bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of local deformations of muon flux angular distribution during CME with GSE-mapping technique
Authors: Astapov I I , Barbashina N S , Dmitrieva A N , Melnikova I A , Osetrova N V , Shutenko V V , Yashin I I 
Published: November 2019

Abstract
Coronal mass ejections (CME) have an impact on the flux of cosmic rays that penetrate the disturbed areas in the heliosphere and the near-terrestrial space. Unlike most ground-based cosmic ray detectors, the URAGAN muon hodoscope (MEPhI) allows to investigate both the integrated counting rate of registered particles and angular characteristics of the muon flux at the ground level. To select the local areas with statistically significant intensity changes, the angular distributions for the last hour and preceding it 24 hours corrected for the barometric effect are used. Angular distributions are smoothed, and the matrix of relative changes of the angular distribution in units of statistical errors is formed. The use of asymptotic directions calculated in advance, the angular cells of the matrix are mapped from the local coordinate system to the GSE coordinate system. The results of the study of GSE-mapping of local deformations of the angular distributions for different types of CMEs are discussed.
Reconstruction of particle’s energy spectrum in experiment with Unfolding technique
Authors: Alekseev V V , Bogomolov Yu V , Dunaeva O A , Mayorov A G , Malakhov V V , Rodenko S A 
Published: November 2019

Abstract
In elementary particle physics, the characteristics of the events can be distorted to varying degrees due to instrumental effects, which leads to inaccuracies in experimental distributions. To solve such difficulties and restore distributions close to the true, a various mathematical approaches are used. In this paper, we examine the quality of unfolding methods for solving this problem. Different variants of unfolding are tested for the quality of restoring the true distribution by simulating the passage of cosmic ray particles through the PAMELA magnetic spectrometer. The following algorithms were analyzed: D’Agostini, SVD and TUnfold.
Some manifestations of two-component dark matter structure in vectorlike hypercolor model
Authors: Bezuglov M , Beylin V , Kuksa V 
Published: November 2019

Abstract
In the framework of vectorlike hypercolor model with two generations it have been considered some peculiarities of diffuse gamma spectrum which is produced in the process of the Dark Matter annihilation. The model suggests two Dark Matter candidates and both of them contribute to this cross section depending on the model parameters. Masses of these DM components are estimated from analysis of kinetics of the DM and data on relic abundance.
Study of CP violation in the process of associated Higgs boson production with a decay into muon pair
Authors: Belyaev N , Konoplich R , Prokofiev K , Reese T 
Published: November 2019

Abstract
After the Higgs boson discovery at the LHC, a lot of additional measurements should be performed to understand in detail the properties of the observed particle. Searches for CP violation in different physics sectors are one of the most promising and important parts of these measurements. Associated Higgs boson production in pp collisions can be a powerful tool for searches for possible CP violation in the Higgs sector. In this paper, the study of CP sensitive observables constructed for a four lepton final state is presented. It is shown that azimuthal angle distributions of leptons in this process demonstrate a strong sensitivity to CP violation at the current limits on Higgs boson coupling parameters and can reveal a genuine mechanism of CP violation.
Weakly bound states of dtμ muonic molecular ion in quantum electrodynamics
Authors: Eskin A V , Korobov V I , Martynenko A P , Sorokin V V 
Published: November 2019

Abstract
The energy spectrum of ground and excited bound states of muonic molecule dtμ is calculated on the basis of stochastic variational method. The basis wave functions of the muonic molecule are taken in the Gaussian form. The matrix elements of the Hamiltonian are calculated analytically. For numerical calculation, a computer code is written in the MATLAB system. As a result, the numerical energy levels of ground and excited states of the muonic molecule dtμ are obtained.
Physical conditions in thin laminar-convective accretion flows
Authors: Malanchev Konstantin L. , Postnov Konstantin A. , Shakura Nikolay I. 
Published: November 2019

Abstract
The physical conditions of convection appearance in laminar accretion flows with microscopic transport coefficients are examined. Hot sparse ionised flow with periods below an hour found to be optically thin and have convective layer. Cold sparse molecular flow with period about a year found to be optically thin too and are fully convective. Ranges of temperature, density and period of optically thick laminar accretion flow are shown.
Studying method of microlensing effect estimation for a cluster of primordial black holes.
Authors: Toshchenko K A , Belotsky K M 
Published: November 2019

