Vladimir M. Shabaev

  (SPbSU & NRC KI - PNPI)

How to observe the vacuum decay in low-energy collisions of heavy ions.
  Abstract:
It is known that in slow collisions of two bare nuclei with the total charge number larger than the critical value, Z_1+Z_2 > Z_c =173, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. Detection of the spontaneous emission of positrons would be the direct evidence of this fundamental phenomenon. However, the spontaneous positron emission is generally masked by the dynamical positron emission, which is induced by a rapidly changing electric field created by the colliding nuclei. For many years it was believed that the vacuum decay can be observed only in collisions with nuclear sticking, when the nuclei are bound for some period of time due to nuclear forces. But to date there is no evidence for the nuclear sticking in such heavy-ion collisions. In our recent papers [I.A. Maltsev et al., PRL, 2019; R.V. Popov et al., PRD, 2020], it was shown that the vacuum decay can be observed without any sticking of the nuclei. This can be done via measurements of the pair-production probabilities or the positron spectra for a given set of nuclear trajectories. The results of this study will be presented in the talk. In addition, some other interesting problems appearing in quantum electrodynamics at strong-coupling regime will be discussed.

M. V. Smirnov

  (Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen Centre for Astroparticle Physics (ECAP), Erlangen, Germany)

Neutrino physics in the experiment KM3NeT/ORCA.
  Video
  Abstract:
The underwater neutrino telescope ORCA, part of the European Neutrino Observatory KM3NeT, is located in the Mediterranean Sea. Due to the high density of digital optical modules, ORCA is sensitive to atmospheric neutrino oscillations. Detector deployment continues. The main purpose of the experimental campaign is to determine the neutrino mass hierarchy.

Aurel Bulgac

  (UW)

Unraveling The Many Facets of Non-Equilibrium Fission Dynamics: A Real-Time Quantum Approach.
  Video
  Abstract:
When comparing nuclear fission at the venerable age of almost 84 years old with other quantum many-body systems (superconductivity, superfluidity, quantum Hall effect, fractional quantum Hall effect, magnetism, etc.) it is surprising to find out how little is known and microscopically justified for this complex quantum non-equilibrium process. In the last decade a significant advancenment was achieved in modeling and disentangling aspects of fission, by means of a pure quantum approach. The level of agreement with observations, without the resort to any unverified theoretical assumptions, uncontrolled numerical approximations, or phenomenology and incorporating only the basic input needed to reproduce most of the well-known properties of nuclei, is surprisingly good. The theoretical framework requires only eight input parameters at most: the nuclear saturation density and energy, surface tension, the symmetry energy and its density dependence to a lesser degree, proton charge, the spin-orbit and the nuclear pairing interaction strengths. Some of our foremost theoretical findings are: i) the strongly damped character of the large amplitude collective motion beyond the outer saddle-point, ii) the fission fragment excitation energies and its sharing mechanism, and the somewhat surprising excitation energy exchange mechanism between the fission fragments before the fission fragments are fully accelerated, iii) the intrinsic fission fragment spins and their unexpected correlation character, iv) the nature and the properties of the non-equilibrium neutrons emitted before the fission fragments are fully accelerated, v) the strongly damped character of the fission fragment shape evolution after they are spatially separated, vi) the total kinetic energy of the fission fragments, vii) and the evolution of these properties with the initial excitation energy of the compound nucleus.

N.V. Nikitin

  (MSU, ITEP, Moscow)

The Bell inequalities and violation of them.
  (Presentation)
  Video
  Abstract:
The 2022 Nobel Prize in Physics was awarded for the experimental measurement of Bell's inequalities's violation. This story started in the 1920's from the discussion between A. Einstein and N. Bohr about the possibility of reducing the quantum paradigm to the classical one. These discussion were transferred to the experimental area in 1964 by J. Bell using some inequality. The violation of this inequality leads to Niels Bohr's win in this discussion. The first experimental results appeared in 1972. Up to the the present time the verification of the Bell inequalities violation continues.

