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00026 #include <cmath>
00027
00028 #include "G4XpimNTotal.hh"
00029 #include "G4SystemOfUnits.hh"
00030
00031 G4XpimNTotal::
00032 G4XpimNTotal()
00033 {
00034 std::pair<double,double> it;
00035 it.first=1105.46 ;it.second= 8.8; theLowEData.push_back(it);
00036 it.first=1139.41 ;it.second= 13.6; theLowEData.push_back(it);
00037 it.first=1165.12 ;it.second= 26.0; theLowEData.push_back(it);
00038 it.first=1198.8 ;it.second= 60.; theLowEData.push_back(it);
00039 it.first=1212.51 ;it.second= 70.; theLowEData.push_back(it);
00040 it.first=1222.84 ;it.second= 72.; theLowEData.push_back(it);
00041 it.first=1233.18 ;it.second= 68.; theLowEData.push_back(it);
00042 it.first=1240.08 ;it.second= 65.; theLowEData.push_back(it);
00043 it.first=1301.86 ;it.second= 30.; theLowEData.push_back(it);
00044 it.first=1335.65 ;it.second= 26.; theLowEData.push_back(it);
00045 it.first=1368.93 ;it.second= 27.; theLowEData.push_back(it);
00046 it.first=1433.81 ;it.second= 30.; theLowEData.push_back(it);
00047 it.first=1496.42 ;it.second= 45.; theLowEData.push_back(it);
00048 it.first=1508.67 ;it.second= 47.; theLowEData.push_back(it);
00049 it.first=1520.84 ;it.second= 45.; theLowEData.push_back(it);
00050 it.first=1568.67 ;it.second= 35.; theLowEData.push_back(it);
00051 it.first=1603.69 ;it.second= 37.; theLowEData.push_back(it);
00052 it.first=1660.54 ;it.second= 58.; theLowEData.push_back(it);
00053 it.first=1674.47 ;it.second= 59.; theLowEData.push_back(it);
00054 it.first=1688.29 ;it.second= 58.; theLowEData.push_back(it);
00055 it.first=1779.57 ;it.second= 36.; theLowEData.push_back(it);
00056 it.first=1881.49 ;it.second= 36.8; theLowEData.push_back(it);
00057 it.first=1978.31 ;it.second= 34.5; theLowEData.push_back(it);
00058 it.first=2038.82 ;it.second= 34.5; theLowEData.push_back(it);
00059 it.first=2115.39 ;it.second= 36.; theLowEData.push_back(it);
00060 it.first=2159.18 ;it.second= 36.3; theLowEData.push_back(it);
00061 it.first=2244.22 ;it.second= 36.; theLowEData.push_back(it);
00062 it.first=2424.78 ;it.second= 33.; theLowEData.push_back(it);
00063 it.first=2664.2 ;it.second= 32.; theLowEData.push_back(it);
00064 it.first=3487.43 ;it.second= 28.; theLowEData.push_back(it);
00065 it.first=4434.76 ;it.second= 26.7; theLowEData.push_back(it);
00066 }
00067
00068 G4double G4XpimNTotal::
00069 CrossSection(const G4KineticTrack& trk1, const G4KineticTrack& trk2) const
00070 {
00071 G4double sqrts = (trk1.Get4Momentum() + trk2.Get4Momentum()).mag();
00072 if(sqrts > theLowEData.back().first/MeV) return thePDGData.CrossSection(trk1, trk2);
00073 G4double result = 0;
00074 size_t i(0), it(0);
00075 if(sqrts<theLowEData[0].first) return 0;
00076 for(i=0; i<theLowEData.size(); i++)
00077 {
00078 if(theLowEData[i].first/MeV>sqrts) break;
00079 it = i;
00080 }
00081 G4double x1 = std::log(theLowEData[it].first);
00082 G4double x2 = std::log(theLowEData[it+1].first);
00083 G4double y1 = std::log(theLowEData[it].second);
00084 G4double y2 = std::log(theLowEData[it+1].second);
00085 G4double x = std::log(sqrts);
00086 G4double y = y1+(x-x1)*(y2-y1)/(x2-x1);
00087 result = std::exp(y);
00088 return result*millibarn;
00089 }