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M. A. Martemianov

Publications and source records attributed to M. A. Martemianov.

11 recordsLinked to original sources
arXiv2026

Nuclear Fragmentation at Intermediate Energies in the DCM-QGSM-SMM Model

The development of nucleus-nucleus interaction models is a rapidly developing area of heavy-ion physics. Recently, a new model DCM-QGSM-SMM, developed at JINR and oriented toward use within the NICA project at energies of several GeV/nucleon, became available. However, the mechanisms of nuclear interactions used in this model can potentially operate effectively at lower energies. In this paper, the model predictions are compared with the FRAGM and FIRST/GSI experimental data in the energy range of nucleus-nucleus interactions starting from 300 MeV/nucleon, as well as with the predictions of other models used in this energy range.

nucl-th↗
arXiv2025

Study of Nucleon Charge-Exchange Processes at $^{12}$C Fragmentation with an Energy of 300 MeV/Nucleon

The search of reactions with nucleon charge-exchange was performed on the FRAGM fragment-separator of the TWAC accelerator complex at fragmentation of carbon nuclei with an energy of 300 MeV/nucleon on a thin beryllium target. The experimental setup, located at an angle of 3.5 degrees to the incident beam, had high momentum resolution. Differential cross sections were measured for $^{11}$Be, $^{12}$B and $^{12}$Be as function of the nuclei momentum. The experimental data were compared with theoretical predictions of various models of nucleus-nucleus interactions and other experimental results. Measurements of nucleon charge exchange processes in this energy region was carried out for the first time. New results were obtained to test theoretical models of nucleus-nucleus interactions.

nucl-ex↗
arXiv2021

Single $π^0$ Production Off Neutrons Bound in Deuteron with Linearly Polarized Photons

The quasifree $\overrightarrowγ d\toπ^0n(p)$ photon beam asymmetry, $Σ$, has been measured at photon energies, $E_γ$, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 to 148$^\circ$. In this kinematic region, polarization observables are sensitive to contributions from the $Δ(1232)$ and $N(1440)$ resonances. The extracted values of $Σ$ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID, and Bonn-Gatchina analyses; while a revised SAID fit, including the new $Σ$ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict $π^0n$ photoproduction observables, based on fits to published data in the channels $π^0p$, $π^+n$, and $π^-p$.

nucl-ex↗
arXiv2019

Cross Section for $γn \to π^0 n$ measured at Mainz/A2

The $γn \to π^0 n$ differential cross section evaluated for 27 energy bins span the photon-energy range 290-813 MeV (W = 1.195-1.553 GeV) and the pion c.m. polar production angles, ranging from 18 deg to 162 deg, making use of model-dependent nuclear corrections to extract pi0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883-MeV electron beam of the Mainz Microtron MAMI was used for the 0-meson production. Our accumulation of 3.6 x 10^6 $γn \to π^0 n$ events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared to predictions of previous SAID, MAID, and BnGa partial-wave analyses and to the latest SAID fit MA19 that included our data. Selected photon decay amplitudes $N^* \to γn$ at the resonance poles are determined for the first time.

nucl-ex↗
arXiv2015

Light fragments from (C + Be) interactions at 0.6 GeV/nucleon

Nuclear fragments emitted at 3.5 degrees in 12C fragmentation at 0.6 GeV/nucleon have been measured. The spectra obtained are used for testing the predictions of four ion-ion interaction models: INCL++, BC, LAQGSM03.03 and QMD as well as for the comparison with the analytical parametrization in the framework of thermodynamical picture of fragmentation.

nucl-ex↗
arXiv2015

Verification of Monte Carlo transport codes against measured small angle p-, d-, and t-emission in carbon fragmentation at 600 MeV/nucleon

Momentum spectra of hydrogen isotopes have been measured at 3.5 deg from C12 fragmentation on a Be target. Momentum spectra cover both the region of fragmentation maximum and the cumulative region. Differential cross sections span five orders of magnitude. The data are compared to predictions of four Monte Carlo codes: QMD, LAQGSM, BC, and INCL++. There are large differences between the data and predictions of some models in the high momentum region. The INCL++ code gives the best and almost perfect description of the data.

nucl-ex↗
arXiv2010

Proposal for taking data with the KLOE-2 detector at the DA$Φ$NE collider upgraded in energy

This document reviews the physics program of the KLOE-2 detector at DA$Φ$NE upgraded in energy and provides a simple solution to run the collider above the $ϕ$-peak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard Model through a precise determination of the anomalous magnetic moment of the muon and the effective fine-structure constant at the $M_Z$ scale. With a luminosity of about $10^{32}$cm$^{-2}$s$^{-1}$, DA$Φ$NE upgraded in energy can perform a scan in the region from 1 to 2.5 GeV in one year by collecting an integrated luminosity of 20 pb$^{-1}$ (corresponding to a few days of data taking) for single point, assuming an energy step of 25 MeV. A few years of data taking in this region would provide important tests of QCD and effective theories by $γγ$ physics with open thresholds for pseudo-scalar (like the $η'$), scalar ($f_0,f'_0$, etc...) and axial-vector ($a_1$, etc...) mesons; vector-mesons spectroscopy and baryon form factors; tests of CVC and searches for exotics. In the final part of the document a technical solution for the energy upgrade of DA$Φ$NE is proposed.

hep-ex↗
arXiv2010

Physics with the KLOE-2 experiment at the upgraded DA$ϕ$NE

Investigation at a $ϕ$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the $e^+ e^-$ physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.

hep-ex↗
arXiv2000

Quasi-coherent interaction of protons with Si28 at Tp=1GeV

The total, elastic and inelastic cross-sections for quasi-coherent interactions of protons with Si28 have been measured using hadron-gamma coincidence method at the energy 1 GeV. The limits for the existence of long-lived excited states of the Si28 nucleus have been obtained in the range of energies from 0 to 0.8 GeV.

hep-ex↗
arXiv1998

The $ΛK$ system production in the hadron interactions

The A-dependence is observed in $x_F$-distributions for the $ΛK^0$ system produced with the small transverse momentum in the neutron-nucleus interactions. For the $Λ$ hyperons similar dependence isn't seen. The result is interpreted as an effect from intermediate excitative nucleon state, which decays into strange particles. Such interpretation is confirmed experimental data on $ΛK$ pair production in the pion-nucleon interactions.

hep-ex↗