Real CMS Data in Real CMS Data in the Classroomthe Classroom

Mike FetskoMills E. Godwin High School

Henrico, VA

Who Am I?Who Am I? Physics teacher for the past 17 years in

Massachusetts and Virginia. Member of QuarkNet since 2000.

Virtual LHC Fellow

I have taught a 2-3 week particle physics unit for 10 years. Students have participated in

masterclass for the past four years Students used CMS e-lab this year

CMS e-LabCMS e-Lab

The BasicsThe Basics

e-lab Videoe-lab Video

MasterclassMasterclass

MC in The ClassroomMC in The Classroom

Masterclass Masterclass ExperiencesExperiences

Particle Physics Boot Particle Physics Boot CampCamp

36 teachers5 fellows

5 problems…is it a Z? W? or J/psi?Talks & Tours

To: All QuarkNet collaboratorsFrom: Tom JordanDate: 18 July 2011

Re: Testing and analysis of early data

As you know, CMS has been actively collecting data from

early running of the LHC. Even though the luminosity and

center-of-mass energy are still below full capacity, we still have

many unique opportunities.

Particle Physics Boot Particle Physics Boot CampCamp

B. Foundations for Data Analysis Completing these milestones gains the team access to the raw data. Each

team member can:Describe the particle your team is investigating, how it is produced and how

it might decay.Explain what is measured in the trackers and calorimetry in CMS. Describe

how these components measure these properties.Describe the effect of a magnetic field on the trajectory of a charged

particle.Present and fully describe five screenshots of 3-D events during the

milestone seminar.Describe how to determine the mass of a particle given its energy and

momentum.Demonstrate how to determine the invariant mass of a moving particle by

measuring its observable decay products.Create a plot of provided data.

Describe the information in each column of your data spreadsheets.

Type RunNo EvNo E1 px1 py1 pz1 pt1 eta1 phi1 Q1

GG 1480292.59E+0

84.02460

5 1.38745-

0.95406-

3.65391 1.68722-

1.51715-

0.60258 1

GG 1480315.6E+08178.165

612.2711

850.0996

6-

170.536 51.6293-

1.91088 1.33059 1

GG 1480312.72E+0

854.9442

7-

6.45774-

46.6403-

28.3169 47.4407-

0.57005-

1.70832 -1

GG 1480293.93E+0

847.2193

8 -42.171-

20.49035.60519

5 46.81190.11918

1-

2.68928 1

Z Boson µ+ + µ-

Myriam Cruz Mike Fetsko Nick Horton Aaron Krehbiel Daria Pennington Darwin Smith Oather Strawderman Jill ZieglerUniversity of Puerto Rico Hampton University Vanderbilt University University of Buffalo Northern Illinois University Virtual Center University of Kansas University of Notre Dame

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Z to µ+µ-

Events with 2 Global MuonsMasses from 80 to 100 GeV

iSpy display of a Z Candidate showing a global and a tracker muon.

CMS Display of Z Candidate with two global muons.

Z Boson Background- Z boson mediates the Weak Force- Electrically neutral particle- Mass = 91.2 GeV/c2

- 100 times as massive as a proton- Half-Life of 3 x 10-25 s- Decays to Hadrons 70%, Neutrinos 20%, Charged

Leptons 10%- Discovered in May 1983 at CERN- Difficult to distinguish from W Bosons because both

particles are heavy and immediately decay

Removing Initial BackgroundEvents with like sign particles were removed since the Z is neutral and charge must be conserved.

• Multiplied Q1 and Q2• Events with result of 1 were discarded

Calculating Invariant MassInvariant mass of the parent particle was calculated from information on the two daughter particles using the following equation:

Histograms and Data CutsInvariant mass was plotted as histogram

• Looking for peak near Z mass• Full data gave reasonable result

Further cuts were made on µ type• First cut removed events with two tracker µ• Second cut removed events containing only

one tracker µ• These cuts removed background, but did not

change peakFinal plot cut directly around peak