Posts Tagged ‘z boson

20
Nov

The LHC

By fzzxtchr 0 Comments
Categories: Topical
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It seems those crazy scientists are ready to play with their toys again; I guess they are still interested in finding out just exactly how the Universe works. Of course you know I’m talking about the Large Hadron Collider. I’m following the success (hopefully) of this venture as they go, step by step, using twitter. If you tweet and would like to follow CERN, go here. I am getting live information as it happens; where the beam is located, what systems are running, etc. And its all LIVE! I love social media!

I’ll just be here, in my classroom, with students who are retaking tests, listening to music, and getting updates on the most expensive, most complicated machine known to man, learning how what causes the Universe to exist in the state in which it does. That is all.

07
Nov

What’s the point, Mr. Bowie?

By fzzxtchr 1 Comment
Categories: Topical
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This was the question posed to me this week when we were discussion particle physics and the Large Hadron Collider in our classroom by an exceptionally bright student. She followed it up with “This just seems like an enormous waste of money.”  I surely see her point. When you have friends at school who come from homes were there’s not enough to eat or when they can’t (or won’t) keep the electric bill paid.

I imagine its also due (at least in part) to the idea students have that “everything that can be known, is”.  As a student in high school, a person who has a constant inflow of information everyday, its easy to think the world is pretty well all figured out. I would say this is not the case, nor will it ever be. That doesn’t mean we shouldn’t stop questioning.  In fact, even if we, as scientists, think the world is all figured out, it would be a huge mistake to stop asking questions. According to Humphrey Davy: “Nothing is so dangerous to the progress of the human mind than to assume that our views of science are ultimate, that there are no mysteries in nature, that our triumphs are complete and that there are no new worlds to conquer.” It is worth mentioning that Davy was the mentor of Michael Faraday, who produced the theory that electrical force and the magnetic force are the same thing. This was the first Unified Theory of Physics, which laid the groundwork for all other unification theories in Physics. So in essence, we can thank Davy for everything we know about Physics, for without his encouragement of Faraday, we might not understand physics much better than we did back in the 1800’s.

I think Albert Einstein said it best: “The important thing is not to stop questioning”.  That is the point! That is why we do research. All of the technology we gain from particle physics research is just a bonus. The reason to do the research is for the knowledge gained.

Thanks for reading.

04
Nov

In my classroom

By fzzxtchr 0 Comments
Categories: Topical
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Today we had a special speaker in our Pre-AP Physics class, Dr. Flera Rizatdinova (who is originally from Moscow and has a very strong Russian accent, which makes the talk much more interesting) from the Oklahoma State University Dept. of Physics. She is a scientist working on the ATLAS collaboration at the Large Hadron Collider. She shared some of the writing she has been doing for the DOE (which I mistakenly confused with the Dept. of Ed. initially) towards the end of her presentation. She was writing for them about the “benefits of particle physics research” which is a subject that arises frequently in my class. I hear something like “Mr. Bowie, isn’t this just an enormous waste of money?”

Dr. Rizatdinova talked extensively about what the questions the LHC is trying to answer (see previous post). This was the deepest part of the presentation and was probably a little above level of my students (but if I don’t set the bar high, they won’t achieve as much, right?).  At the end, she took some questions which was really good for the students. I’m glad they have some opportunities to interact with college professors/scientists.

There wasn’t really any ground-breaking material in her talk. I have been keeping up with the goings-on of the LHC recently and did some research over the summer with Dr. Rizatdinova, so much of this was a review for me. I’m not sure how the students will react to it, I’ll try to get some feedback tomorrow.  I was simply excited about having a real, live scientist in my classroom and wanted to share the experience!

20
Jul

Signal to Noise ratio

By fzzxtchr 0 Comments
Categories: Topical
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This post is from my Summer Research summary which can be found here. Its long and probably a bit boring to many of you, but if you are interested in how I’ve been spending my time, check it out. I am only publishing this because I am proud of the analogy about “Where’s Waldo” and wanted to share that with a broader audience. I had to post all of it, because the analogy alone wouldn’t make any sense without some background.

Any time I hear this phrase (Signal to Noise Ratio), I always think of the guy who once came to my house to work on my cable service. He told me they can sit in their truck and measure the amount of background noise that is leaking from bad connections or improperly insulated wires. They even once told me the signal was turned up/amplified too much which was causing my On Demand problems. (it generally wouldn’t work and kept giving some sort of error code)

In particle physics, when you talk about signal to noise, you are not too far away from this same idea. During particle collisions, there are processes that occur in which we are not really interested. This is called background. That doesn’t mean its not important, it simply means for the particular process at which you are looking, its just not something you want to observe. You would like for your detector to measure this background so that you can then calculate a value for it and subtract it from the actual signal. If you tune out all of the background, you won’t get an accurate depiction of the event in which you are interested. The signal is a value which is predicted (theoretically) by the Standard Model and can be verified (with a particle accelerator) experimentally. If you know the value of your signal, and by know I mean verify a theoretical prediction experimentally, you can then go on to look for new physics above and beyond the energy level at which you are working.

