Luka Leskovec (Author), Stefan Meinel (Author), Marcus Petschlies (Author), John W. Negele (Author), Srijit Paul (Author), Andrew Pochinsky (Author)

Abstract

The decay $B \to \rho \ell \bar{\nu}$ is an attractive process for determining the magnitude of the smallest Cabibbo-Kobayashi-Maskawa matrix element, $|V_{ub}|$, and can provide new insights into the origin of the longstanding exclusive-inclusive discrepancy in determinations of this standard-model parameter. This requires a nonperturbative QCD calculation of the $B \to \rho$ form factors $V$, $A_0$, $A_1$, and $A_{12}$. The unstable nature of the $\rho$ resonance has prevented precise lattice QCD calculations of these form factors to date. Here, we present the first lattice QCD calculation of the $B \to \rho$ form factors in which the $\rho$ is treated properly as a resonance in $P$-wave $\pi \pi$ scattering. To this end, we use the Lellouch-Lüscher finite-volume formalism to compute the $B \to \pi \pi$ form factors as a function of both momentum transfer and $\pi \pi$ invariant mass, and then analytically continue to the $\rho$ 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.

Keywords

fizika osnovnih delcev;interakcije delcev;kvantna kromodinamika na mreži;oblikovni faktorji;physics of elementary particles;particle interactions;lattice QCD;form factors;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FMF - Faculty of Mathematics and Physics
UDC: 539.120.811
COBISS: 234136323 Link will open in a new window
ISSN: 0031-9007
Views: 49
Downloads: 3
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Other data

Secondary language: Slovenian
Secondary keywords: fizika osnovnih delcev;interakcije delcev;kvantna kromodinamika na mreži;oblikovni faktorji;
Type (COBISS): Article
Pages: str. 161901-1-161901-8
Volume: ǂVol. ǂ134
Issue: ǂiss. ǂ16
Chronology: 2025
DOI: 10.1103/PhysRevLett.134.161901
ID: 26265070