Saturday, August 25, 2007

MAGIC gamma ray anomaly as evidence for many-sheeted space-time?

Kea wrote about two recent anomalies in cosmology. The first comment was about the cosmic microwave background anomaly having explanation in terms of a large void of size of orde 108 light years existing much before it should have existed in standard cosmology.

TGD explains this in terms of astrophysical quantum coherence of dark matter predicting that cosmic expansion for quantum coherent dark matter, in particular that in large voids, occurs via discrete quantum leaps increasing the value of gravitational Planck constant and thus the quantum size of system. The smooth expansion predicted by classical cosmology would be obtained only in the average sense. I commented this in previous posting.

Kea mentioned also the recently found gamma ray anomaly.

The MAGIC gamma-ray telescope team has just released an eye-popping preprint (following up earlier work) describing a search for an observational hint of quantum gravity. What they've seen is that higher-energy gamma rays from an extragalactic flare arrive later than lower-energy ones. Is this because they travel through space a little bit slower, contrary to one of the postulates underlying Einstein's special theory of relativity -- namely, that radiation travels through the vacuum at the same speed no matter what? ...

Either the high-energy gammas were released later (because of how they were generated) or they propagated more slowly. The team ruled out the most obvious conventional effect, but will have to do more to prove that new physics is at work -- this is one of those "extraordinary claims require extraordinary evidence" situations. ...

1. TGD based explanation at qualitative level

One of the oldest predictions of many-sheeted space-time is that the time for photons to propagate from point A to B along given space-time sheet depends on space-time sheet because photon travels along lightlike geodesic of space-time sheet rather than lightlike geodesic of the imbedding space and thus increases so that the travel time is in general longer than using maximal signal velocity.

Many-sheetedness predicts a spectrum of Hubble constants and gamma ray anomaly might be a demonstration for the many-sheetedness. The spectroscopy of arrival times would give information about how many sheets are involved.

Before one can accept this explanation, one must have a good argument for why the space-time sheet along which gamma rays travel depends on their energy and why higher energy gamma rays would move along space-time sheet along which the distance is longer.

  1. Shorter wavelength means that that the wave oscillates faster. Space-time sheet should reflect in its geometry the matter present at it. Could this mean that the space-time sheet is more "wiggly" for higher energy gamma rays and therefore the distance travelled longer? A natural TGD inspired guess is that the p-adic length scales assignable to gamma ray energy defines the p-adic length scale assignable to the space-time sheet of gamma ray connecting two systems so that effective velocities of propagation would correspond to p-adic length scales coming as half octaves. Note that there is no breaking of Lorentz invariance since gamma ray connects the two system and the rest system of receiver defines a unique coordinate system in which the energy of gamma ray has Lorentz invariant physical meaning.

  2. One can invent also an objection. In TGD classical radiation field decomposes into topological light rays ("massless extremals", MEs) which could quite well be characterized by a large Planck constant in which case the decay to ordinary photons would take place at the receiving end via decoherence (Allais effect discussed in previous posting is an application of this picture in the case of gravitonal interaction). Gamma rays could propagate very much like a laser beam along the ME. For the simplest MEs the velocity of propagation corresponds to the maximal signal velocity and there would be no variation of propagation time. One can imagine two manners to circumvent to the counter argument.
    1. Also topological light rays for which light-like geodesics are replaced with light-like curves of M4 are highly suggestive as solutions of field equations. For these MEs the distance travelled would be in general longer than for the simplest MEs.
    2. The gluing of ME to background space-time by wormhole contacts (actually representation for photons!) could force the classical signal to propagate along a zigzag curve formed by simple MEs with maximal signal velocity. The length of each piece would be of order p-adic length scale. The zigzag character of the path of arrival would increase the distance between source and receiver.

2. Quantitative argument

A quantitative estimate runs as follows.

