Atmospheric muon flux at sea level, underground, and underwater

Abstract

The vertical sea-level muon spectrum at energies above 1 GeV and the muon intensities at depths up to 18 km w.e. in different rocks and in water are calculated. The results are particularly collated with a great body of the ground-level, underground, and underwater muon data. In the hadron-cascade calculations, we take into account the logarithmic growth with energy of inelastic cross sections and pion, kaon, and nucleon generation in pion-nucleus collisions. For evaluating the prompt muon contribution to the muon flux, we apply the two phenomenological approaches to the charm production problem: the recombination quark-parton model and the quark-gluon string model. We give simple fitting formulas describing our numerical results. To solve the muon transport equation at large depths of a homogeneous medium, we use a semianalytical method, which allows the inclusion of an arbitrary (decreasing) muon spectrum at the medium boundary and real energy dependence of muon energy losses. Our analysis shows that at the depths up to 6-7 km w.e., essentially all underground data on the muon flux correlate with each other and with the predicted one for conventional (π, K)-muons, to within 10 %. However, the high-energy sea-level muon data as well as the data at high depths are contradictory and cannot be quantitatively described by a single nuclear-cascade model.

Atmospheric muons: experimental aspects

“…Table 1 lists the authors and energy range of the reported absolute vertical intensity measurements. It is also shown if the experiment has been used by other reviews, namely "B" (Bugaev et al, 1998), "H&T" (Hebbeker and Timmermans, 2002) and in the Particle Data Group "PDG" (Nakamura et al, 2010). For H&T we report also the final normalization Flint et al (1972), Jakeman (1956), Wilson (1959), Gettert et al (1993), Dmitrieva et al (2006), Crokes and Rastin (1972). of material crossed by the particle in such detectors increases with increase of zenith angle, so the threshold energy for multidirectional muon telescopes depends on θ.…”

Saturation physics in ultra high energy cosmic rays: heavy quark production

“…Its quantification is essential for the cosmic ray physics as well as for neutrinos physics. On one hand, the flux of cosmic ray muons in the atmosphere, underground and underwater provides a way to testing the inputs of nuclear cascade models, that is, parameters of the primary cosmic ray flux (energy spectrum, chemical composition, ...) and particle interactions at high energies [3]. On the other hand, the flux of atmospheric neutrinos and muons at very high energies provides the main background of searches for the muons neutrinos from extra-galactic neutrino sources in the neutrinos experiments JHEP00(2007)000 (e.g.…”

About possible contribution of intrinsic charm component to inclusive spectra of charmed mesons

“…The same is for the sea-like IC model: x c+c = 0.024. For applications in cosmic ray physics (in particular, for calculations of atmospheric spectra of leptons (see, e.g., [23,24])) we need the dependence of dN/dx F on x F , so, we integrate (6) on p ⊥ and change the variables, using the relation…”