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V. Novikov

Publications and source records attributed to V. Novikov.

At least 19 recordsLinked to original sources
arXiv2023

Higher-order reductions of the Mikhalev system

We consider the 3D Mikhalev system, $$ u_t=w_x, \quad u_y= w_t-u w_x+w u_x, $$ which has first appeared in the context of KdV-type hierarchies. Under the reduction $w=f(u)$, one obtains a pair of commuting first-order equations, $$ u_t=f'u_x, \quad u_y=(f'^2-uf'+f)u_x, $$ which govern simple wave solutions of the Mikhalev system. In this paper we study {\it higher-order} reductions of the form $$ w=f(u)+\epsilon a(u)u_x+\epsilon^2[b_1(u)u_{xx}+b_2(u)u_x^2]+..., $$ which turn the Mikhalev system into a pair of commuting higher-order equations. Here the terms at $\epsilon^n$ are assumed to be differential polynomials of degree $n$ in the $x$-derivatives of $u$. We will view $w$ as an (infinite) formal series in the deformation parameter $\epsilon$. It turns out that for such a reduction to be non-trivial, the function $f(u)$ must be quadratic, $f(u)=\lambda u^2$, furthermore, the value of the parameter $\lambda$ (which has a natural interpretation as an eigenvalue of a certain second-order operator acting on an infinite jet space), is quantised. There are only two positive allowed eigenvalues, $\lambda=1$ and $\lambda=3/2$, as well as infinitely many negative rational eigenvalues. Two-component reductions of the Mikhalev system are also discussed. We emphasise that the existence of higher-order reductions of this kind is a reflection of {\it linear degeneracy} of the Mikhalev system, in particular, such reductions do not exist for most of the known 3D dispersionless integrable systems such as the dispersionless KP and Toda equations.

nlin.SI↗
arXiv2018

Integrability of dispersionless Hirota type equations in 4D and the symplectic Monge-Ampere property

We prove that integrability of a dispersionless Hirota type equation implies the symplectic Monge-Ampere property in any dimension $\geq 4$. In 4D this yields a complete classification of integrable dispersionless PDEs of Hirota type through a list of heavenly type equations arising in self-dual gravity. As a by-product of our approach we derive an involutive system of relations characterising symplectic Monge-Ampere equations in any dimension. Moreover, we demonstrate that in 4D the requirement of integrability is equivalent to self-duality of the conformal structure defined by the characteristic variety of the equation on every solution, which is in turn equivalent to the existence of a dispersionless Lax pair. We also give a criterion of linerisability of a Hirota type equation via flatness of the corresponding conformal structure, and study symmetry properties of integrable equations.

nlin.SI↗
arXiv2013

Control of multiscale systems with constraints. 1. Basic principles of the concept of evolution of systems with varying constraints

Physical fundamentals of the self-organizing theory for the system with varying constraints are considered. A variation principle, specifically the principle of dynamic harmonization as a generalization of the Gauss-Hertz principle for the systems with varying internal structure is formulated. In compliance with this principle the system evolves through dynamics of the processes leading to harmonization of the internal multiscale structure of the system and its connections with external actions as a result of minimizing the dynamic harmonization function. Main principles of the shell model of self-organization under the action of the dominating entropic disturbance are formulated.

physics.gen-ph↗
arXiv2013

Control of multiscale systems with constraints. 2. Fractal nuclear isomers and clusters

We consider the influence of the Fermi statistics of nucleons on the binding energy of a new type of nuclear structures such as fractal nuclear clusters (fractal isomers of nuclei). It is shown that the fractal nuclear isomers possess a wide spectrum of binding energies that exceed, in many cases, the values known at the present time. The transition of the nuclear matter in the form of ordinary nuclei (drops of the nuclear fluid) in the state with the fractal structure or in the form of bubble nuclei opens new sources of energy and has huge perspectives. This transition is based on a new state of matter - collective coherently correlated state. It manifests itself, first of all, in the property of nonlocality of nuclear multiparticle processes. We develop a phenomenological theory of the binding energy of nuclear fractal structures and modify the Bethe - Weizsäcker formula for nuclear clusters with the mass number A, charge Z, and fractal dimension D_f. The consideration of fractal nuclear isomers allows one to interpret the experimental results on a new level of the comprehension of processes of the nuclear dynamics. The possibility to determine the fractal dimension of nuclear systems with the help of the method of nuclear dipole resonance for fractal isomers is discussed. The basic relations for fractal electroneutral structures such as the electron-nucleus plasma of fractal isomers are presented.

