Distributed data processing and computing is highly relevant to the BM@N experiment, the first ongoing experiment of the NICA project due to the high data flow, the sequential processing of which would take hundreds of years. The latest BM@N Run alone produced about half a petabyte of raw data, and when the experiment reaches its design parameters, the amount of the data will increase approximately by an order of magnitude. To solve this problem and combine all distributed resources of the experiment into a single computing and storage system as well as provide the automation of job processing flows, the computing software architecture has been developed and is being implemented. It includes a complex of software systems for distributed processing of BM@N data flows and is described in the paper.

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.

The software infrastructure of the BM@N experiment contains a set of various information systems that are essential for the work with experimental and simulated data on all processing stages, including the collection, storage, intermediate processing and physics analysis. Some examples of the systems are the Electronic Logbook Platform, Condition Database and Event Metadata System. In case one of such systems stops functioning, the work with BM@N data by collaboration members gets either impossible or, at least, much less productive. Due to this fact, the timely detection of possible failures in the systems because of software or hardware failures is fairly important. The developed Monitoring Service is used to check the availability and health status of the information systems. This includes measuring, storing, visualizing monitored parameters, such as CPU, memory and disk utilization, DBMS functioning parameters, response times of databases and API endpoints, ping round-trip times, as well as sending alert notifications in case of malfunctions. The current implementation of the BM@N Monitoring Service is presented in detail. A related task of building highly available information services is also briefly noted.

BM@N (Baryonic Matter at Nuclotron) is the first experiment operating and taking data at the Nuclotron/NICA ion-accelerating complex.The aim of the BM@N experiment is to study interactions of relativistic heavy-ion beams with fixed targets. We present a technical description of the BM@N spectrometer including all its subsystems.

The Event Metadata System (EMS) developed for BM@N, a fixed target experiment of the NICA (Nuclotron-based Ion Collider fAcility) project has been designed to store and index event records for particle collisions obtained at the BM@N facility and subsequently reconstructed. The system enables to quickly search for a required set of physics events based on various given criteria for further physics analyses. The main implemented interfaces to the EMS include Web UI (user interface) and REST API (application programming interface), that are presented in the paper in detail. The both interfaces have its own main use patterns, namely, the Web UI is mostly employed for browsing the Event Catalogue and checking its overall state, while the REST API helps to integrate the EMS with other software systems of the experiment, such as the main BM@N framework, BmnRoot to conveniently select events for a particular physics analysis. The interfaces have been developed using Kotlin multiplatform technology, hence, both front-end and back-end components of the Web service are parts of one project using the same programming language and a common codebase.

The Unified Condition Database (called UniConDa) of the BM@N experiment, which is the first experiment of the NICA project, is used as a central storage for vital experiment metadata and various parameters, including session and run information, detector and subsystem parameters, and descriptions of generated simulation files with particle collision events. For an effective work with the database in the existing software environment of the experiment, a set of various tools and services are required. In the paper, a high-level description of the ecosystem of such services, that have been developed and are being actively maintained by the BM@N collaboration, is given, and implementation of a new service for the corresponding information system is presented in detail. The aim of the developed software tool is transferring the condition information from the existing files of ASCII text, CSV and XML formats to the Unified Condition Database. The tool has been successfully used for filling the BM@N Condition Database with information containing parameter data of the first BM@N runs. The software service, called Smart Data Parser, has been developed as a universal processing tool based on JSON schema and supports multiple database engines, so it can be reused later for similar use cases in the experiment.

NICA (Nuclotron-based Ion Collider facility) is a new accelerator complex, which is under construction at the Joint Institute for Nuclear Research in Dubna to study properties of dense baryonic matter. The experiments of the NICA projects have already generated and obtained substantial volumes of event data, and it is expected that the overall number of stored events will increase from the current value of hundreds of millions to several billion events per year. The developed Event Metadata System is required to store and index experimental event records obtained at NICA facilities, allowing to quickly search for only necessary events based on various criteria for further processing and physics analyses. The main aim of the information system that is described is to speed up desired physics analyses and data quality checks. In addition, it allows reducing the load of the NICA computing infrastructure. The Event Metadata System, which is presented in the paper, is integrated with other experimental and software systems, in particular, NICA ROOT-based frameworks and implemented Condition Database. An access and management of the event metadata in the Event Catalogue being used to select only events for a particular physics analysis are provided via several interfaces, such as REST API, Web UI, and a dedicated C++/ROOT interface. The detailed architecture of the system and developed services including monitoring are also presented.