Yu.A. Kulchitsky

  (JINR)

Study of KNO scaling in pp-collisions at energies from 0.9 to 13 TeV using results of the ATLAS at the LHC.
  (Presentation)
  Video
  Abstract:
The results of the study of KNO scaling in proton-proton interactions are presented at the centre-of-mass energies from 0.9 to 13 TeV based on the ATLAS results at the LHC. A comparison with similar results of other experiments at the LHC is given. The KNO distributions tend to be independent of energy for the highest energies.

V.M. Mochalov

  (NRC KI IPHE, Serpukhov)

Spin-Effect Investigation in SPASCHARM Experiment at Serpukhov Accelerator.
  Video

A.P. Serebrov

  (PNPI NRC KI, Gatchina)

The Neutrino-4 experiment - comparison of our result with the results of all other experiments on the search for sterile neutrinos.
   HEPD-THD_Seminar_2023.03.02_Serebrov.A.P.mp4 - Video of A.P. Serebrov's speech.

A.Yu. Voronin

  (P.N. Lebedev Physical Institute of RAN, Moscow)

Quantum states of anti-hydrogen in gravitational field and study of anti-hydrogen properties in GBAR experiment at CERN.
  (GbarПИЯФSeminar.pdf)
  HEPD_Seminar_Voronin_A.Yu._28.02.2023.mp4 - Video of A.Yu. Voronin's speech.

A.V. Derbin

  (PNPI NRC KI, Gatchina)

Measurement of solar CNO neutrinos in the Borexino experiment.
  (CNO_nejtrino_Derbin_seminar_HEPD_2023_v1.pdf)
  HEPD_Seminar_Derbin_A.V._21.02.2023.mp4 - Video of A.V. Derbin's speech.
  (Abstract - The nuclear fusion of hydrogen into helium in stars occurs, in addition to the proton-proton (pp-) chain, which includes only hydrogen and helium isotopes, through the carbon-nitrogen-oxygen (CNO) cycle, in which fusion is catalyzed by C, N and O nuclei. The CNO cycle produces only 1% of all solar energy and is secondary to the Sun. However, for more massive and hotter stars, this cycle is decisive. In 2020-22 the Borexino collaboration, which involves scientists from Russian institutes, for the first time presented the results of detection of neutrinos emitted in the reactions of the CNO cycle on the Sun.)

A.P. Serebrov

  (PNPI NRC KI, Gatchina)

The result of the Neutrino-4 experiment, sterile neutrinos and dark matter, the fourth neutrino and the Hubble constant.
   HEPD-THD_Seminar_2023.02.16_Serebrov.A.P.mp4 - Video of A.P. Serebrov's speech.

V.V.Korenkov

  (M.G. Mescheryakov LIT JINR, Dubna)

Distributed and hybrid computing for Large-scale scientific projects.
  (Korenkov_14.02.23_PNPI.pdf)
  HEPD_Seminar_Korenkov_V.V._14.02.2023.mp4 - Video of V.V.Korenkov's speech.
  (Abstract - The evolution of the global computer infrastructure for experiments at the LHC at CERN (WLCG) is presented. Large-scale scientific projects are being implemented in Russia (PIC, NICA, SKIF, BAYKAL,SILA…), the most important part of which is the creation of computer systems for processing experimental data. It is necessary to create a scientific collaboration in Russia, bringing together key scientific centers and universities participating in large-scale scientific projects.)

M.G Ryskin

  (PNPI NRC KI, Gatchina)

Polarization in inclusive processes (non-perturbative effects).
   (p-inc.pdf)
   HEPD-THD_Seminar_2023.02.09_Ryskin.M.G.mp4 - Video of M.G Ryskin's speech.

N.P. Topchiev

  (P.N. Lebedev Physical Institute, Moscow)

High-Energy Gamma-Ray Astronomy and Current Status of the GAMMA-400.
  HEPD_Seminar_Topchiev_N.P._07.02.2023.mp4 - Video of N.P. Topchiev's speech.
  (Abstract - A review is presented on the study of high-energy (more than 100 MeV) gamma-ray emission on spacecraft and ground-based facilities. Information on the development of the GAMMA-400 gamma-ray telescope for space observatory is presented: the results of calculations of the gamma-ray telescope performance and the results of the calibration of some gamma-ray telescope system prototypes on the positron beam of the S-25R accelerator (Troitsk, LPI).)

