Saturday, January 19, 2013

Is there an inert neutrino there?

There is a very interesting posting by Jester in Resonaances with title How many neutrinos in the sky?. Jester tells about the recent 9 years WMAP data and compares it with earlier 7 years data. In the earlier data the effective number of neutrino types was Neff= 4.34 +/- 0.87 and in the recent data it is Neff= 3.26 +/- 0.35. WMAP alone would give Neff = 3.89 +/- 0.67 also in the recent data but also other data are used to pose constraings on Neff.

To be precise, Neff could include instead of fourth neutrino species also some other weakly interacting particle. The only criterion for contributing to Neff is that the particle is in thermal equilibrium with other massless particles and thus contributes to the density of matter considerably during the radiation dominated epoch.

Jester also refers to the constraints on Neff from nucleosynthesis, which show that Neff∼ 4 us slightly favored although the entire range [3,5] is consistent with data.

It seems that the effective number of neutrinos could be 4 instead of 3 although latest WMAP data combined with some other measurements favor 3.

Addition:Later however a corrected version of the eprint appeared telling that the original estimate of Neff contained a mistake and the correct estimate is Neff=3.84+/- 0.40.

What could Neff=4 mean in TGD framework?

  1. One poses to the modes of the modified Dirac equation the following condition: electric charge is conserved in the sense that the time evolution by modified Dirac equation does not mix a mode with a well-defined em charge with those with different em charge. The implication is that all modes except pure right handed neutrino are restricted at string world sheets. The first guess is that string world sheets are minimal surfaces of space-time surface (rather than those of imbedding space). One can also consider minimal surfaces of imbedding space but with effective metric defined by the anti-commutators of the modified gamma matrices. This would give direct physical meaning for this somewhat mysterious effective metric.

    For the neutrino modes localized at string world sheets mixing of left and right handed modes takes place and they become massive. If only 3 lowest genera for partonic 2-surfaces are light, one has 3 neutrinos of this kind. The same applies to all other fermion species. The argument for why this could be the case relies on simple observation: the genera g=0,1,2 have the property that they allow for all values of conformal moduli Z2 as a conformal symmetry (hyper-ellipticity). For g>2 this is not the case. The guess is that this additional conformal symmetry is the reason for lightness of the three lowest genera.

  2. Only purely right-handed neutrino is completely delocalized in 4-volume so that one cannot assign to it genus of the partonic 2-surfaces as a topological quantum number and it effectively gives rise to a fourth neutrino very much analogous to what is called sterile neutrino. Delocalized right-handed neutrinos couple only to gravitation and in case of massless extremals this forces them to have four-momentum parallel to that of ME: only massless modes are possible. Very probably this holds true for all preferred extremals to which one can assign massless longitudinal momentum direction which can vary with spatial position.

  3. The coupling of νR is to gravitation alone and all electroweak and color couplings are absent. According to standard wisdom delocalized right-handed neutrinos cannot be in thermal equilibrium with other particles. This according to standard wisdom. But what about TGD?

    One should be very careful here: delocalized right-handed neutrinos is proposed to give rise to SUSY (not N=1 requiring Majorana fermions) and their dynamics is that of passive spectator who follows the leader. The simplest guess is that the dynamics of right handed neutrinos at the level of amplitudes is completely trivial and thus trivially supersymmetric. There are however correlations between four-momenta.

    1. The four-momentum of νR is parallel to the light-like momentum direction assignable to the massless extremal (or more general preferred extremal). This direct coupling to the geometry is a special feature of the modified Dirac operator and thus of sub-manifold gravity.

    2. On the other hand, the sum of massless four-momenta of two parallel pieces of preferred extremals is the - in general massive - four-momentum of the elementary particle defined by the wormhole contact structure connecting the space-time sheets (which are glued along their boundaries together since this is seems to be the only manner to get rid of boundary conditions requiring vacuum extremal property near the boundary). Could this direct coupling of the four-momentum direction of right-handed neutrino to geometry and four-momentum directions of other fermions be enough for the right handed neutrinos to be counted as a fourth neutrino species in thermal equilibrium? This might be the case!

    One cannot of course exclude the coupling of 2-D neutrino at string world sheets to 4-D purely right handed neutrinos analogous to the coupling inducing a mixing of sterile neutrino with ordinary neutrinos. Also this could help to achieve the thermal equilibrium with 2-D neutrino species.

Addition: The recent (22.3. 2013) data from Planck satellite give updated view about cosmic microwave background. The data give Neff=3.3 +/- .5 and do not favour inert neutrino. For a nice summary see Resonaances.

For background see the chapter of "p-Adic length scale hypothesis and dark matter hierarchy".


Ulla said...

This resembles Keas thoughts of 'alloneutrino' or mirror neutrino. A talented guy, IQ 126, with actually no brain. This reminds of the decapitated hen, living long after.

Somehow, though, the Sheffield student had lived a perfectly normal life and went on to gain an honours degree in mathematics. This case is by no means as rare as it seems. In 1970, a New Yorker died at the age of 35. He had left school with no academic achievements, but had worked at manual jobs such as building janitor, and was a popular figure in his neighbourhood. Tenants of the building where he worked described him as passing the days performing his routine chores, such as tending the boiler, and reading the tabloid newspapers. When an autopsy was performed to determine the cause of his premature death he, too, was found to have practically no brain at all. Professor Lorber has identified several hundred people who have very small cerebral hemispheres but who appear to be normal intelligent individuals. Some of them he describes as having ‘no detectable brain’, yet they have scored up to 120 on IQ tests.

Ulla said...

Hierarchy labelled by time?

Matti Pitkanen said...

