Measurement of R=\sigma_L/\sigma_T in DeepInelastic Scattering on Nuclei
Abstract
Cross section ratios for deepinelastic scattering from $^3$He, $^{14}$N and $^{84}$Kr with respect to $^2$H have been measured by the HERMES collaboration at DESY using a 27.5 GeV positron beam. The data cover a range in the Bjorken scaling variable $x$ between 0.010 and 0.65, the negative squared fourmomentum transfer $Q^2$ varies from 0.5 to 15 GeV$^2$, while at small values of $x$ and $Q^2$, the virtual photon polarisation parameter $\epsilon$ extends to lower values than previous measurements. From the dependence of the data on $\epsilon$, values for $R_A/R_D$ with $R$ the ratio $\sigma_L / \sigma_T$ of longitudinal to transverse DIS cross sections have been derived and found to be consistent with unity. %The data are compared to measurements performed by NMC, E665, and SLAC %on $^4$He and $^{12}$C, and are found to be different for %$x <$ 0.06 and $Q^2 <$ 1.5 GeV$^2$.
 Publication:

arXiv eprints
 Pub Date:
 October 2002
 arXiv:
 arXiv:hepex/0210068
 Bibcode:
 2002hep.ex...10068H
 Keywords:

 High Energy Physics  Experiment
 EPrint:
 8 pages, 7 figures