Physics of Particles and Nuclei Letters最新文献

Determining centrality is an important task because it allows estimating the size of the collision system in relativistic heavy ion collisions. It provides a tool for comparison of the results from upcoming measurements with the Multi-Purpose Detector (MPD) at NICA with data from other experiments and theoretical model calculations. In this work, a new procedure for centrality determination based on the energy of spectator fragments has been proposed. The validity of the procedure has been checked using the published data from the NA61/SHINE experiment for Pb + Pb collisions at beam momentum p_beam = 13 A GeV/c ((sqrt {{{s}_{{NN}}}} ) = 5.2 GeV).

—New experimental setup for high-precision mass measurement of heavy and superheavy nuclei is being built in Flerov Laboratory of Nuclear Reactions (Dubna). It consists of target unit, gas filled separator of complete fusion products, cryogenic gas stopping cell (CGSC), a radiofrequency system for transporting and cooling a low-energy beam and a multi-reflection time-of-flight mass spectrometer. Simulations of stopping efficiency and extraction time from CGSC were performed for evaporation residues of the complete fusion reactions ⁴⁰Ar + ¹⁴⁴Sm → ^184–xHg + xn, ⁴⁰Ar + ¹⁶⁶Er → ^206–xRn + xn, ⁴⁸Ca + ²⁰⁸Pb → ^256–xNo + xn and ⁴⁸Ca + ²⁴²Pu → ^290–xFl + xn. Internal software based on SRIM and Geant4 was used in the simulations. Optimum parameters for the real experiment, namely, the width of entrance window, pressure of helium buffer-gas in CGSC and the choice of suitable reactions were the main motivation of these simulations.

Modern pixel particle detectors allow possibility to determine coordinates of hit with high accuracy. Some of them, for example Medipix series detectors, provide possibilities to evaluate particle energy deposit. However, pixel detectors have a difficult problem of a dividing of the charge, appeared by interaction with hitting particle, into neighbor pixels. To compensate this effect the clustering procedure is used. The clustering procedure is the process of union of neighbor non-zero pixels. A cluster is a group of pixels with common borders. Sum of energy deposit in pixels of a cluster provide estimation of particle energy with higher accuracy. The clustering procedure usually operates with ready data saved on a computer what required a long time and big amount of memory. Here the clustering algorithm for FPGA to include in DAQ systems of pixel detectors is presented. The including clustering procedure in DAQ reduces amount of memory and time required for data processing.

DUNE is a long-baseline experiment for neutrino oscillation studies. Its near detector complex consists of three main parts. One of them is ND-LAr, the liquid argon time projection chamber (LAr-TPC). In LAr-TPC’s, a light collecting system (LCS) is commonly used as a trigger system. In this work the ND-LAr LCS is considered. The data from ProtoDUNE Dual Phase and Module 0 LAr-TPC prototypes was used to obtain the parameters of scintillation in liquid argon for Geant4 simulation. Then, the response of the Module 0 LCS in events with cosmic muons was compared with the response of its Geant4 model in identical simulated events to estimate the photon detection efficiency of the ND-LAr LCS. After that, single-particle and two-particle events with different shifts in time and space between tracks were simulated to determine the time and spatial resolution of the ND-LAr LCS. Obtained results allow us to judge whether the characteristics of the ND-LAr LCS satisfy the experiment requirements.

In this work we study holographic RG flows in (3)-dimensional supergravity model with a scalar field and non-trivial potential. The holographic RG flow is described by the domain wall solution, which is asymptotically AdS and includes a scalar field and is defined by the Dirichlet boundary conditions. This solution can be interpreted as a deformation of a dual theory either by a relevant operator or a vacuum expectation value (VEV) of the operator. VEVs of the scalar operators are calculated which confirm that the interpretation of the deformation of the dual theory is valid.

One of the main goals of the heavy ion collision experiments is studying the properties of strongly interacting matter created at different states in the overlap region of two intercepting ions. At a relatively low energy of several-GeV per nucleon pair created matter can be characterized by high net baryon densities and relatively low temperatures. The azimuthal anisotropy or produced in the collision hadrons is a valuable probe of the properties of the matter within the overlap region. In this work I present the observation of the scaling properties of the directed flow of protons on energy of the collision as well as the system size. I also elaborate on the directed flow of protons dependence on the geometry of the collision.

t—Progress in the study of a rare decay of a charged kaon is presented. Publications pertaining to this problem are briefly reviewed, and the results obtained are described. The application of the unfolding procedure for the energy spectrum of photons produced in decays is shown.

In this paper we give spectra for biscalar fishnet models in arbitrary dimensions for the zero-magnon and one-magnon cases. We also present the results of the computation of the Regge limit of the correlation functions in terms of Mellin amplitudes in the strong and weak modes of the coupling constant for six-dimensional model

Abstract

Calculating multidimensional integrals with a singularity of type (int ldots int {{{f(x)} mathord{left/ {vphantom {{f(x)} {left( {x - c} right)}}} right. kern-0em} {left( {x - c} right)}}} ) is not a simple task. The methods used to calculate such an integral must effectively bypass the singularity, minimizing the error. This work presents an algorithm that, in the process of calculating the integral, analyzes the area of integration, dividing it into subsegments. Subsegments containing a singularity, as well as those located close to the singularity, are excluded during the final calculation of the integral. Integrals final calulation is carried out using the Monte Carlo integration method. The algorithm allows to calculate both one-dimensional and multidimensional integrals.

Abstract

In high-energy physics experiments the ability to display both detector geometry and physical objects of particle collision events, such as hits and particle tracks has become an essential feature required for physicists to better understand particular collision events as well as to present the physical results to a wider audience. Currently, most experimental collaborations build their own event display solutions with little to no unification between them. In this work, a new event visualization solution for the BM@N (Baryonic Matter at Nuclotron) experiment, a fixed target experiment of the NICA (Nuclotron-based Ion Collider fAcility) project, is presented. The solution is based on VisionForge, a modern open-source visualization system. An important part of the solution is integration of the system with the experiment’s software framework, BmnRoot, which is a CERN ROOT-based environment. Several possible methods of such integration are discussed and the established architecture of the next-generation visualization system is explained.