Physics of Particles and Nuclei最新文献

Abstract

The development and production of relevant products in the microelectronics industry in Russia have been crucially dependent on foreign technologies for several decades. In the current scenario, the need to find a way to gain sanction-free access to cutting-edge electronic components from modern technological processes required for the experiments in the NICA complex seems obvious. The MPD-ITS project aims to achieve this goal by organizing a consortium of interested institutes in Russia and China coordinated by the VBLHEP JINR (Dubna) in Russia and the CCNU (Wuhan) in the People’s Republic of China representing several Chinese institutions for the joint development and production of state-of-the-art Monolithic Active Pixel Sensors (MAPS) for fundamental and applied science experiments, including ASICs-based front-end electronics from the GBTx family which is the standard in modern High Energy Physics experiments for its fast duplex data flow between the high radiation level experimental area and the remote on-line servers, thus making these technologies freely accessible to China and Russia. These chips will be the focus of collaborative research and development for the construction of the NICA setups to be used in fundamental and applied science projects i.e. the MPD Inner Tracking System, and a prototype of a clinical tomograph for the particle Computer Tomography (pCT) for the ARIADNA project. Here we present our current achievements and future developments.

Abstract

Gell-Mann–Low functions can be calculated by means of perturbation theory and expressed as truncated series in powers of asymptotically small coupling parameters. However, it is necessary to know there behavior at finite values of the parameter and, moreover, their behavior at asymptotically large coupling parameters is also important. The problem of extrapolation of weak-coupling expansions to the region of finite and even infinite coupling parameters is considered. A method is suggested allowing for such an extrapolation. The basics of the method are described and illustrations of its applications are given for the examples where its accuracy and convergence can be checked. It is shown that in some cases the method allows for the exact reconstruction of the whole functions from their weak-coupling asymptotic expansions. Gell-Mann–Low functions in multicomponent field theory, quantum electrodynamics, and quantum chromodynamics are extrapolated to their strong-coupling limits.

Abstract

SHiP (Search for Hidden Particles) is a new general purpose experiment on the SPS ring at CERN, which aims to search for hidden particles proposed by numerous theories beyond the Standard Model, potentially explaining dark matter, neutrino oscillations, and baryon asymmetry of the universe. SHiP is declared as a zero background experiment. The key element to achieve this is the muon shielding. On the one hand, it should provide good background suppression, and on the other hand, it should not be too heavy. This paper presents the results of obtaining muon shielding configurations using Bayesian optimization. This made it possible to reduce the background level by 2.5 times while maintaining the mass of shielding at the same level.

Abstract

The state of the relativistic theory of elementary particles, general relativity, and theoretical physics in the Soviet Union in general from the 1960s/70s to present is reviewed. The role of conferences in the organization of scientific research known as “Baldin Autumn” is presented.

Abstract

A new precision three-arm magnetic spectrometer SCAN-3 is under construction for detecting charged (π, K, p) and neutral (n) particles produced at the LHEP Nuclotron internal target in dA collisions. This project is aimed at studies of highly excited nuclear matter. The matter will be studied through observation of its specific decay products, namely, pairs of energetic particles with a wide opening angle, close to 180°. The progress of work on the construction of the spectrometer will be discussed.

Abstract

In a hot and dense medium created in the collisions of heavy ions at high energy large topological fluctuations of QCD fields can occur, leading to possible effects of the local violation of P-symmetry in strong interactions. We proposed a search for charged ({{a}_{0}}) meson decay into three charged pions as a signature of the local strong parity breaking. Using PYTHIA Monte Carlo generator with enabled required decay channels we investigated invariant mass spectrum and analyzed the signal and background contributions. As a result, we estimated minimal number of pp collision events for significant signal of the P-breaking decay.

Abstract—Research of cosmic rays at the Physical Institute of the USSR Academy of Sciences resulted in the construction of the JINR Synchrophasotron. For this purpose the Electro physical Laboratory of the USSR Academy of Sciences was founded in 1953, which became part of JINR in 1956 as the High Energy Laboratory. The initial milestones to develop experiments at the Laboratory on the Synchrophasotron are presented. Leaders and key participants in the experiments are highlighted, as well as the lessons and results relevant today.

The history of construction and development of the Nuclotron and the main physics results obtained at the beams for 30 years of operation are briefly reported.

In the relativistic heavy ion collisions at the collision energies of a few GeV the strongly interacting matter is created at high baryon densities and relatively low temperatures. Azimuthal anisotropy of the produced particles provides a valuable insight into the properties of this form of matter. In this work, we discuss the scaling properties of directed flow of protons with system size as well as the collision energy.

We report about measurement of the ({{e}^{ + }}{{e}^{ - }} to {{pi }^{ + }}{{pi }^{ - }}) process cross section performed with the CMD-3 detector at VEPP-2000 ({{e}^{ + }}{{e}^{ - }}) collider. Integrated luminosity for the measurement is about 88 pb^–1 collected in center-of-mass energy range from 0.32 to 1.2 GeV. Systematic error of the cross section near (rho )(770) resonance is about 0.7%. The cross section values are used for evalution of the hadronic contribution to ({{(g - 2)} mathord{left/ {vphantom {{(g - 2)} 2}} right. kern-0em} 2}) of muon.