ABOUT ONE WAY OF ORGANIZATION UNIFIED SYSTEM FOR REGISTRATION OF SPACE RAYS

At present, at the high-mountain scientific station for the study of the physics of cosmic rays, various, independently operating unique experimental installations are used. The article discusses the ways and methods of combining these installations into a single system, which includes networks of scintillation detectors of the "carpet" type for registration of the electron-photon component, ground and underground monitors for registration of neutron components, calorimeters, Cherenkov detectors, a scintillation spectrometer and a number of other subsystems. The newly created unified system for registering cosmic rays based on the achievements of modern technology and scientific thought will have a high resolution, with a common databank with synchronization in time of operation of separate, independently operating experimental installations. The solution to this problem will make it possible to perform a detailed analysis of the recorded events from a single position, to carry out complex calculations of the spatial distribution, mass composition, and also the energy structure of cosmic rays with a high degree of accuracy.

Polariton condensation and surface enhanced Raman in spherical ZnO microcrystals

Preparation and characterization of polariton Bose–Einstein condensates in micro-cavities of high quality are at the frontier of contemporary solid state physics. Here, we report on three-dimensional polariton condensation and confinement in pseudo-spherical ZnO microcrystals. The boundary of micro-spherical ZnO resembles a stable cavity that enables sufficient coupling of radiation with material response. Exciting under tight focusing at the low frequency side of the bandgap, we detect efficiency and spectral nonlinear dependencies, as well as signatures of spatial delocalization of the excited states which are characteristics of dynamics in polariton droplets. Expansion of the photon component of the condensate boosts the leaky field beyond the boundary of the ZnO microcrystals. Using this, we observe surface polariton field enhanced Raman responses at the interface of ZnO microspheres. The results demonstrate how readily available spherical semiconductor microstructures facilitate engineering of polariton based electronic states and sensing elements for diagnostics at interfaces.

Illuminating the photon content of the proton within a global PDF analysis

Precision phenomenology at the LHC requires accounting for both higher-order QCD and electroweak corrections as well as for photon-initiated subprocesses. Building upon the recent NNPDF3.1 fit, in this work the photon content of the proton is determined within a global analysis supplemented by the LUXqed constraint relating the photon PDF to lepton-proton scattering structure functions: NNPDF3.1luxQED. The uncertainties on the resulting photon PDF are at the level of a few percent, with photons carrying up to \simeq0.5\%≃0.5% of the proton’s momentum. We study the phenomenological implications of NNPDF3.1luxQED at the LHC for Drell-Yan, vector boson pair, top quark pair, and Higgs plus vector boson production. We find that photon-initiated contributions can be significant for many processes, leading to corrections of up to 20\%20%. Our results represent a state-of-the-art determination of the partonic structure of the proton including its photon component.

EVIDENCE OF VARIATION OF THE ACCRETION FLOW GEOMETRY IN GRS 1915 + 105 FROM IXAE AND RXTE DATA

The Galactic microquasar GRS 1915 + 105 exhibits various types of light curves. There is, however, no understanding of when a certain type of light curve will be exhibited and only in a handful of cases, the transitions from one type to another have actually been observed. We study the detailed spectral properties in these cases to show that different classes have different ratio of the power-law photon and the blackbody photon. Since the power-law photons are from the Compton cloud, and the intensity of the power-law photon component depends on the degree of interception of the soft photons by the Compton cloud, we conclude that not only the accretion rate, but the accretion flow geometry must also change during a class transition.