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M. I. Vysotsky

Publications and source records attributed to M. I. Vysotsky.

At least 19 recordsLinked to original sources
arXiv2025

Does the existence of $f_0$ meson enlarge the $K^+ \to π^0π^0π^0 e^+ ν$ decay probability?

We estimate a possible contribution of the two-pion system $f_0(500)$ wide resonance to the decay probability of the super rare decay $K^+ \to 3π^0 e^+ ν$. We vary the width of the resonance from 0.01 MeV to 1000 MeV. We found that the contribution of the narrow resonance in a system of several final state particles into the decay probability is proportional to its width. However it never exceeds the value of the decay probability calculated on free final state particles neglecting the resonance contribution.

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arXiv2025

On the $K^+ \to π^0π^0π^0 e^+ ν$ decay

The OKA Collaboration has obtained a new upper limit on the $K^+ \to π^0π^0π^0 e^+ ν$ decay probability which is 65 times lower than the one currently listed by PDG. However it is still about $10^{4}$ times worse than the theoretical prediction. It was suggested that production of pionium $A_{2π}$ in the final state of the semileptonic $K^+$ decay with subsequent $A_{2π} \to π^0 π^0$ decay will increase the value of theoretical branching ratio due to the absence of five-particle phase space suppression. The estimates done in our paper show that despite the gain in the phase space the decay $K^+ \to A_{2π}π^0 e^+ ν$ appeares to be strongly suppressed because of the smallness of the pionium wave function at zero $π$ mesons separation.

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arXiv2024

libepa -- a C++/Python library for calculations of cross sections of ultraperipheral collisions

The library provides a set of C++/Python functions for computing cross sections of ultraperipheral collisions of high energy particles under the equivalent photons approximation. Cross sections are represented through multiple integrals over the phase space. The integrals are calculated through recurrent application of algorithms for one dimensional integration. The paper contains an introduction to the theory of ultraperipheral collisions, discusses the library approach and provides a few examples of calculations.

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arXiv2021

Production of heavy charged particles in proton-proton ultraperipheral collisions at the Large Hadron Collider: survival factor

Ultraperipheral collisions of high energy protons are a source of approximately real photons colliding with each other. Photon fusion can result in production of yet unknown charged particles in very clean events. The cleanliness of such an event is due to the requirement that the protons survive during the collision. Finite sizes of the protons reduce the probability of such outcome compared to point-like particles. We calculate the survival factors and cross sections for the production of heavy charged particles at the Large Hadron Collider.

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arXiv2021

LHC as a photon-photon collider: bounds on $Γ_{X\toγγ}$

In the relatively recent CMS data, there is a hint on the existence of a resonance with the mass 28 GeV coupling to muons. Such a resonance should also couple to photons through the fermion loop, therefore it can be searched for in ultraperipheral collisions (UPC) of protons. We set an upper bound on the $X γγ$ coupling constant from the data on $μ^+ μ^-$ pair production in UPC at the LHC. Our approach can be used for similar resonances should they appear in the future.

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arXiv2020

Quasistable charginos in ultraperipheral proton-proton collisions at the LHC

We propose a model-independent approach for the search of charged long-lived particles produced in ultraperipheral collisions at the LHC. The main idea is to improve event reconstruction at ATLAS and CMS with the help of their forward detectors. Detection of both scattered protons in forward detectors allows complete recovery of event kinematics. Though this requirement reduces the number of events, it greatly suppresses the background, including the large background from the pile-up.

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arXiv2019

Flavor physics and CP violation

Lectures at the 53rd Winter School of Petersburg Nuclear Physics Institute and European School on High Energy Physics ESHEP2019, Saint-Petersburg, Russia.

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arXiv2018

LHC as a photon-photon collider

Equivalent photon approximation is used to calculate fiducial cross sections for dimuon production in ultraperipheral proton-proton and lead-lead collisions. Analytical formulae taking into account experimental cuts are derived. The results are compared with the measurements reported by the ATLAS collaboration.

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arXiv2018

Dimuon resonance near 28 GeV and muon anomaly

We discuss if the resonance recently observed by CMS can be responsible for the deviation of the experimentally measured muon anomalous magnetic moment from the theoretical prediction.

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arXiv2018

Resonances in positron scattering on a supercritical nucleus and spontaneous production of $e^{+}e^{-}$ pairs

We re-examine the physics of supercritical nuclei, specially focusing on the scattering phase $δ_{\varkappa}$ and its dependence on the energy $\varepsilon$ of the diving electronic level, for which we give both exact and approximate formulas. The Coulomb potential $Zα/r$ is rounded to the constant $Zα/R$ for $r < R$. We confirm the resonant behavior of $δ_{\varkappa}$ that we investigate in details. In addition to solving the Dirac equation for an electron, we solve it for a positron, in the field of the same nucleus. This clarifies the interpretation of the resonances. Our results are compared with claims made in previous works.

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arXiv2016

Looking for chiral anomaly in $K γ\to K π$ reactions

In an experiment currently being performed at the Institute for High Energy Physics, Serpukhov, Russia, a beam of charged kaons is directed on a copper target. In the electromagnetic field of the target nuclei, two reactions occur: $K^+ γ\to K^+ π^0$ and $K^+ γ\to K^0 π^+$. A peculiar distinction between these two reactions is that there is a chiral anomaly contribution in the former reaction, but not in the latter. This contribution can be directly seen through comparison of the cross sections of these reactions near the threshold. We derive expressions for these cross sections taking into account the anomaly and the contribution of the lightest vector mesons.

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