bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations between multiplicities and transverse momenta in nucleus-nucleus collisions from model with cluster of fused color strings
Authors: Andronov E , Kovalenko V
Published: November 2019

The long-range rapidity correlations between the multiplicities (n-n) and the transverse momentum and the multiplicity (pT-n) of charged particles are analyzed in the framework of the simple string inspired model with two types of sources. The sources of the first type correspond to the initial strings formed in a hadronic collision. The sources of the second type imitate the appearance of the emitters of a new kind resulting from interaction (fusion) of the initial strings. The model enabled to describe effectively the influence of the string fusion effects on the strength both the n-n and the pT-n correlations. Modification of the model to the analogue of the “core-corona” mechanism allows to take into account event selection criteria based on centrality and perform a comparison with existing experimental data on correlation measurements in nucleus-nucleus collisions at LHC energies. It is shown that string fusion effects in the model with the core-corona mechanism lead to the change of a sign of the pT-n correlation coefficient with a decrease of a centrality interval width.
The study of the 12C states from the reaction 11B(3He, d)12C
Authors: Starastsin V I , Demyanova A S , Danilov A N , Ogloblin A A , Dmitriev S V , Sergeev V M , Maslov V A , Sobolev Yu G , Goncharov S A , Trzaska W , Heikkinen P , Gurov Y , Belyaeva T L , Burtebaev N
Published: November 2019

The experiment was done to study 11B(3He, d)12C reaction with energy E(3He)=25 MeV. The aim of the experiment is to determine the properties of 12C states at high excitation energies and in particular to verify which of the conflicting spin-parity assignments of the 13.35 MeV state (2− or 4−) should be assigned. Behavior of the experimental angular distribution and also the DWBA calculation correspond to spin parity 4− for 13.35 MeV state.
8He spectroscopy in stopped pion absorption by 11B nuclei
Authors: Chernyshev B A , Gurov Yu B , Lapushkin S V , Leonova T I , Sandukovsky V G
Published: November 2019

Level structure of 8He has been studied in the reaction of stopped pion absorption by 11B nuclei 11B(π−,pd)X. The experiment was carried out at the LANL with a two-arm semiconductor spectrometer. The missing mass spectrum in the range 0 MeV < MM < 50 MeV has been described by the superposition of phase-space distributions and the six states of 8He. Parameters of these states have been compared with data of other experimental and theoretical works.
Why the hydrodynamics is valid at early stage of heavy-ion collisions?
Authors: Zabrodin E E , Bravina L V
Published: November 2019

Evolution of hot and dense nuclear matter produced in central Au+Au collisions at energies of NICA, FAIR, and SPS is studied within two transport models. Two interesting features in the matter behaviour are observed almost from the very beginning of the collisions, at t ≥ 2 fm/c, for all studied reactions. (i) Expansion of the system proceeds with constant entropy-per-baryon ratio. (ii) Effective equation of state has a linear form, P = aε, a ≃ const. Both observations support the formal application of hydrodynamics at the early stages of heavy- ion collisions, when the system is very far from the equilibrium.
STAR Highlights and Future
Authors: Nigmatkulov Grigory
Published: November 2019

We present recent results from the STAR experiment at Relativistic Heavy Ion Collider (RHIC): beam-energy dependence of directed flow of identified particles (including open charm hadrons), flow decorrelation, global and local hyperon polarization, femtoscopic measurements, heavy flavour production, jets, and plan for the future upgrades.
Measurements of quarkonia and open heavy-flavour production in heavy-ion collisions with the ATLAS detector
Authors: Kremer Jakub
Published: November 2019

Measurements of quarkonia produced in ultrarelativistic Pb+Pb collisions provide a means to probe the properties and evolution of the hot and dense medium created in those collisions. Promptly produced quarkonia are directly affected by the interaction with the hot nuclear matter, while non-prompt production allows for the study of b-quark energy loss. The studies of quarkonia production are complemented by measurements of the azimuthal modulation of J/ψ production. Studies of quarkonia and open-charm production in p+Pb collisions provide an additional insight, as they directly probe cold nuclear matter effects. This report will present the most recent ATLAS measurements of charmonia production and flow in Pb+Pb collisions, as well as charmonia and bottomonia production in p+Pb collisions. In addition, results on D meson production and flow will be presented.
Measurement of electroweak boson production in pp, p+Pb and Pb+Pb collisions with the ATLAS detector
Authors: Janus Piotr
Published: November 2019

Measurement of electroweak boson production in different collision systems are of great interest to understanding the partonic structure of heavy nuclei, and serve as a constraint on the initial state in larger collision systems. Their production yields in Pb+Pb with respect to pp collisions provide direct tests of both binary collision scaling and possible modification of parton distribution functions (nPDF) due to nuclear effects. Further, the p+Pb collisions provide a relatively clean environment to study nPDFs in detail. The ATLAS detector has a broad acceptance with excellent performance even in the high occupancy environment of central heavy-ion collisions. In this proceedings the latest ATLAS results on W and Z boson production at the centre-of-mass energy of 5.02 TeV are presented, including updated precise result production in pp collisions. Also photon yields are reported in 8.16 TeV in different collision systems are presented.
Overview of ALICE results on light flavour hadron production
Authors: Riabov V G
Published: November 2019

