Weak kaon production off the nucleon and Watson's theorem

E Saúl-Sala,J.E Sobczyk,M Rafi Alam,L Alvarez-Ruso,J Nieves

doi:10.1016/j.physletb.2021.136349

E Saúl-Sala, J.E Sobczyk + Show 3 more

Open Access

https://doi.org/10.1016/j.physletb.2021.136349

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Abstract

We have improved the tree-level model of Ref. [1] for weak production of kaons off nucleons by partially restoring unitarity. This is achieved by imposing Watson's theorem to the dominant vector and axial-vector contributions in appropriate angular momentum and isospin quantum number sectors. The observable consequences of this procedure are investigated.

Highlights

A good understanding and realistic modeling of neutrino cross sections is important to reduce systematic uncertainties in oscillation experiments [2,3,4,5,6]
The weak processes that could lead to kaons in the final state are either initiated by strangeness conserving (∆S = 0) or strangeness changing (∆S = 1) mechanisms
The ∆S = 1 reactions (1K) are Cabibbo suppressed compared to ∆S = 0 ones (Y K), the latter involve the production of massive strange hyperons (Y ), which pushes the reaction thresholds higher in neutrino energies

Summary

INTRODUCTION

A good understanding and realistic modeling of neutrino cross sections is important to reduce systematic uncertainties in oscillation experiments [2,3,4,5,6]. To extend the validity of the study to higher energies, the hadronic currents were multiplied by a phenomenological global dipole form factor As it is based on tree-level diagrams, this model neither respects the unitarity of the S matrix, nor it satisfies the related Watson’s theorem [17] 1, according to which, the phase of the amplitude is determined by the strong meson-baryon interaction (KN in this case). We address this issue and partially restore unitarity by imposing Watson’s theorem This is achieved by introducing relative phases in the amplitudes derived in Ref.

FORMALISM

Watson’s theorem for weak K-production

RESULTS AND DISCUSSION

CONCLUSION

Basis transformations