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E. V. Zhemchugov

Publications and source records attributed to E. V. Zhemchugov.

17 recordsLinked to original sources
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
arXiv2016

New Physics at 1 TeV?

If decays of a heavy particle S are responsible for the diphoton excess with invariant mass 750 GeV observed at the 13 TeV LHC run, it can be easily accomodated in the Standard Model. Two scenarios are considered: production in gluon fusion through a loop of heavy isosinglet quark(s) and production in photon fusion through a loop of heavy isosinglet leptons. In the second case many heavy leptons are needed or/and they should have large electric charges in order to reproduce experimental data on $σ(pp \to SX) \cdot \mathrm{Br}(S \to γγ)$.

hep-ph↗
arXiv2015

Double Higgs boson production in the Standard Model with extra scalar particles

Three extensions of the scalar sector of the Standard Model are considered: one extra isosinglet, one extra isotriplet, two extra isotriplets (the Georgi-Machacek model). Double Higgs boson production cross section is calculated in all these extensions. Bounds from electroweak precision observables, signal strength measurements and custodial symmetry violation are estimated.

hep-ph↗
arXiv2015

Suppression of $H\to VV$ decay channels in the Georgi-Machacek model

The $H\to ZZ$ decay mode is usually considered as one of the most promising ways to discover new heavy neutral scalar $H$. We show that in the Georgi-Machacek model it is possible to get large enhancement of double SM-like Higgs boson production due to $H$ decays while $ZZ$ and $WW$ decay channels could be highly suppressed.

hep-ph↗
arXiv2015

Extending the Higgs sector: an extra singlet

An extension of the Standard Model with an additional Higgs singlet is analyzed. Bounds on singlet admixture in 125 GeV h boson from electroweak radiative corrections and data on h production and decays are obtained. Possibility of double h production enhancement at 14 TeV LHC due to heavy higgs contribution is considered.

hep-ph↗
arXiv2014

Double Higgs production at LHC, see-saw type II and Georgi-Machacek model

The double Higgs production in the models with isospin-triplet scalars is studied. It is shown that in the see-saw type II model the mode with an intermediate heavy scalar, $pp\to H+X\to 2h+X$, may have the cross section which is compatible with that in the Standard Model. In the Georgi-Machacek model this cross section could be much larger than in SM since the vacuum expectation value of the triplet can be large.

hep-ph↗
arXiv2014

On $Z \to γγ$ decay and cancellation of axial anomaly in $Z \to γγ$ transition amplitude for massive fermions

$Z \to γγ$ decay amplitude is considered and proven to be zero due to properties of polarization vectors and Bose statistics. Triangular diagrams for a pseudoscalar $\to γγ$ and $Z \to γγ$ processes with massive fermions in the loop are explicitely calculated. In the Standard Model axial anomaly vanishes in the sum of these diagrams as Z boson is mixed with one of the Goldstone bosons.

hep-ph↗