Light flavour hadrons are copiously produced in hadronic and heavy-ion interactions and bring a wealth of information about properties of the produced medium and reaction dynamics. Having different masses, quark content and lifetimes, light flavour hadrons do not only serve as general observables in the soft sector, but also play an important role as high transverse momentum probes and signatures of the onset of collectivity in high-multiplicity collisions of small and large systems. In this manuscript, we review the most recent ALICE results on the production of different light-flavour hadrons, including transverse momentum spectra, yields, nuclear modification factors and particle ratios in pp, p-Pb, Xe-Xe and Pb-Pb collisions at LHC energies.
Performance studies for collective flow measurements with CBM at FAIR
Authors: Blau D , Golosov O , Kashirin E , Klochkov V , Selyuzhenkov I
Published: November 2019

We present recent results from CBM performance studies for measurements of the directed (v
1) flow of π+, Ʌ and

K
s
0

. For the performance studies we use the CBMROOT environment for Monte-Carlo simulations and event reconstruction. The Kalman Filter Particle Finder (KFParticleFinder) package is used for hyperon reconstruction via their weak decays, and the Projectile Spectator Detector (PSD) for event plane determination. A status of the fast simulator implementation for the PSD calorimeter response, which is required for high statistics simulation, is also presented.
Monte-Carlo study of long-range correlations of average transverse momentum and multiplicity for strange particles in pp-collisions at the LHC energies
Authors: Sandul V , Feofilov G
Published: November 2019

This study is motivated by the puzzling enhanced production of multi-strange hadrons observed for the first time by the ALICE Collaboration in high-multiplicity pp-collisions at

s

=
7

TeV

at the LHC. We investigate this effect of strangeness enhancement in pp-collisions in the framework of the MC event generator PYTHIA 8 where the collectivity processes are taken into account by the formation of a so-called flavour rope. The latter is hadronized with a larger effective string tension providing the increase of strangeness yield. This concept of the flavour rope, as a source of multi-strange hadrons, extended in rapidity, is being tested by the study of so called long-range correlations (LRC) between the average transverse momentum 〈pT
〉 and multiplicity n for charged particles containing strange quarks produced in high energy pp-collisions.The dependencies of correlation coefficients bn−n, bPT−n
and bPT−PT
on the gap between forward and backward pseudorapidity windows, and on the width of the forward pseudorapidity windows, are studied and the results are discussed.
Measurements of the Higgs boson by ATLAS and CMS
Authors: Tsukerman Ilya
Published: November 2019

Recent results on Higgs boson production and decays in the ATLAS and CMS experiments at the LHC are reviewed. They are mostly based on the analyses of 13 TeV LHC proton-proton collision data accumulated during 2015–2016 or 2015–2017 year exposures. Production cross sections in five main decay channels are measured. These channels are combined to extract the Higgs boson signal strength, mass and couplings. All experimental results are found to be compatible with the Standard Model predictions. Upper limits on non-standard Higgs boson production in different decay modes are also derived.
Proposal of the complete experiment for elastic pp and p(bar)p scattering at SPASCHARM program at U70 accelerator
Authors: Bogdanov A A , Chetvertkova V A , Kalugin N K , Ladygin V P , Mochalov V V , Nurusheva M B , Okorokov V A , Semenov P A , Vasiliev A N , Zherebtsova L S
Published: November 2019

Newly developing SPASCHARM (SPin Asymmetry in CHARMonia) experiment at U70 accelerator will give the unique possibility to measure spin effects with the use of polarized proton and antiproton beams and polarized target. We suggest to carry out the measurements of the pp and p(bar)p elastic scattering spin observables at 16 GeV/c (direct reconstruction of elastic pp and p(bar)p elastic scattering amplitudes at SPASCHARM experiment). To date the direct reconstruction of amplitudes for pp elastic scattering was performed up to 6 GeV/c only, meanwhile there is no available data for p(bar)p elastics scattering. New measurements at SPASCHARM will significantly extend the energy range of the spin studies and will give unique possibility to compare elastic pp and p(bar5)p scattering
The New Results from Multi-quark Exotic States Searches at D0 Experiment
Authors: Popov A
Published: November 2019

Recent results from a search for multi-quark exotic states at D0 experiment (FNAL, USA) are presented. This includes the new data for possible tetraquark state X(5568) decaying to

B
s
0

π
±

, in the channels with semileptonic decays of

B
s
0

mesons. Also, result from the J/ψπ system analysis and an evidence for exotic charged charmoniumlike state Zc
(3900) in semiinclusive weak decays of B-flavored hadrons are presented as well.
Resonance d*(2380) and higher isospin states
Authors: Doroshkevich E A
Published: November 2019

A new isoscalar state in the two-baryon system with mass 2380 MeV and width 80 MeV denoted now d*(2380) has been detected in the experiments at the Juelich Cooler Synchrotron (COSY). Existence or influence of states with higher isospin is a subject of the experiment for studing of the π+π− production in pp collisions. Calculations taking into account isotensor dibaryon resonance in the ΔN with I(Jp
) = 2(1+) provide a good description of the pp → ppπ+π−
total and differential cross sections.
The automation of choosing of the optimal kinematic variables for discrimination of the electroweak Zγ production
Authors: Belyaev N L , Petukhov A M , Soldatov E Yu
Published: November 2019

