Production of strange and charmed baryons in pion induced reactions

Abstract

We study the strangeness and charm productions induced by the pion beam, i.e. the $\pi^-$p $\rightarrow$ $K^{*0}\Lambda$ and $\pi^-$p $\rightarrow$ $D^{*-}\Lambda_c^+$ reactions, based on two different theoretical frameworks: an effective Lagrangian method and a Regge approach. In order to estimate the magnitude of the charm production relative to that of the strangeness production, we assume that the coupling constants for the charmed meson and baryon vertices are the same as those for the strangeness channel. We found that the total cross section for the charm production was about $10^3 - 10^6$ times smaller than that for the strangeness production, depending on theoretical approaches and kinematical regions. We also discuss each contribution to observables for both reactions. In general, the Regge approach explains the experimental data very well over the whole energy region.Comment: 20 pages, 15 figure

K0ΛandD−Λc+production induced b

“…The π − p → D * − Λ + c reaction was suggested as the first experiment and the relevant theoretical works have been discussed recently by us in collaboration with other authors [20,21]. Reference [20] In the present work, we extend the previous investigation [21] to the reaction π − p → D − Λ + c together with the π − p → K 0 Λ using a similar method. We first concentrate on the π − p → K 0 Λ where experimental data exist, so that we are able to fix the parameters such as coupling constants and scale factors.…”

“…To derive the t-channel Regge amplitude, we employ a hybridized approach by replacing the Feynman propagator for vector-meson exchange in the t channel with the Regge propagator arising from the corresponding Regge trajectory [21,34] …”

“…This is due to the fact that the antisymmetric tensor ǫ µραβ q tρ involved in the relevant Lagrangians for K * exchange eliminates the q tµ q tν term by contraction. The C K * (t) represents a scale factor [21], which is defined as…”

“…The high-momentum pion beam line up to 20 GeV will be constructed to produce excited charmed baryons [18,19]. The π − p → D * − Λ + c reaction was suggested as the first experiment and the relevant theoretical works have been discussed recently by us in collaboration with other authors [20,21]. Reference [20] In the present work, we extend the previous investigation [21] to the reaction π − p → D − Λ + c together with the π − p → K 0 Λ using a similar method.…”

“…To fix the Regge parameters such as Regge trajectories and energy scale parameters, we use the non-perturbative Quark-Gluon String Model (QGSM) developed by Kaidalov et al [22][23][24][25] as was done in Ref. [21]. We find that the DΛ + c (KΛ) production is governed by vector-meson D * (K * ) Reggeon exchange at forward angles, whereas by baryon Σ c (Σ) Reggeon exchange at backward angles.…”