class HParticleAngleCor: public TObject

 reset moving average and start with X,Y values
 from global vertex of next event

 calculate new emission angles and emission point based on global vertex.
 Assume that the Rich mirror and Rich housing (+ delta electron shield)
 produce the dominant multiple scattering kick which generate an off-vertex
 behaviour of a particle originating from global vertex.
 Returns kFALSE, if correction fails.In this case: New values = old values

 same as above, get old emission values from ParticleCandidate

 return only angles theta, phi. Emission point is global vertex
 (x,y could be mean values of global vertex)

 calculate new emission angles based on global vertex
 and replace theta and phi of the particle candidate

 calculate new emission point and angles based on global vertex
 and replace theta, phi, z and rho of the particle candidate

 correct angles theta and phi of a rich ring. Accounts for the missing rich
 sector alignment.The lookup table was obtained from fits to ring-track
 matches in theta and phi. Alignment parameters where obtained for beamtime
 Apr12 based on Gen1 Dst's. Values are changed inside HParticleCand!

 correct angles theta and phi of a rich ring. Accounts for the missing rich
 sector alignment.The lookup table was obtained from fits to ring-track
 matches in theta and phi. Alignment parameters where obtained for beamtime
 Apr12 based on Gen1 Dst's. theta, phi in degree, lab coordinate system

 correct angles theta and phi of a rich ring. Its supposed to called after
 recalulating emmission from target ("MS suppresion") for candidate RK theta/phi.
 Accounts for the missing rich sector alignment.
 Lookup table was obtained from fits to ring-track matches in theta and phi.
 Alignment parameters where obtained for beamtime Apr12 based on Gen3 Dst's.
 theta, phi in degree, lab coordinate system.
 nSector is NOT the standard labeling: Sector0 corresponds to nSector=1

 same as realignRichRing(const HParticleCand* pCand, Float_t & thetaCor, Float_t & phiCor)
 but changes the RICH angles inside the candidate

 match angles theta and phi of a track with a rich ring attached in terms of resolution sigma
 Lookup table for sigma was obtained from fits to ring-track matches in 4 theta and 4 phi bins.
 momentum dependence was calculated from 2 momentum bins assuming a constant term
 and a term which reflects multiple scattering: sigma proportional to (1/p + const).
 return value is a normalized matching parameter: radial deviation/sigma
 Matching parameters where obtained for beamtime Apr12 based on Gen2 Dst's.
 theta, phi in degree, lab coordinate system
 thetaSwitch: <= low theta range, > high theta range

 calculate position and direction vectors from a segment which
 is defined by z-point and closest distance to z-axis (rho) and
 by emission angles theta, phi. TMath::PiOver2() = pi/2

 activate / deactivate delta-electron shield.
 This changes the multiple scattering point at small angles
 by an increased radius of the sphere

 beamtime is a character string like "apr12".
 If beamtime defaults are not implemented return value
 is kFALSE otherwise kTRUE

 Use the center of the X-, Y- event vertex distribution.
 For small target/beamspot diameters appropriate. Beamspot smaller
 than global vertex resolution. Set mean Values, if different
 from zero (default)

 Use X-, Y- values from the global vertex determined event by event.
 For large beam spots and large target diameters appropriate.
 Good, if beam spot on target is larger than resolution of global vertex.

 return the (mean) x- and y- vertex points.
 returns kTRUE, if the mean values replace the x- and y points
 of the global event vertex

  return the global vertex position
  v can be Particle::kVertexCluster, Particle::kVertexSegment,
  Particle::kVertexParticle. In case of Particle::kVertexSegment
  and Particle::kVertexParticle the chi2 of the vertex fit is
  checked. If the the fit Particle::kVertexSegment failed the position of
  Particle::kVertexCluster is returned instead. If Particle::kVertexParticle
  fails Particle::kVertexSegment is used if possible otherwise fallback
  is Particle::kVertexCluster.