Inelastic scattering of cosmic ray muons on iron nuclei and the virtual photon shadowing

Hadronic cascade showers originating from inelastic interactions of cosmic ray muons with iron nuclei have been observed in a calorimeter located between two magnetic spectrometers. The separation of those events from the electromagnetic showers has been successfully done in the ranges of the transferred energy v ≳ 50 GeV and its ratio to muon energy v/E ≳ 0,1, by utilizing the difference of their longitudinal cascade developments. The comparison of the obtained μ-Fe cross section with available μ-, e- and σ-proton data as well as μ-, e- and σ-nucleus data indicates that;

• 1 At v ˜ 100 GeV, the virtual photon cross section on iron nucleus is almost the same as the real photon one, at least Q² ≳ 0.1 GeV²/c², and is about 70% of the cross section on proton times the atomic mass number of iron, i.e. the shadowing effect is clearly seen.
• 2 Up to TeV region, this virtual photon cross section on iron does not increase significantly. contrary to the tendency of the real photon cross section on proton around 100 GeV. This suggests most likely that the shadowing still increases with energy at such high energies.

     

Deep inelastic scattering of polarized muons

An introduction is given to the physics of deep inelastic scattering with polarized muon beams on polarized nuclear targets. Earlier results on this subject are reviewed and an outlook is given on current and future experiments in this field.     

Strong variations of cosmic ray muons during thunderstorms

Experimental data about a strong decrease of the intensity of cosmic ray muons are presented. The event occurred during a thunderstorm on September 24, 2007 in Baksan Valley (North Caucasus). The threshold energy of muons is 100 MeV. In comparison with other events of this type detected previously, this event is remarkable by a longer duration (more than an hour and a half) and by the fact that well-pronounced correlations with lightning strokes are observed for the first time.     

雷暴电场对宇宙射线次级粒子μ 子的影响研究

西藏羊八井宇宙射线观测站的中子监测器主要探测宇宙射线次级粒子中能量在500 MeV—20 GeV的核子成分和少量的负μ子成分. 本文分析了2008—2010年观测站附近发生的62次雷暴期间中子监测器和大气平均电场仪的同步观测资料, 发现27次雷暴期间中子监测器计数率发生明显变化, 显著性S>5σ, 其中13次变化显著, 显著性S>10σ . 显著性S>10σ的13次个例信号变化百分比与地面电场场强幅值之间存在大体一致的变化趋势, 而显著性在5σ <S<10σ之间的14次个例信号变化百分比与地面电场场强幅值之间不存在相似的变化趋势. 较强雷暴当顶时中子监测器计数率变化一般不明显, 而中子监测器计数率变化明显的个例则多发生于雷暴云不当顶, 但探测器仍处于雷暴云下部正电荷层的控制范围之内时, 或者当顶雷暴处于形成或消散阶段. Dorman等把雷暴期间中子监测器计数率的变化归因于雷暴云内电场对宇宙射线次级粒子μ子的作用, 并建立了雷暴期间中子监测器计数率变化与雷暴地面电场相关联的理论. 本文分析发现雷暴期间羊八井中子监测器计数率变化与地面电场场强之间相关性较小或者没有相关性, 不支持Dorman的理论.     

Elastic and inelastic scattering of nucleons from 16O

Measurements of differential elastic and inelastic cross sections for neutron scattering from ¹⁶O at incident energies 18 to 26 MeV are presented. In addition to cross sections for neutron scattering differential cross sections for proton scattering up to 66 MeV are described in terms of phenomenological optical model potentials. At 24.5 MeV incident energy inelastic scattering up to 11.5 MeV excitation was measured. The elastic and inelastic compound nucleus contributions were examined. Direct inelastic scattering from the normal parity states was calculated using the DWBA and coupled-channel formalisms. The inelastic scattering cross section from non-normal parity state 2⁻ was calculated using the coupled-channel formalism via multi-step processes. Cross sections due to inelastic scattering from some of the states, which are thought to be members of an excited state rotational band were calculated using both vibrational and rotational approaches and were compared.     

Statistical properties of variations in cosmic ray muons during thunderstorms

An analysis is made of experimental data on variations in muons with a threshold of 100 MeV, detected by the CARPET air shower array in the Baksan Valley during thunderstorms of 2008. It is shown that with using a special criterion for selecting statistically significant variations (0.2%), muon intensity variations are observed in the majority of cases. Their characteristic duration is ∼8 min. Their amplitudes can have different polarities and do not exceed 1%.     

Altitude variation of cosmic ray nucleons derived from feynman scaling hypothesis

The differential proton spectra at different atmospheric depths and the differential neutron spectrum at sea level have been calculated using the scaling hypothesis of Feynman for hadronic inclusive reaction at high energies. In evaluating such values we used the primary nucleon spectrum of Grigorov et al. It is found that the derived spectra fit well the experimental data given by different authors. The estimated neutron-proton flux ratio against atmospheric depths is in accord with the measured data surveyed by Aguirre.The authors express their sincere thanks to Dr. A. Liland for sending his works.     

Bremsstrahlung photons from cosmic ray muons of high and ultrahigh energies

The results from calculations for fluxes of bremsstrahlung photons generated at different depths in the atmosphere by cosmic ray muons with energies of up to 10¹⁰ GeV are presented. It is shown that the generation of charmed particles in the atmosphere, along with the generation of J/ψ mesons, must be taken into account in interpretations of experimental data on studying EASes at high and ultrahigh energies.     

