The calculation predicts a striking split between two specified charm-strange radiative transitions. It gives a width of 45.9 keV for Ds1 (2460) → Ds γ, with an uncertainty of +10.1/−8.5 keV, and 0.55 keV for Ds1 (2536) → Ds γ, with an uncertainty of +1.73/−0.48 keV. These are outputs of a light-cone QCD sum-rule calculation, not direct measurements.
The analysis also reports constructive interference among the lower-state basis-current contributions and destructive interference among the higher-state contributions. In the bottom-strange sector, the two widths are described as comparable within their propagated uncertainties, while the higher state remains destructive.
A calculation built around mixed states
The study asks whether the 1 P1–3 P1 interference mechanism appears within a light-cone QCD sum-rule framework. It models four radiative transitions: Ds1 (2460) → Ds γ, Ds1 (2536) → Ds γ, Bs1 (5750) → Bs γ and Bs1 (5830) → Bs γ.
To describe the physical lower and higher states, the authors rotate independent 3 P1 and 1 P1 basis currents using a sine-and-cosine mixing convention. The numerical analysis uses θDs = 26.6° ± 0.6° and θBs = 38.5° ± 0.1°.
The external photon is treated with a background-field method. The correlation function includes both perturbative photon emission and long-distance contributions represented by photon distribution amplitudes.
The setup retains strange-quark-mass contributions and photon-distribution-amplitude terms through twist four. Hadronic and QCD representations are matched using double Borel transformations and continuum subtraction through quark–hadron duality to obtain the transition form factors.
Uncertainties are obtained by varying QCD and hadronic inputs, the Borel parameter, continuum threshold and mixing angles. The results are reported as medians with central 68% intervals.
The bottom-strange estimates are closer
The model reports median absolute transition form factors of 0.47 (+0.05/−0.05) GeV−1 for Ds1 (2460), 0.04 (+0.04/−0.03) GeV−1 for Ds1 (2536), 0.32 (+0.02/−0.02) GeV−1 for Bs1 (5750) and 0.20 (+0.03/−0.02) GeV−1 for Bs1 (5830).
For the bottom-strange channels, the model predicts 12.0 keV (+2.9/−2.3) for Bs1 (5750) → Bs γ and 8.9 keV (+2.4/−2.0) for Bs1 (5830) → Bs γ. The study describes these estimates as comparable within propagated uncertainties, and the higher state retains destructive interference among its basis-current contributions.
The smallest prediction is sensitive to cancellation
The smaller Ds1 (2536) result is accompanied by a zero crossing in the form factor g2(0) as input parameters change. The analysis describes opposite-sign, comparable basis-current contributions whose cancellation changes with those inputs.
The same channel carries the strongly asymmetric width uncertainty of +1.73/−0.48 keV around the 0.55 keV prediction.
Combining the predicted Ds1 (2536) → Ds γ width with the measured total width gives a predicted branching fraction of 0.60 × 10−3, with an uncertainty of +1.86/−0.52 × 10−3.
A prediction still needs an experimental test
Bs1 (5750) is treated as a theoretically expected lower J^P = 1+ bottom-strange configuration rather than an experimentally established state. Its quoted radiative width is therefore a theoretical benchmark within this calculation.
Measurements of the radiative decays considered here would test the interference-sensitive predictions. Searches for Bs1 (5750) and improved measurements of other radiative modes could constrain the mixing description.
The results remain tied to the chosen light-cone QCD sum-rule framework and its QCD, hadronic, photon-distribution-amplitude, Borel, threshold and mixing-angle inputs. In the cancellation-sensitive Ds1 (2536) channel, the zero crossing changes with those inputs, alongside the strongly asymmetric predicted width interval.
A preprint prediction
The manuscript is identified as arXiv:2608.25843v1 [hep-ph], dated 26 August 2026.
At the adopted mixing inputs, the calculation sets out a sharp contrast between the two charm-strange widths and comparable estimates for the two bottom-strange widths. Those are predictions to compare with measurements of the corresponding radiative decays.
Paper data and sources
Original title: Mixing effects in radiative decays of heavy-strange axial-vector mesons within light-cone QCD sum rules
Authors: T. M. Aliev, S. Bilmis, M. Savci
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-26
DOI: Not available
Original paper · Full text