G.M. Huber, H.P. Blok, T. Horn, et al., ``Charged Pion Form Factor
between Q2=0.60 and 2.45 GeV2, II: Determination
of, and Results for, the Pion Form
Physical Review C 78 (2008) 045203 1-16
Charged Pion Form Factor:
H.P. Blok, T. Horn, G.M. Huber, et al.,
``Charged Pion Form Factor between Q2=0.60 and 2.45
GeV2, I: Measurement of the Cross Section for the
Physical Review C 78 (2008) 045202 1-25
G.M. Huber, H.P. Blok, T. Horn, et al., ``Charged Pion Form Factor between Q2=0.60 and 2.45 GeV2, II: Determination of, and Results for, the Pion Form Factor'', Physical Review C 78 (2008) 045203 1-16 [Download PDF].
The study of exclusive π+/- electroproduction on the nucleon, including separation of the structure functions, is a very useful tool in the study of hadronic structure. In contrast to inclusive (e,e') or photoproduction measurements, the transverse momentum (size) of the scattering constituent and the resolution at which it is probed can be varied independently. Furthermore, ratios of separated response functions can be formed for which nonperturbative corrections may partially cancel, yielding insight into soft-hard factorization at modest Q2. Our results are intriguing, as the ratio of transverse cross sections RT=σπ-T/σπ+T suggests a transition between pion knockout and quark knockout mechanisms as the Mandelstam variable -t is increased. The ratio of longitudinal cross sections RL=σπ-L/σπ+L is also of interest as it confirms the dominance of the pion-pole diagram at low -t, which is necessary for the extraction of the charged pion form factor from electroproduction data. The analysis of these data were very difficult due to the careful rate-corrections required to produce accurate charged pion ratios.
Exclusive, Forward π+/- Electroproduction from Deuterium:G.M. Huber, H.P. Blok, C. Butuceanu, D. Gaskell, T. Horn, et al., ``Separated Response Function Ratios in Exclusive, Forward π+/- Electroproduction'', Physical Review Letters 112 (2014) 182501 1-6 [Download PDF].
G.M. Huber, H.P. Blok, C. Butuceanu, D. Gaskell, T. Horn, et al., ``Separated Response Function in Exclusive, Forward π+/- Electroproduction on Deuterium'', Physical Review C 91 (2015) 015202 1-23 [Download PDF].
During the years 1991-1996, my research was largely performed at the Institute for Nuclear Study of the University of Tokyo. At that time, they had a tagged photon facility and large solid angle detector, TAGX, which was unique in the world for its combination of beam energy (endpoint energy up to 1.2 GeV), large solid angle, wide tagging acceptance, and respectable duty factor (up to 20%), making it optimally suited to answer a number of important questions in intermediate-energy physics. There, I was co-spokesman of two experiments to investigate the prediction of many QCD-based models that the mass and/or width properties of the ρ0 meson are modified in the nuclear medium. Our experiments were performed in the energy region for tagged photons between 600 and 1120 MeV, which is mostly below the ρ0 threshold on the free proton of 1083 MeV. This has a number of advantages.
ρ0 In-Medium Spectral Function Studies:G.M. Huber, G.J. Lolos, Z. Papandreou, ``Probing the ρ0 Mass Modification in the Subthreshold Region on 3He'', Physical Review Letters 80 (1998) 5285-5288 [Download PDF].
This manuscript presents our investigation to identify any ΔNN component in the 3He ground state wavefunction, by comparing pπ+/pπ- photoproduction ratios in the 1 GeV region. This follows an idea originally raised by Lipkin and Lee in 1987 [Phys.Lett.B 182 (1987) 22], but with a number of refinements. This work resulted after I realized that data we had from a separate experiment could contain evidence of this small physical effect. This required a completely different analysis of the data, and a very extensive simulation effort. A lower limit to the configuration probability of 1.5%+/-0.6%+/-0.5% was extracted. Because of the sophistication of the analysis, this result was believed by the accepting referee to be more definitive than any prior work on this topic.
ΔNN Nuclear Wavefunction Analysis:G.M. Huber, G.J. Lolos, et al., ``Probing the ΔNN Component of 3He'', Physical Review C 62 (2000) 044001 1-8 [Download PDF].