scholarly journals Measurement of the γ*γ*→ η' transition form factor and of the e+e−→ π+π−π0π0π0 and π+π−π0π0η cross sections by BABAR

2019 ◽  
Vol 206 ◽  
pp. 05004
Author(s):  
J. William Gary
Keyword(s):  
Form Factor ◽  
Cross Sections ◽  
Transition Form Factor ◽  
Branching Fractions ◽  
Low Energy ◽  
Final States ◽  
Transition Form ◽  
Intermediate Resonance ◽  
Babar Experiment ◽  
Hadronic Final States

Two recent studies from the BABAR experiment at SLAC on low-energy hadronic final states in e+e− annihilations are presented. The first study provides the first-ever measurement of the γ*γ*→ η' transition factor, where γ* denotes an off-shell photon. The second study provides the first-ever measurements of the e+e−→ π+ π−π0π0π0 and π+π−π0π0η cross sections, including studies of the intermediate resonance states and the corresponding J/ψ and ψ(2S) branching fractions.

scholarly journals New results on low energy exclusive hadronic final states from BABAR

2018 ◽  
Vol 172 ◽  
pp. 04002
Author(s):  
J. William Gary
Keyword(s):  
Standard Deviation ◽  
Cross Section ◽  
Cross Sections ◽  
Particle Physics ◽  
Low Energy ◽  
Final States ◽  
Muon Anomalous Magnetic Moment ◽  
The Standard Model ◽  
Babar Experiment ◽  
Hadronic Final States

The 3.6 standard deviation discrepancy between the standard model (SM) prediction for the muon anomalous magnetic moment gμ - 2 and the corresponding experimental measurement is one of the most persistent and intriguing potential signals in particle physics for physics beyond the SM. The largest uncertainty in the SM prediction for gμ - 2 arises from the uncertainty in the measured low energy inclusive e+e- → hadrons cross section. New results from the BABAR experiment at SLAC for the e+e- → π+ π- π0 π0 and e+e- → KK ππ cross sections are presented that significantly reduce this uncertainty. New BABAR results for other low energy exclusive hadronic processes are also discussed.

GAMMA GAMMA PHYSICS AT BELLE

2014 ◽  
Vol 35 ◽  
pp. 1460396 ◽  
Author(s):  
SADAHARU UEHARA ◽  
Keyword(s):  
Form Factor ◽  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Transition Form Factor ◽  
Light Quark ◽  
Transition Form ◽  
Two Photon ◽  
Belle Detector ◽  
Meson Pair

We report a high-statistics measurement of the differential cross section of the process [Formula: see text] with the Belle detector. We study spectroscopy of light-quark resonances and charmonia and test QCD models using the data. We summarize our systematic measurements of different processes of γγ → meson-pair production based on the parameterization of the cross sections and comparison with QCD models. We also report on the measurement of the two-photon π0 transition form factor at Belle.

scholarly journals Measurement of the ϕ → π 0 e + e − transition form factor with the KLOE detector

2016 ◽  
Vol 757 ◽  
pp. 362-367 ◽  
Author(s):  
A. Anastasi ◽  
D. Babusci ◽  
G. Bencivenni ◽  
M. Berlowski ◽  
C. Bloise ◽  
...  
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form

scholarly journals η′transition form factor from space- and timelike experimental data

2016 ◽  
Vol 94 (5) ◽  
Author(s):  
R. Escribano ◽  
S. Gonzàlez-Solís ◽  
P. Masjuan ◽  
P. Sanchez-Puertas
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form

THE ANOMALOUS PROCESS γπ → ππ AND ITS IMPACT ON THE π0 TRANSITION FORM FACTOR

2014 ◽  
Vol 35 ◽  
pp. 1460397
Author(s):  
BASTIAN KUBIS
Keyword(s):  
Form Factor ◽  
Phase Shift ◽  
Theoretical Analysis ◽  
Cross Section ◽  
Transition Form Factor ◽  
P Wave ◽  
Chiral Anomaly ◽  
Transition Form ◽  
Dispersive Representation ◽  
Important Input

The process γπ → ππ, in the limit of vanishing photon and pion energies, is determined by the chiral anomaly. This reaction can be investigated experimentally using Primakoff reactions, as currently done at COMPASS. We derive a dispersive representation that allows one to extract the chiral anomaly from cross-section measurements up to 1 GeV, where effects of the ρ resonance are included model-independently via the ππ P-wave phase shift. We discuss how this amplitude serves as an important input to a dispersion-theoretical analysis of the π0 transition form factor, which in turn is a vital ingredient to the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.

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