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Cosmic rays are the highest-energy particles found in nature. Measurements of the mass composition of cosmic rays with energies of 10(17)-10(18) electronvolts are essential to understanding whether they have galactic or extragalactic sources. It has also been proposed that the astrophysical neutrino signal comes from accelerators capable of producing cosmic rays of these energies. Cosmic rays initiate air showers--cascades of secondary particles in the atmosphere-and their masses can be inferred from measurements of the atmospheric depth of the shower maximum (Xmax; the depth of the air shower when it contains the most particles) or of the composition of shower particles reaching the ground. Current measurements have either high uncertainty, or a low duty cycle and a high energy threshold. Radio detection of cosmic rays is a rapidly developing technique for determining Xmax (refs 10, 11) with a duty cycle of, in principle, nearly 100 per cent. The radiation is generated by the separation of relativistic electrons and positrons in the geomagnetic field and a negative charge excess in the shower front. Here we report radio measurements of Xmax with a mean uncertainty of 16 grams per square centimetre for air showers initiated by cosmic rays with energies of 10(17)-10(17.5) electronvolts. This high resolution in Xmax enables us to determine the mass spectrum of the cosmic rays: we find a mixed composition, with a light-mass fraction (protons and helium nuclei) of about 80 per cent. Unless, contrary to current expectations, the extragalactic component of cosmic rays contributes substantially to the total flux below 10(17.5) electronvolts, our measurements indicate the existence of an additional galactic component, to account for the light composition that we measured in the 10(17)-10(17.5) electronvolt range.

Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-\"bright\" mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-\"quiet\" mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.

In 1945 United States forces captured the Holy Crown of St Stephen. Both Hungary's Stalinist leader Mátyás Rákosi and his successor, János Kádár, demanded its return. Why was a symbol with monarchic, irredentist and religious connotations so desirable to a regime that claimed to be republican, internationalist and secular? This article covers the importance of the Crown to the international and national legitimacy of the regime. It looks at the legal dispute concerning American retention of the Crown, pays particular attention to Rákosi's attempt to exchange it for imprisoned businessman Robert Vogeler in 1950, and finally comments on the popular reception of its return in 1978. (Author abstract)

LOFAR is a new form of radio telescope which can detect radio emission from air showers induced by very high-energy cosmic rays. It can also look for radio emission from particle cascades on the Moon induced by ultra high-energy cosmic rays or neutrinos. To complement the radio detection, we are setting up a small particle detector array LORA (LOfar Radboud Air shower array) within an area of ~300 m diameter in the LOFAR core. It will help in triggering and confirming the radio detection of air showers with the LOFAR antennas. In this paper, we present a short overview about LORA and discuss its current status.

Measurements of the kinematic distributions of J / ψ mesons produced in p –C, p –Ti and p –W collisions at in the Feynman- x region −0.34< x F <0.14 and for transverse momentum up to p T =5.4 GeV/c are presented. The x F and p T dependencies of the nuclear suppression parameter, α , are also given. The results are based on 2.4×10 5 J / ψ mesons reconstructed in both the e + e − and μ + μ − decay channels. The data have been collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The measurement explores the negative region of x F for the first time. The average value of α in the measured x F region is 0.981±0.015. The data suggest that the strong nuclear suppression of J / ψ production previously observed at high x F turns into an enhancement at negative x F .

Observations were made with the Low Frequency Array (LOFAR13), a radio telescope consisting of thousands of crossed dipoles with built-in air-shower-detection capability14. LOFAR continuously records the radio signals from air showers, while simultaneously running astronomical observations. It comprises a scintillator array (LORA) that triggers the read-out of buffers, storing the full waveforms received by all antennas.

A study of the angular distributions of leptons from decays of J / ψ ’s produced in p-C and p-W collisions at has been performed in the J / ψ Feynman- x region −0.34< x F <0.14 and for J / ψ transverse momenta up to 5.4 GeV/ c . The data were collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The results, based on a clean selection of 2.3×10 5 J / ψ ’s reconstructed in both the e + e − and μ + μ − decay channels, indicate that J / ψ ’s are produced polarized. The magnitude of the effect is maximal at low  p T . For p T >1 GeV/ c a significant dependence on the reference frame is found: the polar anisotropy is more pronounced in the Collins-Soper frame and almost vanishes in the helicity frame, where, instead, a significant azimuthal anisotropy arises.