G.B. Safronov

  (INR RAS)

Deepwater neutrino telescope Baikal-GVD: the motivation of the experiment, the status of the detector and the latest results.
   HEPD-THD_Seminar_2023.02.02_Safronov.G.B.mp4 - Video of G.B. Safronov's speech.
   (Abstract - Neutrino propagates at large distances in space without trajectory bending or absorption and thus can provide information about remote sources of high-energy particles. In 2015 a deployment of the 1 km3 -scale neutrino telescope, Baikal-GVD, started in Lake Baikal. The experiment is focused on studies of the neutrino flux in the energy range between ~100 GeV and tens of PeV. Presently an instrumented volume of the detector is more than 0.4 km³ thus being the largest telescope of this kind in the North Hemisphere. In this talk we discuss the motivation of the experiment, status of the detector and the latest results.)

V.V. Koltsov

  (V.G. Khlopin Radium Institute)

Nuclear Isomers as Tool for Study of Vacuum Fluctuations Influence of Electromagnetic Field on Spontaneous Electromagnetic Transition Probability.
  (Kol'tsov-seminar-2023.pdf)
  HEPD_Seminar_Koltsov_V.V._31.01.2023.mp4 - Video of V.V. Koltsov's speech.
  (Abstract - A review of works on studying the effect of changing the frequency spectrum of zero-point fluctuations of the electromagnetic field inside metals on nuclear electromagnetic low energy transitions is presented.)

A.A. Dzyuba

  (PNPI NRC KI, Gatchina)

Investigation of Z boson production in pp interaction at vs=13 ТeV in the LHCb experiment.
  (2023-01-24_Dzyuba_HEPD-PNPI-Seminar_Z-at-pp.pdf)
  HEPD_Seminar_Dzyuba_A.A._24.01.2023.mp4 - Video of A.A. Dzyuba's speech.
  (Abstract - Results of Z boson production study for forward angles in pp interaction at vs=13 ТeV are presented. The measurements are performed by the LHCb experiment at LHC (CERN). The integral and differential cross sections of Z boson production are obtained [1], angular distributions of muon pairs are studied [2], evidence of possible charm quark contribution to the proton wave function is obtained [3]. Detection of Z boson decay muons for calibration allows to measure of the W boson mass [4].
Refs.: [1] JHEP 07 (2022) 026; [2] Phys. Rev. Lett. 129 (2022) 091801; [3] Phys. Rev. Lett. 128 (2022) 082001; [4] JHEP 01 (2022) 036.)

I.I. Strakovsky

  (GWU)

Light Baryon Resonances: Restrictions and Perspectives. [The author dedicates this talk to Yakov Isaakovich Azimov].
   (PNPI2023a.pdf)
   HEPD-THD_Seminar_2023.01.19_Strakovsky.I.I.mp4 - Video of I.I. Strakovsky's speech.
   (Abstract - The problem of nucleon resonances N' with masses below the Delta is considered. We derive bounds for the properties of such states. Some of these are new, while others improve upon existing limits. We discuss the nature of N' states, and their unitary partners, assuming that their existence can be verified.)

G.E. Gavrilov

  (PNPI NRC KI, Gatchina)

The Origin of Spontaneous Self-Sustaining Current in Proportional Chambers of Experiments at the LHC (According to Results of Detector Studies of the LHCb & CMS).
  (2023_01_17_HEPD_seminar.pdf)
  HEPD_Seminar_Gavrilov_G.E._17.01.2023.mp4 - Video of G.E. Gavrilov's speech.
  (Abstract - Over the years of operation the multiwire proportional chambers in the CMS and LHCb experiments at the LHC have shown that the only sign of their aging processes is the appearance of spontaneous self-sustaining currents. Long-term studies have shown that the source of these currents is the formation of unique low threshold emission nanocarbon structures. The nature of occurrence such formations gave a hint for development of the effective methods for emission current suppression, that today have been successfully tested on practice.)