physics.gen-ph↗
arXiv2013

Control over multiscale systems with constraints. 3. Geometrodynamics of the evolution of systems with varying constraints

With the use of the general variational principle of self-organization of systems with varying constraints, namely the principle of dynamical harmonization of systems presented in the first work of the cycle, we advance an approach to the control over the evolution of systems of many particles. The geometric nature of this principle is analyzed. On the basis of the de Broglie--Bohm representation of the Schrödinger equation, we establish a connection of the nonlocality and the coherence of the systems of many particles with mass entropic forces. The defining role of a coherent acceleration and a space-time curvature in the control over the synthesis of new structures in systems with varying constraints is demonstrated. The basic criteria for electromagnetic fields to initiate the processes of self-organizing synthesis and for the quantum properties of a nonlocality on macroscopic scales, which are necessary for the self-organizing synthesis, are formulated.

physics.gen-ph↗
arXiv2005

Observation of the radiative kaon decay K- --> mu-pi0gammanu

Using data collected with the ISTRA+ spectrometer during the 2001 run of the U-70 proton synchrotron in Protvino, we report the first observation of the radiative kaon decay K- -->mu-pi0gammanu. We find Br(Kmu3g)/Br(Kmu3) for two regions 5<Eg<30 and 30<Eg<60 MeV consistent with theoretical predictions. The measured angular distribution asymmetry for the first region, 0.093+/-0.141, is two standard deviations away from the theoretical prediction of 0.354. The measured asymmetry in the T-odd variable is -0.03+/-0.13.

hep-ex↗
arXiv2004

Photon-Neutrino Interactions

We discuss the interaction of photons with neutrinos including two lepton loops. The parity violation in the gamma-nu to gamma-nu channel due to two lepton loops is substantially enhanced relative to the one lepton loop contribution. However there is no corresponding enhancement in the parity conserving amplitude in either the direct or the cross channel.

hep-ph↗
arXiv2004

Search for light pseudoscalar sgoldstino in K- decays

A search for the light pseudoscalar sgoldstino production in the three body K- decay K-->pipi0P has been performed with the ISTRA+ detector exposed to the 25 GeV negative secondary beam of the U70 proton synchrotron. No signal is seen. An upper limit for the branching ratio Br(K->pipi0P), at 90% confidence level, is found to be around 9*10**-6 in the effective mass m(P) range from 0 till 200 MeV, excluding the region near m(pi0) where it degrades to 3.5*10**-5.

hep-ex↗
arXiv2002

Study of the K- -> mu- nu pi0 decay

The decay $K^{-} \to μ^{-} \barν π^{0}$ has been studied using in-flight decays detected with ``ISTRA+'' setup operating in the 25 GeV negative secondary beam of the U-70 PS. About 112K events were used for the analysis. The $λ_{+}$ and $λ_{0}$ slope parameters of the decay formfactors $f_{+}(t)$, $f_{0}(t)$ have been measured : $λ_{+}= 0.0321 \pm 0.004$(stat) $\pm 0.002$(syst) $λ_{0}= 0.0209 \pm 0.004$(stat) $\pm 0.002$(syst); the correlation $d λ_{0}/d λ_{+}=-0.46$ The limits on the possible tensor and scalar couplings have been derived: $f_{T}/f_{+}(0)=-0.021 \pm 0.028$(stat) $\pm 0.014$(theory); $f_{S}/f_{+}(0)=0.004 \pm 0.005$(stat) $\pm 0.005$(theory)

hep-ph↗
arXiv2001

Study of the K- -> pi0 e- nu decay

The decay K- -> pi0 e- nu has been studied using in-flight decays detected with "ISTRA+" setup operating at the 25 GeV negative secondary beam of the U-70 PS. About 130K events were used for the analysis. The lambda_+ parameter of the vector formfactor has been measured: lambda_+ = 0.0293 +- 0.0015(stat) +- 0.002(syst). The limits on the possible tensor and scalar couplings have been derived: f_T/f_+(0)=-0.044 +0.059 -0.057 (stat) f_S/f_+(0)=-0.020 +0.025 -0.016 (stat)