The article discusses the automation of the determination for variables of interest (so-called observables), which allow to distinguish electroweak Zγ
production from the inclusive Zγ
production. The preliminary version of the original automation technique was developed. The output distributions obtained with this technique can be used as the discriminants for machine learning tools to separate rare high energy physics process. An overview of performance and rejection power for the technique is presented.
Observation of the

tt¯H

production
Authors: Mellenthin Johannes
Published: November 2019

The top quark is the heaviest elementary particle in the Standard Model, and has an expected Yukawa coupling of order unity. The value of this coupling is a key ingredient to unravel the nature of the observed Higgs boson. The most favourable production mode which has a direct sensitivity to this coupling is the production of a Higgs boson in association with a top-quark pair,

t

t
¯

H

. The observation of this process, based on the analysis of proton-proton collision data at a centre-of-mass energy of 13 TeV with the ATLAS detector at the Large Hadron Collider, is presented.
Study of P-wave

Bs0

states at the CMS experiment
Authors: Polikarpov Sergey
Published: November 2019

The observation of the

B

s
2

*

(
5840
)

0

→

B
0

K
S
0

decay and the evidence for the

B

s
1

*

(
5840
)

0

→

B
0

K
S
0

decay are presented. The analysis uses the data collected by the CMS experiment at the LHC in proton-proton collisions at

s

=
8

TeV

. In addition, properties of the P-wave

B
s
0

mesons are determined, as well as the mass differences M(B0) − M(B+) and M(B*0) − M(B*+), where the latter is measured for the first time.
Study of tau neutrino production in proton-nucleus interactions
Authors: Gornushkin Yury
Published: November 2019

Tau neutrino properties are not so well known in comparison to those of muon or electron neutrinos. The tau neutrino interaction cross-section was directly measured by the DONUT experiment in 2008 on a basis of 9 registered tau neutrinos, and with a large systematical error of 50% due to a poor knowledge of the tau neutrino flux in this beam dump experiment. However, more accurate measurement of the cross section is needed for future neutrino experiments. It would also allow testing the Lepton Universality (LU) of Standard Model in neutrino interactions. Recently several results for B-meson decays (LHCb, Babar) demonstrated hints of possible LU violation. The tau neutrinos are produced in the Ds meson decays to tau, Ds → τ v
T, and the cascade decay of the tau τ → v
T X. DsTau experiment has been proposed to study the tau neutrino production at CERN SPS. It will measure the Ds production differential cross-section in the proton-tungsten interactions. This will allow reducing of the uncertainty due to the tau neutrino flux in the DONUT result from 50% to 10%. The peculiar Ds cascade decay topology ("double kink") in a few mm range will be detected by nuclear emulsion tracker thanks to its excellent spatial resolution (∼50nm).

In 2016 and 2017, we made test beam exposures of nuclear emulsion modules at CERN SPS 400GeV/c proton beam followed by the pilot run in August 2018. A physics run in 2021 is scheduled. The status and prospects of the DsTau project as well as a review of the modern nuclear emulsion technique and the methods of its data analysis are presented.
Double beta decay experiments: present and future
Authors: Barabash A S
Published: November 2019

Last experimental achievements in double beta decay are presented. Possible progress in this field in the near and far future is discussed. The possibilities to investigate IO (inverted ordering) and NO (normal ordering) region of neutrino mass are considered.
Reactor antineutrino measurements with DANSS experiment
Authors: Alekseev I
Published: November 2019

Experiments with reactor antineutrino provide a wide range of physics opportunities. Solid state scintillator detector DANSS is placed just below the core of 3.1 GW
th
industrial reactor of Kalininskaya Nuclear Power Plant. The detector features the world highest counting rate of 5000 neutrino events per day with the cosmic rays induced background as low as 130 events per day. The talk covers detector performance of a year and a half operation, reactor power measurements via neutrino flux and effects of fuel burning over the reactor campaign.
The first observation of oscillation effect in Neutrino-4 experiment and analysis of measurement results
Authors: Serebrov A , Ivochkin V , Samoilov R , Fomin A , Polyushkin A , Zinoviev V , Neustroev P , Golovtsov V , Chernyj A , Zherebtsov O , Chaikovskii M , Martemyanov V , Tarasenkov V , Aleshin V , Petelin A , Izhutov A , Tuzov A , Sazontov S , Gromov M , Afanasiev V , Zaytsev M , Gerasimov A , Ryazanov D
Published: November 2019

We report Neutrino-4 experiment results of measurements of reactor antineutrinos flux and spectrum dependence on the distance in range 6-12 meters from the center of the reactor core. Using experimental spectrum, we performed the model independent analysis of restrictions on oscillation parameters

Δ

m

14

2

and sin2 2θ
14. The results of this analysis exclude area of reactor and gallium anomaly at C.L more than 99.7% (> 3σ) for values

Δ

m

14

2

<
3

eV

2

and sin2 2θ14 > 0.1. However, we observed an oscillation effect at C.L 2.8σ in vicinity of

Δ

m

14

2

≈
7.3

eV

2

and sin2 2θ
14 ≈ 0.39. The method of coherent addition of results of measurements, which allows us to directly observe the effect of oscillations, is proposed. The analysis of that effect is presented. In general, it seems that the effect predicted in gallium and reactor experiments is being confirmed but at sufficiently large value of

