Time dispersion of muons in EAS

Abstract

Describes the results and conclusions from an experiment set up to measure the time spread of muons in extensive air showers (EAS) detected at the Haverah Park EAS detector array, UK. The pulse risetimes (T70) from 10% to 70% amplitude of the responses from 3*10 m2 muon detectors are studied, and the anomalous pulse structure is investigated. The mean T70 is studied as a function of shower size, zenith angle and core distance and its dependence on shower size is related to the elongation length of the EAS. Fluctuations in T70 are studied as a method of yielding the mass composition of the primary particles. The measured fluctuations in T70 are related to fluctuations in the depth of the electromagnetic cascade maximum. The results yield the same value for both the elongation rate and the fluctuation in the depth of maximum sigma (Xm) of 58(+or-23) g cm-2. The results are consistent with simulation studies that assume protons are still the dominant component of cosmic rays in the energy range 1017 to 1018 eV.

Potential for measuring the longitudinal and lateral profile of muons in TeV air showers with IACTs

“…This may be due to the muon being produced at a large core (or angular) distance from the shower axis, such that the shower is not detected by the telescope. Alternatively, the muon may have triggered the Camera at a slightly different time, such as in advance of the rest of the shower, that the charge integrated over the 16 ns integration window is not sufficient to also contain the shower [16,17].…”

“…The LHC operates at p-p collision centre-of-mass energies of up to 14 TeV, corresponding to an initial CR proton energy of 1.0×10 17 eV. Therefore, within the sub-PeV sensitive range of IACT arrays, good agreement with LHCtuned simulations may be expected, as no extrapolations of hadronic interaction models in energy are required [31].…”

Study of Rare Semileptonic Bc+→D+νν- Decay in the Light-Cone Quark Mode

“…Due to the Glashow-Iliopoulos-Maiani (GIM) mechanism [4], flavor changing neutral current (FCNC) induced semileptonic B decays are rare in the SM because these decays are forbidden at tree level and can proceed at the lowest order only via electroweak penguin and box diagrams [5,6]. Therefore, these decay processes provide sensitive probes to look into physics BSM [7]. They also play a significant role in providing a new framework to study the mixing between different generations of quarks by extracting the most accurate values of Cabibbo-Kobayashi-Maskawa (CKM) matrix elements which help us to test the charge-parity (CP) violation in the SM and to dig out the status of NP [8,9].…”

Features of muon arrival time distributions of high energy EAS at large distances from the shower axis

“…Local arrival time distributions display the internal structure of the shower disc (characterised by various time parameters), but they do not carry information about the shape (curvature) of the front. Nevertheless studies based on simulations of the EAS development [16,19] have shown that mass discrimination effects are just pronounced in observations of ∆τ 1 glob µ . For event-by-event observations with a fluctuating number of muons, the single relative arrival time distributions can be characterised by the mean values ∆τ mean , and by various quantiles ∆τ q , like the median ∆τ 0.50 , the first quartile ∆τ 0.25 and the third quartile ∆τ 0.75 .…”