Physics of Particles and Nuclei Letters最新文献

The seesaw type II mechanism is considered within the framework of a left-right chiral model with a gauge group (SU{{(2)}_{L}} times SU{{(2)}_{R}} times U(1)), the lepton sector of which includes three generations of heavy Majorana neutrinos. The dependence of the mixing parameters of the lightest sterile neutrino as a dark matter particle on the scales of left-right symmetry breaking in the case of direct and inverse hierarchies of active neutrino masses is analyzed.

Monte Carlo models are widely used to study relativistic heavy-ion collisions, that is matter under extreme conditions through the analysis of azimuthal distributions of secondary particles. HYDJET++ is one such model. While initially relying on the true reaction plane method for azimuthal flow calculations, this approach is impractical for experimental comparisons. We enhanced HYDJET++ by implementing additional methods used in experiments, including reaction plane and cumulant techniques. Using this updated model, we simulated Pb–Pb and Xe–Xe collisions at (sqrt {{{s}_{{NN}}}} = 5.02) TeV and (sqrt {{{s}_{{NN}}}} = 5.44) TeV per nucleon pair in c.m.s respectively, calculating ({{v}_{2}}) and ({{v}_{3}}) flows via three methods and comparing them with each other and CMS data. These improvements refine the generator’s applicability, highlight areas requiring further optimization, and expand its potential for future research.

Although neutrino physics has been actively developing for a last few decades some questions are still not answered. One of urgent tasks is to measure neutrino oscillation parameters such as the charge-parity phase ({{delta }_{{{text{CP}}}}}), the neutrino mass ordering, and the octant of the mixing angle ({{theta }_{{{text{23}}}}}). One of the ways to reach a high significant level for these values is to combine data taken from various experiments. Currently operating neutrino accelerator experiments, NOvA and T2K, have been detecting neutrino interactions in electron (anti)neutrino appearance and muon (anti)neutrino disappearance modes, and nowadays these data are the main source of information to estimate unknown neutrino oscillation parameters. The data fitter of accelerator neutrino experiments is created within the GNA software and 2D contours of individual and combined sensitivities to (Delta m_{{{text{32}}}}^{{text{2}}},;{{delta }_{{{text{CP}}}}}) and ({{sin }^{2}}{{theta }_{{{text{23}}}}}) for NOvA and T2K experiments are plotted based on Monte-Carlo simulation and Asimov data.

Numerous applications in physics and technology rely on random number generation: for Monte Carlo purposes, key distribution, and other tasks. For these elaborate hash functions with carefully studied and tuned algorithms have been developed, giving pseudo-random numbers. Depending on the complexity and quality of their output, they vary from very good quality (such as RANLUX with a 10¹⁷¹ repetition period), to fast algorithms, however of lesser period (such as the Mersenne Twister, a factor of ca. ×40 faster). We here present the implementation of a true-random number “multiplier” algorithm. The algorithm relies on a finite set of true-random numbers from a physical source (in our case 0.2 M atmospheric noise random numbers in the range of 0–9999). The algorithm produces new numbers by combining pairs of 2 random numbers from the list, situated at random distance apart. The random offset is calculated by a shift register structure involving both the local rand() generator, and numbers from the list itself, whereby it produces “non-repetitive repetitions”—i.e., our multiplier has no known period. The tests, performed with the DieHarder [1] test suite, show good quality.

We investigate four-dimensional renormalisible gauge-Yukawa theory with all possible dimension-4 operators which exhibit asymptotic safety. We calculated all (beta )-functions and interacting ultraviolet fixed points at 2-loop for gauge, 1-loop for Yukawa and scalar fields.

The Spin Physics Detector (SPD) experiment at the Nuclotron-based Ion Collider fAcility (NICA) is an upcoming project with an extensive physics program aimed at studying the spin structure of the nucleons. The experiment will record data from the collisions of polarized proton and deuteron beams. One of the important particles produced in such collisions is the (Lambda )-hyperon. It is noteworthy because it has already been studied in detail and its polarization can provide information about parton distribution functions of beam particle. At the present stage of the experiment, one of the main tasks is to study the detection of the particles of interest produced in the collisions at the SPD and to optimize the parameters for their selections. This work presents the results of the calculations of detection efficiencies of the (Lambda ) and anti-(Lambda ) hyperons.

We consider Bose–Einstein correlations of direct photons in central Bi–Bi collisions at (sqrt {{{s}_{{NN}}}} ) = 9.2 GeV. Two-photon correlations are calculated in UrQMD hybrid model. Two equations of state, one with the first-order QCD phase transition and the other with the pure hadron gas, are considered to study the effects of the formation of quark-gluon plasma (QGP) and mixed phase on the observables. The extracted correlation radii in out-side-long parametrization demonstrate significant increasing in outward and longitudinal directions for the scenario including QGP, while correlations in side direction are not sensitive to the equation of the state.

Arachidic acid monolayers formed on an aqueous solution of cerium nitrate have been studied by grazing incidence X-ray diffraction. Despite compression beyond the collapse point, the monolayer unexpectedly retains its translational order and develops corrugation. This paper presents a method for simulating the two-dimensional diffraction patterns characteristic of monolayers with perturbed orientational order. The unusual diffraction data obtained from corrugated monolayers during synchrotron experiments are described using this approach.

In the paper, the static and dynamic properties of the pion in the Bethe-Salpeter approach are considered. The rank-one separable kernel of the quark-antiquark interaction is used to solve the equation analytically. Multidimensional integrals describing pion properties are calculated by several numerical methods and compared with previous papers. An error in the calculation of the interaction part of the elastic pion form factor is found. Using the corrected results, the kernel parameters are refitted. The calculated static properties as well as transition and elastic form factors are presented in comparison with the recent experimental data.

The gas flow rate through the cryogenic supply systems of the NICA accelerator complex is a parameter whose measurement plays a decisive role in the operation and maintenance of equipment and in the optimization of the technological process. Monitoring the measurement of compressed helium flow rate through the MO-800 adsorber of oil purification and drying units makes it possible to track the time of production of the adsorbent’s protective effect and replace it in a timely manner. A technique for selecting a diaphragm-type flow meter and measuring the flow through it for the MO-800 No. 4 oil purification and drying unit. A diaphragm with control and measuring instruments was installed on the compressed helium outlet line from the unit in February 2024. In April 2024, a software package for measuring flow, monitoring the residual amount of adsorbent, and promptly informing the operator was developed and implemented as part of the MO‑800 No. 4 automated process control system. Possible applications of diaphragms for measuring the performance of compressor equipment and the refrigeration capacity of cryogenic installations is also examined.