Δ

m

14

2

. An additional analysis of the measurements was performed taking into account inhomogenei ty of the detector and background instability.
Project KATRIN: First results and future plans.
Authors: Titov Nikita A.
Published: November 2019

The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to make a model-independent determination of the active electron antineutrino mass with an upper limit of 0.2 eV/c2 from the analysis of Tritium beta-spectrum shape near the endpoint. Experimental set-up is fully assembled and undergoes multiple tests. Small amount of Tritium molecules were injected at June 2018 and first spectra were measured. Experimental program for the nearest future includes determination of active electron antineutrino mass with an upper limit of 1.0 eV/c2 and preliminary search for sterile neutrinos with several keV mass.
Experiment BEST-2 with a source of 65Zn on gallium target for the search of neutrino oscillations on a short baseline
Authors: Gorbachev V V , Gavrin V N , Ibragimova T V , Kornoukhov V N , Shikhin A A
Published: November 2019

The proposal for an experiment on a 2-zone gallium target of a solar Galliumgermanium neutrino telescope at the Baksan neutrino observatory of the INR RAS with a 65Zn source for short baseline neutrino oscillations search is considered. The possibilities of determining the parameters of oscillations, the necessary characteristics of the neutrino source, the possibility of its production and its use are described. The expected results of measurements with a 65Zn source are compared with the results expected in the experiment BEST with the 51Cr source.
Method to test Lorentz invariance in electron-capture decay by measuring a neutrino recoil force
Authors: Barabanov A L , Titov O A
Published: November 2019

Due to hypothetical Loretz invariance violation, additional terms arise in the differential rate for neutrino radiation accompanying electron capture by polarized nuclei. These terms, as well as the parity-violating term, can be probed by measurement of a small recoil force acting on a radioactive sample. An expression for this force is obtained for the case of allowed Gamow–Teller transitions. We discuss prospects to measure the force by using the methods of the magnetic resonance force microscopy, present a list of the most suitable isotopes and give the numerical estimates for mass and activity of required radioactive samples.
Atomic effects in antineutrino spectrum of 144Pr
Authors: Lomonosov A , Lukyanchenko L , Skorokhvatov M , Titov O
Published: November 2019

Pr-144 isotope is one of the most favorable antineutrino sources for short-baseline experiments aimed at sterile neutrino search. These experiments require precise theoretical knowledge of the antineutrino spectrum. We calculate antineutrino spectrum of Pr-144 taking into account various corrections with emphasis on corrections due to atomic effects.
Cosmic ray electrons and positrons over decade with the PAMELA experiment
Authors: Mikhailov V V , Adriani O , Barbarino G , Bazilevskaya G A , Bellotti R , Boezio M , Bogomolov E A , Bongi M , Bonvicini V , Bruno A , Cafagna F S , Campana D , Carlson P , Casolino M , Castellini G , De Santis C , Di Felice V , Galper A M , Karelin A V , Kleymenova S O , Koldashov S V , Koldobskiy S , Krutkov S Yu , Kvashnin A N , Leonov A A , Malakhov V V , Marcelli L , Martucci M , Mayorova A G , Menn W , Merge M , Mocchiutti E , Monaco A , Mori N. , Munini R , Osteria G , Papini P , Panico B , Pearce M , Picozza P , Ricci M , Ricciarini S B , Simon M , Sparvoli R , Spillantini P , Stozhkov Yu I , Vacchi A , Vannuccini E , Vasiliev G I , Voronov S A , Yurkin Yu T , Zampa G , Zampa N
Published: November 2019

The PAMELA experiment has measured cosmic ray particles and antiparticles fluxes at Earth orbit from June 2006 till January 2016 onboard the Resurs-DK1 satellite. Measurements were carried out during the solar minimum of 23 solar cycle with negative polarity A < 0 of heliospheric magnetic field till the beginning of 24 cycle with positive polarity A > 0. In this paper, the results of observations of electron and positron fluxes are presented in wide energy range from several hundreds MeVs till several TeVs These measurements provide important information to study cosmic ray sources and propagation in Galaxy and heliosphere.
The single mechanism of solar and galactic cosmic rays acceleration arising during the flare process
Authors: Podgorny I M , Podgorny A I
Published: November 2019

Solar flares take place in the solar corona due to release of magnetic energy accumulated in the magnetic field of current sheet during instability of the current sheet.Solar cosmic rays are accelerated in the inductive electric field of the current sheet. The magnetic field of the solar wind forms the shape of an Archimedes spiral and affects the propagation of solar cosmic rays in interplanetary space. The modern detection of giant flares on the class G star dwarfs with the energy significantly exceeding the energy of the solar flares indicates the possibility of proton acceleration beyond the boundary of the solar system to energies significantly greater than the energy of solar cosmic rays. The recent experimental data shows that the energy of the stellar flares can exceed energy of 1036 erg. It is by 3-4 orders greater than the energy of a large solar flare, and, apparently, the energy of the protons accelerated in these stellar flares can significantly exceed the energy of the particles registered from flares on the Sun. Thus, the flare can be a universal astronomical process responsible for proton acceleration on the Sun and on the stars.
Ultra-high energy cosmic rays from supermassive black holes: particle flux on the Earth and extragalactic diffuse emission
Authors: Uryson A V
Published: November 2019

