Publications by authors named "K Arzymatov"

43 Publications

Angular Analysis of the B^{+}→K^{*+}μ^{+}μ^{-} Decay.

Phys Rev Lett 2021 Apr;126(16):161802

Laboratoire Leprince-ringuet (llr), Palaiseau, France.

We present an angular analysis of the B^{+}→K^{*+}(→K_{S}^{0}π^{+})μ^{+}μ^{-} decay using 9  fb^{-1} of pp collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from standard model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner B^{0}→K^{*0}μ^{+}μ^{-} decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.
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http://dx.doi.org/10.1103/PhysRevLett.126.161802DOI Listing
April 2021

Observation of a New Excited D_{s}^{+} Meson in B^{0}→D^{-}D^{+}K^{+}π^{-} Decays.

Phys Rev Lett 2021 Mar;126(12):122002

Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France.

Using pp collision data corresponding to an integrated luminosity of 5.4  fb^{-1} collected with the LHCb detector at a center-of-mass energy of 13 TeV, the B^{0}→D^{-}D^{+}K^{+}π^{-} decay is studied. A new excited D_{s}^{+} meson is observed decaying into the D^{+}K^{+}π^{-} final state with large statistical significance. The pole mass and width, and the spin parity of the new state are measured with an amplitude analysis to be m_{R}=2591±6±7  MeV, Γ_{R}=89±16±12  MeV, and J^{P}=0^{-}, where the first uncertainty is statistical and the second systematic. Fit fractions for all components in the amplitude analysis are also reported. The new resonance, denoted as D_{s0}(2590)^{+}, is a strong candidate to be the D_{s}(2^{1}S_{0})^{+} state, the radial excitation of the pseudoscalar ground-state D_{s}^{+} meson.
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http://dx.doi.org/10.1103/PhysRevLett.126.122002DOI Listing
March 2021

SANgo: a storage infrastructure simulator with reinforcement learning support.

PeerJ Comput Sci 2020 4;6:e271. Epub 2020 May 4.

YADRO, Moscow, Russia.

We introduce SANgo (Storage Area Network in the Go language)-a Go-based package for simulating the behavior of modern storage infrastructure. The software is based on the discrete-event modeling paradigm and captures the structure and dynamics of high-level storage system building blocks. The flexible structure of the package allows us to create a model of a real storage system with a configurable number of components. The granularity of the simulated system can be defined depending on the replicated patterns of actual system behavior. Accurate replication enables us to reach the primary goal of our simulator-to explore the stability boundaries of real storage systems. To meet this goal, SANgo offers a variety of interfaces for easy monitoring and tuning of the simulated model. These interfaces allow us to track the number of metrics of such components as storage controllers, network connections, and hard-drives. Other interfaces allow altering the parameter values of the simulated system effectively in real-time, thus providing the possibility for training a realistic digital twin using, for example, the reinforcement learning (RL) approach. One can train an RL model to reduce discrepancies between simulated and real SAN data. The external control algorithm can adjust the simulator parameters to make the difference as small as possible. SANgo supports the standard OpenAI gym interface; thus, the software can serve as a benchmark for comparison of different learning algorithms.
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http://dx.doi.org/10.7717/peerj-cs.271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924704PMC
May 2020

Observation of Multiplicity Dependent Prompt χ_{c1}(3872) and ψ(2S) Production in pp Collisions.

Phys Rev Lett 2021 Mar;126(9):092001

Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France.

The production of χ_{c1}(3872) and ψ(2S) hadrons is studied as a function of charged particle multiplicity in pp collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2  fb^{-1}. For both states, the fraction that is produced promptly at the collision vertex is found to decrease as charged particle multiplicity increases. The ratio of χ_{c1}(3872) to ψ(2S) cross sections for promptly produced particles is also found to decrease with multiplicity, while no significant dependence on multiplicity is observed for the equivalent ratio of particles produced away from the collision vertex in b-hadron decays. This behavior is consistent with a calculation that models the χ_{c1}(3872) structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the χ_{c1}(3872) state are discussed.
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http://dx.doi.org/10.1103/PhysRevLett.126.092001DOI Listing
March 2021

Measurement of CP Violation in the Decay B^{+}→K^{+}π^{0}.

Phys Rev Lett 2021 Mar;126(9):091802

Physik-Institut, Universität Zürich, Zürich, Switzerland.

A measurement of CP violation in the decay B^{+}→K^{+}π^{0} is reported using data corresponding to an integrated luminosity of 5.4  fb^{-1} collected with the LHCb experiment at a center-of-mass energy of sqrt[s]=13  TeV. The CP asymmetry is measured to be 0.025±0.015±0.006±0.003, where the uncertainties are statistical, systematic, and due to an external input. This is the most precise measurement of this quantity. It confirms and significantly enhances the observed anomalous difference between the direct CP asymmetries of the B^{0}→K^{+}π^{-} and B^{+}→K^{+}π^{0} decays, known as the Kπ puzzle.
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http://dx.doi.org/10.1103/PhysRevLett.126.091802DOI Listing
March 2021