Charm contribution to ultrahigh-energy neutrinos from newborn magnetars

TL;DR

This paper investigates how charm hadrons significantly contribute to ultrahigh-energy neutrino production from newborn magnetars, highlighting their detectability with future neutrino observatories and implications for diffuse flux.

Contribution

It demonstrates that charm hadrons can dominate neutrino production at ultrahigh energies from magnetars, a factor previously neglected in models.

Findings

Charm hadrons dominate neutrino fluence at energies above 10^8 GeV.

Next-generation detectors can observe neutrinos mainly from charm hadrons.

Neutrinos from magnetar-driven merger novae are detectable between 10^2 and 10^3 seconds.

Abstract

Newborn, strongly magnetized neutron stars (so-called magnetars) surrounded by their stellar or merger ejecta are expected to be sources of ultrahigh-energy neutrinos via decay of mesons produced in hadronic interactions of protons which are accelerated to ultrahigh energies by magnetic dissipation of the spindown energy. We show that not only pions and kaons but also charm hadrons, which are typically neglected due to their small production cross sections, can represent dominant contributions to neutrino fluence at ultrahigh energies, because of their short lifetimes, while the ultrahigh-energy neutrino fluence from pion and kaon production is suppressed at early times due to their significant cooling before their decay. We show that the next-generation detectors such as Probe Of Extreme Multi-Messenger Astrophysics (POEMMA), Giant Radio Array for Neurtino Detection (GRAND) and IceCube-Gen2 have a good chance of observing neutrinos, primarily originating from charm hadrons, from nearby magnetars. We also show that neutrinos from nearby magnetar-driven merger novae could be observed in the time interval between $10^2$ s and $10^3$ s, where the charm hadron contribution is dominant for neutrino energies above $10^8$ GeV, of relevance to next generation detectors. We also comment on potential impacts of the charm hadron contribution to the diffuse neutrino flux.