Interactions Of High-energy Muons Research Articles

Interaction of 160-GeV muon with emulsion nuclei

In this work we present some results of the interaction of high-energy muons with emulsion nuclei. The interaction results in emission of a number of fragments as a consequence of electromagnetic dissociation of the excited target nuclei. This excitation is attributed to absorption of photons by the target nuclei due to the intense electric field of the very fast incident muon particles. The interactions take place at impact parameters that allow ultra-peripheral collisions to take place, leading to giant resonances and hence multifragmentation of emulsion targets. Charge identification, range, energy spectra, angular distribution and topological cross-section of the produced fragments are measured and evaluated.

Geant4 Electromagnetic Physics for LHC Upgrade

In this work we present recent progress in Geant4 electromagnetic physics modelling, with an emphasis on the new refinements for the processes of multiple and single scattering, ionisation, high energy muon interactions, and gamma induced processes. The future LHC upgrade to 13 TeV will bring new requirements regarding the quality of electromagnetic physics simulation: energy, particle multiplicity, and statistics will be increased. The evolution of CPU performance and developments for Geant4 multi-threading connected with Geant4 electromagnetic physics sub-packages will also be discussed.

Geant4 simulation of production and interaction of muons

A set of models for Monte Carlo simulation of production and interaction of high energy muons is developed in the framework of the Geant4 toolkit. It describes the following physics processes: ionization of high energy muons with radiative corrections, bremsstrahlung, electron-positron pair production, muon induced nuclear reactions, gamma annihilation into muon pair, positron annihilation into muon pair, and into pion pair. These processes are essential for the LHC experiments, for the understanding of the background in underground detectors, for the simulation of effects related with high-energy muons in cosmic ray experiments and for the estimation of backgrounds in future colliders. The applicability area of the models extends to 1 PeV. The major use-cases are discussed.

Investigations of fast neutron production by high energy muon interactions on different targets

Investigations of fast neutron production by high energy muon interactions on different targets

Trigger and measurement system for small-angle scattering

A system for measurement and selection of small-angle scattering was developed for the study of high-energy muon interactions with nuclei. The trigger decision was obtained by using the information from more than 500 individual scintillation counters placed in and around the beam. They were distributed in 8 successive planes upstream and 4 planes downstream of the target. In the trigger logic, each beam particle in the 5 cm wide beam was identified and, a fast trigger signal was produced, only if the track was consistent with a scattering process. The beam rate was ∼ 10 7 s −1 and the decision time of the trigger processor, built in the FASTBUS standard, was typically 80 ns. The reaction between 280 GeV muons and different target nuclei could be studied down to scattering angles of 1.6 mrad. The trigger rate with these conditions was of the order of 10 −5 per incident beam particle.

Estimate of the background of a gravitational-wave detector due to cosmic rays

The authors examine once more the effect of cosmic rays on a resonating gravitational-wave antenna in view of the very high sensitivities that are required for detecting the supernovae of the Virgo Cluster. They show that, at sea-level, the secondaries generated in the bar by the electromagnetic interaction of high-energy muons produce signals with rates much larger than that expected from supernovae. This inconvenience is eliminated in an underground laboratory.

The vertex and large angle detectors of a spectrometer system for high energy muon physics

A description is given of the detector system which forms the large angle spectrometer and vertex detector of the EMC spectrometer. The apparatus is used in the NA9 experiment which studies the complete hadronic final state from the interaction of high energy muons.

Interaction of high energy muons in association with EAS, with rock and lead

An investigation on the interaction of high energy muons, associated with EAS and having energies greater than several hundred GeV, has been carried out at Kolar Gold Fields. A visual detector consisting of neon flash tube hodoscope has been used together with a scintillator detector to observe the muons and accompanying showers at the underground level.

