Masterclass Starter Kit
Submitted by kcecire
on Monday, August 11, 2014 - 15:12
Description
Guidance and resources for starting a successful new masterclass institute.
Masterclass-in-a-box: CMS W and Z measurement
Introduction
This CMS W and Z measurement uses a special set of events shown in the iSPy-webgl event display program from CMS. There are a 5 sets of 40 events: W candidates, Z candidates, and background. The W candidates decay into an electron and a neutrino or a muon and a neutrino. Neutrinos show up as missing tranverse energy. The Z candidates almost all decay to pairs of muons.
Each group of, optimally, 2-4 students is assigned an event set. Students decide which of the three types each event should be and record this in the tally sheet for their set. If the event is a W candidate, this is recorded along with whether it is a muon or an electron decay. Students will count muons vs electrons when finished and calculate e/μ in the space provided. If the event is a Z candidate, students make note of the mass, round it to the nearest whole number, and record it in the sheet. These values are then used to make a Z mass histogram on the graph space provided. When all students in the masterclass are finished, they will combine tier results into an overall mass plot and a best value of e/μ.
Objectives
After the masterclass activity students will be able to:
- Explain that a general-purpose collider detector is made of a number of subsystems and describe what they are designed to measure.
- Express an increased appreciation for the nature of scientific investigation.
- Identify specific particles and their decays by their signatures.
- Give examples of how bosons can decay into different types of leptons.
- Describe/show how conservation laws and energy-mass conversion apply to particle physics.
- Give examples of conservation of charge in particle decays.
Student goals
- Each small group of students examines a set of 40 events.
- Determine which events are W candidates, Z candidates, or background.
- Determine if W candidates are electron or muon decays. Determine e/μ to test lepton universality in pairs..
- Make mass plot from Z masses. Use to determine mass of Z boson in pairs.
- Each pair reports results and contributes to whole group mass plot and e/μ calculation.
- Discuss results and uncertainty in group.
Data analysis
Students form into pairs; each pair gets a set of 40 events in the form of a PDF file. They can examine these files on computers or the teacher/leader can print them. Each pair of students also gets a PDF data tally sheet - these do need to be printed.
| Event files | Tally sheets | Additional resources |
|---|---|---|
After the alloted time for data analysis (30-60 min), students should combine results. To combine Z mass results, the leader should put a mass plot in front of the group to which all can add their data. Students should also contribute their W→eν and W→μν totals to get an over class result for e/μ.
|
One way to make the Z mass plot is to use post-it notes on the wall; each student adds one note per Z candidate event from the tally sheet. |
It is possible to take a creative approach to counting W events. Here, one hard candy stands in for one W candidate and the W count is taken using a scale. |
Annotated sample events
|
|
Events are shown in "xy-view". showing the roughly cylindrical CMS detector in a cross-section. The proton beams come from a line perpendicular to the page and intersecting the xy-view of the detector in the center. If the proton-proton collision yields a W boson, it promptly decays into either an electron (short green track matched with a green "energy tower" which indicates a deposit in the electromagentic calorimeter) or a muon (longer red track, often leading to muon "hits" in the outer muon system and a neutrino (shown as a dashed purple line for missing Et, which). If the collision creates a Z boson, this promptly decays into two muons. W and Z particles have other decays but they are not used in our sample. Anything which cannot be reasonably described as W→eν, W→μν, or Z→μμ is considered background. Students record W, Z, and background events in the tally sheet. For W candidates, students also record whether the events are W→eν or W→μν. They total these in the space provided and calculate e/μ. For Z candidates, students read the mass associated with the event, round to the nearest whole number, and put in a mass plot provided with their tally sheet. Once the data analysis time is complete, students take their resutls and combine them for the whole masterclass, adding all of the electrons and all of the muons from the W candidates to get a more definitiive e/μ and contributing all theor Z candidate rounded masses to an overall mass plot. A sample tally sheet is below. |
Sample data tally sheet
Masterclass-in-a-box: ATLAS W and Z measurement
Introduction
This ATLAS W and Z measurement uses a special set of events shown in the Minerva event display program based on ATLANTIS. There are a 5 sets of 40 events: W candidates, Z candidates, and background. The W candidtaes decay into an electron and a neutrino or a muon and a neutrino. Neutrinos show up as missing transverse energy above a 20 GeV threshold. The Z candidates all decay to muons.
Each group of 2-4 students is assigned an event set. Students decide which of the three types each event should be and record this in the tally sheet for their set. If the event is a W candidate, this is recorded, along with whether it is a muon or an electron decay. Students will count muons vs electrons when finished and calculate e/μ in the space provided. If the event is a Z candidate, students make note of the mass, round it to the nearest whole number, and record it in the sheet. These values are then used to make a Z mass histogram on the graph space provided. When all students in the masterclass are finished, they will combine tier results into na overall mass plot and a best value of e/μ.
Objectives
After the masterclass activity students will be able to:
- Explain that a general-purpose collider detector is made of a number of subsystems and describe what they are designed to measure.
- Express an increased appreciation for the nature of scientific investigation.
- Identify specific particles and their decays by their signatures.
- Give examples of how bosons can decay into different types of leptons.
- Describe/show how conservation laws and energy-mass conversion apply to particle physics.
- Give examples of conservation of charge in particle decays.
Student goals
- Each pair of students examines a set of 40 events.
- Determine which events are W candidates, Z candidates, or background.
- Determine if W candidates are electron or muon decays. Determine e/μ to test lepton universality in pairs..
