Lattice QCD Calculation of π
Phys Rev Lett
; 130(19): 191901, 2023 May 12.
Article
in En
| MEDLINE
| ID: mdl-37243653
ABSTRACT
We extend the application of lattice QCD to the two-photon-mediated, order α^{2} rare decay π^{0}âe^{+}e^{-}. By combining Minkowski- and Euclidean-space methods we are able to calculate the complex amplitude describing this decay directly from the underlying theories (QCD and QED) which predict this decay. The leading connected and disconnected diagrams are considered; a continuum limit is evaluated and the systematic errors are estimated. We find ReA=18.60(1.19)(1.05) eV, ImA=32.59(1.50)(1.65) eV, a more accurate value for the ratio (ReA/ImA)=0.571(10)(4), and a result for the partial width Γ(π^{0}âγγ)=6.60(0.61)(0.67) eV. Here the first errors are statistical and the second systematic. This calculation is the first step in determining the more challenging, two-photon-mediated decay amplitude that contributes to the rare decay Kâµ^{+}µ^{-}.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Phys Rev Lett
Year:
2023
Type:
Article
Affiliation country:
United States