There is a certain amount of confusion on the relationship between Einstein's Theory of Relativity and the recent experimental results that seem to point towards neutrinos that are faster than light by an amount of about 7 km/s. So let me try to clarify things by answering to the following question:
If neutrinos travel faster than light by 7 km/s, do we need to modify Relativity?
The answer is a clear-cut "Yes"; let me explain why.
Lorentz invariance, which is embodied in the theory of Relativity, has the unescapable consequence that there exists a precise relationship between a free particle's energy E, its momentum p and its mass m:
c being the speed of light. From this equation one immediately obtains the velocity v as:
Then, from m2 >0 follows v<c. This holds for all known particles, with the possible exception of neutrinos for which measurements of the involved physical quantities are much harder than, say, for electrons.
Is it possible to admit v>c in a Lorentz-invariant framework?
In principle yes, by assuming a negative squared mass (m2<0) and hence an imaginary mass. In this case the particle is called a "tachyon" and its velocity is greater than that of light. Tachyons give me a headache, since they lead to mathematically inconsistent theories and to problems with causality. But even forgetting these (major) problems, from a phenomenological point of view OPERA neutrinos cannot be tachyons. In order to understand this, we need a quantitative argument.
If we suppose neutrinos are tachyons, then in order to comply with the value published by OPERA:
which corresponds to the above mentioned 7 km/s, neutrinos must have an imaginary mass with modulus |m c2 | ~ 0.2 GeV. But such a huge scale is totally incompatible with 80 years of neutrino physics. Just to mention one (of many) constraints, the corresponding value for neutrinos coming from the 1987A Supernova would be of the order of 10-6 GeV: five orders of magnitudes smaller than the value required by OPERA.
The "tachyonic way" for OPERA neutrinos is dead, and one has to abandon Lorentz invariance, which is at the heart of Einstein's special relativity. So be it.
If one gives up Lorentz invariance, then the usual relationship between energy and momentum can be broken and one can, in principle, be compatible both with OPERA and with SN1987A. However, then come the real problems as I have signaled in my article:
Unfortunately, it is in italian; I plan to write an updated version in English and to post it in Science 2.0.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- #GAMERGATE Style Harassment Does Not Happen in the Male Dominated Sciences
- Climate Change: It’s Only Human To Exaggerate, But Science Itself Does Not
- From Mindless Physics To Physics Of Mind
- Should First Responders Use Acupuncture And Hypnosis During Disasters?
- 24 hours with Windows 10 on a Surface Pro 3
- How Mitochondria Began - Parasitic Coevolution Gets A New Wrinkle
- Divide And Conquer: Novel Trick Helps Rare Pathogen Infect Healthy People
- "This kind of nonsense is what I am not a fan of - unfortunately, because hypnosis works so infrequently..."
- "It's because scientists don't completely cram their lectures full of politics, blacklist people..."
- "Hank I found this link on Facebook and I see on your about me page you have written a book well..."
- "No correlation? 8 of the 10 wealthiest counties voted for the president in 2008 and 2012. And they..."
- "You think this bothers me? Both gamergate and anti-gamergate supporters are behaving in immature..."
- Natural Resources Defense Council sues EPA to block rollout of Dow Enlist Duo GMO system
- Enviros file suit to block new Dow AgroSciences GMO herbicide and seeds
- Couples can protect children from devastating mutations with new IVF methods
- Food 2.0: Will farmers be able to meet the ecological challenges ahead?
- General Mills’ Cascadian Farm launches ‘bee-friendly’ campaign, GMO critics unimpressed
- Can genes pass from genetically modified food into our blood, posing dangers?
- Viagra protects the heart beyond the bedroom
- Group B streptococcus incidence rises significantly among newborns
- Metabolic genetics research paves way to treating diabetes and obesity
- Myelin vital for learning new practical skills
- Found: 'hidden brain signatures' of consciousness in vegetative state patients