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Vadim A. Naumov

Publications and source records attributed to Vadim A. Naumov.

At least 19 recordsLinked to original sources
arXiv2025

Neutrino Propagation in Quantum Field Theory at Short and Long Baselines

In a quantum field approach to neutrino oscillations, the neutrino is treated as a propagator, while the external initial and final particle states are described by covariant wave packets. For the asymptotic behavior on short and long macroscopic baselines, the wave packet modified neutrino propagator is expressed through asymptotic series in powers of dimensionless Lorentz and rotation invariant variables. In both regimes, leading-order corrections violate the classical inverse-square law and lead to a decrease in the neutrino-induced event rate. The possibility that the so-called reactor antineutrino anomaly can, at least partially, be explained within this approach is discussed.

hep-ph↗
arXiv2024

First combined tuning on transverse kinematic imbalance data with and without pion production constraints

We present the first combined tuning, using GENIE, of four transverse kinematic imbalance measurements of neutrino-hydrocarbon scattering, both with and without pion final states, from the T2K and MINERvA experiments. As a proof of concept, we have simultaneously tuned the initial state and final-state interaction models (SF-CFG and hA, respectively), producing a new effective model that more accurately describes the data.

hep-ex↗
arXiv2022

Neutrino-nucleus CC0$π$ cross-section tuning in GENIE v3

This article summarizes the state of the art of $ν_μ$ and $\barν_μ$ CC0$π$ cross-section measurements on carbon and argon and discusses the relevant nuclear models, parametrizations and uncertainties in GENIE v3. The CC0$π$ event topology is common in experiments at a few-GeV energy range. Although its main contribution comes from quasi-elastic interactions, this topology is still not well understood. The GENIE global analysis framework is exploited to analyze CC0$π$ datasets from MiniBooNE, T2K and MINERvA. A partial tune for each experiment is performed, providing a common base for the discussion of tensions between datasets. The results offer an improved description of nuclear CC0$π$ datasets as well as data-driven uncertainties for each experiment. This work is a step towards a GENIE global tune that improves our understanding of neutrino interactions on nuclei. It follows from earlier GENIE work on the analysis of neutrino scattering datasets on hydrogen and deuterium.

hep-ph↗
arXiv2022

Virtual neutrino propagation at short baselines

Within a covariant perturbative field-theoretical approach, the wave-packet modified neutrino propagator is expressed as an asymptotic expansion in powers of dimensionless Lorentz- and rotation-invariant variables. The expansion is valid at high energies and short but macroscopic space-time distances between the vertices of the proper Feynman macrodiagram. In terms of duality between the propagator and the effective neutrino wave packet, at short times and distances, neutrinos are deeply virtual and move quasiclassically. In the lowest-order approximation, this leads to the classical inverse-square dependence of the modulus squared flavor transition amplitude and related neutrino-induced event rate from distance $L$ between the source and detector, and the above-mentioned asymptotics results in the corrections to the classical behavior represented by powers of $L^2$. This is very different from the long-baseline regime, where similar corrections are given by an asymptotic expansion in inverse powers of $L^2$. However, in both short- and long-baseline regimes, the main corrections lead to a decrease in number of neutrino events.

hep-ph↗
arXiv2021

Running axial mass of the nucleon as a phenomenological tool for calculating QE neutrino-nucleus cross sections

We suggest an empirical rule-of-thumb for calculating the cross sections of charged-current quasielastic (CCQE) and CCQE-like interactions of neutrinos and antineutrinos with nuclei. The approach is based on the standard relativistic Fermi-gas model and on the notion of neutrino energy dependent axial-vector mass of the nucleon, governed by a couple of adjustable parameters, one of which is the conventional charged-current axial-vector mass. The inelastic background contributions and final-state interactions are therewith simulated using GENIE 3 neutrino event generator. An extensive comparison of our calculations with earlier and current accelerator CCQE and CCQE-like data for different nuclear targets shows good or at least qualitative overall agreement over a wide energy range. We also discuss some problematical issues common to several competing contemporary models of the CCQE (anti)neutrino-nucleus scattering and to the current neutrino interaction generators.

hep-ph↗
arXiv2021

Hadronization Model Tuning in GENIE v3

The GENIE neutrino Monte Carlo describes neutrino-induced hadronization with an effective model, known as AGKY, which is interfaced with PYTHIA at high invariant mass. Only the low-mass AGKY model parameters were extracted from hadronic shower data from the FNAL 15 ft and BEBC experiments. In this paper, the first hadronization tune on averaged charged multiplicity data from deuterium and hydrogen bubble chamber experiments is presented, with a complete estimation of parameter uncertainties. A partial tune on deuterium data only highlights the tensions between hydrogen and deuterium datasets.

hep-ph↗
arXiv2021

Recent highlights from GENIE v3

The release of GENIE v3.0.0 was a major milestone in the long history of the GENIE project, delivering several alternative comprehensive neutrino interaction models, improved charged-lepton scattering simulations, a range of beyond the Standard Model simulation capabilities, improved experimental interfaces, expanded core framework capabilities, and advanced new frameworks for the global analysis of neutrino scattering data and tuning of neutrino interaction models. Steady progress continued following the release of GENIE v3.0.0. New tools and a large number of new physics models, comprehensive model configurations, and tunes have been made publicly available and planned for release in v3.2.0. This article highlights some of the most recent technical and physics developments in the GENIE v3 series.

