Rivet analyses

Measurement of the continuum of dimuons produced in high-energy proton-nucleus collisions

Experiment: E288 (Fermilab p-N)

Inspire ID: 153009

Status: VALIDATED

Authors: none listed

References: - Phys. Rev., D23(1981), 604-633 - DOI: 10.1103/PhysRevD.23.604

Beams: p+ p+

Beam energies: (13.7, 13.7)GeV

Run details: none listed

We report final results of a series of measurements of continuum dimuon production in proton-nucleus collisions at Fermilab. New results with 6 times more statistics are included.

Source code:E288_1981_I153009.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DileptonFinder.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"

namespace Rivet {


  /// Measurement of dimuon continuum in proton-nucleus collisions
  class E288_1981_I153009 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(E288_1981_I153009);


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

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

      // Initialise and register projections
      DileptonFinder zfinder(91.2 * GeV, 0.0, Cuts::abseta < 15.0 && Cuts::abspid == PID::MUON,
                             Cuts::massIn(3.5 * GeV, 30.0 * GeV));
      declare(zfinder, "DileptonFinder");

      // Book histograms
      // 400 GeV and y = 0.03
      book(_hist_pT_M_400, {5., 6., 7., 8., 9., 10., 11., 12., 13., 14.});
      for (auto& b : _hist_pT_M_400->bins()) {
        book(b, 9, 1, b.index());
      }

      int Nbin = 50;
      book(_h_m_DiMuon, "DiMuon_mass", Nbin, 0.0, 30.0);
      book(_h_pT_DiMuon, "DiMuon_pT", Nbin, 0.0, 20.0);
      book(_h_y_DiMuon, "DiMuon_y", Nbin, -8.0, 8.0);
      book(_h_xF_DiMuon, "DiMuon_xF", Nbin, -1.5, 1.5);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      const DileptonFinder& zfinder = apply<DileptonFinder>(event, "DileptonFinder");
      if (zfinder.particles().size() >= 1) {

        double Zmass = zfinder.bosons()[0].momentum().mass() / GeV;
        double Zpt = zfinder.bosons()[0].momentum().pT() / GeV;
        double Zpl = zfinder.bosons()[0].momentum().pz() / GeV;
        double Zy = zfinder.bosons()[0].momentum().rapidity();
        //double ZE    = zfinder.bosons()[0].momentum().E();

        double xf = 2. * Zpl / sqrtS();
        _h_xF_DiMuon->fill(xf);
        _h_m_DiMuon->fill(Zmass / GeV);
        _h_pT_DiMuon->fill(Zpt);
        _h_y_DiMuon->fill(Zy);
        double Zymin = -1.0;
        double Zymax = 1.03;
        double Z_y_width = Zymax - Zymin;
        if (Zy > Zymin && Zy < Zymax) {
          // Edsigma^3/dp^3 = 2E/(pi*sqrts)dsigma/dx_F/dq_T^2 = 1/pi dsigma/dy/dq_T^2
          // normalisation of Zy bin width = Zwidth
          if (Zpt > 0) _hist_pT_M_400->fill(Zmass, Zpt, 1. / 2. / Zpt / Z_y_width);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_hist_pT_M_400, crossSection() / femtobarn / (sumOfWeights() * M_PI));
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DGroupPtr _hist_pT_M_400;
    Histo1DPtr _h_m_DiMuon;
    Histo1DPtr _h_pT_DiMuon;
    Histo1DPtr _h_y_DiMuon;
    Histo1DPtr _h_xF_DiMuon;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(E288_1981_I153009);

}