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Thread: more on the Big Bang creating a universe - anti universe pair

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    Default more on the Big Bang creating a universe - anti universe pair



    Remember this thread?

    Universe has antimatter partner running backwards in time from the Big Bang

    Well, the paper for it is here:

    https://arxiv.org/abs/1803.08930?fbc...5FERVQ8XW_sfis

    https://journals.aps.org/prl/abstrac...K6tNXbaAF4wQYU

    We propose that the state of the Universe does not spontaneously violate CPT. Instead, the Universe after the big bang is the CPT image of the Universe before it, both classically and quantum mechanically. The pre- and postbang epochs comprise a universe-antiuniverse pair, emerging from nothing directly into a hot, radiation-dominated era. CPT symmetry selects a unique QFT vacuum state on such a spacetime, providing a new interpretation of the cosmological baryon asymmetry, as well as a remarkably economical explanation for the cosmological dark matter. Requiring only the standard three-generation model of particle physics (with right-handed neutrinos), a Z2 symmetry suffices to render one of the right-handed neutrinos stable. We calculate its abundance from first principles: matching the observed dark matter density requires its mass to be 4.8×108  GeV. Several other testable predictions follow: (i) the three light neutrinos are Majorana particles and allow neutrinoless double β decay; (ii) the lightest neutrino is massless; and (iii) there are no primordial long-wavelength gravitational waves. We mention connections to the strong CP problem and the arrow of time.
    So the matter-antimatter asymmetry and dark matter problems get solved simultaneously and additional predictions are made. Nice. I guess we need to start calling this the CPT universe.

    If this is true, then there is no need for the axion particle. All it did was explain CPT asymmetry and provide a dark matter candidate. But it hasn't been searched for as exhaustively as WIMPs so that still needs checking experimentally.

    Dr Hossenfelder has read the papers (see her facebook page) and reports in part:

    It's a genuinely new idea, and for all I can tell it's not obviously wrong and not in conflict with observation, which is a good start.

    However, at the present stage it also has some argumentative gaps that need to be filled. Eg, they don't actually know what is going on in the first moments of the universe, so they have to make some assumptions that suit their needs. Which isn't wrong but also not very convincing.

    On the other hand, assuming that those gaps can be filled, it's a fairly minimalistic model in that it doesn't assume many new things. And it also makes some testable predictions (eg that the light neutrinos are Majorana), which is good.
    But Dr H provides an additional valuable insight although left handedly. The particles involved might already be seen and detected but not with statistics sufficient to claim discovery yet.

    There has been a claim that the anomalous ANITA events may be a signal of the type of dark matter particle that Boyle et al are discussing ...., but if you look at the details, you will note that to explain the ANITA events you need to introduce a self-interaction for the dark matter particles that the Boyle et al paper does not have. So it's not really the same model.
    Yes, but it's not a big difference either. Self interactions need to be included to match the lack of cusps in DM halos anyway.

    The paper is found here:
    https://arxiv.org/abs/1803.11554?fbc...zZl_n2uA3DxZ6I

    We explain the two upgoing ultra-high energy shower events observed by ANITA as arising from the decay in the Earth's interior of the quasi-stable dark matter candidate in the CPT symmetric universe. The dark matter particle is a 480 PeV right-handed neutrino that decays into a Higgs boson and a light Majorana neutrino. The latter interacts in the Earth's crust to produce a tau lepton that in turn initiates an atmospheric upgoing shower. The fact that both events emerge at the same angle from the Antarctic ice-cap suggests an atypical dark matter density distribution in the Earth.
    The bolding is mine.

    There is a lot of chewy goodness here. So I'll post more as time permits.
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    Default Re: more on the Big Bang creating a universe - anti universe pair

    Looking at the ANITA detections first, I'm pleasantly surprised to see Vernon Barger on the author list. He must be in his 80s now and is still kicking..... nice.

    The paper notes that the observed events indicate that the Standard Model for neutrino interactions does not explain the observations.

    The ANITA experiment is a balloon borne observation platform.

    https://en.wikipedia.org/wiki/Antarc...nsient_Antenna

    So the detection is of radio waves produced in the ice cap by the cosmic ray cascades. Because of geometric factors and the attenuation properties of the Earth's mass and ice cap the detector is most sensitive in the direction of 30 degrees with respect to the horizon.

    The idea is that the Earth accumulates DM particles which are trapped gravitationally and sink into its body.
    A dense population of νR,1 is expected at the center of the Earth because as the Earth moves through the halo, the νR,1 scatter with Earth matter, lose energy and be- come gravitationally trapped. An accumulated νR,1 then decays into a Higgs and an active neutrino that propa- gates through the Earth and produces a τ lepton near the Earth’s surface. The particular angle of the ANITA events is a combination of the dark matter distribution in the Earth, the neutrino interaction cross section, and the τ survival probability.
    Here the νR,1 refers to the DM particle, a right handed neutrino.

    Also of note:
    Quasi-stable right-handed neutrinos will also accumulate in the core of the Sun and the Moon, and on decay will produce a flux of high-energy neutrinos. However, the neutrinos will not escape the Sun or the Moon, and the latter does not have an atmosphere in which the Ï„ leptons can produce showers, so consequently the flux from these sources is unobservable.
    helicon64, bladekeeper and Gabby76 like this.
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