Estimating the impact of the QCD dynamics on the determination of the high energy astrophysical neutrino flux

The number of ultra-high energy neutrinos arriving at IceCube depends on the energy dependence of the astrophysical neutrino flux and neutrino cross-section. In this paper, we investigate the impact of different assumptions for the description of the QCD dynamics at high energies on the determination of the normalization $$\Phi _{Astro}$$ Φ Astro and spectral index $$\gamma $$ γ of the astrophysical neutrino flux. The distribution of neutrino events at the IceCube is estimated considering the DGLAP, BFKL, CGC and BBMT approaches and the best estimates for $$\Phi _{Astro}$$ Φ Astro and $$\gamma $$ γ are determined using a maximum likelihood fit comparing the predictions with the distribution of observed events at IceCube. Moreover, we also investigate if the increase in the effective exposure time expected in IceCube-Gen2 will to allow us to disentangle the QCD dynamical effects from the description of the astrophysical neutrino flux.

Superheavy dark matter from string theory

Explicit string models which can realize inflation and low-energy supersymmetry are notoriously difficult to achieve. Given that sequestering requires very specific configurations, supersymmetric particles are in general expected to be very heavy implying that the neutralino dark matter should be overproduced in a standard thermal history. However, in this paper we point out that this is generically not the case since early matter domination driven by string moduli can dilute the dark matter abundance down to the observed value. We argue that generic features of string compactifications, namely a high supersymmetry breaking scale and late time epochs of modulus domination, might imply superheavy neutralino dark matter with mass around 1010–1011 GeV. Interestingly, this is the right range to explain the recent detection of ultra-high-energy neutrinos by IceCube and ANITA via dark matter decay.