The $Λ_{b} \to Λ$ transition form factors in perturbative QCD approach
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866915765399060480 |
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| author | Yang, Lei Han, Jia-Jie Chang, Qin Yu, Fu-Sheng |
| author_facet | Yang, Lei Han, Jia-Jie Chang, Qin Yu, Fu-Sheng |
| contents | In this work, we investigate the $Λ_b \to Λ$ transition form factors in the perturbative QCD (PQCD) approach, incorporating higher-twist light-cone distribution amplitudes (LCDAs). The resulted form factors show that higher-twist LCDAs are dominant numerically. By combining our PQCD predictions at low-$q^2$ with lattice QCD results at high-$q^2$, $z$-series expansion fits are performed to parametrize the form factors over the full kinematic range. We also provide the prediction for physical observables in the rare decay $Λ_b \to Λμ^+ μ^-$, including the differential branching fraction, dilepton longitudinal polarization fraction, and forward-backward asymmetries (lepton-side, hadron-side, and combined lepton-hadron). Our obtained form factors are consistent with those in other theoretical methods within the uncertainties. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_18069 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The $Λ_{b} \to Λ$ transition form factors in perturbative QCD approach Yang, Lei Han, Jia-Jie Chang, Qin Yu, Fu-Sheng High Energy Physics - Phenomenology In this work, we investigate the $Λ_b \to Λ$ transition form factors in the perturbative QCD (PQCD) approach, incorporating higher-twist light-cone distribution amplitudes (LCDAs). The resulted form factors show that higher-twist LCDAs are dominant numerically. By combining our PQCD predictions at low-$q^2$ with lattice QCD results at high-$q^2$, $z$-series expansion fits are performed to parametrize the form factors over the full kinematic range. We also provide the prediction for physical observables in the rare decay $Λ_b \to Λμ^+ μ^-$, including the differential branching fraction, dilepton longitudinal polarization fraction, and forward-backward asymmetries (lepton-side, hadron-side, and combined lepton-hadron). Our obtained form factors are consistent with those in other theoretical methods within the uncertainties. |
| title | The $Λ_{b} \to Λ$ transition form factors in perturbative QCD approach |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2508.18069 |