Over the past decades, cosmology has become largely based on experimental data, the most important sources of which are studies of the cosmic microwave background (CMB). CMB is present in the Universe since the very first moments of its existence, and the features of CMB recorded now reflect the fundamental processes of the evolution of the Universe. These processes cause a weak anisotropy of CMB, which is no more than 0.01 percent. The structure of anisotropy, which is interpreted on the basis of a sufficiently detailed standard theory of primary recombination, allows us to establish the most important cosmological parameters. One of these parameters is the Hubble constant (more precisely, the Hubble parameter). However, the difference between the value of the Hubble constant, obtained from the results of the Planck mission, and obtained from independent local measurements, is 10%. Such a big difference is called the Hubble tension problem, and is an important problem of cosmology. The interpretation of the Planck measurements (as well as the interpretation of WMAP results, where a close value of the Hubble constant is obtained) is critically based on the predictions of the standard recombination theory. This work shows that the recombination rate is higher than predicted by standard theory and is caused by the excitation of the kinetic degrees of freedom of hydrogen atoms, which is ignored by standard theory. The calculations performed demonstrate that taking into account this process leads to a good coincidence of the values of the Hubble constant obtained from the results of the Planck experiment and local measurements.
Cosmic Rays (CR), which provide crucial insights into the structure and evolution of the universe and astronomical phenomena such as supernovae, hold significant importance in the realms of physics and astrophysics.Simultaneously, CRs pose a challenge in astronomical observations due to their generation of hot pixels, necessitating the need for their fluxes to be accurately determined and eliminated from charge-coupled device (CCD) images.To address this, it is essential to measure the cosmic ray background at large observatories.In response, we developed a cosmic-ray muon detector utilizing scintillation technology, employing a plastic scintillator and a photomultiplier tube.We utilized the DRS4 Evaluation Board ver.5.1 read-out system for signal reception and processing.Our measurements were conducted at the ATA50 Telescope on the Atatürk University campus and at the site of Turkey's largest telescope, the Eastern Anatolia Observatory (DAG), using our custom-designed cosmic ray muon detector (CRMD).For the calculation of cosmic ray flux, we applied the Time of Flight (TOF) method, which calculates the flight time of cosmic rays passing through scintillators positioned vertically on a shelf.Data analysis was conducted using our Python code and ROOT programs.Cosmic ray-muon measurements involved placing the detector at various zenith angles.At the DAG site (elevation 3170 m), we observed a cosmic ray flux of 0.0450 cm -2 s -1 sr -1 .Conversely, at the lower altitude ATA50 Telescope site (elevation 1855 m), the flux was measured at 0.0235 cm -2 s -1 sr -1 .Notably, a 1-meter thick concrete structure was found to reduce cosmic muon measurements by 56%.Furthermore, the flux values obtained at 30°, 45°, 60°, 75° angles showed compatibility with theoretical predictions and were compared with existing literature values.These findings demonstrate the reliability, stability, and costeffectiveness of our custom-designed detector.
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