hep-ex↗
arXiv2001

Final results from the Palo Verde Neutrino Oscillation Experiment

The analysis and results are presented from the complete data set recorded at Palo Verde between September 1998 and July 2000. In the experiment, the $\nuebar$ interaction rate has been measured at a distance of 750 and 890 m from the reactors of the Palo Verde Nuclear Generating Station for a total of 350 days, including 108 days with one of the three reactors off for refueling. Backgrounds were determined by (a) the $swap$ technique based on the difference between signal and background under reversal of the positron and neutron parts of the correlated event and (b) making use of the conventional reactor-on and reactor-off cycles. There is no evidence for neutrino oscillation and the mode $\nuebar\to\barν_x$ was excluded at 90% CL for $\dm>1.1\times10^{-3}$ eV$^2$ at full mixing, and $\sinq>0.17$ at large $\dm$.

hep-ex↗
arXiv2001

Precision measurements, extra quark-lepton generations and 50 GeV neutrinos

The existence of extra chiral generations with all fermions heavier than $m_Z$ is strongly disfavored by the precision electroweak data. However the data still allow a few extra generations if the neutral leptons have masses close to 50 GeV. Such heavy neutrino can be searched in the reaction $e^+ e^- \to N\bar{N}γ$. Existence of 50 GeV neutrinos makes standard model Higgs boson invisible.

hep-ph↗
arXiv2000

Neutron production by cosmic-ray muons at shallow depth

The yield of neutrons produced by cosmic ray muons at a shallow depth of 32 meters of water equivalent has been measured. The Palo Verde neutrino detector, containing 11.3 tons of Gd loaded liquid scintillator and 3.5 tons of acrylic served as a target. The rate of one and two neutron captures was determined. Modeling the neutron capture efficiency allowed us to deduce the total yield of neutrons $ Y_{tot} = (3.60 \pm 0.09 \pm 0.31) \times 10^{-5}$ neutrons per muon and g/cm$^2$. This yield is consistent with previous measurements at similar depths.

hep-ex↗
arXiv2000

Results from the Palo Verde Neutrino Oscillation Experiment

The $\nuebar$ flux and spectrum have been measured at a distance of about 800 m from the reactors of the Palo Verde Nuclear Generating Station using a segmented Gd-loaded liquid scintillator detector. Correlated positron-neutron events from the reaction $\nuebar$p$\to$e^+n were recorded for a period of 200 d including 55 d with one of the three reactors off for refueling. Backgrounds were accounted for by making use of the reactor-on and reactor-off cycles, and also with a novel technique based on the difference between signal and background under reversal of the e^+ and n portions of the events. A detailed description of the detector calibration, background subtraction, and data analysis is presented here. Results from the experiment show no evidence for neutrino oscillations. $\nuebar\to\barν_x$ oscillations were excluded at 90% CL for $\dm>1.12\times10^{-3}$ eV^2 for full mixing, and $\sinq>0.21$ for large $\dm$. These results support the conclusion that the observed atmospheric neutrino oscillations does not involve $ν_{\rm e}$.

hep-ex↗
arXiv1999

Search for Neutrino Oscillations at the Palo Verde Nuclear Reactors

We report on the initial results from a measurement of the anti-neutrino flux and spectrum at a distance of about 800 m from the three reactors of the Palo Verde Nuclear Generating Station using a segmented gadolinium-loaded scintillation detector. We find that the anti-neutrino flux agrees with that predicted in the absence of oscillations to better than 5%, excluding at 90% CL $\rm\barν_e - \barν_x$ oscillations with $Δm^2 > 1.12\times 10^{-3}$ eV^2 for maximal mixing and $\sin^2{2θ} > 0.21$ for large $Δm^2$.

hep-ex↗
arXiv1998

Sudden To Adiabatic Transition in Beta Decay

We discuss effects in beta decays at very low beta energies, of the order of the kinetic energies of atomic electrons. As the beta energy is lowered the atomic response changes from sudden to adiabatic. As a consequence, the beta decay rate increases slightly and the ejection of atomic electrons (shake off) and subsequent production of X rays is turned off. We estimate the transition energy and the change in decay rate. The rate increase is largest in heavy atoms, which have a small Q value in their decay. The X ray switch-off is independent of Q value.

nucl-th↗