#lines of code writen with a hashtag like this are comments, and will be ignored when you run the code.

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

%matplotlib inline

muons = pd.read_csv('http://opendata.cern.ch/record/545/files/Dimuon_DoubleMu.csv')

len(muons)

muons.head()

fig = plt.figure(figsize=(20, 10))

plt.hist(muons.M, 300, range = (0,150))

plt.xlabel('Invariant mass (GeV/$c^2$)', fontsize = 15)
plt.ylabel('Number of events \n', fontsize = 15)
plt.title('Measured distribution of events with two muons \n', fontsize = 15)

plt.show()

bump = muons[(muons.M >= 2) & (muons.M <= 4)]

fig = plt.figure(figsize=(15, 10))

plt.hist(bump.M, 300, range = (2,4))

plt.xlabel('Invariant mass (GeV/$c^2$)', fontsize = 15)
plt.ylabel('Number of events \n', fontsize = 15)
plt.title('Measured distribution of events with two muons \n', fontsize = 15)

plt.show()