PoS - Proceedings of Science
Volume 256 - 34th annual International Symposium on Lattice Field Theory (LATTICE2016) - Weak Decay and Matrix Elements
Lattice QCD calculation of form factors for $\Lambda_b \to \Lambda(1520) \ell^+ \ell^-$ decays
S. Meinel,* G. Rendon
*corresponding author
Full text: pdf
Pre-published on: December 27, 2016
Published on: March 24, 2017
Experimental results for mesonic $b \to s \mu^+ \mu^-$ decays show a pattern of deviations from Standard-Model predictions, which could be due to new fundamental physics or due to an insufficient understanding of hadronic effects. Additional information on the $b \to s \mu^+ \mu^-$ transition can be obtained from $\Lambda_b$ decays. This was recently done using the process $\Lambda_b \to \Lambda \mu^+ \mu^-$, where the $\Lambda$ is the lightest strange baryon. A further interesting channel is $\Lambda_b \to p^+ K^- \mu^+ \mu^-$, where the $p^+ K^-$ final state receives contributions from multiple higher-mass $\Lambda$ resonances. The narrowest and most prominent of these is the $\Lambda(1520)$, which has $J^P=\frac32^-$. Here we present an ongoing lattice QCD calculation of the relevant $\Lambda_b \to \Lambda(1520)$ form factors. We discuss the choice of interpolating field for the $\Lambda(1520)$, and explain our method for extracting the fourteen $\Lambda_b \to \Lambda(1520)$ helicity form factors from correlation functions that are computed in the $\Lambda(1520)$ rest frame. We present preliminary numerical results at a pion mass of 340 MeV and a lattice spacing of 0.11 fm. This calculation uses a domain-wall action for the $u$, $d$, and $s$ quarks and a relativistic heavy-quark action for the $b$ quark, and is based on gauge-field configurations generated by the RBC and UKQCD Collaborations.
DOI: https://doi.org/10.22323/1.256.0299
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.