  New expressions are derived for photoemission, which allow experimental
electron energy loss data to be used for estimating losses in photoemission.
The derivation builds on new results for dielectric response and mean free
paths of strongly correlated systems of two dimensional layers. Numerical
evaluations are made for $Bi_{2}Sr_{2}CaCu_{2}O_{8}$ (Bi2212) by using a
parametrized loss function. The mean free path for Bi2212 is calculated and
found to be substantially larger than obtained by Norman et al in a recent
paper. The photocurrent is expressed as the convolution of the intrinsic
approximation for the current from a specific 2D layer with an effective loss
function. The observed current is the sum of such currents from the first few
layers. The photo electron from a specific $CuO$ layer is found to excite low
energy acoustic plasmon modes due to the coupling between the $CuO$ layers.
These modes give rise to an asymmetric power law broadening of the photo
current an isolated two dimensional layer would have given. We define an
asymmetry index where a contribution from a Luttinger lineshape is additive to
the contribution from our broadening function. Already the loss effect
considered here gives broadening comparable to what is observed experimentally.
A superconductor with a gapped loss function is predicted to have a
peak-dip-hump lineshape similar to what has been observed, and with the same
qualitative behavior as predicted in the recent work by Campuzano et al.
