FROM TH2F
constant
18.531913951966505+-0.6347185949873999
chi2/ndof = 8.650006932918185
plane
3.296648707199843+-1.4550600925010773
invpt slope = 18.41755841348964+-1.2334218396119057
theta slope = 5.852441511521422+-2.2812062124888013
chi2/ndof = 3.7868372462831346
from tgraph2D
constant
23.28420172820647+-2.022570918074228
chi2/ndof = 245.44758721269667
plane
4.6729263455598264+-2.5320047295106547
invpt slope = 18.535770146979715+-1.7823645079994712
theta slope = 12.608610760774578+-4.319203769926064
chi2/ndof = 84.67964239683492