A5101942907- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Quantum, superfluid, helium dynamics
- Nuclear physics research studies
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Noncommutative and Quantum Gravity Theories
- High-pressure geophysics and materials
- Advanced NMR Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Superconducting Materials and Applications
- Advanced Chemical Physics Studies
- Quantum and Classical Electrodynamics
- Quantum Mechanics and Applications
- Scientific Research and Discoveries
- Model Reduction and Neural Networks
- Neural Networks and Applications
TU Wien
2011-2021
Peter the Great St. Petersburg Polytechnic University
1992-2017
St Petersburg University
2015-2016
Stefan Meyer Institute for Subatomic Physics
2004-2009
Austrian Academy of Sciences
2004-2009
Telstra (Australia)
2005
European Organization for Nuclear Research
2005
Bauman Moscow State Technical University
1992-2002
Max Planck Institute for Nuclear Physics
1997
The Abdus Salam International Centre for Theoretical Physics (ICTP)
1994-1996
We report on precision resonance spectroscopy measurements of quantum states ultracold neutrons confined above the surface a horizontal mirror by gravity potential Earth. Resonant transitions between several lowest are observed for first time. These demonstrate that Newton's inverse square law is understood at micron distances an energy scale $1{0}^{\ensuremath{-}14}\text{ }\text{ }\mathrm{eV}$. At this level precision, we able to provide constraints any possible gravitylike interaction. In...
We present phase shift measurements for neutron matter waves in vacuum and low pressure Helium using a method originally developed scattering length interferometry. search shifts associated with coupling to scalar fields. set stringent limits chameleon field, prominent quintessence dark energy candidate. find that the constant β is less than 1.9×107 n=1 at 95% confidence level, where n an input parameter of self-interaction field φ inversely proportional φn.
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, tune-defined as number of precessions per turn-is given by ν(s)=γG (γ Lorentz factor, G gyromagnetic anomaly). At 970 MeV/c, deuteron spins coherently precess at a frequency ≈120 kHz in Cooler Synchrotron COSY. The deduced from up-down asymmetry deuteron-carbon scattering. time interval 2.6 s, was determined with precision order 10^{-8}, 1×10^{-10} for continuous 100 s accelerator cycle. This...
We analyze the sensitivity of all experimentally observable asymmetries and energy distributions for neutron ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay with a polarized an unpolarized proton electron, lifetime to contributions order ${10}^{\ensuremath{-}4}$ interactions beyond standard model (SM). SM in linear approximation respect Herczeg phenomenological coupling constants, introduced at hadronic level. Such is good enough analysis SM. show that such correlation coefficients depend only...
ABSTRACT We analyse the Einstein–Cartan gravity in its standard form <?CDATA ${ \mathcal R }=R+{{ K }}^{2}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> <mml:mo>=</mml:mo> <mml:mi>R</mml:mi> <mml:mo>+</mml:mo> <mml:msup> <mml:mrow> mathvariant="italic"></mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:math> , where }\ \mathrm{and}\ R$?> <mml:mspace width="0.33em" /> <mml:mi>and</mml:mi> are Ricci scalar...
We calculate the chameleon field potential for ultracold neutrons bouncing on top of one, or between two, neutron mirrors in gravitational Earth. For resulting nonlinear equations motion, we give approximate analytical solutions and compare them with exact numerical ones which propose fit. The obtained may be used quantitative analysis contributions a to transition frequencies quantum states bound
The nuclear $K$-shell electron-capture (EC) and positron (${\ensuremath{\beta}}^{+}$) decay constants, ${\ensuremath{\lambda}}_{\mathrm{EC}}$ ${\ensuremath{\lambda}}_{{\ensuremath{\beta}}^{+}}$ of H-like ${}^{140}{\mathrm{Pr}}^{58+}$ He-like ${}^{140}{\mathrm{Pr}}^{57+}$ ions, measured recently in the experimental storage ring (ESR) at GSI, were calculated using standard weak interaction theory. ratios $R={\ensuremath{\lambda}}_{\mathrm{EC}}/{\ensuremath{\lambda}}_{{\ensuremath{\beta}}^{+}}$...
According to experimental data at GSI, the rates of number daughter ions, produced by nuclear K shell electron capture decays H-like heavy ions with one in shell, such as ;{140}Pr;{58+}, ;{142}Pm;{60+}, and ;{122}I;{52+}, are modulated time periods T_{EC} order a few seconds, obeying an A scaling = A/20 s, where is mass mother nuclei, amplitudes a_{d};{EC} approximately 0.21. We show that these can be explained terms interference two massive neutrino eigenstates. The appearance term due...
We analyze a dynamics of ultracold neutrons (UCNs) caused by interactions violating Lorentz invariance within the Standard Model Extension (SME) (Colladay and Kostelecký (1997) [3] (2004) [1]). use effective non–relativistic potential for derived Lane (1999) [47] calculate contributions these to transition frequencies transitions between quantum gravitational states UCNs bouncing in field Earth. Using experimental sensitivity qBounce experiments we make some estimates upper bounds parameters...
