A lattice QCD study of $B\to\pi\pi l\nu$

by Luka Leskovec (Jozef Stefan Institute)

Tuesday 14 Feb 2023, 16:00 → 18:00 Europe/Zurich

online (CERN)

$V_{𝑢𝑏}$ is the smallest and least known of all CKM matrix elements; it's currently determined primarily through the exclusive process $B\to\pi l \nu$. I will present progress toward a lattice QCD determination of the $V_{ub}$​ matrix element from a novel transition -- the $B\to\pi\pi l \nu$ process, where the $\pi\pi$ system is in a P-wave and features the $\rho(770)$ resonance as an enhancement. The calculation is performed an ensemble with $N_f=2+1$ isotropic clover fermions wiht $L≈3.6$ fm and a pion mass of 320 MeV; for the b-quark we use the anisotropic clover action. After a brief overview of the theoretical framework, I will discuss some preliminary results.

leskovec_btopipiellnu.pdf