While driving from Oklahoma City to Stillwater, I had an epiphany on how to explain the concept of “signal to noise ratio”. Think about the popular children’s books and games called “Where’s Waldo?” Remember those? (try it by double clicking the picture to find Waldo) You stare at a picture looking for a goofy-faced kid who is wearing a red and white striped sweater with a similarly-colored knit cap. You look and look and look until finally he pops out of the background, plainly obvious and you wonder “why didn’t I seem him sooner?” The key is the red and white striped sweater. If not for that, it would be nearly impossible for you to see Waldo. He would blend into the background.This is especially true as you advance to harder and harder levels of the game. There are more and more people in the picture, therefore Waldo is harder and harder to spot.

Studying the Z boson, as we are, is the “putting on of the sweater”. We are painting a better picture of what the signal, the actual Z boson looks like. When we advance to the next level of the game, i.e. searching for the Higgs, we will have a better understanding of what the background looks like so scientists may then look at whats left and determine whether there is evidence for the Higgs or not. If not, the Standard Model will have to be revised.

Let me know what you think and as usual, thanks for reading.

jb

13
Jul

i know, this is only interesting to me…

By fzzxtchr 0 Comments
Categories: Topical
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Image courtesy of wikimedia.org

But since I am getting so much information during my research, I am going to just throw some of what I am learning out there. Its not groundbreaking, in fact, this really is “just” a confirmation of what is already

known about particles according to the Standard Model.  I think its really interesting; even more so when I am actually able to understand some (most) of it. What I hope to accomplish is just to put down my thoughts on the very informal lecture I got today.  So, here goes:

I am studying a particle called the Z boson. It was designated “Z” back in the 60’s because it was thought at the time that this was the last particle that would need to be named. Boy, were they wrong! See the Particle Adventure for a glimpse at the enormous number of particles that have been discovered and/or predicted since then.

The Z boson was predicted in the late 60’s (1968 I believe) when the electroweak theory was described by three guys who shared the 1979 Nobel prize for it. Zed (as I have taken to calling him) was actually discovered at CERN in 1983, but the theory was given a significant boost in 1973 when Fermilab (using the Gargamelle Bubble Chamber) found evidence for what are called “neutral current reactions”. These had been predicted by the electroweak theory.  By the way, Zed is a neutral particle (no electric charge), hence, neutral current reaction.

What does it do, you ask? Zed is one of two particles, yes, I said PARTICLE that is responsible for the weak nuclear force. This is how scientists are best able to interpret the data; force are “carried” by an exchange of particles, i.e. gluons(responsible for the strong nuclear force) and the as-yet-undiscovered graviton(which, it is thought, is responsible for gravity.)

Zed and his brothers (cousins?) the W+ and W- are very, very, very massive particles, relatively speaking (no pun intended).  These three particles are also very short lived. You just THOUGHT a mayfly had a short life (about 24 hours); the particles only “live” on the order of 10^-25 seconds! After that, their most likely decay channels are either a pair of muons (μ) or an electron-anti electron pair(e- or e+). The data with which I am working are primarily μ pair decays (tomorrow I should see some elecctron-anti electron data).  The cool thing about this is that these types of decays have a VERY specific energy range which shows up in a particle detector. My energy range is about 91 GeV (that’s giga-electron volts or billion electron volts). While that may sound like a lot (it is for a particle), its not that much on the scale of everyday life.

My data is such that all of the “events” are those that have a specific energy above 15 GeV (now you know what that means) AND have two (or even three) muons showing up in the muon detector. Without going into a lecture on Quantum Mechanics (thanks Mr. Bohr, Mr. Heisenberg, and Mr. Schrödinger), I get a peak, or maximum number of events that are in the 80-110 GeV range, with a peak right around 90 or 91 GeV.  This means that the rest mass, or invariant mass, of the Z boson 91 GeV. In plain english, that means that the amount of energy a Z boson has, at rest, is 91 billion electron volts. Our purpose is not to verify that, because our in the case of a muon detector, it isn’t set up to measure with the highest degree of accuracy (although there are detectors with that purpose, such as the electromagnetic calorimeter part of the detector).

So, what you ask, is the purpose? Well, I haven’t yet figured that out and frankly, I’m a little afraid to ask! I’m sure I WILL ask, but it hasn’t come up in conversation or lecture just yet.  According to Mr. Einstein, “if we knew what we were doing, it wouldn’t be called research”. I like that. I am going to keep that in the forefront of my mind when I’m not sure what I am doing and when I am not sure what I am supposed to be doing. I will just call it research. I can’t wait for some of this information to digest in my brain so I can figure out how to make this relevant for students. Indirect observation anyone?

thanks for reading,

jb

Oklahoma City Time

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