arXiv subjects

Andrey Popov

Publications and source records attributed to Andrey Popov.

4 recordsLinked to original sources

arXiv2020

Non-collinear rotational Doppler effect

The frequency shift of a helical light beam experiencing the rotation near the axis deferring from its own axis (conical evolution) is studied theoretically. Both the energy and the kinematic approaches lead to a paradoxical conclusion that after a whole cycle of the system rotation the beam does not return to its initial state. Another paradox is manifested in the peculiar behavior of the beam transverse pattern rotation at different geometric parameters of the evolving system. A fundamental role of the detecting system motion is substantiated. The special "natural" observer's motion is found for which both paradoxes are eliminated. Relations of the described facts with the Hannay's geometric phase concept are discussed.

physics.optics↗

arXiv2019

Interference Effects in $t{\bar t}$ Production at the LHC as a Window on New Physics

Many extensions of the Standard Model contain (pseudo)scalar bosons with masses in the TeV range. At hadron colliders, such particles would predominantly be produced in gluon fusion and would decay into top quark pair final sates, a signal that interferes with the large QCD background $gg \to t\bar t$. This phenomenon is of interest for searches for by the LHC experiments. Here, we consider the signal and background interference in this process and study it in various benchmark scenarios, including models with extra singlet (pseudo)scalar resonances, two-Higgs doublet models, and the minimal supersymmetric extension of the SM with parameters chosen to obtain the measured light Higgs mass (the hMSSM). We allow for the possible exchanges of beyond the SM vector-like particles as well as scalar quarks. We calculate the possible interference effects including realistic estimates of the attainable detection efficiency and mass resolution. Studies of our benchmark scenarios indicate that searches with an LHC detector could permit the observation of the $t\bar t$ final states or constrain significantly large regions of the parameter spaces of the benchmark scenarios.

hep-ph↗

arXiv2014

Identification of signal events in a search for $H\to b\bar b$ produced in association with single top quarks

The CMS collaboration has performed a search for an associated production of Higgs bosons and single top quarks in the $H\to b\bar b$ decay channel. The measurement is challenged by a complex multijet final state and an overwhelming background from top-quark pair production. These proceedings address a particular aspect of the search and describe the procedure deployed to discriminate the signal process from backgrounds.

hep-ex↗

arXiv2014

Measurements of single top-quark production in pp collisions by the CMS experiment

A summary of studies of electroweak top-quark production performed by the CMS collaboration is presented. The results include measurements of production cross sections, extraction of the value of $|V_{tb}|$, determination of W-boson helicity in top-quark decays and top-quark spin asymmetry, and a search for anomalous couplings in the Wtb vertex. No deviations from predictions of the standard model are found.

hep-ex↗