Gamma emission in deep inelastic scattering of neutrinos by nucleons

The emission of gamma rays due to weak neutral currents in the deep inelastic scattering of neutrinos (or antineutrinos) by nucleons is analyzed. Various possibilities for determining various structure functions for the reaction v(v)Nv(v)Xare examined. The structure functions are derived in the quarkparton model.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 36–39, April 1984.     

Study of the charge asymmetry in electromagnetic interactions of cosmic ray muons

The Durgapur cosmic ray spectrograph has been utilised to study the electromagnetic interaction of cosmic ray muons in iron in the momentum range 5–100 GeV/c. The dependence of the interaction cross section on the charge of the muons for the production of a single electron secondary due to the knock-on process and for two and more two electrons due to both knock-on and pair production has been investigated.The ratio of the interaction cross section for positive muons to that for negative muons in the magnetic-iron has been found to be 0.952 ± 0.045 for the production of one secondary particle. For production of two and more than two secondaries the ratios are 1.05 ± 0.09 and 0.91 ± 0.08 respectively. The present results do not indicate any charge asymmetry of cosmic ray muons in respect of electromagnetic interactions in iron.     

Rising inelastic cross-section and the attenuation of cosmic rays nucleons in the atmosphere

The intensity of C.R. nucleons in the atmosphere is calculated at high energies for energy dependent inelastic cross-section. It is found that the spectrum of C.R. nucleons becomes steeper with atmospheric depth (xgr/cm²) and behaves like E^?γ^?xB/λ_o.     

The energy spectrum of neutrons produced by cosmic ray muons in LVD

The energy spectrum of neutrons produced by cosmic ray muons in the underground detector LVD (3650 m.w.e.) is obtained for the energy range of 30–450 MeV. The spectrum is derived using the energy release spectrum of neutron interaction products in 1.5 m³ scintillation counters.     

Energy spectrum of cosmic ray muons above 10 TeV according to BUST data

The energy spectrum of cosmic ray muons in the range of several TeV to PeV obtained through the analysis of multiple interactions of muons (the pair meter technique) in the Baksan Underground Scintillation Telescope (BUST) is presented. Results are compared with prior BUST data on the muon energy spectrum measurements and data of other experiments, along with calculations for different muon spectrum models.     

Vector meson production by inelastic scattering of polarized electrons off polarized nucleons

A general analysis of vector meson production by inelastic scattering of polarized electrons (or muons) off polarized nucleons is presented. Cross section and vector meson decay angular distribution are discussed in terms of s-channel helicity amplitudes for natural and unnatural parity exchange. The question of experiments suitable for analyzing the more refined dynamical features of ?⁰-production is discussed in detail. Estimates are given for the effects to be expected from unnatural parity exchange.     

Intra-nuclear cascading in deep inelastic scattering of 150 GeV muons in emulsion

An experimental search is presented for the existence of intra-nuclear cascading which, for small values of the Bjorken scaling variable ω, is the only mechanism of particle multiplication in the target nucleus. Our data indicate that cascading does exist as one of the effective mechanisms of particle multiplication in μ-nucleus collisions. No significant variation of the observed multiplicity with ω is observed.     

Radiative effects in deep inelastic scattering of polarized leptons by polarized nucleons

Low-order electromagnetic corrections to deep inelastic scattering of polarized leptons by polarized nucleons are derived and investigated using a covariant method. Thorough numerical calculations of the corrections to cross sections and to the measured asymmetry are carried out for μp (ep) scattering in the range of lepton energy E = 200–500 GeV (10–16 GeV). The sensitivity of the corrections to the choice of the structure functions is investigated. The electromagnetic corrections to the asymmetry are found to be less than 10% within the greatest part of the kinematical region, but if x ～ 0, y ～ 1 they can reach a few tens of percent. The lowest order neutral current contribution to the asymmetry is obtained within the framework of standard electroweak interaction theory and the quark parton model. It is found this effect may be significant, especially in the kinematical range where electromagnetic corrections are negligible.     

Energy losses of high-energy muons and τ-leptons in inelastic scattering by nuclei

A hybrid model is used to calculate the losses of muons and τ-leptons in inelastic scattering by nuclei in water and in ground. The model includes soft and semihard photoprocesses and also hard scattering with an exchange by a γ-photon and a Z₀-boson. In the calculations, nuclear effects, such as shading and antiscreening of nucleons, the EMC effect, and the Fermi motion of nucleons in a nucleus, are considered. The distinction in scattering between a particle and an antiparticle, conditioned by an admixture of a weak neutral current, is discussed. Comparison with other calculations is given. Formulas for the coefficients of energy losses of muons and τ-leptons in water and in ground are obtained which approximate the calculation results over a wide interval of energies: 10²–10⁹ GeV. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 82–86, March, 2006.     

Lateral distribution of EAS muons measured for the primary cosmic ray energy around 100 TeV

The muonic component of the extensive air showers (EAS) is of great importance for the astroparticle physics. It carries the information about the properties of primary cosmic ray (CR) particles, such as their mass, and electromagnetic and hadronic nature. It provides a sensitive test for the hadronic interaction models, which are inevitable for describing the cascade shower development of cosmic rays in EAS experiments. The YangBaJing Hybrid Array (YBJ-HA) experiment has been in operation since the end of 2016. Surface detectors are used for the measurements of primary energy, angular direction and core position of a shower event, while underground muon detectors are used for measuring the density of muons at various locations. Using the data obtained by the YBJ-HA experiment,this work reports the first measurement of the lateral muon distribution for the primary cosmic ray energy in the 100TeV region. The punch-through effect is evaluated via MC simulation.