We present the results of an analysis of the large-scale anisotropy of cosmic rays in the PeV range. The Rayleigh formalism is applied to the right ascension distribution of extensive air showers ...measured by the KASCADE (Karlsruhe Shower Core and Array Detector) experiment. The data set contains about 10 super(8) extensive air showers in the energy range 0.7-6 PeV. No hints of anisotropy are visible in the right ascension distributions in this energy range. This accounts for all showers, as well as for subsets containing showers induced by predominantly light or heavy primary particles, respectively. Upper flux limits for Rayleigh amplitudes are determined to be between 10 super(-3) at a primary energy of 0.7 PeV and 10 super(-2) at 6 PeV.
Previous results obtained by KASCADE-Grande using the QGSjetII-02 hadronic interaction model have shown that the energy spectrum of cosmic rays between 1016eV and 1018eV exhibits a significant ...hardening at approximately 2×1016eV and a slight but statistically significant steepening close to 1017eV. Moreover, the analysis with QGSjetII-02 suggests that the break observed around 1017eV is caused by the heavy component of primary cosmic rays. In this paper, we report on the results of similar analyses performed using the SIBYLL 2.1 and EPOS 1.99 hadronic interaction models to interpret the data. The present results confirm qualitatively the previous findings. However, the intensity of the all-particle spectrum, the positions of the hardening and steepening of the spectrum, as well as the relative abundance of the heavy and light mass groups depend on the hadronic interaction model used to interpret the data.
The KASCADE experiment measures extensive air showers induced by cosmic rays in the energy range around the so-called knee. The data of KASCADE have been used in a composition analysis showing the ...knee at 3–5
PeV to be caused by a steepening in the light-element spectra T. Antoni et al., (KASCADE Coll.), Astropart. Phys. 24 (2005) 1–25. Since the applied unfolding analysis depends crucially on simulations of air showers, different high-energy hadronic interaction models (QGSJet and SIBYLL) were used. The results have shown a strong dependence of the relative abundance of the individual mass groups on the underlying model. In this update of the analysis we apply the unfolding method with a different low energy interaction model (FLUKA instead of GHEISHA) in the simulations. While the resulting individual mass group spectra do not change significantly, the overall description of the measured data improves by using the FLUKA model. In addition data in a larger range of zenith angle are analysed. The new results are completely consistent, i.e. there is no hint to any severe problem in applying the unfolding analysis method to KASCADE data.
We study the thermodynamics of the quark gluon plasma with lattice simulations in the continuum limit up to 1 GeV temperature where we show that a perturbative description already applies. We ...calculate the effect of the presence of charm quark in the equation of state and also describe the topological features of quantum chromodynamics. This conference contribution is based on Nature 539 (2016) no. 7627, 69–71 and Phys. Rev. D 92 (11) (2015), 114505.
The Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR) at Darmstadt will be a dedicated heavy-ion experiment for the investigation of baryonic matter ...at highest net-baryon densities. A RICH detector with CO
2 as radiator gas is being developed for clean and efficient electron identification which will be necessary for the measurement of some of the key observables of the physics program of CBM. The status of the development of this RICH detector and results on R&D activities concerning self-triggered readout electronics for PMTs, studies on the usage of wavelength-shifting films, as well as the evaluation of glass mirrors from industrial providers will be presented.
Wavelength-shifting (WLS) films were applied on UV-extended front windows of multianode photomultiplier tubes (MAPMTs) in order to increase the sensitivity of the MAPMTs at shorter wavelengths. The ...WLS material contained p-Terphenyl as photoactive component, which absorbs shorter wavelength photons (<300nm) and re-emits fluorescence photons around 350nm, i.e., at the maximum of the PMTs׳ sensitivity. The films were applied by means of dip-coating and the film performance was studied with respect to quantum efficiency, film homogeneity, and crosstalk on the MAPMTs. Using WLS-film-covered MAPMTs in a gaseous Ring Imaging Cherenkov detector, the number of detected photoelectrons per ring increased by up to 21% in an in-beam test.
The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >1020 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ∼50 Mpc through interactions ...with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or γ-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.
The Compressed Baryonic Matter (CBM) experiment is a dedicated heavy ion collision experiment at the FAIR facility. It will be one of the first HEP experiments which works in a triggerless mode: data ...received in the DAQ
from the detectors will not be associated with events by a hardware trigger anymore. All raw data within a giventime period will be collected continuously in containers, so-called time-slices. The task of the reconstruction algorithms is to create events out of this raw data stream. In this contribution, the optimization of the reconstruction software in the RICH detector to the free-streaming data flow is presented. The implementation of ring reconstruction algorithms which use time measurements of the hits as an additional parameter is discussed.
Event reconstruction in the RICH detector of the CBM experiment at FAIR Adamczewski, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net-baryon densities and moderate temperatures. One of the key signatures ...will be di-leptons emitted from the hot and dense phase in heavy-ion collisions. Measuring di-electrons, a high purity of identified electrons is required in order to suppress the background. Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). In order to access the foreseen rare probes, the detector and the data acquisition have to handle interaction rates up to 10 MHz. Therefore, the development of fast and efficient event reconstruction algorithms is an important and challenging task in CBM. In this contribution event reconstruction and electron identification algorithms in the RICH detector are presented. So far they have been developed on simulated data but could already be tested on real data from a RICH prototype testbeam experiment at the CERN-PS. Efficient and fast ring recognition algorithms in the CBM-RICH are based on the Hough Transform method. Due to optical distortions of the rings, an ellipse fitting algorithm was elaborated to improve the ring radius resolution. An efficient algorithm based on the Artificial Neural Network was implemented for electron identification in RICH. All algorithms were significantly optimized to achieve maximum speed and minimum memory consumption.
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