arXiv subjects

M. F. Taragin

Publications and source records attributed to M. F. Taragin.

22 records · Page 2Linked to original sources

arXiv1995

Effect of $NN$-correlations on predictions of nuclear transparencies for protons, knocked-out in high $Q^2\,(e,e'p)$ reactions

We study the transparency $\cal T$ of nuclei for nucleons knocked-out in high-energy semi-inclusive $(e,e'p)$ reactions, using an improved theoretical input, discussed by Nikolaev et al. We establish that neglect of $NN$-correlations between the knocked-out and core nucleons reduces nuclear transparencies by $\approx 15 \%$ for light, to $\approx 10\%$ for heavy nuclei. About the same is predicted for transparencies, integrated over the transverse or longitudinal momentum of the outgoing proton. Hadron dynamics predicts a roughly constant $\cal T$ beyond $Q^2\approx $2 GeV$^2$, whereas for all targets the largest measured data point $Q^2$=6.7 GeV$^2$ appears to lie above that plateau. Large error bars on those data-points preclude a conclusion regarding the onset of colour transparency.

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arXiv1995

Description of inclusive scattering of few_GeV electrons from finite A nuclei and nuclear matter

We study $eA$ scattering in a model where the total nuclear structure function is a convolution of components $W_N$ for an isolated nucleon and $W_{\NA}$ for a nucleus composed of point-nucleons. $W_N$ is represented by its elastic and lowest-energy inelastic parts, while $W_{\NA}$ is computed from its asymptotic limit, supplemented by final state interactions due to binary collisions between the knocked-out and core nucleons. $(q/M)W_{\NA}$ per nucleon appears to be practically independent of mass number $A$ and momentum transfer $q$. Consequently, predicted inclusive cross sections per nucleon for given kinematic conditions hardly depend on the target and the same can be extracted from the data. Exceptions are low energy loss regions, where relatively small cross sections are shown to be sensitive to details of the single nucleon momentum distribution and to FSI, involving multiple collisions. The agreement with the data is good.

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arXiv1994

Nuclear transparencies for nucleons, knocked-out under various semi-inclusive conditions

Using hadron dynamics we calculate nuclear transparencies for protons, knocked-out in high-$Q^2$, semi-inclusive reactions. Predicted transparencies are, roughly half a standard deviation above the NE18 data. The latter contain the effects of binned proton missing momenta and mass, and of finite detector acceptances. In order to test sensitivity we compare computed transparencies without restrictions and the same with maximal cuts for missing momenta and the electron energy loss. We find hardly any variation, enabling a meaningful comparison with data and predictions based on hadron dynamics. Should discrepancies persist in high-statistics data, the above may with greater confidence be attributed to exotic components in the description of the outgoing proton.

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arXiv1993

Inclusive scattering of electrons from nuclear matter in the few GeV range

We study Final State Interaction effects (FSI) in inclusive electron scattering of several GeV from nuclear matter. We consider separately the cases of 'elastic' and 'inelastic' knockout of respectively a nucleon and a non-nucleonic particle. For the former category FSI have been calculated, using the first cumulant approximation of a relativistic generalization of the theory of Gersch et al, including intermediate NN states states with produced hadrons. We also discuss a formal expression for the first cumulant approximation on the basis of the PWIA. FSI between an inelasticlly knocked-out particle and core nucleons are neglected. We present two scaling analyses of the data, from which the above 'inelastic' contributions have been been removed. The data expressed in a relativistic West variable show scaling of a much better quality than the same in the IA scaling variable. Predictions for inclusive cross sections in the two first cumulant versions are presented and discussed. We make a critical comparison of the above with the IA approach of Benhar et al and their results.

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