Neutrino mass paper

Weren't tachyons only instabilities in fields and not actual particles?

 

I don't see where it has been accepted. If a referee, I would probably not accept it. There's very little new here - Ehrlich has been going on about this for more than a decade.

It is absolutely true that the neutrino mass experiments that measure m-squared allow it to go negative in their fits. To do otherwise biases the result high. It is also true that these measurements come out negative - the PDG average is -0.6 +/- 1.9 and the statement "Given troubling systematics which result in improbably negative estimators of m2 in many experiments we use only Kraus 05 and Lobashev 99 (I think they mean Aseev 11) for our average." They then go on to comment on exactly how these two measurements are better than the ones they supersede and how the systematics are better controlled.

As for the cosmological measurements, I am not at all surprised that if one replaces constants in the calculation that the results shift, nor that with the right set, the mass squared can go negative. However, what I don't see is a good argument that these are the right constants to use, apart from the fact that they give interesting conclusions.

For me to believe neutrinos are tachyons, I would prefer to see one strong piece of evidence rather than a lot of weak ones.

 

Existence of Tachyons is not yet established. But If it establish it would be actual particles with imaginary mass energy and negative time. Further they will loss energy with increase in time.

 

http://phys.org/news/2014-12-faster-than-light-particles.html

This article is mentioning it to be accepted in journal Astroparticle Physics http://www.journals.elsevier.com/astroparticle-physics/

However On Journal Webpage It is not there

 

For me negative neutrino masses squared would be a disaster, because then what kind of cosmological contribution would one have?...So indeed systematic errors can play important role in determining the value.

 

I read it here:

(From this page.)

 

check this part of your link containing details http://en.wikipedia.org/wiki/Tachyon#Fields_with_imaginary_mass
It is for field whose uncondensed states are tachyons but after tachyonic condensation they become positive squared mass.
But its only one case which is partially tachyonic as final excitations are not tachyons, only intermediate are. Even Higgs Boson has imaginary mass in uncondensed phase
Tachyons is rather general term whether possible or not, but include excitation which would actually travel faster than light

 

Yes.

 

Thanks for that. But this only treats scalar tachyons which isn't useful when we talk about neutrinos. I checked some QFT texts but non of them treat tachyons(which isn't surprising). Not much was on internet too. Can you suggest a text that treats tachyons?(Specially fermionic ones)

 

But I think whether or not the following sentence is true, depends to a high extent on the equation that the particle obeys. This is the main reason I ask for further references. Or its a general thing not depending much on spin?

 

If neutrinos are Tachyons, wouldn't the neutrinos from SN1987A have arrived here much earlier? Is this addressed in the paper? My internet connection is very poor, and loading it is taking some time lol.

 

From what I know of neutrinos from SN1987A, the fact that they arrived ~3 hours ahead of the light means their speed is bound very close to the speed of light. It originated from the LMC I believe, so it has been traveling to us for ~150,000 years... that they arrived only 3 hours early limits their speed to c to one part in a billion.