What is CLEO?



In [1]:

    
from IPython.display import Image
Image(filename='images/cleo_det_proc.jpg',width=400)









    Out[1]:

$$e^+e^- \rightarrow \chi \chi$$

The CLEO-II detector was designed to measure the properties of particles produced in the collisions of electrons and positrons supplied by CESR.

The CLEO-II detector was made of many. many sub-detectors and when the particles are created in each electron-positorn collision, they fly through these detectors and we are able to measure in which direction all these particles went.



In [2]:

    
from IPython.display import Image
Image(filename='images/kpipi_color_enhanced-resized.png',width=400)









    Out[2]:

These types of displays of the detector can be challenging to understand and at the end of the day, it's not what we scientists actually analyze. We use this information to get the electric charge, energy, and momentum of these particles, and that's about it.

Let's go take a look at some of that data!

The first step is to import some helper functions. One is to get the collisions data out of the files, and the other is to display the particles that are produced in these collisions.



In [3]:

    
import sys
sys.path.append("../tools/")

import cleo_tools as cleo

Next, we will open the file and pull out the collision data. This will return a Python list of all the collisions in that file.

You can use these data to visualize individual collisions or to perform a data analysis on all the collisions.



In [4]:

    
infile = open('../data/small_CLEO_test_file.dat')
collisions = cleo.get_collisions(infile)

number_of_collisions = len(collisions)
print("# of electron-positron collisions: %d" % (number_of_collisions))

import matplotlib.pylab as plt
%matplotlib notebook
# Uncomment the following line if you want your plots to be displayed in a separate interactive window.
#%pylab qt









    



# of electron-positron collisions: 101

Let's take a look at some of these collisions!



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cleo.display_collision3D(collisions[6])



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cleo.display_collision3D(collisions[3])



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cleo.display_collision3D(collisions[6])

What are we looking at here?

The green lines represent the electrons colliding.
The other lines represent particles created in the collisions. The length of these lines tell us how much momentum (or energy) they have. The colors are different particles/object.
- Red - pions
- Orange - kaons
- Blue - muons
- Green - electrons
- Gray - photons

You can also make plots of the properties of the particles.



In [8]:

    
energies = []

for collision in collisions:
    
    pions,kaons,muons,electrons,photons = collision
    
    for pion in pions:
        energy = pion[0]
        energies.append(energy)

plt.figure(figsize=(4,4))        
h = plt.hist(energies)

So now you know how to play around with data from CLEO-II. What do you want to do next? :)



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