First physics results of the BM@N experiment at the Nuclotron/NICA complex are presented on π+ and K+ meson production in interactions of an argon beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 A GeV. Transverse momentum distributions, rapidity spectra and multiplicities of π+ and K+ mesons are measured. The results are compared with predictions of theoretical models and with other measurements at lower energies.

The NICA collider complex currently under construction at the Joint Institute for Nuclear Research in Dubna is aimed at creating and investigating hot baryonic matter under extreme conditions. During offline and even online data processing, a large set of various parameters of experiment systems and conditions, under which the experiments are conducted, are required for experimental event reconstruction, detector simulation, physics analysis and quality assurance. To solve the task of storing the required parameters and information on the NICA experiments, which are necessary for further processing of the obtained experimental data (as well as simulated events), an information system has been developed on the basis of the condition database. For convenient management of the data stored in the database called Unified Database, a web application has been implemented for viewing, searching, managing and visualizing information on the experiments of the NICA project, such as information on sessions and runs, detectors, parameters and parameter values, and, in addition, generated simulation files. Furthermore, the developed information system provides collaboration members with a set of auxiliary services, such as data inspection and monitoring services, which improve the functionality of the system and make it more convenient. The paper presents the information system and its components including the condition database, user interfaces and web application, and implemented related services.

Particle collision experiments are known to generate a substantial amount of data that must be storedand then analyzed. Typically, only a small subset of all collected events is relevant when performing aparticular physics analysis task. Although it is possible to obtain the required subset of event recordsdirectly, by iterating through the whole volume of the collected data, the process is very time andresource consuming. Instead, a more convenient approach widely used in modern particle collisionexperiments is to have an event metadata or indexing system that stores summary properties of allevents and allows for the fast search for and retrieval of only necessary events based on given criteria.Such a system, called the Event Metadata System, has been developed for the current fixed-target andfuture collider experiments of the NICA project. The design of the system, its components, userinterfaces and the REST API service, its integration with existing experiment systems and software, aswell as associated challenges, are presented.

Acquiring, storing, processing and analyzing experimental and simulated data are an integral part of all modern high-energy physics experiments. These tasks are of particular importance in the experiments of the NICA megaproject at the Joint Institute for Nuclear Research (JINR) due to the high interaction rate and particle multiplicity of ion collision events. Therefore the task of automating the considered processes for the NICA complex is a very urgent topic. This article describes the status of the development of new information systems as well as a set of convenient information services for collaboration members to automate storing and processing of data and information on the experiments. The Geometry Information System and Online Electronic Logbook, which are on the final stage of implementation, are presented. In addition, the design of the Condition Database and Event Metadata System, which are scheduled to be completed next year, are described in detail. The systems provide storing of information required for event processing and physics analysis and organize a transparent, unified access and data management throughout the life cycle of the scientific research in the NICA megaproject. One of the key aspects-the integration of the information systems with the experiment software systems-is also presented.

The processing and analysis of experimental and simulated data are an integral part of all modern high-energy physics experiments. These tasks are of particular importance in the experiments of the NICA project at the Joint Institute for Nuclear Research due to the high interaction rate and large particle multiplicity of ion collision events, therefore, the task of automating the considered processes for the NICA complex has particular relevance. The paper describes a new information system based on the Condition Database, as well as related services to automate storing, managing, searching and using various parameters and operation modes of the on-going and future NICA experiments for experimental and simulated data processing. The implemented system provides the necessary information for event processing and physics analysis tasks, and organises the transparent, unifiedaccess to and management of the required parameter data in scientific research. The scheme and purposes of the Condition Database, its attributes, key aspects of the development are described. In addition, a common deployment system of the developed database and related services for the NICA experiments is noted.

Information systems of experiments make a significant contribution to solving automation tasks of data collecting, storing, processing and analysis, and are used to support a lot of types of experiment activities. The article is devoted to one of information systems being actively employed in particle collision experiments—Event Metadata System, which provides a database containing information on summary properties of physics events and references to their storage location, and ensures fast search through stored event metadata. The Event Metadata System for the NICA experiments is based on the Event Catalogue and provides recording and managing information being necessary for a convenient search for events required in physics analyses.

