Chakraborty, B., Parrott, W.G., Bouchard, C. , Davies, C.T.H. , Koponen, J. and Lepage, G.P. (2021) Improved Vcs determination using precise lattice QCD form factors for D → Kℓν. Physical Review D, 104(3), 034505. (doi: 10.1103/PhysRevD.104.034505)
![[img]](https://eprints.gla.ac.uk/style/images/fileicons/text.png) |
Text
246983.pdf - Published Version Available under License Creative Commons Attribution. 2MB |
Abstract
We provide a 0.8%-accurate determination of V c s from combining experimental results for the differential rate of D → K semileptonic decays with precise form factors that we determine from lattice QCD. This is the first time that V c s has been determined with an accuracy that allows its difference from 1 to be seen. Our lattice QCD calculation uses the Highly Improved Staggered Quark (HISQ) action for all valence quarks on gluon field configurations generated by the MILC collaboration that include the effect of u , d , s and c HISQ quarks in the sea. We use eight gluon field ensembles with five values of the lattice spacing ranging from 0.15 fm to 0.045 fm and include results with physical u / d quarks for the first time. Our calculated form factors cover the full q 2 range of the physical decay process and enable a Standard Model test of the shape of the differential decay rate as well as the determination of V c s from a correlated weighted average over q 2 bins. We obtain | V c s | = 0.9663 ( 53 ) latt ( 39 ) exp ( 19 ) η E W ( 40 ) EM , where the uncertainties come from lattice QCD, experiment, short-distance electroweak and electromagnetic corrections, respectively. This last uncertainty, neglected for D → K ℓ ν hitherto, now needs attention if the uncertainty on V c s is to be reduced further. We also determine V c s values in good agreement using the measured total branching fraction and the rates extrapolated to q 2 = 0 . Our form factors enable tests of lepton flavour universality violation. We find the ratio of branching fractions for D 0 → K − with μ and e in the final state to be R μ / e = 0.9779 ( 2 ) latt ( 50 ) E M in the Standard Model, with the uncertainty dominated by that from electromagnetic corrections.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Davies, Professor Christine and Parrott, Mr William and Bouchard, Dr Chris and Koponen, Dr Jonna |
| Authors: | Chakraborty, B., Parrott, W.G., Bouchard, C., Davies, C.T.H., Koponen, J., and Lepage, G.P. |
| College/School: | College of Science and Engineering > School of Physics and Astronomy |
| Journal Name: | Physical Review D |
| Publisher: | American Physical Society |
| ISSN: | 2470-0010 |
| ISSN (Online): | 2470-0029 |
| Published Online: | 24 August 2021 |
| Copyright Holders: | Copyright © 2021 American Physical Society |
| First Published: | First published in Physical Review D 104(3): 034505 |
| Publisher Policy: | Reproduced under a Creative Commons License |
University Staff: Request a correction | Enlighten Editors: Update this record
Altmetric
Altmetric