Abstract
Primordial black holes (PBH) attracted especially great attention last time. It is possible candidate not only to dark matter, but to supermassive black holes, gravitational waves events from black hole merger and others. However, recently there appeared constraints on PBH abundance from different observations. The given work is devoted to the model of PBH cluster in which some constraints can be avoided. We investigate effect of gravitation microlensing for PBH cluster. Analysis of respective data could alleviate limitations coming from them, but also could make it possible to test this model discriminating between the models of single and clustered PBHs.
Gravity theory tests with observations of stars near the black hole at the Galactic Center
Authors: Zakharov Alexander 
Published: November 2019

AbstractOne could say that 2018 is very special year since 55 years ago quasars were discovered, the Kerr solution has been found and the First Texas Symposium on Relativistic Astrophysics has been organized. In addition, 50 years ago, in 1968 the pulsar discovery paper has been published and the black hole concept has presented by J. A. Wheeler in his groundbreaking paper which was based on his report in December 1967. In last years remarkable achievements have been done in gravitational physics and related observations, in particular, gravitational waves and binary black holes with high stellar masses have been discovered, VLT, Keck and GRAVITY observe trajectories of bright stars and gas clouds near the Galactic Center (GC) with improving accuracy. It is clear that the Galactic Center (Sgr A*) is a specific place. Our Sun is located at a distance around 8 kpc from the Galactic Center (GC). Earlier, astronomers suggested a number of different including exotic ones such as boson stars, fermion balls, neutrino balls, a cluster of neutron stars. Some of these models are ruled out or significantly constrained with consequent observations. A supermassive black hole with mass around 4 × 106Mʘis the most realistic model for GC. Precision observations of bright stars near the Galactic Center and observations of bright structures near the black hole at the Galactic Center to reconstruct shadow structure around the black hole with current and future observational VLBI facilities such as the Event Horizon Telescope give opportunities to test alternative theories of gravity. In particular, we got a graviton mass constraint which is comparable and consistent with constraints obtained recently by the LIGO-Virgo collaboration. We consider opportunities to improve current graviton mass mass constraints with future observations of bright stars. Similarly, from an analysis of bright star trajectories one could constrain a tidal charge which was predicted by a gravity theory with an additional dimension.
The gravitational dynamics of the primordial black holes cluster
Authors: Khromykh Leonid A. , Kirillov Alexander A. 
Published: November 2019

Abstract
We consider the numerical simulation of the N-body problem related to the primordial black holes (PBHs) cluster. To study the dynamics of the system we use modified NBODY6++ code aimed at the simulation of globular star clusters. Some qualitative results describing the evolution of the system are discussed. It is shown that the cluster successfully survives to the redshift z ∼ 20 ÷ 40 (despite evaporation and coalescence of the PBHs). Starting from this moment an accretion begins to play significant role in speeding up the mass growth of the massive bodies.
On generalized Melvin solutions for Lie algebras of rank 3
Authors: Bolokhov S V , Ivashchuk V D 
Published: November 2019

Abstract
A multidimensional generalization of Melvin’s solution for an arbitrary simple Lie algebra G is considered. The gravitational model contains n 2-forms and l > n scalar fields, where n is the rank of G. The solution is governed by a set of n functions Hs
(z) obeying n ordinary differential equations with certain boundary conditions imposed. It was conjectured earlier that these functions should be polynomials (the so-called fluxbrane polynomials). The polynomials Hs
(z), s = 1,…, 6, corresponding to the Lie algebra E
6 are obtained. They depend upon integration constants Qs
, s = 1,…, 6 . The polynomials obey symmetry and duality identities. The latter ones are used in deriving asymptotic relations for solutions at large distances which are presented in the paper. The power-law asymptotic relations for E
6 - polynomials at large z are governed by integer-valued matrix v = A
−1 (I + P), where A
−1 is inverse Cartan matrix, I is identity matrix and P is permutation matrix, corresponding to a generator of the Z
2-group of symmetry of the Dynkin diagram. The 2-form fluxes Φ
s
are calculated, s = 1, …, 6.
Superheavy objects composed of nuclear and dark matter
Authors: Gani Vakhid A. , Khlopov Maxim Yu. , Voskresensky Dmitry N. 
Published: November 2019

