A note on Charmed and Bottomed Pentaquark Production by Fragmentation

TL;DR

The paper addresses how heavy-quark fragmentation governs the production of heavy pentaquarks Theta_c^0 and Theta_b^+. It estimates fragmentation probabilities f( cbar → Theta_c^0 ) ≈ (2–7)×10^-3 and f( bbar → Theta_b^+ ) ≈ (5–20)×10^-3 from known charm/bottom fragmentation data, then converts these into collider cross sections for HERA, LEP, and the Tevatron. The results indicate observable yields at LEP and the Tevatron, with Theta_c^0 already observed at HERA and Theta_b^+ offering strong discovery potential at LEP/Tevatron but more limited prospects at HERA. These findings support experimental searches and clarify the production dynamics of heavy pentaquarks via fragmentation.

Abstract

H1 Collaboration recently observed the charmed pentaquark. In this short note, we point out that the dominant production mechanism for pentaquark consisting of a heavy quark is heavy quark fragmentation. We obtain a crude estimate on the fragmentation probability for charm quark into Theta_c^0, based on the known fragmentation probabilities of charm quark into mesons and baryons: f(c-bar --> Theta_c^0) =~ (2-7) x 10^{-3}. Similarly, we also obtain the fragmentation probability for bottom quark into Theta_b^+: f(b-bar --> Theta_b^+) =~ (5-20) x 10^{-3}. We also estimate the prospect of observing Theta_c^0 and Theta_b^+ at HERA, LEP, and Tevatron.