To Ulla:

If their is resemblance to Kea's thoughts it is accidental. Right-handed neutrino is the mystery of recent day physics. Neutrino is massive which seems to require that both right and left handed neurino mix. Therefore right handed neutrino should exist. It however does not couple to known interactions except gravitation. What interaction would cause the mixing? This is the problem for all extensions of standard model.

An additional problem is that there are some indications for inert neutrino and purely righthanded massless neutrino would be excellent candidate here. It should be however in thermal equilibrium with other massless particles during radiation dominated era. Is this possible if it interacts only gravitationally. Could mixing cause the thermalization?

In standard model it is hopeless to try to put these pieces together. In TGD the localization of all particles except purely right handed neutrinos to 2-D string world sheets forced by the condition that electric charge is well-defined (different charge states do not mix) might allow to achieve this.

Right handed neutrino would also generate SUSY: the guess is that is unbroken but this is just guess motivated by the fact that it is extremely difficult to detect purely right handed neutrino. One can also imagine that there is more delicate SUSY breaking mechanism: the p-adic length scale characterizing different superpartners is different: otherwise they obey same mass formula. Situation is open.

The dynamics of the right handed neutrino would be simple: follow the leader, the ordinary particle which it accompanies. This correlates the momentum direction of right handed direction with that of the leader and means correlation possibly making possible thermal equilibrium. Also the mixing of ordinary 2-D string world sheet neutrino and 4-D right handed neutrino could take place and thermalize.

Matti Pitkanen said...

To Ulla:

The clock based on using particles Compton time as unit (very short!) is a fantastic technic advancement. No new physics.

Ulla said... This paper investigates quantum mechanical and thermodynamic arrows in a time-neutral formulation of quantum mechanics for a number of model cosmologies in fixed background spacetimes. We find that a general universe may not have well defined arrows of either kind. When arrows are emergent they need not point in the same direction over the whole of spacetime. Rather they may be local, pointing in different directions in different spacetime regions. Local arrows can therefore be consistent with global time symmetry.

Ulla said...

Sabine has a post about it, also New Scientist. I got an idea that biology may use time in a special way... also your time in biology... there is so much to learn. This is basics that you have talked much about, but is seldom heared by others.

Santeri Satama said...

"...also your time in biology...

Ulla said...

Hamed said...

Dear Matti,

The basic object (partonic surface) in TGD is just what we see from the object that is intersection of space-time surface and CD*CP2.
One can define two orbits for the partonic surface. The one is in the direction of CP2 that makes it light-like wormhole throat that connect the object to the background space-time sheet and the other one is in the direction of time coordinate of M4.
“Evolving 2-surfaces define 3-D light-like wormhole throat orbits since they have neither
Minkowskian nor Euclidian signature”
This evolving 2-surface is not time evolution of 2-surface? Just some orbit of It, in the direction of CP2.
But we know wormhole contacts are regions with Euclidian signature of induced metric. Why you say they have neither Minkowskian nor Euclidian signature?

Matti Pitkanen said...

Dear Hamed,

below my comments.

[Hamed] One can define two orbits for the partonic surface. The one is in the direction of CP2 that makes it light-like wormhole throat that connect the object to the background space-time sheet and the other one is in the direction of time coordinate of M4.

[MP] I am not sure what you mean with two time evolutions. For instance, for CP_2 type vacuum extremal which cannot be distinguished from CP_2 the M^4 projection is light-like random curve in M^4 and one can see the projection as analog of time evolution of a point like particle. Inherently Eucidian object CP_2 has characteristics of massless particle as imbedded 4-surface.

One can continue the space-like 3-surface at the end of space-time sheet to Minkowskian directions and speak about orbit in Minkowski space. One can also continue it as an Euclidian wormhole throat to another space-time sheet.

Formally one can regard the Euclidian portion of space-time region as a line of generalized Feynman diagram and it really looks like that! Note that Feynman wanted to get space-time geometry from Feynman diagrams and string theorists from string diagrams: I want to get Feynman diagrams from space-time geometry;-).

[Hamed] “Evolving 2-surfaces define 3-D light-like wormhole throat orbits since they have neither
Minkowskian nor Euclidian signature” This evolving 2-surface is not time evolution of 2-surface?

MP] It is!

[Hamed] But we know wormhole contacts are regions with Euclidian signature of induced metric. Why you say they have neither Minkowskian nor Euclidian signature?

[MP] We are speaking about boundary between Euclidian and Minkowskian region. The signature is between Minkowskian and Euclidian. Signature of four metric at 3-D wormhole orbit is (0,-1-1-1) rather than Minkowskian (1,-1,-1,-1) or Euclidian (-1,-1,-1,-1). Four metric is degenerate and this is why 3-surface is also light-like.


Matti Pitkanen said...

To Ulla:

Nice to see that not all theoreticians have not made final decision about the arrow of time as Lubos has done.

Also Copenhagen interpretation is questioned: now by Steven Weinberg. Lubos did not like at all about this: Some of us can change their views even at the age of 79! Encouraging.

Lubos mentions also very strange changes of a pulsar luminosity in X ray range correlated with its magnetic field. Magnetic body of pulsar with dark matter with large hbar inducing quantum phase transitions in the scale of the pulsar?;-)

Ulla said...

A reformulation of Copenhagen interpretation must be a very sour apple for Lubos. Also the fact that he hardly ever mentions the Zeilinger group, which de fact has got several big steps forward lately, not in the Copenhagen interpretation agenda at all, what I can see? They will certainly get the Nobel some year.

Here is also something 'impossible', attracting light.

Ulla said... DNA as a quantum computer, or quantum antenna?

Matti Pitkanen said...

To Ulla:

Much more than reformulation of Copenhagen interpretation is needed. This is not only about interpretation. Basic ontological assumptions must be updated and Lubos is conservative.