Weak kaon production off the nucleon

The weak kaon production off the nucleon induced by neutrinos is studied at the low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. This process is also potentially important for the analysis of proton decay experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are $f_{\pi }$, the pion decay constant, Cabibbo’s angle, the proton and neutron magnetic moments, and the axial vector coupling constants for the baryons octet, $D$ and $F$, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. The studied mechanisms are the main source of kaon production for neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva and T2K.

Figure 1

Feynman diagrams for the process $\nu N\to l{N}^{\prime }K$. First row from left to right: contact term (labeled CT in the text), kaon pole term (KP); second row: $u$-channel diagram $(Cr\Sigma ,Cr\Lambda )$ and pion ($\eta$) in flight ($\pi P$), $(\eta P)$.

Figure 2

Contribution of the different terms to the total cross section for the ${\nu }_{\mu }p\to \mu K^{+}p$ reaction.

Figure 3

Contribution of the different terms to the total cross section for the ${\nu }_{\mu }n\to \mu K^{0}p$ reaction.

Figure 4

Contribution of the different terms to the total cross section for the ${\nu }_{\mu }n\to \mu K^{+}n$ reaction.

Figure 5

Cross sections as a function of the neutrino energy for single kaon production vs associated production obtained with Genie [15].

Figure 6

$\frac{d\sigma }{d{Q}^2}$ at $E_{\nu }=1\mathrm{GeV}$ for single kaon production induced by neutrinos. The curves are labeled according to the final state of the process.