K}} p \rightarrow Y K{\bar{K}} \pi $$ K ¯ p → Y K K ¯ π reactions with $${\bar{K}} = {\bar{K}}^0, K^-$$ K ¯ = K ¯ 0 , K - and $$Y=\Sigma ^0, \Sigma ^+, \Lambda $$ Y = Σ 0 , Σ + , Λ , in the region of $$K{\bar{K}} \pi $$ K K ¯ π invariant masses of $$1200-1550$$ 1200 - 1550 MeV. The strong coupling of the $$f_1(1285)$$ f 1 ( 1285 ) resonance to $$K^* {\bar{K}}$$ K ∗ K ¯ makes the mechanism based on $$K^*$$ K ∗ exchange very efficient to produce this resonance observed in the $$K{\bar{K}} \pi $$ K K ¯ π invariant mass distribution. In addition, in all these reactions one observes an associated peak at 1420 MeV which comes from the $$K^* {\bar{K}}$$ K ∗ K ¯ decay mode of the $$f_1(1285)$$ f 1 ( 1285 ) when the $$K^*$$ K ∗ is placed on shell at higher invariant masses. We call the attention to the possibility that the peaks observed in other reactions where the “$$f_1(1420)$$ f 1 ( 1420 ) ” is observed have a similar origin.

Radiative decays of f1(1285) as the K*K̅ molecular state *

“…However, the study in Ref. [15] shows that is not a genuine resonance and it shows up as a peak because of the and decay modes of around MeV. In fact, as discussed by the PDG [7], although these two states are well known, their nature remains to be established.…”