2,612 research outputs found

    Study of corrections for anomalous coupling limits due to the possible background BSM contributions

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    The search of the anomalous couplings is one of the possible ways to find any deviation from the Standard Model. The effective field theory is used to parameterize the anomalous couplings in the Lagrangian with the operators of higher dimensions, constructed from the SM fields. In the classical way, the limits on the Wilson coefficients of these operators are set based on beyond the Standard Model contributions induced for signal process, whereas the ones induced for background processes are assumed to be negligible. This article provides a study of the corrections to the limits on Wilson coefficients by accounting beyond the Standard Model contributions induced for background processes. The studies of Z(ννˉ)γjjZ(\nu\bar{\nu})\gamma jj and W(ν)γjjW(\ell\nu)\gamma jj productions in pppp collisions with s=13\sqrt{s}=13 TeV and conditions of the ATLAS experiment at the LHC are used as example. Cases of collected during Run II and expected from Run III integrated luminosities of 139 fb1^{-1} and 300 fb1^{-1} are considered. The expected 95% CL limits on coefficients fT0/Λ4f_\text{T0}/\Lambda^4, fT5/Λ4f_\text{T5}/\Lambda^4, fM0/Λ4f_\text{M0}/\Lambda^4 and fM2/Λ4f_\text{M2}/\Lambda^4 are obtained both in classical way and in the way, where the corrections from background anomalous contributions are applied. Corrected one-dimensional limits from Z(ννˉ)γjjZ(\nu\bar{\nu})\gamma jj and W(ν)γjjW(\ell\nu)\gamma jj productions are up to 9.1% and 4.4% (depending on operator) tighter than the classical ones respectively. Corrected combined limits are up to 3.0% (depending on operator) tighter than the classical ones. Corrections to two-dimensional limits are also obtained, corrected contours are more stringent, than the classical ones, and the maximal improvement is of 17.2%

    Application of deep learning methods to the study of magnetic phenomena

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    Nowadays, methods and techniques of Machine Learning and Deep Learning are being used in various scientific areas. They help to automatize calculations without losing in quality. In this paper the applying of convolutional neural network was considered in frame of problems from statistical physics and computer simulation of magnetic films. In a frame of the first task, CNN was used to determine critical Curie point for Ising model on 2D square lattice. Obtained results were compared with classical Monte-Carlo methods and exact solution. Systems of various lattice sizes and the influence of the size effect on the results' accuracy were considered. Also, authors considered the classical two-dimensional Heisenberg model, a spin system with direct short-range exchange, and studied of its competition with the Dzyaloshinskii-Moriya interaction. A neural network was applied to the recognition of Spiral (Sp), Spiral-skyrmion (SpSk) Skyrmion (Sk), Skyrmion-ferromagnetic (SkF) and Ferromagnetic (FM) phases of the Heisenberg spin system with magnetic skyrmions. The advantage of CNN's application over conventional methods for determination of skyrmion's phases was revealed.Comment: 6 pages, 3 figure

    Stimulation of reparation in a linear wound model in rats by Bischofit gel

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    The article is to evaluate Bischofit gel reparative activity in a linear wound model in rat

    Search for f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay with VES detector

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    The isospin violating decay f1(1285)π+ππ0f_1(1285)\to\pi^+\pi^-\pi^0 has been studied at VES facility. This study is based at the statistics acquired in πBe\pi^- Be interactions at 27, 36.6 and 41 GeV/c in diffractive reaction πN(f1π)N\pi^- N \to (f_1 \pi^-) N. The f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay is observed. The ratio of decay probabilities BR(f1(1285)π+ππ0)BR(f_1(1285) \to \pi^+\pi^-\pi^0) to BR(f1(1285)ηπ+π)BR(ηγγ)BR(f_1(1285) \to \eta \pi^+\pi^-) \cdot BR(\eta \to \gamma\gamma) is 1.4\sim\:1.4%.Comment: 10 pages, 8 figures, presented at XII Conference on Hadron Spectroscop

    Puzzles of Dark Matter - More Light on Dark Atoms?

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    Positive results of dark matter searches in experiments DAMA/NaI and DAMA/LIBRA confronted with results of other groups can imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a specific nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground Dark matter detection using its nuclear recoil. However, low energy binding of OHe with sodium nuclei can lead to annual variations of energy release from OHe radiative capture in the interval of energy 2-4 keV in DAMA/NaI and DAMA/LIBRA experiments. At nuclear parameters, reproducing DAMA results, the energy release predicted for detectors with chemical content other than NaI differ in the most cases from the one in DAMA detector. Moreover there is no bound systems of OHe with light and heavy nuclei, so that there is no radiative capture of OHe in detectors with xenon or helium content. Due to dipole Coulomb barrier, transitions to more energetic levels of Na+OHe system with much higher energy release are suppressed in the correspondence with the results of DAMA experiments. The proposed explanation inevitably leads to prediction of abundance of anomalous Na, corresponding to the signal, observed by DAMA.Comment: Contribution to Proceedings of XIII Bled Workshop "What Comes beyond the Standard Model?
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