Study of low-energy physics with high-energy muon interactions in nuclear emulsion

Study of low-energy physics with high-energy muon interactions in nuclear emulsion

Reply to "Study of low-energy physics with high-energy muon interactions in nuclear emulsion"

Reply to "Study of low-energy physics with high-energy muon interactions in nuclear emulsion"

The total photonuclear cross section at high energies as determined from the neutron production by fast muons

A study has been made of the production of evaporation neutrons in the interaction of high-energy muons with lead nuclei. The detected neutrons arise from the direct electromagnetic interaction of the fast muons with lead nuclei and the interaction of photons from cascades initiated by knock-on electrons. Information about the total photonuclear cross section at high energies can be obtained from this muon interaction experiment by considering the virtual photon spectrum of the muons. The measured value of the product of the cross section per lead atom and mean multiplicity corresponds to those calculated on the Kessler theory under the assumption of a constant photonuclear cross section above 1 GeV. The experimental results disagree with the assumptions made by Hodgson and Jameel who predict a decrease of the total photonuclear cross section at high energies.

Study of the nuclear and electromagnetic interactions of high-energy muons

Cascade showers produced by high-energy cosmic muons at large zenith angles have been studied by means of an ionization calorimeter. The method of separation of electromagnetic and nuclear showers is described. The angular distribution and energy spectrum of the nuclear showers are given. An estimate of the photonuclear cross section at high energy [Formula: see text] is made using both the virtual photon spectrum developed by Weizsäcker and Williams (WW) and the theory of Kessler and Kessler (1957; KK). It is equal to (2.0 ± 1.1) × 10−28 cm2/nucleon for WW and (0.15 ± 0.08) × 10−28 cm2/nucleon for KK. The experimental electromagnetic showers with energy ~1012 eV were compared with the theoretical cascade curves. The experimental and theoretical data are in good agreement if the value of the radiation length in iron is equal to (13.8 ± 0.3) g cm−2.

Horizontal air showers induced by muons with energy above 1013 eV

We have been observing horizontal air showers to study the high-energy interactions of muons. Nine horizontal air showers of size greater than 104 and zenith angle above 70° were observed. Two of these showers showed evidence that they are not pure electromagnetic showers but nucleonic showers. One shower contained a nuclear-active particle which produced a nuclear interaction in the cloud chamber, and the other shower contained a muon which penetrated about 103 g cm−2 of iron absorber. The size distribution of the horizontal showers was compared with the calculated one assuming that the nuclear interaction of high-energy muons was negligible. The discrepancy between the experimental distribution and the calculated one is reduced if the nuclear interaction of high-energy muons is taken into account, which supports our view that the horizontal air showers (at least some fraction of them) are produced by nuclear interactions of high-energy muons.

Energy dependence of photonuclear effect and muon intensity under rock

We attempt to verify the high-energy behaviour of the photo-nuclear cross section σγ which is expected to be dominated by the exchange of a Regge pole, by analysing the information on the intensity-depth curve of muons under rock.We first discuss the nuclear interactions of high-energy muons and compare our calculations with the available data on muons at the accelerators or under rock. Then we compare the muon integral spectrum obtained from under-rock results and from our range-energy relation with the one measured directly at sea level. We conclude that there is no evidence of the supposed energy dependence of the cross section.

High energy muon interactions - C.E.R.N. work on weak interactions

What I have to say will consist largely of speculation, because no unusual feature of muon interactions at high energies has yet been established. Considerable efforts have been made in the last few years to find an anomalous effect, but so far the result has been negative. This is probably because we have not yet reached high enough energies, as will become evident during the course of this talk. Figure 19 shows a number of possible interactions of the muon, which will be considered in detail below. There is first the electromagnetic coupling to the photon, with coupling constant e satisfying e 2 = 1/137 (figure 19( a )). Figure 19( b ) shows the weak interaction coupling, to the intermediate boson W ± (which is here assumed to exist). To obtain the correct strength for the overall weak four-fermion interaction one requires g 2 / m 2 w = G weak = 10 -5 / m 2 N , where m N is the nucleon mass. Thus only the ratio of g 2 to m 2 w is fixed.