- #1
ndung200790
- 519
- 0
Please teach me this:
In chapter 18.4 Peskin&Schoeder(QFT) they consider the annihilation of electron and positron to hadron.Ignoring the mass of the electron,we have:
σ(e^{+}e^{-})=(1/2s)ImM(e^{+}e^{-}→e^{+}e^{-}).
We have:
iM=(-ie)^{2}u^{-}(k)\gamma_{\mu}v(k_{+}(-i/s)(i\Pi^{\mu\nu}_{h}(q))(-i/s)v^{-}(k_{+}\gamma_{\nu}u(k).
I do not understand why they can write:
i∏^{\mu\nu}_{h}(q)=-e^{2}\intd^{4}xe^{iqx}<T{J^{\mu}(x)J^{\nu}(0)>.
Where J^{\mu} is the electromagnetic current of quarks.
Thank you very much for your kind helping.
In chapter 18.4 Peskin&Schoeder(QFT) they consider the annihilation of electron and positron to hadron.Ignoring the mass of the electron,we have:
σ(e^{+}e^{-})=(1/2s)ImM(e^{+}e^{-}→e^{+}e^{-}).
We have:
iM=(-ie)^{2}u^{-}(k)\gamma_{\mu}v(k_{+}(-i/s)(i\Pi^{\mu\nu}_{h}(q))(-i/s)v^{-}(k_{+}\gamma_{\nu}u(k).
I do not understand why they can write:
i∏^{\mu\nu}_{h}(q)=-e^{2}\intd^{4}xe^{iqx}<T{J^{\mu}(x)J^{\nu}(0)>.
Where J^{\mu} is the electromagnetic current of quarks.
Thank you very much for your kind helping.