Cosmic rays accelerated to ultra-high energies (E >4⋅1019 eV) in electric fields in accretion discs around supermassive black holes are discussed. Particle injection spectra are assumed to be harder than those formed in acceleration at shock fronts. It turned out that cosmic rays with injection spectra supposed contribute a little in the particle flux detected with ground-based arrays. But in the extragalactic space particles generate a noticeable flux of the diffuse gamma-ray emission compared with the data obtained with Fermi LAT instrument (onboard the Fermi space observatory). The intensity of neutrinos generated by cosmic rays propagating in the extragalactic space is also derived. The model intensity of cascade neutrinos is much lower than that of astrophysics neutrino. It is concluded that possibly supermassive black holes are cosmic ray sources which contribute slightly to the particle flux detected on the Earth, but these sources should be taken into account analyzing components of extragalactic diffuse gamma-ray emission.
Comparing EAS registered with PRISMA-32 array and CWC NEVOD
Authors: Gromushkin D M , Bogdanov F A , Bulan A V , Yurin K O
Published: November 2019

Results of comparing events detected with two detectors of the Experimental complex NEVOD: PRISMA-32 array and Cherenkov water calorimeter (CWC) NEVOD – are presented. The PRISMA-32 is an array for simultaneous registration of the EAS electron-photon and neutron components. It consists of 32 en-detectors deployed over the area of about 500 m2, along the perimeter of the CWC NEVOD. The CWC NEVOD is a detector of a calorimetric type with a volume of 2000 cubic meters in which the registration system of 91 quasispherical modules (546 FEU-200 photomultipliers) is placed. CWC provides measurement of the intensity of Cherenkov radiation from any direction with practically the same efficiency.
Influence of magnetic field and density of environment on collimation of laboratory jet
Authors: Shatalov N A , Chechetkin V M , Kalashnikov I Yu , Krauz V I
Published: November 2019

In this work a numerical simulation of the propagation of a plasma bunch in the experimental plasma focus facility was carried out to determine the parameters influencing on the value of an opening angle. Both the experiment and the numerical simulations are supposed to have the same dimensionless parameters as astrophysical jets. The dependence of the jet opening angle on the magnitude of the magnetic field and the ratio of the densities of the jet itself and the surrounding plasma was investigated. Due to the obtained results, it became possible to determine the dominant factor responsible for jet collimation.
Radiative transitions of electrons between Landau levels in a moderately strong magnetic field
Authors: Kuznetsov A V , Zabrodina O I
Published: November 2019

We investigate the processes of radiative electron transitions between Landau levels in a moderately strong magnetic field. Under such conditions, it is necessary to take into account transitions in which both the initial and final electrons can be in states corresponding to arbitrary Landau levels. The results obtained can be used in calculating the efficiency of electron-positron plasma generation under the conditions of a Kerr black hole accretion disk.
Cosmic muons measurements in the DANSS experiment
Authors: Samigullin Eduard
Published: November 2019

DANSS is a highly segmented detector, which contains 2500 one meter long plastic scintillator strips. The DANSS detector is placed under an industrial reactor of the Kalininskaya Nuclear Power Plant. The distance to the core is varied on-line from 10.7 to 12.7 m, and the primary task of the experiment is a search for short-distance neutrino oscillations. This work contains results of the cosmic muons study based on the data obtained with the DANSS detector. In order to achieve these results, the specific algorithm of muon track reconstruction with 97 % efficiency was developed. We also present some preliminary results on the annual variability in the flux of cosmic muons, an evaluation of the < Ethrcosθ > parameter and the correlation coefficient.
A cluster approach to the analysis of experimental data of the NEVOD-EAS shower array
Authors: Shulzhenko I A , Ardashev V A , Chiavassa A , Dobrynchuk L V , Gromushkin D M , Likiy O I
Published: November 2019

The NEVOD-EAS array for the detection of extensive air showers in the energy range 1015–1017 eV is being created in MEPhI on the basis of the Experimental complex NEVOD. The array will allow independent estimations of the size, axis position and arrival direction of EAS registered by the detectors of the experimental complex. The NEVOD-EAS registering system is organized in a cluster principle, and data analysis is performed using a newly developed cluster approach. The features of this approach to the NEVOD-EAS experimental data analysis are discussed.
SMASH model and atmospheric neutrino mass splitting
Authors: Das C.R. , Huitu Katri , Kärkkäinen Timo
Published: November 2019

Five fundamental problems - neutrino mass, baryogenesis, dark matter, inflation, strong CP problem - are solved at one stroke in a model, dubbed as “SM-A-S-H” (Standard Model-Axion-Seesaw-Higgs portal inflation) by Andreas Ringwald et. al. The Standard Model (SM) particle content is extended by three right-handed SM-singlet neutrinos Ni
, a vector-like color triplet quark Q, a complex SM-singlet scalar field σ that stabilises the Higgs potential, all of them being charged under Peccei-Quinn (PQ) U (1) symmetry, the vacuum expectation value vσ
∼ 1011 GeV breaks the lepton number and the Peccei-Quinn symmetry simultaneously. We found that numerically SMASH model not only solves five fundamental problems but also the sixth problem “Vacuum Metastability” through the extended scalar sector and can predict approximately correct atmospheric neutrino mass splitting around 0.05 eV and the solar neutrino mass splitting around 0.009 eV.
Description of processes passing at finite space-time intervals in the framework of quantum field theory
Authors: Egorov V O , Volobuev I P
Published: November 2019

