MUON LIFETIME AND TIME DILATION EFFECT

Measuring the stopping rate of muons, as a function of depth in the atmosphere to demonstrate the time dilation effect of special

relativity.Melinda Jolley

THE MUON WAS SO UNEXPECTED THAT, REGARDING ITS DISCOVERY, NOBEL LAUREATE ISIDOR ISAAC RABI FAMOUSLY QUIPPED, “WHO ORDERED THAT?”

Where do muons come from?

• Not completely sure• Somewhere in deep space?• Very recent NASA research

Muons were originally thought to be meson• It’s name is a combination of

mu and meson• Femi Coupling Constant (

The Muon• Nope, it is a Lepton

• Nicknamed ‘The Heavy Electron’• 𝜇± →e± +2 ν

THE GOALS OF MY EXPERIMENT Determine the

Measured Lifetime of the Muon• Muon Physics • Moun.exe

• Accepted τ = 2.20 µs

The Fermi Coupling Constant

• Use the measured τ

Is there no Time Dilation?

• Rates of Muon decays at one elevation

• Approximation for rate at second elevation

• Correction factors for Energy Loss over distance and

Variations in the shape of the muon energy spectrum

CORRECTING FOR ENERGY LOSS

• .

THE MUON ENERGY

SPECTRUM

THE PREDICTIONS

• = • =

THE EQUIPMENT USED

• Scintillator is placed at the bottom of a black anodized

aluminum alloy tube• Plastic Scintillator made of

Organic Transparent Material

HOW THE DATA LOOKS

MY DATA

• High Voltage set to -1154 Volts• Threshold Voltage set to 206 MeV• First location: Pueblo, CO, Elevation 1420 m• Second location: Monarch Mountain Base Summit, CO, Elevation 3290 m• ΔH= 1870 m

• Much more Pueblo Data than Monarch Data

FERMI COUPLING CONSTANT • Accepted value:

• Pueblo value : • Monarch value :

• Mass of the Muon = • Reduced Planck’s Constant =

STOPPING RATES

• Pueblo’s Stopping Rate = • Monarch’s Stopping Rate =

RATES ACCOUNTING FOR

ENERGY LOSS

• t=6.28 µsec or • . • , , •

• Remember t is the transit time assuming no Time Dilation

• t’ assumes Time Dilation Effects

MUON ENERGY SPECTRUM

CORRECTIONAND PREDICTIONS

GREAT INCONSISTENCY OF THE MEASURED ANSWER WITH THE HYPOTHESIS THAT THERE IS NO

RELATIVISTIC TIME DILATION EFFECTS ON THE MUON

The data was consistent with the Relativistic Time Dilation Hypothesis.

“

”IF WE KNEW WHAT IT WAS WE WERE DOING, IT WOULD NOT BE CALLED

RESEARCH, WOULD IT  

Einstein

Thanks to:Dr. BrownDr. WallinMy family

Special thanks to Annika, Thomas, and Olivia