Posts tagged ‘leptons’

July 11th, 2012

The Standard Model of Particle Physics Written Out

by Max Andrews

With the recent discovery of a new boson, which is likely to be the elusive Higgs boson, the standard model for particle physics would not be complete.  Keep in mind that this only confirms the model that has been used for a long time now.  This explains the early moments after the big bang where there was the electroweak force which separated and became the electromagnetic and weak nuclear forces (there’s also the strong nuclear force).  This doesn’t unify the theory of gravity. Physicists must still develop a theory of quantum gravity.

October 7th, 2011

Neutrinos Faster Than Light or Extra Dimensions?

by Max Andrews

Source: CERN Press

By now we’ve all heard of the news coming out of CERN and OPERA on 23 September that the Italian accelerator, OPERA, measured neutrinos traveling faster than the speed of light.  I didn’t comment on the finding right away because I wanted to do some research on the claims and on what exactly happened.  So here are my two-cents.

So, what exactly is a neutrino?  A neutrino is a fundamental particle and crucial for the standard model of particle physics.  The neutrino comes tin three types: [associated with] the electron, muon, and tauon, which are fermions and part of leptons.  The have no electric charge and interact only via the weak nuclear force (see the Oxford Companion to Cosmology for more on this).  These particle are incredibly difficult to detect and pass through our bodies all the time (this is a nice little Italian cartoon that has an excellent depiction of neutrinos).

So, what happened?  CERN sent the neutrinos 730lm to the Italian accelerator OPERA.  The journey only took 2.43 milliseconds and the scientists timed it to within 10 nanoseconds. (A millisecond is a thousandth of a second, 1/1,000s and a nanosecond is a billionth of a second, 1/1,000,000,000s).  The neutrinos arrived 60 nanoseconds earlier than they would have if they were traveling at the speed of light (c = 299,792,458 m/s). There are three options of what could have happened.

  1. Option One.  The experiment was in error and the calculations are simply incorrect.
  2. Option Two.  The speed of light is not the cosmic speed limit and there must be slight adjustments for relativity theory.
  3. Option Three.  The neutrinos took a shortcut through extra dimensions.

Option One: Experimental Error.  The OPERA team spent three years trying to calculate and find every error they could possibly find.  The neutrinos are produced by colliding protons into a graphite target to produce pions and travel a 1km tunnel and decay to produce neutrinos.  Electronic delays in the timing system that records when protons arrive at the graphite target introduce uncertainty.  However, this margin of error is 5 nanoseconds. Where the pions decay is also unknown, which produces an error of 0.2 ns.  Measuring the distance is also difficult because the OPERA lab in Gran Sasso is inside of a mountain, which is undetectable to GPS.  However, the distance can still be calculated to within 20 cm.  The error is 0.67 ns.  With the other errors taken into consideration, the total error bar is 7.4 ns.  Remember, if experimental error is going to be the prevalent option the errors have to account for 60 nanoseconds.

Option Two: Adjusting Relativity.  If it really is the case that the neutrinos did travel faster than the speed of light then Einstein isn’t completely thrown to the curb.  There must be a theory that will account for this that will be closer to the truth.  This has historical precedence.  Newtonian physics were thought to explain the universe until Einstein came around with the concept of relativity.  Newton wasn’t necessarily wrong, Einstein just provided a more accurate theory.  If neutrinos can travel faster than c then we need another Einsteinian discovery.  Not that big of deal.

Option Three: Extra Dimensions.  It may be the case that the neutrinos, when travel with an incredible amount of energy, travel through the smaller curled up dimensions.  Consider the neutrinos traveling into the fourth dimension, this would actually make the distance much shorter.  Hopefully this illustration will help.  Take a piece of paper and draw a straight line across the paper.  Label one end of the line A and the other B.  This line is one-dimensional.  Take the paper and fold it so it creates an upward arch.  Now, if you were to travel from A to B by going through the paper instead of curving around the outside of the paper then the distance would be shorter.  This may, perhaps, be what happened to the neutrinos. (For more information on the discovery see New Scientist No. 2832, October 1-7 2011).

I tend to lean more towards option three, that the neutrinos passed through the smaller extra dimensions.  This would be an incredible development that would contribute to and, possibly, confirm a prediction of string theory.  Part of this may be wishful thinking on my part but this may potentially be an incredible empirical find that would confirm the mathematics.  Now, what about further philosophical or theological implications?  I don’t think this has too much of an impact on philosophy or theology that hasn’t already been addressed concerning the philosophy of science or of scientific theology.  For more on these implications see “The Relationship Between Science and Philosophy,” “Einstein, the Big Bang, and Natural Theology,” “Einstein on Free Will,” and “Einstein’s Impact on the Epistemic Method.”