Objectives

Participating teachers will:

• Apply classical physics principles to reduce or explain the observations in data investigations.
• Identify and describe ways that data are organized for determining any patterns that may exist in the data.
• Create, organize and interpret data plots; make claims based on evidence and provide explanations; identify data limitations.
• Develop a plan for taking students from their current level of data use to subsequent levels using activities and/or ideas from the workshop.

We will also provide opportunities to engage in critical dialogue among teaching colleagues about what they learn in the workshop.

Agenda

Resources

• Large Hadron rap

• LHC in 10 min

For the Go-Bag

• Bag of marbles
• The Dower Rutherford Apparatus
• Extra rulers and protractors
• Multiple packs and colors of stickies
• Red and green cups
• Roll of double sided tape
• Roll of painter’s tape (multiple color)
• Sharpies
• Laptop connection cables
• Multiple pens
• Pad of graph paper
• Yellow pad of paper
• At least one print-out of every activity
• USB drive
• Quark Workbench puzzle pieces

Through the development of activities and workshops such as the Particle Physics Masterclass, CMS and Ligo e-Labs the LHC Fellows:

1. Acquaint teachers with contemporary, high energy physics experiments and data analysis.

2. Prepare teachers to bring contemporary, high energy physics into their classroom.

In one sentence:

LHC fellows get high energy physics data into the hands of teachers and students.

See below.

Tiny URL for this page: http://tinyurl.com/atl-imc-update16.

Hypatia web display is unchanged. Remind mentors and teachers that it needs to be installed on each machine the students will use thus:

• Download from http://hypatia.phys.uoa.gr/Downloads/HYPATIA/Hypatia_7.4_Masterclass.zip to the machine itself or to a USB drive.
• Unzip the file into a folder. 
• Go to the ATLAS page at /page/atlas-z-path-measurement-2016, find the appropriate data group, and choose it. Enter the login and password.
• Download the appropriate data.
• Hypatia should end up on the desktop of each student machine with one dataset, either by direct download or distribuing it with a USB drive.

Run through some events together in Hypatia. Be sure to save results by choosing File > Export Invariant Masses in the Invariant Mass Window.

Upload and examine results:

• Go to OPlot at http://cernmasterclass.uio.no/OPloT-US/. Make sure you use the "US" version. 
• Log in as a student, find an appropriate day, and upload the data. For orientations, you can use 2016-Jan-01.
• Go through some of the plots to reminnd those present.
• OPloT currently needs updating.

Website

• The website is reachable from http://www.physicsmasterclasses.org.
• Go to the Z-path. This is being updated but the old version will suffice until then.

Library

• Located at http://tinyurl.com/mc2016lib (long URL is /page/masterclass-library-project-map-2016)
• Most items in place, still developing
• Key features:
  • Classroom Preparation
  • ATLAS page
  • ATLAS documentation (via ATLAS page)
  • Videoconferences page
• Show pages and explain, briefly, how they are useful.

Vidyo check:

• Audio - most important
• Video
• Share desktop, be sure they can read it
• Remind users that they should mute when not broadcasting, log in 15 min before videocon

Q&A

See list.

Tiny URL for this page: http://tinyurl.com/cms-imc-update16.

New event display version, iSpy-webgl, recommended for WZH masterclass (Note: WebGL = Web Graphics Library.)

• http://ispy-webgl-masterclass.web.cern.ch/ispy-webgl-masterclass/ - this is on the CERN server, works well
• https://www.i2u2.org/elab/cms/ispy-webgl/ - on the i2u2 server, future "official" site, not yet 100% ready.
• New features
  • Missing Et now white, thick transverse track
  • Electron tracks and deposits now green
  • Pick tool allows students to decide between tracks for validity
• Familiarize yourself with screencast and refer to it (but you cannot show effectively in a Vidyo connection)
  • informal sceencast I made for fellows (helpful but out of date)
  • new screencast v0 (better)
• Changes will show in CMS masterclass website but are not all available yet (see below)
• Old iSpy-online still recommended for J/Ψ masterclass and still works for WZH if needed

Try iSpy-webgl out with CIMA

• CIMA on i2u2: https://www.i2u2.org/elab/cms/cima/index.php
• If this is not working, explain that it will be restored soon and use: http://leptoquark.hep.nd.edu/sschoppmann/

Website

• Dev website (not official home but has more updated features)
• Official home - will be ready in time for IMC

Library

• Located at http://tinyurl.com/mc2016lib (liong URL is /page/masterclass-library-project-map-2016)
• Most items in place, still developing
• Key features:
  • Classroom Preparation
  • CMS page
  • CMS documentation
  • Videoconferences
• Show pages and explain, briefly, how they are useful.

