Search results for "High momentum"
showing 6 items of 6 documents
Deuteron electrodisintegration near threshold at high momentum transfer
1983
Electrodisintegration of the deuteron near the break-up threshold is a particularly striking example of the existence of exchange currents (EC). While the conventional one-body current contribution grossly underestimates the experimental cross-section up to a momentum transfer of aboutq μ 2 =15 fm−2, the inclusion of EC—dominantly π-MEC—leads to a drastic increase in satisfactory agreement with experimental data up toq 2=9 fm−2.
THE PARTON DISTRIBUTIONS IN NUCLEONS: A QUARK MODEL ANALYSIS
1995
We use a laboratory frame description based on quark model wave functions to study the parton distributions in the nucleon. The present approach incorporates two major improvements, namely, it has the correct support and the renormalization group evolution is carried out to next-to-leading order. We obtain initially the parton distributions arising from the Isgur-Karl wave function. The failure of the latter to reproduce, even approximately, the data motivates us to analyze different scenarios, i.e. additional high momentum components and nonvanishing gluon distributions at the initial scale. We conclude that in order to understand data at various scales complex models simultaneously, it i…
The role of electromagnetic form factors in meson exchange currents
1988
The question of electromagnetic form factors, i.e. F1V versus GEV, to be used in isovector meson exchange currents in nonrelativistic calculations is critically reviewed. None of the various arguments given earlier in favour of F1V have been found valid. Furthermore, model dependence of theoretical calculations on deuteron threshold disintegration due to e.m. form factor fits and potential models is found to be substantial. In view of these results, relativistic effects have to be included for a clear understanding of this process in the high momentum transfer region.
High-momentum components in the 1p orbitals of 16O
1995
Abstract We have investigated that part of the proton momentum distribution of 16O that is linked through the (e, e′p) reaction to low-lying discrete states in 15N. The MAMI facility with its new generation of 100%-duty-cycle electron accelerator has allowed to cover in this experiment the previously not accessible momentum range of 265
Comment on the Deuteron Structure FunctionA(q2)at High Momentum Transfers
1976
Calculations of A (q/sup 2/) were performed for various NN potentials and electromagnetic nucleon form factors at q/sup 2/=0--160 fm/sup -2/ with inclusion of isobar configurations and meson exchange currents, indicating that recent elastic electron scattering experiments do not rule out the existence of isobar configurations and meson exchange currents in the deuteron as has been conjectured. (AIP)
Measurement of the Time-like Pion Transition Form Factor at BESIII
2019
The pion transition form factor is an important input to the dispersive approaches of the Standard Model calculations for the anomalous magnetic moment of the muon. We report the prospects of a first measurement at high momentum transfer in the time-like region performed at BESIII. The aim is to improve the uncertainty of the hadronic light-by-light calculations and to shed light on the BaBar-Belle puzzle in the space-like region.