[ROOT] Re: how draw the .M() of the sum of TLorentzVector

From: Rene Brun (brun@pcbrun.cern.ch)
Date: Tue Jun 15 2004 - 19:05:29 MEST


Hi Francesco,

TTree::Draw cannot add two TLorentzVectors. I agree that this would be a 
nice feature to perform operations between vectors and then call a 
function on the final object.
The only syntax that would work is:
 res->Draw("p4_pi1_eta_rec_fit.M() + p4_pi2_eta_rec_fit.M()")
but, obviously, this is not what you want

Rene Brun

On 15 Jun 2004, 
Francesco Perfetto 
wrote:

> Hi all,
> 
> I would like add 2 or more TLorentzVector for then take the .M().
> After I open my root file with TBrowser in which there are the
> TLorentzVector I do at command line:
> 
> root [1] .L $ROOTSYS/lib/libPhysics.so
> root [2] res->Draw("(p4_pi1_eta_rec_fit + p4_pi2_eta_rec_fit).M()")
> 
> (WHERE p4_pi1_eta_rec_fit. and p4_pi2_eta_rec_fit. are 2 my
> TLorentzVector)
> 
> but I have the following error:
> 
> *ERROR 30 :
>  Bad numerical expression :"(p4_pi1_eta_rec_fit+p4_pi2_eta_rec_fit).M()"
> root [3]
> 
> There is anyone that can help me?
> 
> Thanks in advance.
> Francesco.
> 



This archive was generated by hypermail 2b29 : Sun Jan 02 2005 - 05:50:08 MET