Vidyo check:

• Audio - most important
• Video
• Share desktop, be sure they can read it
• Remind users that they should mute when not broadcasting, log in 15 min before videocon

Q&A

See list.

What if you want to build the most energetic particle accelerator in the world and you want it to fit into a pre-existing 27 km circumference tunnel?

Parts list:

• Source of particles (in this case, protons)
• Pre-accelerators
• Shovel (understatement)
• Lots of helium (why?)
• What else?

Let's get at one aspect of the problem:

How do we keep protons at 7 TeV (max design energy) running around in a 27 km circle?

Let's do the simplest possible classical calculation, imagining the LHC is a big cyclotron in a uniform magnetic field with no need to worry about relativity (that is, model it as what it really isn't). Here are some notes:

Try this calculation out and see what you get!

This may seem like a small field...because it is. We need to take into account the relativistic momentum of the protons (max 7 TeV/c = 7000 GeV/c):

Do the calculation: it will still understate the magnetic fields needed by more than an order of magnitude. The reason is that we cannot have a single uniform magnetic field. Rather, the proton paths are bent by over 1000 dipole magnets placed around the ring

Let's bring in somre resources:

• Facts about the magnets
• LHC faq
• About those GeV and TeV units.

Now what if the dipoles each runs with an 8 Tesla magnetic field and we imagine it is basically a powerful electromagnet made from #8 gauge wire? (It isn't, of course.) What current would it run?

More notes:

(You can find out how to get the diameter of a particular gauge of wire here.)

This puts us in the ballpark...and it is a lot of current. So why do we need all that helium again?

Here is what we do with all those high-energy, high-momentum protons:

• We collide them for a maximum collision energy of 14 TeV.
• We use large detectors to measure what comes out of the collisions.
• We use conservation laws to work backwards from those measurements to understand their parent particles that were made in the collisions.
• We use triggering to look for the most interesting physics.
• We send the data out for analysis to a worldwide grid.

Speaking of detectors...

Some special relativity

If you have measure muon time of flight, you can calculate the speed of the muon and the Lorentz factor for the muons.

For example, if the distance the muons travel is, say, d = 10 m and the TOF is measured as t = 34.0 nanoseconds, then

The fraction of the speed of light "beta" is

The Lorentz factor "gamma" is

Another way to get "gamma" for a particle is to use the energy and mass relationship. 

In our example, we can use E = γmc² to find the energy of our muon, since we know the invariant mass of a muon is m = 106 MeV/c²:

Application to accelerators

The ILC will be 30-50 km long and energize electrons and positrons to 250 GeV or more so that they will collide with energies upwards of 500 GeV:

(Learn more in this Wikipedia article.)

Imagine we want to build a muon-antimuon collider about the size and energy of the ILC. We might want to do this to make a smaller collider with similar properties, because:

1. Muon-antimuon and electron-positron collisions yield substantially the same results. Both are leptons with no structure we can detect, meaning the entire energy of the collion can go into creating one particle or particle pair, leaving no background.
2. Muons are much more massive. The ratio of masses is m_μ/m_e = (106 MeV/c²)/(0.511 MeV/c²) = 207. This means, in accelerating, they yield much less energy per unit mass and, therefore, it is more practical to build a circular collider (like the LHC) with counter-rotating beams. This saves space and makes it easier to build.
3. In the LHC, the circulating beam allows physicists to collide the same bunches of beam particles again and again, so they do not have to be continually made and accelerated. A "fill" of beam particles in the accelerator can last up to 24 hours.

So, why not build a muon collider? Some people are working on this concept, most notably in the MICE experiment. 

However, there is one other fact that is important to this: the lifetime of the muon is approximately 2.18 μs.

Let's think about this again after doing some calculations:

1. In its own reference frame, how far does a 2 GeV muon travel in one lifetime? How far might it go in our reference frame, as observers? Does a cosmic ray muon travel far enough to reach the surface of earth if it is created at an altitude of 15 km? Explain.
2. Now imagine that you have a 250 GeV muon (similar in energy to an electron in ILC). What is the value of gamma? Beta? What is its lifetime in our reference frame? 
3. How long will it take before a sample of 250 GeV muons has decayed so that only 1% are left in our reference frame? About how long would a "fill" be?

Discuss the benefits of a muon collider vs. the benefits of ILC.