We consider a novel quantum field-theoretical approach to the description of processes passing at finite space-time intervals based on the Feynman diagram technique in the coordinate representation. The most know phenomena of this type are neutrino and neutral kaon oscillations. The experimental setting of these processes demands that the rules of passing to the momentum representation in the Feynman diagram technique be adjusted in accordance with it, which leads to a modification of the Feynman propagator in the momentum representation. The approach does not make use of wave packets: both initial and final particle states are described by plane waves, which simplifies the calculations considerably. We demonstrate the validity of the formalism by applying it to describing the decay of an unstable particle and neutrino oscillations. It is shown that the considered approach correctly reproduces the known results.
Exponential operator method for finding exact solutions of the propagator equation in the presence of a magnetic field
Authors: Iablokov S N , Kuznetsov A V
Published: November 2019

A general method of obtaining the exact analytical solutions of the propagator equations for charged particles in the presence of a constant magnetic field is developed. The method is applied to calculate the exact electron propagator in a strong magnetic field.
Reconnection of magnetic fields in neutron stars driven by the electron mass term in the triangle anomaly
Authors: Dvornikov Maxim , Semikoz Victor B.
Published: November 2019

The Adler-Bell-Jackiw anomaly for massive particles is studied in an external magnetic field. The contributions of the mean spin and the pseudoscalar are accounted for in the quasiclassical approximation. The equation for the evolution of the magnetic helicity with the new quantum corrections is derived. We show that the quantum contribution to the helicity evolution can overcome the classical one in the dense degenerate matter which can be present in the core of a neutron star. The application of the obtained results for the interpretation of magnetar bursts are discussed.
Kinks in the relativistic model with logarithmic nonlinearity
Authors: Belendryasova E , Gani V A , Zloshchastiev K G
Published: November 2019

We study the properties of a relativistic model with logarithmic nonlinearity. We show that such model allows two types of solutions: topologically trivial (gaussons) and topologically non-trivial (kinks), depending on a sign of the nonlinear coupling. We focus primarily on the kinks' case and study their scattering properties. For the kink-antikink scattering, we have found a critical value of the initial velocity, which separates two different scenarios of scattering. For the initial velocities below this critical value, the kinks form a bound state, which then decays slowly. If the initial velocities are above the critical value, the kinks collide, bounce and eventually escape to infinities. During this process, the higher initial velocity is, the greater is the elasticity of the collision. We also study excitation spectrum of the kink solution.
Footprints of Non-Inflationary Cosmology in Programs OLIMPIA and Synthesis of Heavy Elements
Authors: Avetissian Ara K
Published: November 2019

In this work we are going to apply one of main ideas of “Non-Inflationary Cosmology”, established by author as an alternative theory of cosmology – the analogue of the phenomenon of 6-photonic capture of Higgs bosons in Bose-Einstein condensate in the early Universe – as a possible scenario for the implementation and further possible development of two Russian programs “OLIMPIA” and “Synthesis of heavy elements”. Offered by us and thoroughly discussed phenomenon of “the cold trapping of baryons within 6-photonic potential well” may be additional or even possible alternative mechanism to the well-known “mechanism of cold synthesis of nuclei”.
Graviton-to-photon conversion effect in magnetized relativistic plasma
Authors: Postnov K A , Simkin I V
Published: November 2019

The graviton-to-photon conversion effect in a magnetized relativistic lepton plasma is considered. This effect can be important for the possible generation of electromagnetic radiation accompanying coalescence of relativistic compact neutron star – black hole binaries. The relativistic electron-positron plasma can be generated near the surface of a rotating magnetized neutron star (a radio pulsar). The formation of a relativistic compact binary containing a pulsar and a black hole is predicted by the evolution of massive binary stars. Prior to the coalescence of such a binary due to gravitational wave (GW) emission, a fraction of the GW power can be converted in the plasma outflow into a low-frequency electromagnetic (EM) waves, which can lead to additional radio power prior to the coalescence. Using the graviton- to-photon conversion mechanism in an external magnetic field, we calculate the fraction of GW power converted into the EM radiation in the relativistic plasma. The result is found to depend on the neutron star spin period P, plasma Lorentz factor γ and the cascade multiplicity λ, but independent of the neutron star magnetic field: K ≃ 10−35(P/1 s)2(γ/105)2(λ/105)−2. The possibility of the detection of the non-thermal EM counterparts from neutron star – black hole coalescences in the forthcoming GW observations by aLIGO/Virgo detectors is briefly discussed.
Search for events in the LVD detector coinciding with gravitational signals from the collapse of close binary systems
Authors: Agafonova N Yu , Ashikhmin V V , Dobrynina E A , Enikeev R , Malgin A S , Ryazhskaya O G , Shaliryanova I R , Yakushev V F
Published: November 2019

The results of the search for events detected by the Large Volume Detector coinciding with the gravitational signals from the GW150914, GW151226, GW170104, GW170608, GW170814 and GW170817 are presented.
On Firewalls in quantum-corrected General Relativity
Authors: Nurmagambetov A J , Park I Y
Published: November 2019