Primordial black holes (PBHs) are black holes which may form in the early Universe through the gravitational collapse of primordial cosmological density fluctuations. Due to Hawking radiation these PBHs are supposed to evaporate by emitting particles. Recent developments in the experimental searching for evaporating PBHs in the local Universe are reviewed. The multimessenger techniques of searching for signals from evaporating PBHs are discussed.

We consider the inflationary model in which the inflaton $\ensuremath{\phi}$ couples to another scalar field $\ensuremath{\chi}$ via the interaction ${g}^{2}(\ensuremath{\phi}\ensuremath{-}{\ensuremath{\phi}}_{0}{)}^{2}{\ensuremath{\chi}}^{2}$ with a small coupling constant $g$ (${g}^{2}\ensuremath{\sim}{10}^{\ensuremath{-}7}$). We assume that there is a sequence of ``trapping points'' ${\ensuremath{\phi}}_{0i}$ along the inflationary trajectory where particles of the $\ensuremath{\chi}$ field become massless and are rather effectively produced. We calculate the power spectrum of inflaton field fluctuations originating from a backreaction of $\ensuremath{\chi}$ particles produced using the Schwinger's ``in-in'' formalism. We show that the primary curvature power spectrum produced by these backreaction effects is blue, which leads to a strong overproduction of primordial black holes (PBHs) in the subsequent radiation era.

We study the process of primordial black hole (PBH) formation at the beginning of radiation era for the cosmological scenario in which the inflaton is a pseudo-Nambu-Goldstone boson (axion) and there is a coupling of the inflaton with some gauge field. In this model inflation is accompanied by the gauge quanta production and a strong rise of the curvature power spectrum amplitude at small scales (along with non-Gaussianity) is predicted. We show that data on PBH searches can be used for a derivation of essential constraints on the model parameters in such an axion inflation scenario. We compare our numerical results with the similar results published earlier, in the work by Linde et al.

We consider the early Universe scenario which allows for production of non-Gaussian curvature perturbations at small scales. We study the peculiarities of a formation of primordial black holes (PBHs) connected with the non-Gaussianity. In particular, we show that PBH constraints on the values of curvature perturbation power spectrum amplitude are strongly dependent on the shape of perturbations and can significantly (by two orders of magnitude) deviate from the usual Gaussian limit P-zeta less than or similar to 10(-2). We give examples of PBH mass spectra calculations and PBH constraints for the particular case of the curvaton model.

We consider the mixed inflaton-curvaton scenario in which quantum fluctuations of the curvaton field during inflation lead to a relatively large curvature perturbation spectrum at small scales. We use the model of chaotic inflation with quadratic potential including supergravity corrections leading to a large positive tilt in the power spectrum of the curvaton field. The model is characterized by the strongly inhomogeneous curvaton field in the Universe and large non-Gaussianity of curvature perturbations at small scales. We obtained the constraints on the model parameters considering the process of primordial black hole (PBH) production in radiation era.

We consider several early Universe models that allow for production of large curvature perturbations at small scales. As is well known, such perturbations can lead to formation of primordial black holes (PBHs). We briefly review the today's situation with PBH constraints and then focus on two models in which strongly non-Gaussian curvature perturbations are predicted: the hybrid inflation waterfall model and the curvaton model. We show that PBH constraints on the values of curvature perturbation power spectrum amplitude are strongly dependent on the shape of perturbations and can significantly (by two orders of magnitude) deviate from the usual Gaussian limit P_ζ≲ 10^-2. We give examples of PBH mass spectra calculations for both inflationary models.

We consider the process of primordial black hole (PBH) formation originated from primordial curvature perturbations produced during waterfall transition (with tachyonic instability), at the end of hybrid inflation. It is known that in such inflation models, rather large values of curvature perturbation amplitudes can be reached, which can potentially cause a significant PBH production in the early Universe. The probability distributions of density perturbation amplitudes in this case can be strongly non-Gaussian, which requires a special treatment. We calculated PBH abundances and PBH mass spectra for the model, and analyzed their dependence on model parameters. We obtained the constraints on the parameters of the inflationary potential, using the available limits on $\beta_{PBH}$.