- Make mass plot from Z masses. Use to determine mass of Z boson in pairs.
- Each pair reports results and contributes to whole group mass plot and e/μ calculation.
- Discuss results and uncertainty in group.
Data analysis
Students form into pairs; each pair gets a set of 40 events in the form of a PDF file. They can examine these files on computers or the teacher/leader can print them. Each pair of students also gets a PDF data tally sheet - these do need to be printed.
| Event files | Tally sheets | Additional resources |
|---|---|---|
After the alloted time for data analysis (30-60 min), students should combine results. To combine Z mass results, the leader should put a mass plot in front of the group to which all can add their data. Students should also contribute their W→eν and W→μν totals to get an over class result for e/μ.
|
One way to make the Z mass plot is to use post-it notes on the wall; each student adds one note per Z candidate event from the tally sheet. |
It is possible to take a creative approach to counting W events. Here, one hard candy stands in for one W candidate and the W count is taken using a scale. |
Annotated sample events
|
|
Events are shown with "xy-view" and "lego plot". The xy-view shows the roughly cylindrical ATLAS detector in a cross-section. The proton beams come from a line perpendicular to the page and intesecting the xy-view of the detector in the center. If the proton-proton collision yields a W boson, it promptly decays into either a muon (blue track leading to red muon indicator) or an electron (blue track leading to a yellow shower in the electromagnetic calorimeter and a yellow electron indicator) and a neutrino (shown as red arrow for missing Et, ehich should be greater than 20 GeV). If the collision creates a Z boson, this promptly decays into two muons. W and Z particles have other decays but they are not used in our sample. Anything which cannot be reasonably described as W→eν, W→μν, or Z→μμ is considered background. Students record W, Z, and background events in the tally sheet. For W candidates, students also record whether the events are W→eν or W→μν. They total these in the space provided and calculate e/μ. For Z candidates, students read the mass associated with the event, round to the nearest whole number, and put in a mass plot provided with their tally sheet. Once the data analysis time is complete, students take their resutls and combine them for the whole masterclass, adding all of the electrons and all of the muons from the W candidates to get a more definitiive e/μ and contributing all theor Z candidate rounded masses to an overall mass plot. A sample tally sheet is below. |
Sample data tally sheet
Masterclass-in-a-Box
Tiny URL for this page: http://tinyurl.com/wzbox.
This is a description of a set of Masterclass-related activities you can take with you anywhere, including to places with little or no IT support. The set contains, in order of appearance:
Rolling with Rutherford activity to learn about particle physics experimental methods by analogy.
Particle Cards, for an introduction to the Standard Model.
Introductory Slides and Analysis Slides for students.
Special ATLAS and CMS measurements in simplfied PDF versions.
USB drive with all the files.
Various and sundry useful items.
Masterclass start: organize teachers
Who:
Local high school physics teachers with interest in
- new ideas
- particle physics
- opportunities for their most motivated students
- learning and being involved in masterclasses.
How:
Use outreach and education resources at your institution
Talk with colleagues who have high school age children
Local physics teacher groups
Number:
To start, 1-3 good teachers. More is possible.
Next:
E-mail them about interest, invite them over for a chat.
Help:
Masterclass Starter Project Home
HOME MC-IN-A-BOX IMC LIBRARY
Tiny URL for this page: http://tinyurl.com/mcsk-main.
This page is constructed to help a new masterclass leader get International Masterclasses up and running for the first time.
The Masterclass Project Chart below shows the major activities associated with running a masterclass with approximate intervals in which they should be accomplished. The times in days are based around the day of the masterclass, though at the very beginning of the process the exact day may not be known. Each task on the chart is linked to a page that describes the task and how it may be accomplished. The tasks are also listed and briefly described below the chart and in the organizational timeline. Further information is linked under Masterclass Project Tasks.
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Organization and assistance:Organizational timeline, a very helpful alternative view to the Project Chart. Masterclass Coordinators
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Masterclass Project Tasks
Organize teacher group. This is the initial phase of organizing a masterclass. A small cadre of high school physics teachers is helpful to select students for the masterclass, prepare them ahead of time, bring them on the masterclass day, and help the tutors to assist the students. They will also be most likely to carry out any follow-on.
Orientation. It is helpful to have an Orientation to the masterclass for the masterclass tutors and the teachers to familiarize them with masterclass logistics, the particulars of their masterclass measurement, and how to choose and prepare students. It is best if it is facilitated by an experienced masterclass leader; when this is not possible, the new leader should facilitate with the help of this Starter Kit and collegial advice.
Form student group. With advice and guidelines from the masterclass leader, each teacher should choose a limited number of motivated students to participate the masterclass. The overall number of participants should be limited, especially in the first year.
Prepare students. This is normally the reponsibility of the teacher, though other arrangements are possible. The purpose is to give students some background in particle physics so that they will have a higher comfort level at the masterclass and be able to get more out of it. Three hours of preparation is recommended.
Prepare institute. The leader and tutors must be sure that the institution is organized so that all participants will have what they need for the masterclass.
Masterclass day. This is the big day: demonstrations, presentations, tours, and, most important, the masterclass measurement followed by analysis and discussion of results.
Follow-up. This phase is often overlooked. After the masterclass, there will be students who have developed a keen interest in particle physics. There are practical ways we can help students continue their inquiry and their work with physicists and each other.
Resources
| Images | Videos and animations | Downloads | Links |
|---|---|---|---|
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ATLAS CMS |
ATLAS H-->2gamma animated mass plot |
Hypatia 7.4 |
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