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A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds
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A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Dec 20, 2015

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Page 1: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

A Search for theSM Higgs Boson

by Burt DeWilde

Kalamazoo College

Against all odds

Page 2: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

The Standard Model (again)

Particles grouped into generations by mass

Higgs field with non-zero VEV causes EWSB -> mass

Higgs boson is the particle associated with this field

Page 3: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

The Tevatron

Page 4: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

The D0 Detector

Page 5: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Run I vs. Run II

Increase in center-of-mass energy->1.96TeV

Increase in number of bunches, decrease in spacing of bunches

Much higher luminosity (Hopefully) enough for

Higgs boson detection

Page 6: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Higgs Production Modes

Page 7: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Higgs Decay Modes

bb channel dominant up to M=135GeV

Z boson decays into two muons less frequent, but also cleaner channel

Page 8: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Neural Network Structure

Page 9: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Variables: Signal, Background, and Data

Page 10: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Variables: Signal, Background, and Data

Page 11: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Training Method Comparison

Page 12: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Signal Significancevs. Training Method

Page 13: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Optimal # of Epochsfor # of Hidden Neurons

Page 14: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Signal Significance vs.Optimal # of Neurons/Epochs

Page 15: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Signal Significance vs.NN Weighting Scheme

Page 16: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Invariant Mass Distributionsfor Potential Higgs Masses

Page 17: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Signal Significance vs.Invariant Mass Base Cut

Page 18: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=105GeV

Page 19: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=115GeV

Page 20: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=125GeV

Page 21: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=135GeV

Page 22: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=145GeV

Page 23: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

NN Results forHiggs M=155GeV

Page 24: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Importance of the Results

NN achieves better signal/background discrimination than cuts on Mjj alone

NN analysis gives better signal significance than conventional analysis

Integrated luminosity required for Higgs detection reduced 40-70%

Not too shabby

Page 25: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.

Acknowledgements

Andy Haas, for meaning, direction, and data The Nevis crew, for troubleshooting and

much-needed moral support The National Science Foundation, for

research experience and money

Page 26: A Search for the SM Higgs Boson by Burt DeWilde Kalamazoo College Against all odds.