We consider the information loss paradox at different angles, from the standard semi-classical approximation of General Relativity to the recently proposed scenarios of black holes evolution caused by effects of gravity quantization. Focusing on the Firewall proposal, we study the loop effects on the geometry and boundary conditions in black hole spacetimes and analyze the energy measured by an infalling observer near their horizons. As a result we obtain a trans-Planckian energy transition for the time-dependent black hole solution on the quantum-induced AdS background, the importance of which for the black hole (in)formation is discussed.
Magnetic field contribution to black-hole-hedgehog’s solution in GraviWeak unification
Authors: Das C.R. , Laperashvili L.V. , Nielsen H.B. , Sidharth B.G.
Published: November 2019

In the framework of Multiple Point Principle (MPP), where the existence of the two degenerate vacua of the Universe, the first, ElectroWeak vacuum with ≈ 246 GeV (“true vacuum”), and the second at Planck scale ∼ 1018 GeV (“false vacuum”); we investigated the gravitational black-hole-hedgehog's solution with magnetic field contribution in the GraviWeak unification model described by f(R) gravity. We have considered the phase transition from the “false vacuum” to the “true vacuum” and confirmed the stability of the ElectroWeak vacuum. The “false vacuum” defect configurations for the black-hole-hedgehog have given a global monopole and this monopole has been “swallowed” by the black-hole with core mass M

BH
≈ 3.65 × 1018 GeV and radius δ ≈ 6 × 10−21 GeV−1. The horizon radius of the black-hole-hedgehog is around rh
≈ 1.14δ.
Gravitational Hertz experiment in dielectrics, excited by intense laser pulses
Authors: Gorelik V S
Published: November 2019

The possibility of generating and detection of high-frequency gravitational waves based on parametric optical processes in dielectric media excited by intense laser emission is analyzed. The theory predicts the feasibility of the Hertz gravitational laboratory experiment in dielectric media at the presence of strong constant magnetic field with illumination of this media by intense ultra short laser pulses of visible or ultraviolet ranges. Parametric conversion of ultra short intense laser pulses with frequency ω0 to a gravitational wave with frequency ωg=2ω0 and reconversion process of gravitational radiation to optical radiation at resonance condition for some dielectrics and photonic structures are predicted
Studying the possibility of FSR suppression in DM decay in dependence of the mass of intermediate particle and vertex
Authors: Solovyov M L , Belotsky K M , Kamaletdinov A H , Esipova E A
Published: November 2019

In this proceedings we study possibility of final state radiation (FSR) in the process of dark matter (DM) decay/annihilation. Two possibilities are considered independently: one-cascade annihilation through intermediate particle (a), and parameterized interaction vertex. The mass of a and vertex parameters are used to try to suppression FSR. Suppression is necessary to avoid limit from cosmic gamma-radiation preventing DM explanation of positron anomaly in CR. Finally, it may seem that a little suppression can be reached by fine-tuning the mass of a, and vertex parameters do not help to do it in the considered cases.
Incoherent X-ray diffraction radiation for noninvasive diagnostics of transverse size of ultrarelativistic beams
Authors: Tishchenko A A , Sergeeva D Yu , Strikhanov M N
Published: November 2019

Polarization radiation, which includes diffraction radiation, transition radiation, Smith-Purcell radiation, and others, can be a good instrument for beam diagnostics. All information about the beam size is contained in the so-called form-factor of the beam. The form-factor represents the sum of two parts corresponding to the coherent and incoherent radiation. Contrary to the general opinion the incoherent part does not always equal unity. In this report we give theoretical description of the incoherent part of the form-factor both for Gaussian and uniform distribution of the ultrarelativistic particles in the bunch. We show that the incoherent form-factor depends on the transverse size of the beam, and discuss the new opportunities for non-invasive diagnostics of ultrarelativistic electron beams.
Fabrication of reactor target from enriched 50Cr for artificial neutrino source
Authors: Kozlova J P , Veretenkin E P , Gavrin V N , Danshin S N , Ibragimova T V , Komarov B A
Published: November 2019

The fabrication of the enriched 50Cr target for the artificial 51Cr neutrino source with activity > 3 MCi for the experiment BEST is presented. The processes of obtaining a target in the form of disks with a thickness of 4 mm and a diameter of 84 and 88 mm required to achieve the necessary activity using the reactor SM-3 are considered, including: enrichment of natural chromium in the form of oxyfluoride by gas centrifugation, electrolytic reduction and refining of metallic chromium, as well as the formation of chromium disks by spark plasma sintering.
Status of UCN supersource at WWR-M reactor
Authors: Serebrov A P , Lyamkin V A , Fomin A K , Koptyuhov A O , Prudnikov D V , Samodurov O Yu , Ilatovskiy V A , Keshishev K O , Boldarev S T
Published: November 2019

The WWR-M reactor at NRC «Kurchatov Institute» - PNPI is going to be equipped with high-density ultracold neutron source. Method of UCN production is based on their accumulation in the superfluid helium at 1.2 K temperature. Thus, the source will provide the UCN density at EDM spectrometer equals to ρ = 1.3⋅104 cm−3 which is 2 order magnitude greater than the output density of existing UCN source in the world. An extensive program of fundamental researches such as measuring of neutron lifetime and searching of neutron-antineutron oscillation is planned. In addition, CN and VCN beams are going to be equipped with condensed matter physics experimental setups. The design of the UCN source has been completed, complex tests at full-scale model showed that is possible to maintain superfluid helium under reactor heat load; calculations of an UCN source passive shielding, which ensures source safe operation, is completed. At the moment the process of UCN source manufacturing is taking place.
Hadronic shower properties in highly granular calorimeters with different absorbers
Authors: Chadeeva Marina
Published: November 2019

