The k2-dependence of the transverse pion electroproduction cross section in a generalized born term model

Gutbrod, F.; Krämer, G.

doi:10.1016/0550-3213(72)90612-8

Cited by 27 publications

(15 citation statements)

References 15 publications

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“…Brauel et al [12] similarly used the Born term model of Gutbrod and Kramer [21] to extract F π . The presence of the nucleon and its structure complicates the theoretical model used, and so an unavoidable implication of this method is that the extraction of the pion form factor becomes model dependent.…”

Section: Experiments and Cross Section Data Analysismentioning

confidence: 99%

Determination of the pion charge form factor forQ2=0.60–1.60 GeV2

Tadevosyan¹,

Blok²,

Huber³

et al. 2007

Phys. Rev. C

187

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The data analysis for the reaction 1 H(e, e ′ π + )n, which was used to determine values for the charged pion form factor Fπ for values of Q 2 =0.6-1.6 GeV 2 , has been repeated with careful inspection of all steps and special attention to systematic uncertainties. Also the method used to extract Fπ from the measured longitudinal cross section was critically reconsidered. Final values for the separated longitudinal and transverse cross sections and the extracted values of Fπ are presented.

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Section: Experiments and Cross Section Data Analysismentioning

confidence: 99%

Determination of the pion charge form factor forQ2=0.60–1.60 GeV2

Tadevosyan¹,

Blok²,

Huber³

et al. 2007

Phys. Rev. C

187

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“…To study neutron physics, liquid deuterium targets and gaseous helium targets are available. The study of the 16 O nucleus is also possible thanks to a Waterfall target.…”

Section: Target Systemmentioning

confidence: 99%

“…This method, known as the Born term model method, knew a first improvement with the model of Gutbrod and Kramer [16]. In the Born term model, the nucleon form factors are considered to be the on-shell nucleon form factors, whereas at the nucleon-pion vertex, the nucleon is off-shell.…”

Section: Hadron Form Factors In Pion Electroproductionmentioning

confidence: 99%

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Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

Fuchey

2010

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“…The contact term is used to restore gauge invariance. Born-amplitude based models [1,2] indicate that for values of the invariant mass W above the resonance region and for not too large values of Q 2 , the longitudinal part σ L of the cross section for pion electroproduction at small values of −t is dominated by the t-channel process. The other response functions (transverse σ T and interference terms σ LT and σ T T ) are relatively small.…”

Section: Introductionmentioning

confidence: 99%

Separated response functions in exclusive, forwardπ±electroproduction on deuterium

Huber¹,

Blok²,

Butuceanu³

et al. 2015

Phys. Rev. C

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Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q 2 , and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π − and π + electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data.Purpose: Perform the first complete separation of the four unpolarized electromagnetic structure functions L/T /LT /T T in forward, exclusive π ± electroproduction on deuterium above the dominant resonances.Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central Q 2 values of 0.6, 1.0, 1.6 GeV 2 at W =1.95 GeV, and Q 2 = 2.45 GeV 2 at W =2.22 GeV. There was significant coverage in φ and ǫ, which allowed separation of σL,T,LT,T T . 2Results: σL shows a clear signature of the pion pole, with a sharp rise at small −t. In contrast, σT is much flatter versus t. The longitudinal/transverse ratios evolve with Q 2 and t, and at the highest Q 2 = 2.45 GeV 2 show a slight enhancement for π − production compared to π + . The π − /π + ratio for transverse photons exhibits only a small Q 2 -dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The σT T /σT ratio also drops rapidly with Q 2 , qualitatively consistent with s-channel helicity conservation. The π − /π + ratio for longitudinal photons indicates a small isoscalar contamination at W =1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics. Conclusions: The separated cross sections are compared to a variety of theoretical models, which generally describe σL but have varying success with σT . Further theoretical input is required to provide a more profound insight into the relevant reaction mechanisms for longitudinal and transverse photons, such as whether the observed transverse ratio is indeed due to a transition from pion to quark knockout mechanisms, and provide useful information regarding the twist-3 transversity generalized parton distribution, HT .

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The k2-dependence of the transverse pion electroproduction cross section in a generalized born term model

Cited by 27 publications

References 15 publications

Determination of the pion charge form factor forQ2=0.60–1.60 GeV2

Determination of the pion charge form factor forQ2=0.60–1.60 GeV2

Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

Separated response functions in exclusive, forwardπ±electroproduction on deuterium

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