使用Root/C++时出错：“TTree”的初始化没有匹配的构造函数

我试图绘制两个衰变μ子的Z玻色子的不变质量。我正在使用MadGraph和Root。MadGraph模拟事件p>Z>mu+和mu-并创建包含事件的.root文件。我称之为模拟事件生成

<>使用根分析数据并绘制直方图，我必须用C++编写代码。代码如下：

#ifdef __CLING__
R__LOAD_LIBRARY(libDelphes)
#include "TFile.h"
#include "TTree.h"
#include "TCanvas.h"
#include "TH1F.h"
#include <iostream>
#include "classes/DelphesClasses.h"
#include "external/ExRootAnalysis/ExRootTreeReader.h"
#include "external/ExRootAnalysis/ExRootResult.h"
#else

class ExRootTreeReader;
class ExRootResult;
using namespace std;
#endif

void readEvents(const char *inputFile)
{

 gSystem->Load("libDelphes");

 TChain chain("Delphes");
 chain.Add(inputFile);


 ExRootTreeReader *treeReader = new ExRootTreeReader(&chain);
 Long64_t numberOfEntries = treeReader->GetEntries();

 TTree *tree = new TTree(&chain);

 TClonesArray *branchMuon = treeReader->UseBranch("Muon");
 //Long64_t numberOfMuons = branchMuon->GetEntries();

 TClonesArray *branchElectron = treeReader->UseBranch("Electron");
 Long64_t numberOfElectrons = branchElectron->GetEntries();


cout << "There are " << numberOfEntries << " entries in your ntuple" << endl;

UInt_t  Muons;
Float_t MuonEta1;
Float_t MuonPhi1;
Float_t MuonPt1;
Float_t MuonEta2;
Float_t MuonPhi2;
Float_t MuonPt2;

tree->SetBranchAddress("MuonEta1", &MuonEta1);
tree->SetBranchAddress("MuonPhi1", &MuonPhi1);
tree->SetBranchAddress("MuonPt1", &MuonPt1);
tree->SetBranchAddress("MuonEta2", &MuonEta2);
tree->SetBranchAddress("MuonPhi2", &MuonPhi2);
tree->SetBranchAddress("MuonPt2", &MuonPt2);

TH1F *histDiMuonMass = new TH1F("mass", "M_{inv}(mu+[1], mu-[2]); M_inv (GeV/c^2); Events", 50, 0.0, 1500);
for(Int_t entry = 0; entry < numberOfEntries; ++entry)
{
 treeReader->ReadEntry(entry);

 Long64_t numberOfMuons = branchMuon->GetEntries();

 //Muons += entry;



 //Muon *muon1, *muon2, *muon3, *muon4;
 TLorentzVector muon1;
 TLorentzVector muon2;

 muon1.SetPtEtaPhiM(MuonPt1, MuonEta1, MuonPhi1, 0.1);
 muon2.SetPtEtaPhi(MuonPt2, MuonEta2, MuonPhi2, 0.1);


if(branchMuon->GetEntries() == 4)
{


 TLorentzVector Z = muon1 + muon2;
 histDiMuonMass->Fill(Z.M());
}
}
cout << "There are " << Muons << " entries in your ntuple" << endl;
histDiMuonMass->Draw();
}

但是，我得到以下错误：

In file included from input_line_1563:1:
/mnt/c/1/MG5_aMC_v2_6_6/Delphes/examples/readEvents.C:30:20: error: no matching constructor for initialization of 'TTree'
 TTree *tree = new TTree(&chain);
                   ^     ~~~~~~
/home/cucip/builddir/include/TTree.h:295:4: note: candidate constructor not viable: no known conversion from 'TChain *' to 'const TTree' for 1st argument; remove &
   TTree(const TTree& tt) = delete;
   ^
/home/cucip/builddir/include/TTree.h:291:4: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   TTree();
   ^
/home/cucip/builddir/include/TTree.h:292:4: note: candidate constructor not viable: requires at least 2 arguments, but 1 was provided
   TTree(const char* name, const char* title, Int_t splitlevel = 99, TDirectory* dir = gDirectory);
   ^
In file included from input_line_1563:1:
/mnt/c/1/MG5_aMC_v2_6_6/Delphes/examples/readEvents.C:72:8: error: no member named 'SetPtEtaPhi' in 'TLorentzVector'
 muon2.SetPtEtaPhi(MuonPt2, MuonEta2, MuonPhi2, 0.1);

有人知道是什么导致了这个错误吗？我如何修复它

非常感谢

通过调用新的TTree&chain，您试图调用TTree的构造函数，并为其提供一个TChain*链的类型是TChain，因此&chain是指向TChain的指针

TTree的构造函数要么没有参数，要么有两个常量字符*通常是字符串文字，要么是TString的.Data，要么是std:：string的.c_str，要么是ROOT的表单输出

您似乎试图调用已删除的构造函数TTreeconst TTree&tt=delete，但由于以下几个原因，该构造函数不起作用：

你提供了一个指向TTree的指针，而不是一个TTree的引用，甚至从我的头顶上都不确定如果没有&的话，从TChain到TTree的转换是否有效。 构造函数被删除，因此它实际上不存在，无法调用。 但是，从外观上看，您希望将TChain用作TTree*，这不需要您这边的任何代码，因为TChain通过继承已经是TTree了。所以，你可以用链子。而不是tree->，或者如果由于我在示例中没有看到的原因，更需要使用指针变量，则创建一个TTree*，即只创建指向TTree的指针，而不是在堆上创建实际的TTree，并通过执行以下操作从新操作符获取指向它的指针

TTree*tree=&chain；

---

然而，我得到的新错误是TChain:：SetBranchAddress:未知分支->TChain:：SetBranchAddress:未知分支->TChain:：SetBranchAddress:未知分支->MuonPhi1错误TChain:：SetBranchAddress:未知分支->TChain:：SetBranchAddress:未知分支->MuonEta2错误TChain:：SetBranchAddress:未知分支->TChain:：SetBranchAddress:unknown branch->MuonPt2中的MuonPhi2错误可能来自这里，这不是代码本身的问题，但意味着您的代码与您试图访问的输入文件不匹配，而这些数据并不存在。如果不访问tag_1_delphes_events.root，恐怕很难说。

In file included from input_line_1563:1:
/mnt/c/1/MG5_aMC_v2_6_6/Delphes/examples/readEvents.C:30:20: error: no matching constructor for initialization of 'TTree'
 TTree *tree = new TTree(&chain);
                   ^     ~~~~~~
/home/cucip/builddir/include/TTree.h:295:4: note: candidate constructor not viable: no known conversion from 'TChain *' to 'const TTree' for 1st argument; remove &
   TTree(const TTree& tt) = delete;
   ^
/home/cucip/builddir/include/TTree.h:291:4: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   TTree();
   ^
/home/cucip/builddir/include/TTree.h:292:4: note: candidate constructor not viable: requires at least 2 arguments, but 1 was provided
   TTree(const char* name, const char* title, Int_t splitlevel = 99, TDirectory* dir = gDirectory);
   ^
In file included from input_line_1563:1:
/mnt/c/1/MG5_aMC_v2_6_6/Delphes/examples/readEvents.C:72:8: error: no member named 'SetPtEtaPhi' in 'TLorentzVector'
 muon2.SetPtEtaPhi(MuonPt2, MuonEta2, MuonPhi2, 0.1);