Observation of a rare beta decay of the charmed baryon with a Graph Neural Network
Abstract The beta decay of the lightest charmed baryon $${\Lambda }_{c}^{+}$$ Λ c + provides unique insights into the fundamental mechanism of strong and electro-weak interactions, serving as a testbed for investigating non-perturbative quantum chromodynamics and constraining the Cabibbo-Kobayashi-M...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-01-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-024-55042-y |
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| Summary: | Abstract The beta decay of the lightest charmed baryon $${\Lambda }_{c}^{+}$$ Λ c + provides unique insights into the fundamental mechanism of strong and electro-weak interactions, serving as a testbed for investigating non-perturbative quantum chromodynamics and constraining the Cabibbo-Kobayashi-Maskawa (CKM) matrix parameters. This article presents the first observation of the Cabibbo-suppressed decay $${\Lambda }_{c}^{+}\to n{e}^{+}{\nu }_{e}$$ Λ c + → n e + ν e , utilizing 4.5 fb−1 of electron-positron annihilation data collected with the BESIII detector. A novel Graph Neural Network based technique effectively separates signals from dominant backgrounds, notably $${\Lambda }_{c}^{+}\to \Lambda {e}^{+}{\nu }_{e}$$ Λ c + → Λ e + ν e , achieving a statistical significance exceeding 10σ. The absolute branching fraction is measured to be (3.57 ± 0.34stat. ± 0.14syst.) × 10−3. For the first time, the CKM matrix element $$\left\vert {V}_{cd}\right\vert$$ V c d is extracted via a charmed baryon decay as $$0.208\pm 0.01{1}_{{{{\rm{exp.}}}}}\pm 0.00{7}_{{{{\rm{LQCD}}}}}\pm 0.00{1}_{{\tau }_{{\Lambda }_{c}^{+}}}$$ 0.208 ± 0.01 1 exp. ± 0.00 7 LQCD ± 0.00 1 τ Λ c + . This work highlights a new approach to further understand fundamental interactions in the charmed baryon sector, and showcases the power of modern machine learning techniques in experimental high-energy physics. |
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| ISSN: | 2041-1723 |