Underground physics in Japan, present and future

Summary This paper proceeds in three parts: i) We first review underground facilities in Japan. ii) Next, we show Super MUTRON project which is planned to progress at the Ohya-cho underground. The most important purpose of Super MUTRON is to detect muon pairs and muon bundles expected from quark gluon plasma and other processes. iii) Finally, we discuss about Japanese projects which will be completed at the Gran Sasso tunnel.

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Riassunto Questo lavoro è diviso in tre parti: i) prima si passano in rassegna le apparecchiature sotterranee in Giappone, ii) inoltre si espone il progetto Super MUTRON che sta per essere realizzato sottoterra nell'Ohya-cho. Lo scopo piú importante del Super MUTRON è quello di rilevare coppie di muoni e fasci di muoni previsti nel plasma di quark gluonici e altri processi. Infine si discutono i progetti giapponesi che saranno completati nel tunnel del Gran Sasso.

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Резюме Эта статвя состоит из трех частей. Вначале мы приводим обзор подземных исседований в Японии. Затем описывается проект эксперимента супер-MUTRON, который планируется провести в подземной лаборатории Ohya-cho. Наиболее важная цель этого эксперимента состоит в детектировнии мюнных пар и групп мюонов, которые, как предполагается, генерируются в кварк-глюонной плазме и в друтих процессах. И наконец, мы обсуждаем проекты японских работ в туннеле Гран Cacco.

     

Diffuse galactic and extragalactic radiation in the far infra-red

Summary We present the results of a balloon flight devoted to the observation of the diffuse sky radiation in the wave-length region (150÷400) and (350÷3000) μm, at angular scales larger than six degrees. Observations of dust emission and distribution are discussed. Paper presented at the Congress ?Galactic and Extragalactic Dark Matter?, Roma, 28 to 30 June 1983.     

Broad-band X-ray spectrum of the bright Seyfert galaxy Mkn 509

Summary One of the brightest X-ray Seyfert galaxies, Mkn 509, has been observed with the X-ray satellite EXOSAT. Wide-band ((0.05÷35) keV) spectral information is now available at the same time. Different filters have been rotated in front of the low-energy telescope. The overall spectrum is best fitted by a two-component power law. The intensity and the spectral index of the soft component are in agreement with the extrapotation of the UV spectrum; the high-energy component exhibits a spectral index harder than reported by previous observations and a correspondingly lower intensity. Therefore, at least for this source, the predicted low-energy spectral turnover is a smooth prolungation of the UV spectrum rather than a sharp discontinuity. Paper presented at the 2° Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May – 2 June 1984.     

The EXOSAT and Einstein observations of 1E0630+178 (?Geminga?) as complementary data sets

Summary Data for the soft X-ray source 1E0630+178 are now available from four independent measurements of the Einstein and EXOSAT missions. These are presented and compared in the light of the different characteristics and energy response of the different X-ray imaging detectors used (IPC, LE 1, LE 2). The time variability on medium (∼ hours) time scale is also investigated. The X-ray data used for this work have been collected in part during the Einstein Observatory Guest Observer Program and in part from the EXOSAT mission.     

Search for UHE cosmic sources with a large-area underground muon detector

Summary The newly discovered gamma-ray emission from Cyg-X 3 with energies up to 2·10¹⁶eV gives the first evidence that particle acceleration in galactic gamma-ray sources can reach energies of the order of 10⁴ TeV. We discuss the detectability of this type of sources by an underground muon tracking detector with area of the order of ∼1000 m² and the physical information which could be obtained in this way. Paper presented at the 2° Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–2 June 1984.     

High-energy multiple muons viewed from the observation of gamma-ray families at mountain altitudes

Summary Based on the knowledge of the nature of primary cosmic rays inferred from the observations of gamma-ray family events with the largescale emulsion chamber experiments at Mt. Fuji and at Mt. Kanbala, the three-dimensional Monte Carlo simulation on the high-energy multiple-muon events has been carried out. By comparing the simulation results with the presently available observed ones, it is concluded that the hypothesis for the composition of primary cosmic rays being heavy-nuclei dominant, given from the analysis of gamma-ray family events, is quite consistent with the observed results on the lateral spread of multiple-muon events.

