$B \to ρ\ell \barν$ resonance form factors from $B \to ππ\ell \barν$ in lattice QCD
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arXiv
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| Autores principales: | , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866916708355145728 |
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| author | Leskovec, Luka Meinel, Stefan Petschlies, Marcus Negele, John Paul, Srijit Pochinsky, Andrew |
| author_facet | Leskovec, Luka Meinel, Stefan Petschlies, Marcus Negele, John Paul, Srijit Pochinsky, Andrew |
| contents | The decay $B \to ρ\ell \barν$ is an attractive process for determining the magnitude of the smallest CKM matrix element, $|V_{ub}|$, and can provide new insights into the origin of the long-standing exclusive-inclusive discrepancy in determinations of this Standard-Model parameter. This requires a nonperturbative QCD calculation of the $B \to ρ$ form factors $V$, $A_0$, $A_1$, and $A_{12}$. The unstable nature of the $ρ$ resonance has prevented precise lattice QCD calculations of these form factors to date. Here, we present the first lattice QCD calculation of the $B \to ρ$ form factors in which the $ρ$ is treated properly as a resonance in $P$-wave $ππ$ scattering. To this end, we use the Lellouch-Lüscher finite-volume formalism to compute the $B \to ππ$ form factors as a function of both momentum transfer and $ππ$ invariant mass, and then analytically continue to the $ρ$ resonance pole. This calculation is performed with $2+1$ dynamical quark flavors at a pion mass of approximately 320 MeV, and demonstrates a clear path toward results at the physical point. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_00903 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | $B \to ρ\ell \barν$ resonance form factors from $B \to ππ\ell \barν$ in lattice QCD Leskovec, Luka Meinel, Stefan Petschlies, Marcus Negele, John Paul, Srijit Pochinsky, Andrew High Energy Physics - Lattice High Energy Physics - Experiment High Energy Physics - Phenomenology The decay $B \to ρ\ell \barν$ is an attractive process for determining the magnitude of the smallest CKM matrix element, $|V_{ub}|$, and can provide new insights into the origin of the long-standing exclusive-inclusive discrepancy in determinations of this Standard-Model parameter. This requires a nonperturbative QCD calculation of the $B \to ρ$ form factors $V$, $A_0$, $A_1$, and $A_{12}$. The unstable nature of the $ρ$ resonance has prevented precise lattice QCD calculations of these form factors to date. Here, we present the first lattice QCD calculation of the $B \to ρ$ form factors in which the $ρ$ is treated properly as a resonance in $P$-wave $ππ$ scattering. To this end, we use the Lellouch-Lüscher finite-volume formalism to compute the $B \to ππ$ form factors as a function of both momentum transfer and $ππ$ invariant mass, and then analytically continue to the $ρ$ resonance pole. This calculation is performed with $2+1$ dynamical quark flavors at a pion mass of approximately 320 MeV, and demonstrates a clear path toward results at the physical point. |
| title | $B \to ρ\ell \barν$ resonance form factors from $B \to ππ\ell \barν$ in lattice QCD |
| topic | High Energy Physics - Lattice High Energy Physics - Experiment High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2501.00903 |