We give a precision analysis of the correlation coefficients electron energy spectrum and angular distribution ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay radiative neutron with polarized to order ${10}^{\ensuremath{-}3}$. The calculation is carried out within standard model, contributions ${10}^{\ensuremath{-}3}$ caused by weak magnetism proton recoil taken next-to-leading in large mass expansion, corrections $\ensuremath{\alpha}/\ensuremath{\pi}\ensuremath{\sim}{10}^{\ensuremath{-}3}$...
We analyze a possibility to probe beyond-Riemann gravity (BRG) contributions, introduced by Kostelecky and Li (see Phys. Rev. D 103, 024059 (2021) 104, 044054 (2021)) on the basis of Effective Field Theory (EFT) 69, 105009 (2004). carry out such an analysis calculating BRG contributions transition frequencies quantum gravitational states ultracold neutrons (UCNs). These are being used for test interactions beyond Standard Model (SM) General Relativity (GR) in qBOUNCE experiments. improve...
The chiral perturbation theory is developed at the quark level within extended Nambu-Jona-Lasinio model, which we used for low-energy approximation of QCD in leading order large N expansion. In terms constituent-quark loop diagrams analyze all main effects caused by first corrections current-quark-mass expansions. For correct description η→3π decays confirm important role final-state interaction quoted Gasser and Leutwyler.
For the ${\ensuremath{\beta}}^{\ensuremath{-}}$-decay of neutron we analyze continuum-state and bound-state decay modes. We calculate rates, electron energy spectrum for mode, angular distributions probabilities The theoretical results are obtained new value axial coupling constant ${g}_{A}=1.2750(9)$, recently by H. Abele [Prog. Part. Nucl. Phys. 60, 1 (2008)] from fit experimental data on coefficient correlation spin momentum mode. take into account contribution radiative corrections...
As we have pointed out in (arXiv:1806.10107 [hep-ph]), the existence of neutron dark matter decay modes "n -> chi + anything", where "chi" is a fermion, for solution lifetime problem changes priorities and demands to describe "tau_n = 888.0(2.0)s", measured beam experiments defined by p Standard Model (SM). The latter requires axial coupling constant "lambda" be equal "lambda - 1.2690" [hep-ph]). Since such an excluded experimental data reported PERKEO II UCNA Collaborations, 888.0(2.0)s"...
We analyze the electron-energy and angular distribution of neutron ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay with a polarized electron an unpolarized proton, calculated by Ivanov et al. [Phys. Rev. C 95, 055502 (2017)] within standard model (SM), taking into account contributions interactions beyond SM. After absorption vector axial-vector axial coupling constant Cabibbo-Kobayashi-Maskawa (CKM) matrix element [Bhattacharya al., Phys. D 85, 054512 (2012) so on] these are scalar tensor...
According to recent experimental data at GSI, the rate of number daughter ions 140Ce58+, produced by nuclear K-shell electron capture (EC) decay H-like ion 140Pr58+, is modulated in time with a period T_d = 7.06(8) sec and an amplitude a_(EC) 0.20(2). We show that this phenomenon can be explained neutrino-flavour mixing derive value for difference squared masses Delta m^2_(21) m^2_2 - m^2_1 2.22(3)x10^(-4) eV^2.
We analyse a change of deficit reactor antineutrinos at distances smaller than 100 m by changing the lifetime neutron from tau_n = 885.7 s to 879.6 s, calculated for axial coupling constants lambda - 1.2694 and 1.2750, respectively, in order get result corresponding new world average value 880.1(1.1) s. calculate angular distribution cross section inverse beta-decay, taking into account contributions "weak magnetism" recoil next-to-leading large baryon mass expansion radiative corrections...
We calculate the contributions of weak magnetism and proton recoil order O(Ee2∕mN2)∼10−5, i.e. to next-to-next-to-leading in large nucleon mass expansion, neutron lifetime correlation coefficients beta decay, where Ee mN are electron energy mass, respectively. analyze electron-energy angular distribution for decay with a polarized neutron, an unpolarized proton. Together Wilkinson's corrections (Wilkinson, 1982; radiative O(αEe∕mN)∼10−5 Ivanov et al., 2019), calculated as next-to-leading...
Neutrons are the ideal probes to test gravity at short distances – electrically neutral and only hardly polarizable. Furthermore, very slow, so-called ultracold neutrons form bound quantum states in potential of Earth. This allows combining experiments with powerful resonance spectroscopy techniques, as well tests interplay between mechanics. In last decade, q Bounce collaboration has been performing several measurement campaigns cold neutron facility PF2 Institut Laue-Langevin. A new...
By using the extended Nambu-Jona-Lasinio model for low-energy approximation of QCD we derive formulas, being due to spontaneous breaking chiral symmetry and bosonization, allowing express matrix elements any operator with current-quark fields in definition terms this determined via constituent-quark interacting low-lying meson states appearing as [Formula: see text]-collective excitations, which have self-interactions too.
The low-energy theorem, derived by Terent'ev within the framework of current algebra, is proved at quark level Extended Nambu–Jona-Lasinio model. proposed method allows to evaluate a vacuum expectation value any time-ordered product QCD-hadronic currents in terms constituent-quark loops and low-lying meson exchanges.