  1. The source in question is quasar Makarian 501 with redshift z= .034. Gamma flares of duration about 2 minutes were observed with energies in bands .25-.6 TeV and 1.2-10 TeV. The gamma rays in the higher energy band were near to its upper end and were delayed by about Δ τ=4 min with respect to those in the lower band. Using Hubble law v=Hct with H= 71 km/Mparsec/s, one obtains the estimate Δτ/τ= 1.6×10-14.

  2. A simple model for the induced metric of the space-time sheet along which gamma rays propagate is as a flat metric associated with the flat imbedding Φ= ωt, where Φ is the angle coordinate of the geodesic circle of CP2. The time component of the metric is given by

    gtt=1-R2ω2.

    ω appears as a parameter in the model. Also the embeddings of Reissner-Norström and Schwartschild metrics contain frequency as free parameter and space-time sheets are quite generally parametrized by frequencies and momentum or angular momentum like vacuum quantum numbers.

  3. ω is assumed to be expressible in terms of the p-adic prime characterizing the space-time sheet. The parametrization to assumed in the following is

    ω2R2=Kp-r.

    It turns out that r=1/2 is the only option consistent with the p-adic length scale hypothesis. The naive expectation would have been r=1. The result suggests the formula

    ω2 = m0mp with m0= K/R

    so that ω would be the geometric mean of a slowly varying large p-adic mass scale and p-adic mass scale.

    The explanation for the p-adic length scale hypothesis leading also to a generalization of Hawking-Bekenstein formula assumes that for the strong form of p-adic length scale hypothesis stating p≈ 2k, k prime, there are two p-adic length scales involved with a given elementary particle. Lp characterizes particle's Compton length and Lk the size of the wormhole contact or throat representing the elementary particle. The guess is that ω is proportional to the geometric mean of these two p-adic length scales:

    ω2R2 = x/[2k/2k1/2].

  4. A relatively weak form of the p-adic length scale hypothesis would be p≈ 2k, k an odd integer. M127 corresponds to the mass scale me5-1/2 in a reasonable approximation. Using me≈.5 MeV one finds that the mass scales m(k) for k=89-2n, n=0,1,2...,6 are m(k)/TeV= x, with x=0.12, 0.23, 0.47, 0.94, 1.88, 3.76, 7.50. The lower energy range contains the scales corresponding to k=87 and 85. The higher energy range contains the scales corresponding to k=83,81,79,77. In this case the proposed formula does not make sense.

  5. The strong form of p-adic length scale hypothesis allows only prime values for k. This would allow Mersenne prime M89 (intermediate gauge boson mass scale) for the lower energy range and k=83 and 79 for the upper energy range. A rough estimate is obtained by assuming that the two energy ranges correspond to k1=89 and k2=79.

  6. The expression for τ reads as τ= (gtt)1/2t. The expression for Δτ/τ is given by

    Δ τ/τ=(gtt)-1/2Δ gtt/2≈ R2Δ ω2 = x[(k2p2)-1/2-(k1p1)-1/2] ≈x(k2p2)-1/2= x×2-79/2(79)-1/2.

    Using the experimental value for Δτ/τ one obtains x≈.45. x=1/2 is an attractive guess.

It seems that one can fairly well say that standard cosmology is making a crash down while TGD is making a breakthrough after breakthrough as the interpretation becomes more and more accurate. TGD is patiently waiting;-). Interesting to see how long it still will take before sociology of science finally gives up and the unavoidable happens.

For background see the chapter The Relationship Between TGD and GRT.

2 Comments:

At 12:58 PM, Blogger Kea said...

So much to write about - it's hard to keep up! Keep up the good work.

 
At 8:41 PM, Blogger Matti Pitkanen said...

Last years have fantastic period for me. A breakthrough in the mathematical understanding and interpretation of TGD meaning a profound revolution in world view and this continual flow of anomalies providing support for it. Theoretician could not wish for more. I would be so happy to share this journey of discovery with colleagues but you know: pride and prejudice...

 

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