The+Final+Blog+with+corrections

=FINAL BLOG(some corrections)= This last semester I have been working with the CMS, (Compact Muon Solenoid), and trying to understand how the detector works, along with the particles that go in and out of it. Before we started looking at different events in the detector, I worked on learning the many parts of the CMS, along with what particles are made of. I learned about up and down quarks that make up the protons and other small particles. Also, I learned about the four fundamental forces in nature. These forces are the strong, weak, electromagnetic, and gravitational. The strong force works with holding the protons and neutrons together with quarks. The weak force is what helps the particles decay into other forms. Electromagnetic forces help make particles by holding the electrons together to the neutrons and protons. The last force, gravity, is the most common force that we see in our daily lives with massive objects. We are still looking for a way to fully understand gravity, and we are looking at a particle to help learn more about some missing ideas. This particle is called the Higgs Boson, and scientists think that it will explain why particles have mass along with other important ideas. After learning about what makes up the particles, I learned more about the detector and how it works. The first layer is the tracker, which has a magnetic charge. This part of the CMS detects any charge that a particle has. The magnet bends the electron in the way that it is charged, which is one way of helping us know what particle it could be. After the tracker, there is the e-cal. This layer is important because it detects where the electron and photon ends up. We can distinguish between the two when they land in the e-cal by looking at the tracker and noticing whether the particle showed going through there. If it did, we know that it is an electron. If not, we know that the particle did not have a charge and that it is a photon. The H-Cal is the next layer, and this is where both the neutral and charged hadrons stop. Again, you can tell which particle is which by looking at the tracker. The final layers are made of iron, which were made for the muon. The muon is what I have spent most of the semester looking at because it is an important particle in the detector. Below is a picture of what the different parts of the detector look like: The muon is a negative particle that is in a category under leptons. It is similar to an electron, because it seems to not be made into smaller sub-atomic particles. The big difference that I know from working with the CMS is that the muons can come from outer space, and they come down to the earth. There are so many, and they are so small that they go through us and everything around us all the time and we never realize it. Also, as I said in the paragraph above, muons go all the way through the detector without stopping in any layers. Towards the end of the semester we started working on a final project, which included looking for muons in the detector. Here is a picture of what an event in the CMS looks like. I took out all of the other hits from other particles so that there were just hits from the muons coming out of the collision. As you can see the muons go through the detector, and that there are two of them. From looking at this event we can see how the particles collided, and the two muons from the collision seem symmetrical to each other. These muons cancel each other out when they go away from each other like this because the momentum never changes from the collision of the two particles going in. (This is a cancel in charge, not in momentum) After I looked at the 3D displays of the many different events in the CMS detector, I moved on to looking at many different graphs in many eyes. Looking at scatterplots and histograms helped me to realize different patterns that were happening during collisions with particles. Scatterplots were important with comparing two different ideas. Here is an example of a graph:

This graph is interesting because as you can see, the energy is low. I noticed that there is a steady level of energy moving in a straight line with the mass, and around 90 Gev there is some energy. This shows that there is probably a z particle, because the z particle shows up with a mass around 80 to 90 Gev. My final project for the semester was to look at cosmic rays and see how they were effecting the detector. Cosmic rays are muons that come down to the earth from outer space. It was what I was talking about when I was contrasting electrons to muons. Because they can come down from outer space, it is sometimes difficult to know if the muons are coming out of the detector, or if it is just coming down from space. Luckily, the CMS is built underground in Switzerland, and so for the most part scientists dont have to worry about determining what is coming from the detector or from outer space. This is because muons have a tough time getting through the ground to the detector. Unfortunately, there are still a few places that needed to looked at. There are holes going down to the detector at some parts because the workers had to be able to drop the parts down to where it was going to be assembled. The entire detector is 17 miles long, and so there had to be a few places where the pieces were brought down. Here is a picture of the size of the CMS. Since the holes were able to give an opening for the muons to come down into the detector, there are places where scientists have to watch to make sure we are getting the right data. This is where our project starts. We wanted to see if data that we were taking from our events had muons coming down onto the detector. We started with 100,000 events, which gave us a lot data to trim in order for us to see how the muons effected our data. By using histograms in many eyes, we were able to see where the hole was in our detector and we were also able to see where the muons were coming from. To start off with our data, we made cuts to eta and phi. Eta is looking at the detector from the side, and it helps scientists see the angle at which particles are coming out of the detector. Phi is looking straight on, and shows the angle of the particles coming out from this side. This was important for us because we know that muons come almost straight down from space, and that it will come down straight from the top of the detector since it is coming from space. We know that muons can not come through the earth, but we also have to look at the bottom half of the detector as well though because for the particle to be a muon it has to be back to back event. For Eta, we added the two events together, (Eta1+Eta2), because the negative to the positive would give us close to 0. Here is a histogram of the cuts: For phi, we did the absolute value of phi2-phi1. We did this because we wanted to see the particles that would come around pi, or 3.14. This is because phi is measured by more of a unit circle with 180 degrees is pi. Therefore, we want the muons coming down through the detector and going straight through. Here is another histogram that shows the cuts that we made to phi in order to see the if we had muons from space: This shows that the particles are coming down from around the top (right shows the positive 1.57, while the negative is coming straight down the bottom at -1.57). This shows that we know that the particles are coming straight up and down. Now that we know that there are muons, we worked on finding out where the hole was coming from. By combining both etas and phis into one column, we were able to see that from eta, the hole was at the left side. (We see that from adding all of the etas together in one column. This shows us where most of the particles are coming from because of the "angle" of eta.) Here is a picture of what we saw when combining both of the columns into one for both eta and phi: This project helped me to become much more familiar with working in particle physics, and I learned more about using different websites and programs such as many eyes and excel. By looking at 100,000 data set and looking for cosmic rays, I learned more about the detector and how it worked, which I thought was very interesting. Now that I have a better understanding of how the detector works, and I can filter data to find out important details in the data, I want to work more on different projects by using the same techniques. Also, I have been working on MATLAB for a while, and I would like to add this skill into maybe working on adding a program that will help see the histograms. I would also like to add things to make a program that will be even more helpful than many eyes. Here is a picture of a histogram I have made with data from one of our sets from particle physics: So far in computer programming, we have learned basic codes for using the MATLAB program, and we have worked with matrices and other graphs and animations. It will be nice to do more to add the two together later on this next semester. I am very excited about everything that I can do with these two skills.