hep-ph↗
arXiv2021

Neutrino-Nucleon Cross-Section Model Tuning in GENIE v3

We summarise the results of a study performed within the GENIE global analysis framework, revisiting the GENIE bare-nucleon cross-section tuning and, in particular, the tuning of a) the inclusive cross-section, b) the cross-section of low-multiplicity inelastic channels (single-pion and double-pion production), and c) the relative contributions of resonance and non-resonance processes to these final states. The same analysis was performed with several different comprehensive cross-section model sets available in GENIE Generator v3. In this work we performed a careful investigation of the observed tensions between exclusive and inclusive data, and installed analysis improvements to handle systematics in historic data. All tuned model configurations discussed in this paper are available through public releases of the GENIE Generator. With this paper we aim to support the consumers of these physics tunes by providing comprehensive summaries of our alternate model constructions, of the relevant datasets and their systematics, and of our tuning procedure and results.

hep-ph↗
arXiv2013

Extended Grimus-Stockinger theorem and inverse square law violation in quantum field theory

We study higher-order corrections to the Grimus-Stockinger theorem dealing with the large-distance asymptotic behavior of the wave-packet modified neutrino propagator within the framework of field-theoretical description of the neutrino oscillation phenomenon. We discuss the possibility that these corrections are responsible for breakdown of the classical inverse-square law (ISL) at the macroscopic distances. In particular the ISL violation can be an explanation of the well-known reactor antineutrino anomaly.

hep-ph↗
arXiv2011

Neutrino Velocity Anomalies: A Resolution without a Revolution

We argue that the neutrino advance of time observed in MINOS and OPERA experiments can be explained in the framework of the standard relativistic quantum theory as a manifestation of the large effective transverse size of the eigenmass neutrino wavepackets.

hep-ph↗
arXiv2010

A diagrammatic treatment of neutrino oscillations

We present a covariant wave-packet approach to neutrino flavor transitions in vacuum. The approach is based on the technique of macroscopic Feynman diagrams describing the lepton number violating processes of production and absorption of virtual massive neutrinos at the macroscopically separated space-time regions ("source" and "detector"). Accordingly, the flavor transitions are a result of interference of the diagrams with neutrinos of different masses in the intermediate states. The statistically averaged probability of the process is representable as a multidimensional integral of the product of the factors which describe the differential flux density of massless neutrinos from the source, differential cross section of the neutrino interaction with the detector and a dimensionless factor responsible for the flavor transition. The conditions are analyzed under which the last factor can be treated as the flavor transition probability in the usual quantum-mechanical sense.

hep-ph↗
arXiv2008

Quasielastic axial-vector mass from experiments on neutrino-nucleus scattering

We analyze available experimental data on the total and differential charged-current cross sections for quasielastic neutrino and antineutrino scattering off nucleons, measured with a variety of nuclear targets in the accelerator experiments at ANL, BNL, FNAL, CERN, and IHEP, dating from the end of sixties to the present day. The data are used to adjust the poorly known value of the axial-vector mass of the nucleon.

hep-ph↗
arXiv2006

Time-to-Space Conversion in Neutrino Oscillations

We study the neutrino oscillation problem in the framework of the wave packet formalism. The neutrino state is described by a packet located initially in a region S (source) and detected in another region D at a distance R from S. We examine how the oscillation probability as a function of variable R can be derived from he oscillation probability as a function of time t, the latter being found by using the Schrodinger equation. We justify the known prescription "t --> R/c" without referring to a specific form of the neutrino wave packet and only assuming the finiteness of its support. The effect of the oscillation damping at large R is revealed. For an illustration, an explicit expression for the damping factor is obtained using Gaussian packet.

hep-ph↗
arXiv2006

Axial masses in quasielastic neutrino scattering and single-pion neutrinoproduction on nucleons and nuclei

We analyse available experimental data on the total charged-current neutrino-nucleon and antineutrino-nucleon cross sections for quasielastic scattering and single-pion neutrinoproduction. Published results from the relevant experiments at ANL, BNL, FNAL, CERN, and IHEP are included dating from the end of sixties to the present day, covering muon neutrino and antineutrino beams on a variety of nuclear targets, with energies from the thresholds to about 350 GeV. The data are used to adjust the poorly known values of the axial masses.

hep-ph↗
arXiv2005

How to Sum Contributions into the Total Charged-Current Neutrino-Nucleon Cross Section

The total charged-current (anti)neutrino-nucleon cross section is usually estimated by the sum of contributions from quasi-elastic scattering (QES), single-pion production through baryon resonances (RES), and deep inelastic scattering (DIS) with an appropriate scratching the phase space of the RES and DIS contributions. However the resulting total cross section is very sensitive to the value of the cut-off in invariant mass of the final hadron system produced in RES and DIS. We examine available experimental data on the QES and total CC cross sections in order to extract the best-fit value for this cut-off. By using the same data set we attempt to adjust the poorly known values of the axial mass for QES and RES.

hep-ph↗
arXiv2004

Lepton Polarization in Neutrino-Nucleon Interactions

We derive generic formulas for the polarization density matrix of leptons produced in neutrino and antineutrino collisions and briefly consider some important particular cases. Next we employ the general formalism in order to include the final lepton mass and spin into the popular model by Rein and Sehgal for single pion neutrinoproduction.

hep-ph↗
arXiv2004

Polarization of Tau Leptons Produced in Quasielastic Neutrino--Nucleon Scattering

A numerical analysis of the polarization vector of tau leptons produced through quasielastic neutrino and antineutrino interactions with free nucleons is given with two models for vector electromagnetic form factors of proton and neutron. The impact of G parity violating axial and vector second-class currents is investigated by applying a simple heuristic model for the induced scalar and tensor form factors.

hep-ph↗