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"source": [
"# PyROOT Exercise 1: Histogram Drawing"
]
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"source": [
"## Exercise\n",
"\n",
"Write a python macro `ExerciseHist.py`.\n",
"\n",
"1. Open the `Zmumu.root` file and load the tree called `physics`.\n",
"2. Create two histograms with 40 bins ranging from 0 to 0.2 GeV to plot the muon masses.\n",
"3. Fill the histograms with leading and subleading muon mass from branches `lep1_m` and `lep2_m`.\n",
"4. Calculate the mean values and RMSs.\n",
"5. Calculate the integrals.\n",
"\n",
"Bonus questions:\n",
"1. Are the integrals the same and why?\n",
"2. Write the histogram to a file."
]
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"source": [
"## Solution"
]
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"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Welcome to JupyROOT 6.28/00\n"
]
}
],
"source": [
"import ROOT\n",
"%jsroot on"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Leading muon mass: mean=0.105476; rms=0.007434\n",
"Subleading muon mass: mean=0.105479; rms=0.005120\n",
"Leading muon mass integral: 2495706.0\n",
"Subleading muon mass integral: 2496792.0\n"
]
},
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\n",
"\n"
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""
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"source": [
"from ROOT import gStyle, TCanvas, TFile, TH1D\n",
"\n",
"gStyle.SetOptStat(0)\n",
"\n",
"file = TFile(\"Zmumu.root\")\n",
"tree = file.Get(\"physics\")\n",
"\n",
"canvas = TCanvas(\"canvas\", \"\", 800, 600)\n",
"\n",
"hist_1 = TH1D(\"hist_1\", \"Leading lepton mass\", 40, 0, 0.2)\n",
"hist_2 = TH1D(\"hist_2\", \"Subleading lepton mass\", 40, 0, 0.2)\n",
"tree.Draw(\"lep1_m >> hist_1\", \"\", \"PLC\")\n",
"tree.Draw(\"lep2_m >> hist_2\", \"\", \"PLC same\")\n",
"canvas.Draw()\n",
"\n",
"print(f\"Leading muon mass: mean={hist_1.GetMean():.6f}; rms={hist_1.GetRMS():.6f}\")\n",
"print(f\"Subleading muon mass: mean={hist_2.GetMean():.6f}; rms={hist_2.GetRMS():.6f}\")\n",
"\n",
"print(f\"Leading muon mass integral: {hist_1.Integral()}\")\n",
"print(f\"Subleading muon mass integral: {hist_2.Integral()}\")"
]
}
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