We find out the connection between the unintegrated gluon distribution at low intrinsic transverse momenta and the inclusive spectrum of the hadrons produced in pp collision at LHC energies in the mid-rapidity region and low hadron transverse momenta. The parameters of this distribution are found from the best description of the LHC data. Its application to the analysis of ep deep inelastic scattering allows us to obtain the results which describe reasonably well the H1 and ZEUS data on the structure functions at low x. A connection between the soft processes at LHC and small x physics at HERA has been found. PACS number(s): 12.38.-t, 13.85.-t

Hadron inclusive spectra in pp collisions are analyzed within the modified quarkgluon string model including both the longitudinal and transverse motion of quarks in the proton in the wide region of initial energies. The self-consistent analysis shows that the experimental data on the inclusive spectra of light hadrons like pions and kaons at ISR energies can be satisfactorily described at transverse momenta not larger than 1-2 GeV/c. We discuss some difficulties to apply this model at energies above the ISR and suggest to include the distribution of gluons in the proton unintegrated over the internal transverse momentum. It leads to an increase in the inclusive spectra of hadrons and allows us to extend the satisfactory description of the data in the central rapidity region at energies higher than ISR.

The origin and nature of extreme energy cosmic rays (EECRs), which have energies above the 5 · 10 19 eV, the Greisen-Zatsepin-Kuzmin (GZK) energy limit, is one of the most interesting and complicated problems in modern cosmic-ray physics. Existing ground-based detectors have helped to obtain remarkable results in studying cosmic rays before and after the GZK limit, but have also produced some contradictions in our understanding of cosmic ray mass composition. Moreover, each of these detectors covers only a part of the celestial sphere, which poses problems for studying the arrival directions of EECRs and identifying their sources. As a new generation of EECR space detectors, TUS (Tracking Ultraviolet Set-up), KLYPVE and JEM-EUSO, are intended to study the most energetic cosmic-ray particles, providing larger, uniform exposures of the entire celestial sphere. The TUS detector, launched on board the Lomonosov satellite on April 28, 2016, from Vostochny Cosmodrome in Russia, is the first of these. It employs a single-mirror optical system and a photomultiplier tube matrix as a photodetector and will test the fluorescent method of measuring EECRs from space. Utilizing the Earth's atmosphere as a huge calorimeter, it is expected to detect EECRs with energies above 10 20 eV. It will also be able to register slower atmospheric transient events: atmospheric fluorescence in electrical discharges of various types including precipitating electrons escaping the magnetosphere and from the radiation of meteors passing through the atmosphere. We describe the design of the TUS detector and present results of different ground-based tests and simulations.

Abstract. TUS (Tracking Ultraviolet Set-up), the first orbital detector of extreme energy cosmic rays (EECRs), those with energies above 50 EeV, was launched into orbit on April 28, 2016, as a part of the Lomonosov satellite scientific payload. The main aim of the mission is to test a technique of registering fluorescent and Cherenkov radiation of extensive air showers generated by EECRs in the atmosphere with a space telescope. We present preliminary results of its operation in a mode dedicated to registering extensive air showers in the period from August 16, 2016, to November 4, 2016. No EECRs have been conclusively identified in the data yet, but the diversity of ultraviolet emission in the atmosphere was found to be unexpectedly rich. We discuss typical examples of data obtained with TUS and their possible origin. The data is important for obtaining more accurate estimates of the nocturnal ultraviolet glow of the atmosphere, necessary for successful development of more advanced orbital EECR detectors including those of the KLYPVE (K-EUSO) and JEM-EUSO missions.

TUS (Tracking Ultraviolet Set-up) is the world's first orbital detector of ultra-high-energy cosmic rays (UHECRs). It was launched into orbit on 28th April 2016 as a part of the scientific payload of the Lomonosov satellite. The main aim of the mission was to test the technique of measuring the ultraviolet fluorescence and Cherenkov radiation of extensive air showers generated by primary cosmic rays with energies above ∼100 EeV in the Earth atmosphere from space. During its operation for 1.5 years, TUS registered almost 80,000 events with a few of them satisfying conditions anticipated for extensive air showers (EASs) initiated by UHECRs. Here we discuss an event registered on 3rd October 2016. The event was measured in perfect observation conditions as an ultraviolet track in the nocturnal atmosphere of the Earth, with the kinematics and the light curve similar to those expected from an EAS. A reconstruction of parameters of a primary particle gave the zenith angle around 44̂ but an extreme energy not compatible with the cosmic ray energy spectrum obtained with ground-based experiments. We discuss in details all conditions of registering the event, explain the reconstruction procedure and its limitations and comment on possible sources of the signal, both of anthropogenic and astrophysical origin. We believe this detection represents a significant milestone in the space-based observation of UHECRs because it proves the capability of an orbital telescope to detect light signals with the apparent motion and light shape similar to what are expected from EASs. This is important for the on-going development of the future missions KLYPVE-EUSO and POEMMA, aimed for studying UHECRs from space.