## Neutrino Data Could Spell Trouble For Relativity 279 279

Science News has an exploration of the deeper implications of neutrino oscillation, one experimental confirmation of which we discussed last month.

*"The new findings could even signal a tiny breakdown of Einstein's theory of special relativity. ... MINOS [for Main Injector Neutrino Oscillation Search] found that during a 735-kilometer journey from Fermilab to the Soudan Underground Laboratory in Minnesota, about 37 percent of muon antineutrinos disappeared — presumably morphing into one of the other neutrino types — compared with just 19 percent of muon neutrinos. ... That difference in transformation rates suggests a difference in mass between antineutrinos and neutrinos. ... With the amount of data collected so far, there's just a 5% probability that the two types of particles weigh the same."*
## statistics fail (Score:4, Informative)

From the article, "there’s a 5 percent probability that the two types of particles weigh the same." Except, that would require a Bayesian statistical analysis and a prior. The thing to remember about confidence intervals is that the interval is random while the true value is stationary, so if you want to make statements about randomness, you have to make statements about the interval. Example, "An experiment conducted this way would find more muon antineutrinos than muon neutrinos disappear 95% of the time."

## CPT = Lorentz Invariance (Score:5, Informative)

## Re:CPT = Lorentz Invariance (Score:2, Informative)

Or alternatively just read this wikipedia section [wikipedia.org].

## CPT Symmetry (Score:5, Informative)

If the interactions of particles are thought of as a movie, CPT symmetry requires that whatever physics occurs during the show must be the same whether the film is run forward or backward (time), viewed through a mirror (parity) and repopulated with each particle being replaced by an antiparticle (charge).

This is unclear at best. CPT symmetry says that when the film is run backward AND seen through a mirror AND all particles are replaced with the anti-particles (and vice versa) then the physics should be the same.

If you change just one, for example by running the film backward but without the mirror or the the particle exchange, or if you change two, for example, running the film backward and with the mirror but no particle exchange, then the physics will change.

## Re:CPT = Lorentz Invariance (Score:5, Informative)

It's a lot easier than tossing out your beloved theory or trying to build it up from scratch based on solid scientific evidence to support each individual tenet. I think the latter is what needs to be done, but it will take time. We need to re-figure out what we know absolutely. IOW, what aspects of special relativity are not contradicted by a CPT violation? If the Lorentz Transformation is called into question then so is science fiction's much beloved time dilation And what about the Twins Paradox? Yikes.

Time dilation has been observed in a number of different contexts, most famously by putting atomic clocks on airplanes and measuring the resulting slow down as they fly around the globe. Even if SR fails, time dilation is still an experimentally verified fact.

## Re:statistics fail (Score:4, Informative)

## Re:Relativity is just a model (Score:3, Informative)

## Re:CPT = Lorentz Invariance (Score:3, Informative)

## Re:Relativity is just a model (Score:3, Informative)

The aim is to seek laws of physics that are absolute, inviolable, and a complete description of space, time, and mass-energy.I may be stretching beyond my capacity here, but isn't that a pipe dream? Won't any laws of physics will be mathematical formulae? And I thought it was accepted that no significantly powerful mathematical system can be both complete and consistent. It seems to me that a physics laws would be subject to that same limitation. The search for ever finer models is wonderful, important, and really the basis of all human progress -- but at some point I accepted that we'll never get to the bottom. It's an infinite regress.

If I am misunderstanding the situation, I'd love to know how.

Cheers.

## Re:Relativity is just a model (Score:2, Informative)

Sorry, but I'm a mathematician... so everything you physicists do is just a model to me

Math exists in a vacuum, and most Math researchers attempt to force observations of real life to fit within their formulas, which is just plain wrong. Physics observes real life, and attempts to describe it (using Math).

Or in other words, pure Math is essentially worthless until it is applied to the real world... and when you do that, it's not Math it's Physics.

For example, take the commonly known Math equation 1+1=2. This appears to be correct to the Math student, but then the Physics student comes along and says "Umm, exactly HOW do you expect me to believe that 1 apple + 1 orange = 2 slashdot Trolls?". It's how the equation is

appliedthat determines if it is correct or not.So with all of that in mind, I would propose that it is really Math which is "just" a model, while Physics is an actual explanation.

## Re:CPT = Lorentz Invariance (Score:5, Informative)

"Time dilation has been observed in a number of different contexts"Indeed! Without taking time dialation into account GPS locations would systematically drift about 10km/day.

## Re:I think I had an astronomy prof that talked abo (Score:5, Informative)

But a theory is more than just that, it's a mental model of reality, the context for sensory input. Einstein's General Relativity and Newton's Laws of Motion are fundamentally different: Newton took time and space to be a passive background, while Einstein made spacetime an active participant in events. The two theories don't just differ a little bit on their results, they represent fundamentally different ways of looking at reality.

But in a way your professor was right: a theory is "just a" tool for understanding reality, in the same way as you brains "just" allow you to think.

## Re:Newton's laws would be a great example (Score:4, Informative)

Oh, one other point - a large part of why we teach them in High School and basic undergraduate physics classes is that they don't require a lot of math beyond algebra and trig, and maybe a little calculus (some knowledge of integration and differentiation can still be useful even with Newton's Laws), but when you start looking at the more accurate models of relativity and things, it starts to take knowledge of much more advanced math, which High School students and undergrads(well, most of them anyhow) won't know or understand.

## Re:Newton's laws would be a great example (Score:2, Informative)

Not to mention all the esoteric stuff that people still do based on Newton's laws. Astronomers even computer simulate collisions of galaxies using classical physics.

But then again, there are times when relativity matters. If you have a fast-moving spacecraft with a radiolink you need to consider things like space contraction and time contraction. Otherwise you will tune your radios wrong. NASA didn't take it into account in the radio module of their Titan lander when they launched it, but were able to fix it in software en route...