Hyperfine Mixing and Final-Spin Redistribution in Inclusive Ξbc→ Hcc+X
Abstract
In this work, we study the effect of hyperfine mixing on the inclusive weak transition Ξbc→ Hcc+X, which has been proposed as a useful channel for searching for beauty-charmed baryons. Starting from the inclusive heavy-diquark framework, we include mixing between the scalar and axial-vector bc configurations and decompose the final doubly charmed system into the Jf=1/2 and Jf=3/2 spin sectors. Within a minimal scalar-to-axial transition model, and for a benchmark scalar-channel normalization of order unity at zero recoil, we find that the interference between the scalar and axial components is large in the separate spin sectors but cancels after summing over the two members of the adopted ground-state ccq spin multiplet, ΓAS1/2=−ΓAS3/2. Consequently, the spin-summed inclusive rate is less sensitive to hyperfine mixing than the direct ground-state contribution, provided feed-down from the spin-excited Ξcc* partner is experimentally unresolved. For a scalar-channel normalization of order unity, the direct contribution can be strongly spin selective: Ξbc(1) dominantly feeds the Jf=1/2 Ξcc channel, whereas Ξbc(2) dominantly feeds the Jf=3/2 Ξcc* sector. We test this pattern for several convention-matched literature admixtures and for a separately labeled decay-interference diagnostic angle, together with the dependence on the scalar-to-axial normalization and recoil-shape choice. The cancellation of the spin-summed interference is a consequence of baryon spin recoupling within the spectator and common-multiplet assumptions, whereas the magnitude of the spin selectivity is conditional on the magnitude and relative phase of the scalar-to-axial transition.
Related
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BibTeX
@misc{ahmed2026hyperfine,
title = {{Hyperfine Mixing and Final-Spin Redistribution in Inclusive $Ξ_bc\to H_cc+X$}},
author = {Ishtiaq Ahmed},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.24406},
eprint = {2608.24406},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.24406},
}
RIS
TY - UNPB
TI - Hyperfine Mixing and Final-Spin Redistribution in Inclusive Ξ_bc→ H_cc+X
AU - Ishtiaq Ahmed
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2608.24406
UR - https://arxiv.org/abs/2608.24406
AB - In this work, we study the effect of hyperfine mixing on the inclusive weak transition Ξ_bc→ H_cc+X, which has been proposed as a useful channel for searching for beauty-charmed baryons. Starting from the inclusive heavy-diquark framework, we include mixing between the scalar and axial-vector bc configurations and decompose the final doubly charmed system into the J_f=1/2 and J_f=3/2 spin sectors. Within a minimal scalar-to-axial transition model, and for a benchmark scalar-channel normalization of order unity at zero recoil, we find that the interference between the scalar and axial components is large in the separate spin sectors but cancels after summing over the two members of the adopted ground-state ccq spin multiplet, Γ_AS^1/2=−Γ_AS^3/2. Consequently, the spin-summed inclusive rate is less sensitive to hyperfine mixing than the direct ground-state contribution, provided feed-down from the spin-excited Ξ_cc^* partner is experimentally unresolved. For a scalar-channel normalization of order unity, the direct contribution can be strongly spin selective: Ξ_bc^(1) dominantly feeds the J_f=1/2 Ξ_cc channel, whereas Ξ_bc^(2) dominantly feeds the J_f=3/2 Ξ_cc^* sector. We test this pattern for several convention-matched literature admixtures and for a separately labeled decay-interference diagnostic angle, together with the dependence on the scalar-to-axial normalization and recoil-shape choice. The cancellation of the spin-summed interference is a consequence of baryon spin recoupling within the spectator and common-multiplet assumptions, whereas the magnitude of the spin selectivity is conditional on the magnitude and relative phase of the scalar-to-axial transition.
ER -