Abstract
We consider a model of OHe atomic dark matter formed by Coulomb binding of the hypothetical stable double-charged massive O
– – particles with nuclei of primordial helium. Such a dark matter can be captured by ordinary matter forming superheavy nuclei. We propose a possibility of self-bound by nuclear and electromagnetic interaction O-nuclearites as well as more massive gravitating ones and discuss effect of accumulation of OHe atoms in stars and their effect in stellar evolution.
Bound orbits near black holes with scalar hair
Authors: Potashov I M , Tchemarina Ju V , Tsirulev A N 
Published: November 2019

Abstract
We consider spherically symmetric black holes with minimally coupled scalar fields and concentrate our attention on asymptotically flat self-gravitating configurations having the event horizons located at radii much smaller than 2m. We think of such configurations as rigorous mathematical models of the gravitating objects, surrounded by dark matter, in the centres of normal galaxies. It turns out that the radius of the event horizon of a scalar field black hole always less than the Schwarzschild radius of vacuum black hole of the same mass and can be arbitrary close to zero. In astronomical observations, a key role in distinguishing between black holes, wormholes, and naked singularities plays measuring parameters of bound quasiperiodic orbits, in particular, the shape of an orbit and the angle of precession of its pericentre. We consider a typical two-parameter family of compact scalar field black holes and compute numerically the shapes of some bound orbits. We find that a key feature of bound orbits around a compact black hole is that the angle between closest pericentre points is either negative or, at least, less than that for the Schwarzschild black hole of the same mass.
The AEgIS experiment: towards antimatter gravity measurements
Authors: Khalidova O , Aghion S , Amsler C , Antonello M , Belov A , Bonomi G , Brusa R S , Caccia M , Camper A , Caravita R , Castelli F , Cerchiari G , Comparat D , Consolati G , Demetrio A , Noto L D , Doser M , Evans C , Fani M , Ferragut R , Fesel J , Fontana A , Gerber S , Giammarchi M , Gligorova A , Guatieri F , Hackstock P , Haider S , Hinterberger A , Holmestad H , Kellerbauer A , Krasnický D , Lagomarsino V , Lansonneur P , Lebrun P , Malbrunot C , Mariazzi S , Marton J , Matveev V , Müller S , Nebbia G , Nedelec P , Oberthaler M , Pagano D , Penasa L , Petracek V , Prelz F , Prevedelli M , Rienaecker B , Robert J , Røhne O , Rotondi Alberto , Sandaker H , Santoro R , Smestad L , Sorrentino F , Testera G , Tietje I , Vujanovic M , Widmann E , Yzombard P , Zimmer C , Zmeskal J , Zurlo N 
Published: November 2019

Abstract

AE

g
¯

IS

(Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is a CERN based experiment aiming to probe the Weak Equivalence Principle of General Relativity with antimatter by studying free fall of antihydrogen in the Earth’s gravitational field. A pulsed cold beam of antihydrogen produced by charge exchange between Rydberg positronium and cold antiprotons will be horizontally accelerated by an electric field gradient. The free fall of antihydrogen will then be measured by a classical moire deflectometer. An overview of the experimental setup, present status of the experiment along with current achievements and results is presented.
Measurement of the energy spectra and of the angular distribution of the Transition Radiation with a silicon strip detector
Authors: Loparco F , Alozy J , Belyaev N , Campbell M , Cherry M , Dachs F , Doronin S , Filippov K , Fusco P , Gargano F , Heijne E , Konovalov S , Krasnopevtsev D , Llopart X , Mascagna V , Mazziotta M N , Pernegger H , Ponomarenko D , Prest M , Pyatiizbyantseva D , Radomskii R , Rembser C , Romaniouk A , Savchenko A A , Schaefer D , Schioppa E J , Shchukin D , Sergeeva D Yu , Shulga E , Smirnov S , Smirnov Y , Soldani M , Spinelli P , Strikhanov M , Teterin P , Tikhomirov V , Tishchenko A A , Vallazza E , van Beuzekom M , van der Heijden B , Vorobev K , Zhukov K 
Published: November 2019

