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Changeset a07b54c in git


Ignore:
Timestamp:
04/14/20 19:45:19 (6 weeks ago)
Author:
Roberto Preghenella <preghenella@…>
Branches:
master
Children:
974f5bc
Parents:
09ffaee
git-author:
Roberto Preghenella <preghenella@…> (04/05/20 19:17:47)
git-committer:
Roberto Preghenella <preghenella@…> (04/14/20 19:45:19)
Message:

Proper calculation of the DCAz coordinate

File:
1 edited

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  • modules/ParticlePropagator.cc

    r09ffaee ra07b54c  
    135135  Double_t l, d0, dz, p, ctgTheta, phip, etap, alpha;
    136136  Double_t bsx, bsy, bsz;
    137 
     137  Double_t s0, s1, sd;
     138 
    138139  const Double_t c_light = 2.99792458E8;
    139140
     
    297298      zd = z + (TMath::Sqrt(xd * xd + yd * yd) - TMath::Sqrt(x * x + y * y)) * pz / pt;
    298299
     300      // proper calculation of the DCAz coordinate
     301      // s0: track circle parameter at the track origin
     302      // s1: track circle parameter at the closest approach to beam pipe
     303      // sd: s1-s0 signed angular difference
     304      s0 = atan2(y - y_c, x - x_c);
     305      s1 = atan2(yd - y_c, xd - x_c);
     306      sd = atan2(sin(s1 - s0), cos(s1 - s0));
     307      zd = z - r * pz / pt * sd;
     308     
    299309      // use perigee momentum rather than original particle
    300310      // momentum, since the orignal particle momentum isn't known
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