The 39th International Symposium on Lattice Field Theory (Lattice 2022)

Aug 8 – 13, 2022
Hörsaalzentrum Poppelsdorf
Europe/Berlin timezone

The search for new physics in $B \to K \ell^+\ell^-$ and $B \to K \nu\bar{\nu}$ using precise lattice QCD form factors

Aug 8, 2022, 4:50 PM
20m
CP1-HSZ/1st-1.002 - HS6 (CP1-HSZ)

CP1-HSZ/1st-1.002 - HS6

CP1-HSZ

50
Oral Presentation Weak Decays and Matrix Elements

Speaker

William Parrott (University of Glasgow)

Description

We present HPQCD's improved scalar, vector and tensor form factors for $B \to K$ semileptonic decays, using the heavy-HISQ formalism for more accurate normalisation of the weak currents. Working with masses close to the physical $b$ on the finest ensemble and including three ensembles with physical light quarks, we cover the full physical $q^2$ range with good precision. Our uncertainties at $q^2=0$ are a factor of three better than earlier work.

We compare Standard Model observables using our form factors to experimental measurements for the rare flavour changing neutral current processes $B \to K \ell^+\ell^-$ and $B \to K \nu\bar{\nu}$ and discuss the significance of the tensions that arise.

Primary author

William Parrott (University of Glasgow)

Co-authors

Prof. Christine Davies (University of Glasgow) Dr Chris Bouchard (University of Glasgow)