CandUtils/interface/helicityAngle.h

0001 #ifndef CandUtils_helicityAngle_h
0002 #define CandUtils_helicityAngle_h
0003 /**  helicityAngle

0004  *

0005  * Utility function that returns the helicity angle

0006  * It is defined as the angle between the candidate

0007  * momentum and one of the daughters momentum in the

0008  * mother's center-of-mass reference frame.

0009  * This angle has a two-fold ambiguity (h, pi - h ), and

0010  * by convention the angle smaller than pi/2 is chosen.

0011  *

0012  * \author Luca Lista, INFN

0013  *

0014  * \version $Revision: 1.7 $

0015  *

0016  * $Id: helicityAngle.h,v 1.7 2007/12/11 08:42:52 hegner Exp $

0017  *

0018  */
0019 #include "DataFormats/Candidate/interface/CandidateFwd.h"
0020
0021 /// return the helicity angle for two particles.

0022 double helicityAngle(const reco::Candidate& mother, const reco::Candidate& daughter);
0023
0024 /// return the helicity angle of a two body decay with daughter automatically retreived

0025 /// Note: asserts if the candidate does not have two daughters

0026 double helicityAngle(const reco::Candidate& c);
0027
0028 #endif