Re: TLorentzVector

From: Victor Perevoztchikov (perev@bnl.gov)
Date: Wed Nov 03 1999 - 17:24:35 MET


"M. Sievers" wrote:
> 
> On Wed, 3 Nov 1999, Nick van Eijndhoven wrote:
> 
> > Hi Victor,
> > Maybe I am missing a point here, but the dotproduct you mention
> > below has to my opinion no physical meaning and as such I would
> > say should not be supported or at least the user should receive a
> > warning message that he/she is doing nonsense.
> > However, as I said I may be missing a point here and then I am
> > saying nonsense.
> 
> I'd say a dot product with a three-Vector makes sense much in the same way
> as an angle to a three-vector does! You could make a four-vector for
> example by taking tracking information for the momentum and calorimeter
> information for the energy (should be possible...). And you should still
> be able to compare it to other tracks!
> 
> Bye,
> Mike
Completely agree. A simple example. You have some direction (3 vector D)
and momentum of a track 4 vector P. Scalar production of them provide you
cosine of angle between them. Then this angle is used to estimate effectivity
 etc.

Victor


> 
> --------------------------------------------------------------------------
> Michael Sievers
> Michael.Sievers@desy.de
> --------------------------------------------------------------------------
> esa$ gcc -Wall -o ariane5 ariane4.c
> ariane4.c: 666: warning: long float implicitly truncated to unsigned type
> esa$ ariane5

-- 
Victor M. Perevoztchikov   perev@bnl.gov  perev@vxcern.cern.ch       
Brookhaven National Laboratory MS 510A PO Box 5000 Upton NY 11973-5000
tel office : 631-344-7894; fax 631-344-4206; home 631-345-2690



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