set term png enhanced transparent 
set grid
set key bottom right
unset logscale; set logscale y
set title 'gamma p —> pi0 p'
set xlabel 't (GeV^2)'
set ylabel 'Dsig/Dt (micro b/GeV^2)'
set output 'plotwitht.png'
plot 'output.txt' using 1:3 w l ls 2 lw 3 lc rgb "blue" title 'MS Model'

set grid
set key bottom right
unset logscale; set logscale y
set title 'gamma p —> pi0 p'
set xlabel 'Cos theta’
set ylabel 'Dsig/DOmega (micro b)'
set output 'plotwithc.png'
plot 'output.txt' using 2:4 w l lt -1 lw 3 lc rgb "red" title 'MS Model'