Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69574120200202Excited states energy corrections of hydrogen atom at the order of & alpha4 using NRQED as an effective field theoryExcited states energy corrections of hydrogen atom at the order of & alpha<sup>4</sup> using NRQED as an effective field theory33401488FAS. M. ZebarjadM. BigdeliJournal Article20200202 In this paper, we calculate Hydrogen hyperfine splitting (HFS) at the order a4 by using NRQED as an effective field theory. We also show the leading-order contribution of nuclear size to the energy correction of Hydrogen atom . In this paper, we calculate Hydrogen hyperfine splitting (HFS) at the order a4 by using NRQED as an effective field theory. We also show the leading-order contribution of nuclear size to the energy correction of Hydrogen atom . https://ijpr.iut.ac.ir/article_1488_a21e0c590c668a27af8e197c47b5d850.pdf