FASER2

Abstract:

Pulsar wind nebulae (PWNe) are main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit non-thermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution cannot be excluded. A possible hadronic contribution to the high-energy gamma-ray emission inevitably leads to the production of neutrinos. Using 9.5 years of all-sky IceCube data, we report results from a stacking analysis to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters. In the absence of any significant correlation, we set upper limits on the total neutrino emission from those PWNe and constraints on hadronic spectral components.

Abstract:

The heliocentric redshifts (zhel) reported for 150 Type Ia supernovae in the Pantheon compilation are significantly discrepant from their corresponding values in the JLA compilation, with 58 having differences between 5 and 137 times the measurement uncertainty. Both catalogues include corrections to the redshifts & magnitudes of the supernovae to account for the motion of the heliocentric frame relative to the `CMB rest frame', as well as corrections for the directionally coherent bulk motion of local galaxies with respect to this frame. The latter is done employing modelling of peculiar velocities which assume the ΛCDM cosmological model but nevertheless provide evidence for residual bulk flows which are discordant with this model. Until recently these peculiar velocity corrections in the Pantheon catalogue were made at redshifts exceeding 0.2 although no data on which to base such corrections is available. We study the impact of these vexed issues on the 4.4σ discrepancy between the Hubble constant of 67.4±0.5 km/s/Mpc inferred from observations of CMB anisotropies by Planck assuming ΛCDM, and the measurement of e.g. 73.5±1.4 km/s/Mpc by the SH0ES project which extended the local distance ladder using Type Ia supernovae. Using the same methodology as the latter study we find that for supernovae whose redshifts are discrepant between Pantheon and JLA with Δzhel > 0.0025, the Pantheon redshifts favour H0 ≃ 72 km/s/Mpc, while the JLA redshifts favour H0 ≃ 68 km/s/Mpc. Thus the discrepancies between publicly available SNe Ia datasets are sufficient to undermine the claimed `Hubble tension'. We further note the systematic variation of H0 by ∼6-9 km/s/Mpc across the sky seen in multiple datasets, implying that it cannot be measured to better than ∼10% precision in a model-independent manner.

Abstract:

We present a measurement of atmospheric tau neutrino appearance from oscillations with three years of data from the DeepCore sub-array of the IceCube Neutrino Observatory. This analysis uses atmospheric neutrinos from the full sky with reconstructed energies between 5.6 GeV and 56 GeV to search for a statistical excess of cascade-like neutrino events which are the signature of nutau interactions. For CC+NC (CC-only) interactions, we measure the tau neutrino normalization to be 0.73 +0.30 -0.24 (0.57 +0.36 -0.30) and exclude the absence of tau neutrino oscillations at a significance of 3.2 sigma (2.0 sigma) These results are consistent with, and of similar precision to, a confirmatory IceCube analysis also presented, as well as measurements performed by other experiments.

Abstract:

The flux of high-energy neutrinos passing through the Earth is attenuated due to their interactions with matter. The interaction rate is modulated by the neutrino interaction cross section and affects the flux arriving at the IceCube Neutrino Observatory, a cubic-kilometer neutrino detector embedded in the Antarctic ice sheet. We present a measurement of the neutrino cross section between 60 TeV and 10 PeV using the high-energy starting events (HESE) sample from IceCube with 7.5 years of data. The result is binned in neutrino energy and obtained using both Bayesian and frequentist statistics. We find it compatible with predictions from the Standard Model. Flavor information is explicitly included through updated morphology classifiers, proxies for the the three neutrino flavors. This is the first such measurement to use the three morphologies as observables and the first to account for neutrinos from tau decay.