set term svg background rgb 'white'
set out 'plot.svg'
set xlabel 'energy [GeV]'
set ylabel 'Sigma-bkg [arb. un.]'
f(x)=A*G*G/4/( (x-E)**2+G**2/4 )
A=2
E=126
G=2
fit f(x) 'higgs.data' using 1:2:3 zerror via A,E,G
set samples 200
plot \
 'higgs.data' with errorbars title 'ATLAS gamma-gamma data'\
,'out.txt' with lines title 'Breit-Wigner chi-squared fit'\
,f(x) with lines title 'gnuplot fit'