Year: 2021
Type: article
Abstract: We present the first lattice QCD determination of the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}^{*}(1520)$ vector, axial vector, and tensor form factors that are relevant for the rare decays ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}^{*}(1520){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$. The lattice calculation is performed in the ${\mathrm{\ensuremath{\Lambda}}}^{*}(1520)$ rest frame with nonzero ${\mathrm{\ensuremath{\Lambda}}}_{b}$ momenta, and is limited to the high-${q}^{2}$ region. An interpolating field with covariant derivatives is used to obtain good overlap with the ${\mathrm{\ensuremath{\Lambda}}}^{*}(1520)$. The analysis treats the ${\mathrm{\ensuremath{\Lambda}}}^{*}(1520)$ as a stable particle, which is expected to be a reasonable approximation for this narrow resonance. A domain-wall action is used for the light and strange quarks, while the $b$ quark is implemented with an anisotropic clover action with coefficients tuned to produce the correct ${B}_{s}$ kinetic mass, rest mass, and hyperfine splitting. We use three different ensembles of lattice gauge-field configurations generated by the RBC and UKQCD collaborations, and perform extrapolations of the form factors to the continuum limit and physical pion mass. We give Standard-Model predictions for the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}^{*}(1520){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ differential branching fraction and angular observables in the high-${q}^{2}$ region.
Authors: Stefan Meinel, Gumaro Rendon
Institutions: University of Arizona, Brookhaven National Laboratory
Language: Latvian
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Awards: G1039895795, G111697547, G241279073, G272672434, G3204085874, G3226045097, G357145406, XSEDE 2.0: Integrating, Enabling and Enhancing National Cyberinfrastructure with Expanding Community Involvement, G3850097093, G4354484304, G4382344593, G4392917094, G4972998915, G498139845, G5590740066, G5633341255, G5765906131, G6733788163, G6806689448, G7406122311, G7463374569, G7861570460, G872144517, G8866302460, UNIVERSITY OF ARIZONA HIGH ENERGY PHYSICS PROGRAM, G969889393
OpenAlex ID: W3087168492