Predictions of masses for light hybrid baryons

Abstract

Within the method of parity-projected QCD sum rules, we study the mass spectra of light hybrid baryons with $I(J^{P})=1/2(1/2^{\pm}), 3/2(1/2^{\pm}), 1/2(3/2^{\pm}), 3/2(3/2^{\pm})$ by constructing the local $qqqg$ interpolating currents. We calculate the correlation functions up to dimension eight condensates at the leading order of $α_{s}$. The stable QCD Lapalce sum rules can be established for the positive-parity $N_{1/2^+}, Δ_{3/2^+}, Δ_{1/2^+}$ and negative-parity $N_{1/2^-}, N_{3/2^-}, Δ_{1/2^-}$ channels to extract their mass spectra. The lowest-lying hybrid baryons are predicted to be the positive-parity $N_{1/2^+}$ state around 2.01 GeV. These hybrid baryons mainly decay into conventional baryon plus meson final states. We propose to search for the light hybrid baryons through the $Υ/ψ(3686)$ decays via the three-gluon emission mechanism in BESIII and BelleII experiments. Hopefully our studies of the light hybrid baryons will be useful for understanding the excited baryon spectrum and the behavior of gluonic degrees of freedom in QCD.

Figures (5)

• Figure 1: Feynman diagrams involved in the calculations.
• Figure 2: Variations of hadron mass with (a) continuum threshold $s_{0}$ and (b) Borel parameter $M_{B}^{2}$ for the hybrid baryon with $I(J^{P})=1/2(1/2)^{+}$ from $J_{7}$.
• Figure 3: Mass spectra for both negative-parity and positive-parity hybrid baryons.
• Figure 4: Possible production mechanisms of light hybrid baryons from $\Upsilon/\psi(3686)$ decays.
• Figure 5: Possible decay mechanisms of light hybrid baryon to gluon-rich channels.