rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

LHCB_2017_I1621811

Differential Decay rates for $\Lambda_b^0\to \Lambda_c^+ \mu^-\bar{\nu}_\mu$
Experiment: LHCB (LHC)
Inspire ID: 1621811
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardsomn
References:
  • Phys.Rev.D 96 (2017) 11, 112005
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing Lambda_b0 baryons, originally pp

Differential decay rates for semileptonic $\Lambda_b^0\to \Lambda_c^+ \mu^-\bar{\nu}_\mu$ decays

Source code: LHCB_2017_I1621811.cc
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief Lambda_b0 -> Lambda_c+ semi-leptonic
  class LHCB_2017_I1621811 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2017_I1621811);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(UnstableParticles(), "UFS");

      // Book histograms
      book(_h_q2 , 1, 1, 1);
    }

    // Calculate the Q2 using mother and daugher meson
    double q2(const Particle& B, int mesonID) {
      FourMomentum q = B.mom() - filter_select(B.children(), Cuts::pid==mesonID)[0];
      return q*q;
    }
    
    // Check for explicit decay into pdgids
    bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
      // Trivial check to ignore any other decays but the one in question modulo photons
      const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
      if (children.size()!=ids.size()) return false;
      // Check for the explicit decay
      return all(ids, [&](int i){return count(children, hasPID(i))==1;});
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      for (const Particle& p :  apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==5122)) {
	if(p.pid()>0) {
	  if(isSemileptonicDecay(p, {4122, PID::MUON, PID::NU_MUBAR})) {
	    _h_q2->fill(q2(p, 4122));
	  }
	}
	else {
	  if(isSemileptonicDecay(p, {-4122, PID::ANTIMUON, PID::NU_MU})) {
	    _h_q2->fill(q2(p, -4122));
	  }
	}
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // normalize to unity
      normalize(_h_q2);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_q2;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(LHCB_2017_I1621811);

}