The CALICE collaboration develops and tests highly granular calorimeter prototypes for future collider experiments. The scintillator-SiPM-based prototypes of hadron calorimeters with steel and tungsten absorbers were exposed to test beams from the CERN SPS in 2007-2011. The paper presents a comparison of hadronic shower properties observed in the test beam data. The application of software compensation technique is discussed for the energy reconstruction in calorimeters with different level of compensation. It was observed from the experimental data that the achieved improvement of relative energy resolution is about 20% for the noncompensating calorimeter, while it is less than 5% for the compensating one.
Compact neutron generators for the calibration of low background experiments
Authors: Chepurnov AS , Gromov MB , Ionidi V Yu , Kaplii A A , Kirsanov MA , Klenin A A , Kolesnikov D A , Kubankin A S , Maslenkina A Yu , Oleinik A N , Selivanova D A , Shchagin A V
Published: November 2019

In the coming years, the compact monoenergetic neutron generators (CNG) producing up to 104 n/s may become an alternative to the standard neutron sources based on radioactive isotopes for the calibrations of neutrino and dark matter detectors. Such neutron generators have a typical size of about several centimetres, they may be manufactured using low-background materials and may require only low voltage power supply for operation. We discuss the advantages and disadvantages of two main types of the compact neutron generators, namely a pyroelectric neutron source and a high voltage neutron generator. Also the results of the technical analysis of the possibilities to apply such sources for the calibration of low-background experiments are given, the variant of the internal device design is shown and the full-size compact neutron generator prototype are presented.
Compact x-ray spectrometer based on thermoluminescent detectors
Authors: Grigoryeva I G , Khil’ko M V , Salakhutdinov G Kh
Published: November 2019

A small-sized pulsed x-ray spectrometer was designed and developed. The spectrometer is designed to study pulsed x-rays in the energy range of quanta 1-30 keV. The spectrometer is an assembly of thermoluminescent LiF detectors arranged one after another. Thermoluminescent detectors record x-ray radiation and are used as filters for selection of x-ray radiation in the spectrum. Thermoluminescent LiF detectors are immune to electromagnetic interference, and their response is linear in a wide dynamic range of the absorbed radiation dose (from 20 mSv to 10 Sv). Calibration measurements and test tests have shown good performance and reliability of the small-sized spectrometer.
Modernization of the pulse shape discrimination method for neutron and gamma quanta in scintillation detector
Authors: Chepurnov A S , Ivanenko M I , Kirsanov M A , Klimanov S G , Kubankin A S
Published: November 2019

In this paper, we investigated the efficiency of several known and new methods of digital pulse shape discrimination for neutrons and gamma quanta. Experimental data were obtained on a setup consists of a Pu-Be neutron source, organic p-terphenyl scintillation detector and 14 bits, 500 MHz sampling rate flash-ADC with capability to store and upload to the host computer long waveforms for further analysis. A comparison is made in between the results of using traditional and new methods for calculating the signal separation efficiency of Figure of Merit (FOM). The best known from the literature value of the efficiency of neutron and gamma quanta discrimination for the Pu-Be source is FOM = 1.5. We obtained the separation efficiency FOM = 1.77 in the scintillation detector with the p-terphenyl crystal, by a new method. Note also that for the known liquid scintillator BC-501A FOM≈1. A new method of scintillation detector pulse shape discrimination from neutrons and gamma quanta is used to detect the neutron yield from compact neutron generator that is created on the basis of carbon nanotubes.
Calibration and Performance of the ATLAS Tile Calorimeter
Authors: Petukhova Krystsina
Published: November 2019

The Tile Calorimeter (TileCal) of the ATLAS experiment at the LHC is the central hadronic calorimeter designed for the reconstruction of hadrons, jets, tau-particles and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibers to photomultiplier tubes (PMTs). The readout is segmented into about 5000 cells, each of them being read out by two PMTs in parallel. The TileCal calibration system comprises Cesium radioactive sources, laser, charge injection elements, and an integrator based readout system. Combined information from all systems allows to monitor and to equalize the calorimeter response at each stage of the signal evolution, from scintillation light to digitization. The performance of the calorimeter has been established with cosmic ray muons and the large sample of the proton-proton collisions. The response of high momentum isolated muons is used to study the energy response at the electromagnetic scale, isolated hadrons are used as a probe of the hadronic response. The calorimeter time resolution is studied with multi-jet events. A description of the different TileCal calibration systems and the results on the calorimeter performance during the LHC Run 2 will be presented.
Study of the SiPM double component recovery time
Authors: Bychkova Oksana V , Ilyin Andrey L , Kayumov Fred F , Parygin Pavel P , Philippov Dmitry E , Popova Elena V , Stifutkin Alexey A , Vinogradov Sergey L
Published: November 2019

The recovery time of the Hamamatsu SiPM linear assembly was measured. The assembly contains eight SiPMs of 2.8mm active area diameter; pixel size is 15xl5mkm2. The assembly is used for Phase1 upgrade in hadron calorimeter of the CMS experiment. Recovering process is found to depend on the number of the pixels fired and varied from 7 ±1 ns to 23 ± 3 ns for 50 Ohm readout impedance.