Photon-tagged energy flow in inclusive endpoint B decays
- 1Tianjin University
Abstract
A bstract : We introduce a B -decay tagged energy correlator (BTEC) to resolve the angular structure of energy flow in inclusive B decays in the endpoint region, focusing on the direct-photon contribution to B̅→ Xsγ B ¯ → X s γ . At leading power and at the natural collinear angular scale τ ~ s ~ Q Λ QCD , we derive a factorization relation involving the standard hard coefficient and B -meson shape function together with a new measured quark jet function; no new leading-power nonperturbative function is introduced. We calculate the measured jet function at one-loop accuracy and verify that its angular integral reproduces the standard inclusive quark jet function. For the central Bosch-Lange-Neubert-Paz parameter set, an illustrative benchmark gives 3 – 16% migration outside the fixed angular cuts τ c = 2 – 4 GeV ² . With an independently constrained shape function, the angular cumulatives provide a closure test of leading-power endpoint factorization and are sensitive to direct- O ₇ power corrections and resolved-photon effects. The BTEC thereby adds information on the angular structure of the inclusive recoil jet beyond the ordinary photon spectrum and may improve signal-background discrimination when their energy-flow profiles differ.
Versions
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BibTeX
@article{zhao2026photontagged,
title = {{Photon-tagged energy flow in inclusive endpoint B decays}},
author = {Shuai Zhao},
journal = {Journal of High Energy Physics},
year = {2026},
month = nov,
doi = {10.1007/jhep11(2026)028},
url = {https://link.springer.com/article/10.1007/JHEP11(2026)028},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Photon-tagged energy flow in inclusive endpoint B decays
AU - Shuai Zhao
PY - 2026
DA - 2026/11/04
JO - Journal of High Energy Physics
DO - 10.1007/jhep11(2026)028
UR - https://link.springer.com/article/10.1007/JHEP11(2026)028
AB - A bstract : We introduce a B -decay tagged energy correlator (BTEC) to resolve the angular structure of energy flow in inclusive B decays in the endpoint region, focusing on the direct-photon contribution to B̅→ X_sγ B ¯ → X s γ . At leading power and at the natural collinear angular scale τ ~ s ~ Q Λ QCD , we derive a factorization relation involving the standard hard coefficient and B -meson shape function together with a new measured quark jet function; no new leading-power nonperturbative function is introduced. We calculate the measured jet function at one-loop accuracy and verify that its angular integral reproduces the standard inclusive quark jet function. For the central Bosch-Lange-Neubert-Paz parameter set, an illustrative benchmark gives 3 – 16% migration outside the fixed angular cuts τ c = 2 – 4 GeV ² . With an independently constrained shape function, the angular cumulatives provide a closure test of leading-power endpoint factorization and are sensitive to direct- O ₇ power corrections and resolved-photon effects. The BTEC thereby adds information on the angular structure of the inclusive recoil jet beyond the ordinary photon spectrum and may improve signal-background discrimination when their energy-flow profiles differ.
SN - 1029-8479
ER -