Antineutrino induced Lambda(1405) production off the proton

Abstract

We have studied the strangeness changing antineutrino induced reactions ${\bar{\nu }}_{l}p\to l^{+}\varphi B$, with $\varphi B=K^{-}p$, ${\bar{K}}^{0}n$, ${\pi }^0\Lambda$, ${\pi }^0{\Sigma }^0$, $\eta \Lambda$, $\eta {\Sigma }^0$, ${\pi }^{+}{\Sigma }^{-}$, ${\pi }^{-}{\Sigma }^{+}$, $K^{+}{\Xi }^{-}$ and $K^0{\Xi }^0$, using a chiral unitary approach. These ten coupled channels are allowed to interact strongly, using a kernel derived from the chiral Lagrangians. This interaction generates two $\Lambda (1405)$ poles, leading to a clear single peak in the $\pi \Sigma$ invariant mass distributions. At backward scattering angles in the center of mass frame, ${\bar{\nu }}_{\mu }p\to {\mu }^{+}{\pi }^0{\Sigma }^0$ is dominated by the $\Lambda (1405)$ state at around 1420~MeV while the lighter state becomes relevant as the angle decreases, leading to an asymmetric line shape. In addition, there are substantial differences in the shape of $\pi \Sigma$ invariant mass distributions for the three charge channels. If observed, these differences would provide valuable information on a claimed isospin I=1, strangeness S=-1 baryonic state around 1400 MeV. Integrated cross sections have been obtained for the $\pi \Sigma$ and $\bar{K}N$ channels, investigating the impact of unitarization in the results. The number of events with $\Lambda (1405)$ excitation in ${\bar{\nu }}_{\mu }p$ collisions in the recent antineutrino run at the MINERvA experiment has also been obtained. We find that this reaction channel is relevant enough to be investigated experimentally and to be taken into account in the simulation models of future experiments with antineutrino beams.

13 pages and 9 figures. Minor revision; a discussion about lQCD results added to the Introduction

References in corpus (11)

• K^- p scattering length from scattering experiments
• Constraints on the chiral unitary $\bar{K}N$ amplitude from $\pi \Sigma K^{+}$ photoproduction data
• Progress and open questions in the physics of neutrino cross sections
• Measurement of the Sigma pi photoproduction line shapes near the Lambda(1405)
• Lineshape of the Lambda(1405) Hyperon Measured Through its Sigma0 pion0 Decay
• Photoproduction of Lambda(1405) and Sigma^{0}(1385) on the proton at E_γ= 1.5-2.4 GeV
• Kaonic production of Lambda(1405) off deuteron target in chiral dynamics
• Measurement of Coherent Production of ${\pi }^{\pm }$ in Neutrino and Anti-Neutrino Beams on Carbon from $E_{\nu }$ of $1.5$ to $20$ GeV
• Measurement of Ratios of ${\nu }_{\mu }$ Charged-Current Cross Sections on C, Fe, and Pb to CH at Neutrino Energies 2-20 GeV
• Weak Quasi-elastic Production of Hyperons
• The role of the $\Lambda (1405)$ in the $pp\to p{K}^{+}\Lambda (1405)$ reaction