Rivet analyses referenceBELLE_2006_I658082Mass distributions in $B^-\to\Lambda_c^+\bar{p}\pi^-$Experiment: BELLE (KEKB) Inspire ID: 658082 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY
Measurement of mass distributions in $B^-\to\Lambda_c^+\bar{p}\pi^-$. The mass distributions were read from figure 2, which is not corrected, while the corrected helicity distribution was read from figure 3. Source code: BELLE_2006_I658082.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/DecayedParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief B- -> Lambdac+ pbar pi-
10 class BELLE_2006_I658082 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2006_I658082);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // Initialise and register projections
23 UnstableParticles ufs = UnstableParticles(Cuts::abspid==521);
24 declare(ufs, "UFS");
25 DecayedParticles BP(ufs);
26 // treat Lambda_c, Sigma_c and sigma_c* as stable
27 BP.addStable( 4122);
28 BP.addStable(-4122);
29 declare(BP, "BP");
30 for (unsigned int ix=0; ix<2; ++ix) {
31 book(_h[ix],1,1,1+ix);
32 }
33 book(_h[2],2,1,1);
34 }
35
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 DecayedParticles BP = apply<DecayedParticles>(event, "BP");
40 // loop over particles
41 for (unsigned int ix=0;ix<BP.decaying().size();++ix) {
42 int sign = 1;
43 if (BP.decaying()[ix].pid()<0 && BP.modeMatches(ix,3,mode )) sign = 1;
44 else if (BP.decaying()[ix].pid()>0 && BP.modeMatches(ix,3,modeCC)) sign =-1;
45 else continue;
46 const Particle& lamC = BP.decayProducts()[ix].at( sign*4122)[0];
47 const Particle& pbar = BP.decayProducts()[ix].at(-sign*2212)[0];
48 const Particle& pim = BP.decayProducts()[ix].at(-sign*211 )[0];
49 double mLamCPi = (lamC.mom()+pim .mom()).mass();
50 double mPbarPi = (pbar.mom()+pim .mom()).mass();
51 double mLamCPB = (lamC.mom()+pbar.mom()).mass();
52 if (mLamCPi>2.6 && mLamCPB>3.5) _h[0]->fill(mPbarPi);
53 if (mLamCPi>2.6 && mPbarPi>1.6) _h[1]->fill(mLamCPB);
54 if (mLamCPB<3.6) {
55 LorentzTransform boostB = LorentzTransform::mkFrameTransformFromBeta(BP.decaying()[ix].mom().betaVec());
56 FourMomentum pLamC = boostB.transform(lamC.mom());
57 FourMomentum pLamCPB = boostB.transform(lamC.mom()+pbar.mom());
58 LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pLamCPB.betaVec());
59 pLamC = boost2.transform(pLamC);
60 double cTheta = pLamC.p3().unit().dot(pLamCPB.p3().unit());
61 _h[2]->fill(cTheta);
62 }
63 }
64 }
65
66
67 /// Normalise histograms etc., after the run
68 void finalize() {
69 normalize(_h, 1.0, false);
70 }
71
72 /// @}
73
74
75 /// @name Histograms
76 /// @{
77 Histo1DPtr _h[3];
78 const map<PdgId,unsigned int> mode = { { 4122,1},{-2212,1}, {-211,1}};
79 const map<PdgId,unsigned int> modeCC = { {-4122,1},{ 2212,1}, { 211,1}};
80 /// @}
81
82
83 };
84
85
86 RIVET_DECLARE_PLUGIN(BELLE_2006_I658082);
87
88}
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