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Riassunto Si effettua la simulazione di Monte Carlo tridimensionale sugli eventi di muoni multipli ad alta energia, basandosi sulla conoscenza della natura dei raggi cosmici primari inferita dalle osservazioni degli eventi della famiglia di raggi gamma con gli esperimenti su larga scala della camera ad emulsione sul Monte Fuji e sul Monte Kanbala. Confrontando i risultati della simulazione con quelli osservati attualmente disponibili, si conclude che l'ipotesi della composizione dei raggi cosmici primari in cui predominano i nuclei pesanti, data dall'analisi degli eventi della famiglia di raggi gamma, risulta del tutto coerente con i risultati osservati sulla diffusione laterale degli eventi a muoni multipli.

     

4-Geodesy

Summary As familiar geodesy determines the shape of the Earth from measurements of distances between selected points, so 4-geodesy has for ideal to determine spacetime geometry—and through it masses of celestial objects—by measurements of distances of selected stars from the Earth and from each other. Crucial to this enterpise is a means for determining distances transverse to the line of sight. A ?lighting-profile? method is outlined for determining transverse distance: 1) trace the flash of light from a supernova as the resulting illumination makes its way to the distant galaxy, and 2) compare the observed ?lighting profile? with the canonical shape calculated in the appendix. Paper presented at the Congress ?Galactic and Extragalactic Dark Matter?, Roma, 28 to 30 June 1983.     

16-month periodicity of cosmic-ray intensity

Summary Data from four neutron monitors, Climax (1953–1976), Deep River (1964–1977), Mt. Norikura (1957–1983) and Tokyo (1970–1983) are analysed. Power spectra reveal peaks at frequency 1c/16 months for all the stations. Harmonic analysis for the 16-month period is performed after eliminating the long-term solar-cycle variation. There is general agreement in the phases of the mean vectors for various neutron monitors. The amplitude averaged over all the four stations is 0.41±0.01, while it is higher for the two stations having lower cut-off rigidity as compared to that of the other two. The vectors are seen to become more consistent in phase for periods of minimum solar activity than those for maximum-activity period. The summation dials reveal abrupt changes in the directions of the 16-month wave vector corresponding to the reversal of polarity of the solar magnetic field. Comparison of the 16-month wave of sunspot activity with that of cosmic-ray intensity, however, does not show any significant correlation.

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Riassunto Si analizzano dati da quattro monitor di neutroni, Climax (1953–1976), Deep River (1964–1977), Mt. Norikura (1957–1983) e Tokyo (1970–1983). Gli spettri di frequenza rivelano picchi alla frequenza di 1 ciclo ogni 16 mesi per tutte le stazioni. Si effettua un'analisi armonica per un periodo di 16 mesi dopo aver eliminato la variazione del ciclo solare a lungo termine. Esiste un accordo generale riguardo alle fasi dei vettori medi per vari monitor di neutroni. L'ampiezza media rispetto a tutte e quattro le stazioni è di 0.41±0.01, mentre risulta superiore per le due stazioni che presentano una rigidità di taglio inferiore alle altre due. Si osserva una crescente coerenza di fase dei vettori in periodi di attività solare minima, rispetto a quella in periodi di attività massima. I grafici della somma rivelano cambiamenti repentini nelle direzioni del vettore d'onda di 16 mesi, corrispondenti all'inversione di polarità del campo magnetico del Sole. Il confronto di un'onda di 16 mesi dell'attività delle macchie solari con quella dell'intensità dei raggi cosmici, tuttavia, non mostra nessuna correlazione significativa.

     

Evidence for an increasing 59 s period in the X-ray emission from Geminga

Summary Einstein Observatory and EXOSAT X-ray data from 1E0630+178 reveal a ∼50% periodic emission at ≳59s. This confirms the early SAS-II and COS-B findings on 2CG 195+04 atE>50 MeV and provides the temporal signature for the identification of Geminga. The observations, spanning over a decade (1973–1983), also suggest a very high positive which has become still higher in 1979–1983. The X-ray data used for this work have been collected in part during the Einstein Observatory Guest Observer Program and in part from the EXOSAT mission.     

Cosmic radiation, production of antimatter and their implications

Summary The puzzles connected with the observation of a large ratio, the measured rising ratio of e⁺/e⁻ and some other unsolved, important problems led some theorists to conceive of the extra-galactic origin of cosmic rays and to postulate the existence of the antigalaxies. We have attempted here to understand the problems on the basis of the simple leaky box model (SLBM) with one particular phenomenological model for particle production, and some very recent observational features of high-energy collisions that call for theoretical attention. The conclusion is: the agreements are still not satisfactory if we accept and adhere to the correctness of the previous data. In recent times there has been a dramatic change in the situation with regard to this discrepancy. The latest data have just been taken note of but the conclusions are arrived at here more on the basis of the earlier data than on the recent ones as they necessitate further confirmation.