Color octet contribution in exclusive P-wave charmonium decay into octet and decuplet baryons

Abstract

In the last years, the need of the colour octet state in inclusive P-wave charmonium decay has been firmly established. However, the implications of this in the corresponding exclusive reactions have not been fully recognized. We argue for the necessity of the colour octet in P-and higher-wave quarkonium decay. Using a set of phenomenologically constructed baryon wavefunctions, we consider the χ J decay into octet and decuplet baryon-antibaryon pair. By doing so, we subject the wavefunctions to a test of applicability. We show that the colour singlet component alone is insufficient to account for experimental measurements and only by including the colour octet contribution can the partial theoretical decay widths be brought into range of the data. By the present and earlier applications of the set of wavefunctions, they show themselves to be reasonable model wavefunctions at around the scale Q 2 ∼ 10-20 GeV 2 .

Improved measurements of χcJ→Σ+ΣAblikim1, Ачасов2, Ahmed3 et al. 2018Phys. Rev. D4140View full textAdd to dashboardCite

“…The results are consistent with and improve on the precision compared to the world average values. The current results on χ c1;2 → Σ þΣ− and Σ 0Σ0 are in good agreement with theoretical predictions based on the color octet contribution model [4]. The results for χ c0 → Σ þΣ− and Σ 0Σ0 are still inconsistent with the prediction [3] based on the charm meson loop mechanism.…”

“…The results are listed in Table II, together with the values from theoretical predictions [2][3][4], previous measurement from BESIII [6], CLEO [5] and the PDG world averages [17] for comparison. Note that we use the prediction of the decay χ c0 → Σ −Σþ from Ref.…”

“…In the decay χ cJ → Σ þΣ− , only the radiative photon is considered for the uncertainty of photon detection. The tracking and particle identification (PID) [17], previous measurement from BESIII publications [6], CLEO [5] and theoretical predictions [2][3][4] for comparison. To make an objective comparison, the BF of χ cJ → ΣΣ decays from previous BESIII are corrected with the newest BF of ψð3686Þ → γχ cJ from Ref.…”

“…Contributions of the color octet mechanism (COM) [1] to decays of P-wave heavy quarkonia have been proposed for more than two decades, and many theoretical predictions for exclusive χ cJ decays to baryon anti-baryon pairs [2][3][4] have been made. However, there are large differences between predictions and the experimental measurements, e.g., the branching fractions (BF) of χ c0 → Σ þΣ− and Σ 0Σ0 decays as measured by CLEO-c [5] and BESIII [6] are observed to violate the helicity selection rule from perturbative QCD (pQCD) [7][8][9] and also do not agree with models based on the charm meson loop mechanism [3,10,11].…”

Observation ofχcJdecaying into thepp¯K+K−final sta

“…The color octet mechanism (COM) has been shown to play an important role in describing these P-wave quarkonium decays [2][3][4][5]. Many COM predictions for χ cJ decays into meson pairs and pp pairs are in agreement with earlier experimental results.…”