February

To start off the new semester, I was asked a question from previous work in december. With the help of Dr. Loughran I was able to revisit my paragraph, and reply to the question down below more fully, explaining more about how we see the parent rest frame for the data set.

What do you mean by this: whose rest state are we looking from? The cosmic ray? It's not at rest with respect to us. This is a tough problem. Hint: the "particle" whose rest state we seem to be in is not a particle at all. But the software acts otherwise. What does the software report about what you think is a cosmic ray? What is this data set, anyway...what does it take to get in here? Why are CRs here, if they are? See if you can produce a clear account of these issues. This is precise writing, not an easy task. Jan 28, 2013 4:54 pm To start off, the data set is a dimoun event. That means, to make it into the data set, the software has to see two particles coming out of the detector. We know that Cosmic rays are here in the detector because I know that there is a hole where the cosmic rays can come into and go through the detector. Also, through the graphs that we looked at with this dimoun set at the beginning of the school year we saw through different parameters that there are cosmic rays in the data. When talking about rest frame for a particle, it means that if you were riding on the particle, to you the particle isn't moving, but the surroundings are. This is the rest state We are looking at, from where the "two particles" are going at different directions from you, so to you it seems like they are cancelling each other out. The software sees the cosmic ray as a rest state even though it is just a particle passing through the detector because the software only picks up on particles coming from the center of the detector where the collision is.

28, 2013 5:12 pm take 2: When we talk about at rest, we mean that the software believes that the parent particle (Z boson) is at rest. I say that the software believes, instead of knows, because we are looking at cosmic rays that are going straight through the detector instead of two muons that are coming from the parent particle at the collision. The rest state that the software sees isn't really even an actual rest state because technically there wasn't a parent particle. But what we are able to see from the detector's information is that since the particles are back to back, momentum cancels out, and Energy equals Mass.

To start off with my new project for the next semester, I am looking at the geometry of the L.H.C., particularly the CMS detector. I am doing this because there is a shaft that the builders of the CMS used in order to get the materials down to the tunnel below. Because they did this, there are cosmic rays that enter through the shaft and interfere with the data in the CMS. We found this data last semester, and found out how many cosmic rays there were in the data set. I am beginning my research with the LHC and the perameters of its size and shape. The LHC has six detectors. The tunnel's circumference is seventeen miles, and it gets as deep as 574 feet. CMS: 25 meters long, and fifteen meters in diameter. The CMS detector is underneath a cavern at Cessy, France.



Here is the picture of the total LHC, or Large Hadron Collider. From this, we can see that CMS is on the north side of the detectors, and is the farthest away from the other detectors.

The CMS detector was assembled in 15 parts before being brought down into the area wher it was completely put together. This i where we are trying to find the angle and the depth of the hole. If we can find the depth of the hole, we can use geometry to find the angles that are involved when we detect cosmic rays in the detector.

Here are some websites I have found, and I am posting the links here first. [] [] []

To find the specifications needed for the detector, we need the height and width of the detector. I found through different internet sources that the length of the tunnel is 100 meters.

Through reading different articles, I have found information that says that the assembly hall is 94 meters by 23 meters. It says that it is 23 meters wide, and I don't know if this is referring to the tunnel. I know that they are dropping the parts down a point 5 tunnel, which is supposedly the best place to bring the parts down. Here is a picture pulled from a file I recieved from Jamie. He sent me this paper that had a lot of important facts about the construction of the CMS parts, especially why it is good that they built the parts above, instead of in a cavern below. Through reading many different articles, I am finding that not much/ if any was written on the location of the CMS from the shaft in the cavern, or the width of the shaft. This makes it difficult to find out where the muons are coming from.

In part of the file Jamie sent me, I think I found an important paragraph explaining the main chamber, along with maybe the diameter of the shaft: The more detailed features of the CMS experimental cavern are shown in Fig. 14.2. The main access shaft, 23 m in diameter, provides a 16 m × 16 m opening for the installation of the magnet and the detector units. A second access shaft, 9 m in diameter, provides installation access to the other end of the detector. This is necessary, since the limited crane clearance over the detector does not allow large objects to be transported between the two endcap regions. The rails are embedded in the concrete floor and inclined by 1.23% to be parallel to the slope of the beam line. The central part of the floor section is lowered by 3 m in order to provide access under the magnet for services. This volume is also connected to the counting room and the service areas via 'chicanes'.

I think the most important part of this paragraph is the main shaft where the CMS is (23 meter in diameter). This gives us verification from the other source I found, and now I am able to confirm that the main point 5 shaft is 23 meters. I am confused by the fact that it says that there is also a sixteen by sixteen meter opening for the shaft, but I think that that is just the bottom of the shaft going into the cavern.

Now I am starting to find the location of where the detector is underground. As we see here, part of the CMS detector is right underneath the main shaft.

I have now started with google sketchup to create a measured model of the CMS detector with the tunnel and the hole to see where the cosmic rays could be coming from. I have posted pictures below of my work so far: (all of the measurements of the lengths of the sides and such are in the bottom right corner of the program screen.)

length of the tunnel is 40 meters

diameter of the hole is 22 meters

Length of the side of the CMS detector



The width of the CMS detector is 14 meters

Starting to work with the shape of the detector.