IceCube can constrain the intrinsic charm of the proton

Abstract

The discovery of extraterrestrial neutrinos in the ∼ 30 TeV -PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic-ray particles interacting in the Earth's atmosphere. It is conventional to use the calculations of charm hadroproduction using gluon splitting g → cc alone. However, QCD predicts an additional "intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimate the prompt neutrino spectrum due to intrinsic charm. We find that the atmospheric prompt neutrino flux from intrinsic charm is comparable to those calculated using QCD computations not including intrinsic charm, once we normalize the intrinsic charm differential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major questions in high energy physics phenomenology.

Forward charm-production models and prompt neutrinos at IceCube

“…However, this is the region of x F in which the differential cross section is suppressed, and we shall see that the effect on the neutrino flux is small. 2 Our prediction for the prompt neutrino flux when including intrinsic charm contribution is consistent with results from other recent works [21][22][23]. It is significantly below the intrinsic charm contribution to the flux discussed in [24], which uses Λ 0,± production data from fixed-target experiments to deduce constraints on D 0,± production assuming extreme values of fractional momentum transferred to the finalcc pair.…”

Prompt neutrinos and intrinsic charm at SHiP

“…[11][12][13][14] and normalized according to ref. [22] for their evaluation of the atmospheric neutrino flux, we find a significant increase in the number of events from tau neutrinos and antineutrinos at SHiP.…”

“…The overall normalization of intrinsic charm remains to be fixed, the value of which is of great interest in the context of the prompt atmospheric flux [20][21][22]. Charm production in the atmosphere, followed by its prompt decay into leptonic or semileptonic decay modes, is the dominant contribution to the atmospheric neutrino flux at sufficiently high energies [20-24, 36, 51-56].…”

Constraints on neutrino speed, weak equivalence principle violation, Lorentz invariance violation, and dual lensing from the first high-energy astrophysical neutrino source TXS 0506+056

“…Predictably, a lot of excitement have been generated by this momentous discovery [3][4][5][6][7][8][9][10][11]. Together with the prior discovery of a diffuse flux of high-energy astrophysical neutrinos [12,13], these observations provide us a new way to probe beyond the Standard model physics [14][15][16][17][18][19][20][21][22], new IceCube signal morphologies [23,24], and atmospheric prompt neutrinos [25][26][27][28][29][30][31][32].…”