Abstract
We plan to develop an advanced Transition Radiation Detector (TRD) for hadron identification in the TeV momentum range, based on the simultaneous measurement of the energies and of the emission angles of the Transition Radiation (TR) X-rays with respect to the radiating particles. To study the feasibility of this project, we have carried out a beam test campaign at the CERN SPS facility with 20 GeV/c electrons and muons up to 300 GeV/c. To detect the TR X-rays and the radiating particles, we used a 300 μm thick double-sided silicon strip detector, with a strip readout pitch of 50 μm. A 2 m long helium pipe was placed between the radiators and the detector, in order to ensure adequate separation between the TR X-rays and the radiating particle on the detector plane and to limit the X-ray absorption before the detector. We measured the double-differential (in energy and angle) spectra of the TR emitted by several radiators. The results are in good agreement with the predictions obtained from the TR theory.
GEM detectors for the Upgrade of the CMS Muon Forward system
Authors: Mocellin Giovanni 
Published: November 2019

Abstract
The CMS experiment is one of the two general purpose experiments at the CERN LHC. During LHC Phase-2 starting from 2026, the instantaneous luminosity delivered to CMS will reach 5 × 1034 cm−2s−1, resulting in high particle fluxes that require the detector to be upgraded. The forward regions, corresponding to the endcaps of the detectors, will be most affected. In the muon endcap system, triple-GEM chambers will complement the existing Cathode Strip Chambers, leading to a better identification of the muon tracks and a reduction of the trigger rate due to the suppression of fake candidates. Additionally, the forward coverage will be extended.
GEM chambers are being built in production sites spread in 7 countries around the world for the first station of the muon endcaps. Each chamber has an area of approximately 1 m2. Thus, high requirements on the uniformity across the detector are needed and the GEM chambers undergo multiple quality control tests. In parallel with the production and testing of the chambers, 10 GEM chambers have been integrated in CMS and are currently under commissioning (slice test). Such a test is essential to prepare for the upcoming installation and integration.
This contribution gives an introduction to GEM chambers and presents some results of the performance tests, both for quality control and slice test.
4π semiconductor beta-spectrometer for measurement of 144Ce – 144Pr spectra
Authors: Bakhlanov S , Derbin A , Drachnev I , Kotina I , Lomskaia I , Muratova V , Pilipenko N , Semenov D , Unzhakov E 
Published: November 2019

Abstract
Precision measurements of beta-spectra have always been and are still playing an important role in several fundamental physical problems, predominantly in neutrino physics. Magnetic and electrostatic spectrometers possess the superior energy resolution, but at the same time such devices appear to be very complex and large-scale setups. Since the electron free path at 3 MeV (which is, basically, the maximum beta-transition energy for long-living isotopes) does not exceed 2 g/cm3, solid state scintillation and ionization detectors were effectively employed for detection of electron. In case of semiconductor detectors there is a significant probability of back-scattering from the detector surface that depends on the detector material. This issue could be overcome by constructing a beta-spectrometer with 4π geometry, fully covering the source and capable of detecting backscattered electrons. Here we present a technology allowing production of a beta-spectrometer based on silicon detectors and having 4π geometry. The spectrometer developed had been fitted with a 144Ce-144Pr radioactive source and has demonstrated capability of performing precision beta-spectrometry for this nuclides.
The Nuclotron-based Ion Collider Facility Project. The Physics Programme for the Multi-Purpose Detector
Authors: Geraksiev N.S. 
Published: November 2019

Abstract
The Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR), Dubna, Russia. The main goal of the planned facility is to provide accelerated particle beams for a wide range of experimental studies of the hot and dense strongly interacting QCD matter generated during collisions. The NICA project in its entirety allows for a fixed target experimental site, as well as two interaction points. The heavy ion programme includes two planned detectors: Baryonic Matter at Nuclotron (BM@N) - a fixed target experiment with extracted Nuclotron beams; and a collider-mode experiment at one of the interaction points - the MultiPurpose Detector (MPD). For the NICA collider, the accelerated beams by design will consist of particles ranging from protons and light nuclei to fully stripped gold ions. Beam energies will span

s

p
p

=
12
−
27

GeV

with luminosity Lpp
≥ 1 × 1030 cm−2s−1, and

s

A
u
A
u

=
4
−
11

GeV

, and average luminosity LAuAu
= 1 × 1027 cm−2s−1. The second interaction point is planned to be occupied by a third experiment - Spin Physics Detector (SPD), which will focus on the investigation of nucleon spin structure and polarization phenomena through the use of polarized proton and deuteron beams. A brief overview of the Multi-Purpose Detector is presented along with the major sub-detector systems. The MPD research programme will focus on multiple observables including collective flow, particle multiplicity and spectra. Special attention will be given to strangeness production and vector mesons, event-by-event fluctuations and hadron femtoscopy measurements. Several feasibility studies are referenced.
A U.S.-based Electron-Ion Collider
Authors: Guzey V 
Published: November 2019

