![]() Concerning the atmospheric and solar sectors, besides the data considered previously, we give updated analyses of IceCube DeepCore and Sudbury Neutrino Observatory data, respectively. In the present study we include up-to-date analyses from a number of experiments. We present an updated global fit of neutrino oscillation data in the simplest three-neutrino framework. We demonstrate that a DUNE-like detector can explore a wide range of parameter space in ALP-photon coupling gaγ vs ALP mass ma, including some regions unconstrained by existing bounds the “cosmological triangle” will be fully explored and the sensitivity limits would reach up to ma∼3–4 GeV and down to gaγ∼10−8 GeV−1. Moreover, the high-capability near detectors allow for discrimination between ALP signals and potential backgrounds, improving the signal sensitivity further. Therefore, ALPs interacting with photons can be produced (often energetically) with high intensity via the Primakoff effect and then leave their signatures at the near detector through the inverse Primakoff scattering or decays to a photon pair. The high-intensity proton beam impinging on a target can not only produce copious amounts of neutrinos, but also cascade photons that are created from charged particle showers stopping in the target. ![]() We point out that future neutrino experiments, such as DUNE, possess competitive sensitivity to ALP signals. The current iteration of the project includes the BICEP3 telescope and the Keck Array, both located at the South Pole.Axionlike particles (ALPs) provide a promising direction in the search for new physics, while a wide range of models incorporate ALPs. The various BICEP telescopes measure CMB polarization to a high degree of precision, with the goal of identifying the physical processes at work in the first instants of the cosmos. The Center for Astrophysics | Harvard & Smithsonian is home to the Kovac Lab, which has developed the BICEP program in collaboration with NASA’s Jet Propulsion Laboratory and other institutions. Astronomers use modern telescopes to look for that polarization, in hopes of seeing the behavior of the universe when it was only a fraction of a second old. Points that were far apart at recombination today were neighbors before inflation, so they have nearly the same temperature.Īccording to theory, inflation left its mark on the CMB in the form of the twisting of light known as polarization. The most popular explanation for this is “ inflation”: a tiny fraction of a second after the Big Bang, quantum fluctuations caused the universe to expand at an extreme rate. Two points on the CMB on opposite sides of the sky shouldn’t have almost exactly the same temperature, since they weren’t close together at recombination. The overwhelming sameness of the CMB also tells us something about the early universe. Likewise, larger anisotropies wouldn’t produce the universe we see. Without those small irregularities, there wouldn’t be any galaxies, and we wouldn’t be here to observe them. The smaller anisotropies reveal the tiny fluctuations in density that gave rise to the pattern of galaxies and galaxy clusters we see today, which astronomers call the large-scale structure of the universe. Measuring the larger-sized anisotropies reveals how much dark energy, dark matter, and ordinary matter are contained in the universe. The term for that in cosmology is “isotropic”, and the small deviations from perfect sameness are called anisotropies. The CMB looks almost exactly the same, no matter what part of the sky we look at. The CMB provides the best data we have on the early universe, and the structure of the cosmos on the largest scales.Ĭredit: ESA and the Planck Collaboration The Baby Picture of the Universe ![]() Because recombination happened everywhere in the universe, we see CMB light coming from all directions. Today, we see this light as the cosmic microwave background. ![]() This light corresponds to a temperature today of 2.7 Kelvin: 2.7º C above absolute zero, or -455º F. Light from recombination was very energetic, but it cooled off with the rest of the universe, until it reached the microwave portion of the spectrum. The joining of electrons to nuclei produced a lot of light, which could now travel through the less soupy universe and even reach us, 13.8 billion years later. That event is called “recombination”, and it made the cosmos transparent. ![]() Those collisions also meant the cosmos was opaque, because photons couldn’t travel far.īut about 380,000 years after the Big Bang, the expansion of the universe allowed the first stable atoms to form. No stable atoms existed in the early universe, because collisions between particles of light called photons and matter kept knocking electrons away. ![]()
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