Asset Details
Do you wish to reserve the book?
Two-pion contribution to hadronic vacuum polarization
Hey, we have placed the reservation for you!
By the way, why not check out events that you can attend while you pick your title.
Oops! Something went wrong.
Looks like we were not able to place the reservation. Kindly try again later.
Are you sure you want to remove the book from the shelf?
Two-pion contribution to hadronic vacuum polarization
Do you wish to request the book?
Two-pion contribution to hadronic vacuum polarization
Please be aware that the book you have requested cannot be checked out. If you would like to checkout this book, you can reserve another copy
We have requested the book for you!
Your request is successful and it will be processed during the Library working hours. Please check the status of your request in My Requests.
Oops! Something went wrong.
Looks like we were not able to place your request. Kindly try again later.
Journal Article
Two-pion contribution to hadronic vacuum polarization
2019
Overview
A
bstract
We present a detailed analysis of
e
+
e
−
→
π
+
π
−
data up to
s
=
1
GeV in the framework of dispersion relations. Starting from a family of
ππ P
-wave phase shifts, as derived from a previous Roy-equation analysis of
ππ
scattering, we write down an extended Omnès representation of the pion vector form factor in terms of a few free parameters and study to which extent the modern high-statistics data sets can be described by the resulting fit function that follows from general principles of QCD. We find that statistically acceptable fits do become possible as soon as potential uncertainties in the energy calibration are taken into account, providing a strong cross check on the internal consistency of the data sets, but preferring a mass of the
ω
meson significantly lower than the current PDG average. In addition to a complete treatment of statistical and systematic errors propagated from the data, we perform a comprehensive analysis of the systematic errors in the dispersive representation and derive the consequences for the two-pion contribution to hadronic vacuum polarization. In a global fit to both time- and space-like data sets we find
a
μ
ππ
|
≤ 1 GeV
= 495.0(1.5)(2.1) × 10
− 10
and
a
μ
ππ
|
≤ 0.63 GeV
= 132.8(0.4)(1.0) × 10
− 10
. While the constraints are thus most stringent for low energies, we obtain uncertainty estimates throughout the whole energy range that should prove valuable in corroborating the corresponding contribution to the anomalous magnetic moment of the muon. As side products, we obtain improved constraints on the
ππ P
-wave, valuable input for future global analyses of low-energy
ππ
scattering, as well as a determination of the pion charge radius, 〈
r
π
2
〉 = 0
.
429(1)(4) fm
2
.
Publisher
Springer Berlin Heidelberg,Springer Nature B.V,Springer Berlin,SpringerOpen