Abstract
An Electron-Ion Collider (EIC) in USA is currently discussed as a next-generation facility for high-energy nuclear physics. The main goal of the EIC is to study fundamental questions of Quantum Chromodynamics, which include the origin of the nucleon mass and spin and the three-dimensional structure of the nucleon in terms of quarks and gluons, the emergent properties of dense systems of gluons, and influence of nuclear matter on distributions of quarks and gluons and propagation of color charges through it. The EIC machine designs are aimed at achieving variable center of mass energies of 20 – 100 GeV, upgradable to 150 GeV, high degree of polarization ( 70%) of beams of electrons, protons and light nuclei, high collision luminosity of 1033–34 cm–2s–1, and ion beams from deuteron to heaviest (Lead) nuclei. In this contribution, we present the current status of the EIC project, its physics program, and proposed designs of EIC realization.
The Carpet-3 multipurpose shower array for searching cosmic diffuse gamma rays with energy Eγ > 100 TeV
Authors: Kudzhaev A U , Dzhappuev D D , Afashokov Yu Z , Gorbacheva E A , Dzaparova I M , Khadzhiev M M , Klimenko N F , Kurenya A N , Lidvansky A S , Mikhailova O I , Ptitsyna K V , Petkov V B , Romanenko V S , Yanin A F 
Published: November 2019

Abstract
An experiment for measuring the flux of cosmic gamma rays with energy above 100 TeV is currently being prepared at the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences. At present the plastic scintillation counters with a total continuous area of 410 m2 are installed in the muon detector (MD) underground tunnels, and they are totally equipped with electronics. Six modules of shower detectors have been already placed on the surface of the MD absorber. In each of them 9 standard plastic scintillation counters are placed with an area of 1 m2 each. These modules are components of the ground surface part of Carpet-3 shower array. The data acquisition system for this array is almost ready. Expected flux limits for cosmic diffuse gamma rays of galactic origin in this work is close to existing experimental limits in the range lower than about 5 PeV, and with improved sensitivity of Carpet-3 one can hope to detect this flux or at least to obtain the best upper limit.
On application of wobbler in experiments with cylindrical targets
Authors: Suleymenov E M , Barminova H Y 
Published: November 2019

Abstract
For the experiments with irradiation of cylindrical targets by intense heavy ion beams which are actual for fundamental and applied researches (laboratory astrophysics, heavy ion inertial fusion, ion therapy, industry) it is necessary to shape the driver beam with hollow geometry. The wobbling method is of interest for such experiments. In the paper one of the problems of the method is considered leading to possible symmetry violation. The results of the simulation of the rotated beam dynamics are presented.
Neutron lifetime measurement with the big gravitational trap for ultracold neutrons. Current state and future prospects.
Authors: Serebrov A P , Kolomensky E A , Fomin A K , Krasnoschekova I A , Vassiljev A V , Prudnikov D V , Shoka I V , Chechkin A V , Chaikovskiy M E , Varlamov V E , Ivanov S N , Pirozhkov A N , Geltenbort P , Zimmer O , Jenke T , Van der Grinten M , Tucker M 
Published: November 2019

Abstract
A new measurement of the neutron lifetime, carried out with the aid of a large gravitational spectrometer made in Petersburg Institute of Nuclear Physics (PNPI) is presented: τn = 881.5 ± 0.7 ± 0.6 s. In our experiment the measurement of neutron lifetime is carried out using the method of storing ultracold neutrons in a material trap with gravitational barrier. Further improvement of the obtained result can be achieved at the helium temperatures. Here we present our neutron lifetime result, modified installation scheme and the first results of cryogenic tests are discussed.