arXiv subjects

Leonid Serkin

Publications and source records attributed to Leonid Serkin.

7 recordsLinked to original sources

arXiv2025

Revisiting the soft-hard separation in the transverse momentum spectra of $pp$ collisions

We study the separation of soft and hard components in the transverse momentum spectra of charged particles as measured by ALICE in proton-proton collisions at $\sqrt{s}$ = 2.76, 5.02 and 13 TeV at the LHC. The soft component is described by a Boltzmann fit, while the residual spectra are identified as a hard QCD-like fragmentation contribution. After separation, the subtracted spectra show no significant evolution in shape or peak position with multiplicity, consistent with a two-component interpretation. Mean transverse momenta for both contributions remain nearly constant across multiplicity classes, while Pythia 8 Monte Carlo simulations confirm these trends. The robustness of the decomposition is demonstrated by a comparison between simulations with and without color reconnection, yielding consistent results. The terms `soft' and `hard' are used as operational labels within this framework and should not be interpreted as uniquely identified dynamical components. Our results are consistent with the two-component description as a viable and physically motivated alternative to hydrodynamical interpretations.

hep-ph↗

arXiv2025

The impact of artificial intelligence: from cognitive costs to global inequality

In this paper, we examine the wide-ranging impact of artificial intelligence on society, focusing on its potential to both help and harm global equity, cognitive abilities, and economic stability. We argue that while artificial intelligence offers significant opportunities for progress in areas like healthcare, education, and scientific research, its rapid growth -- mainly driven by private companies -- may worsen global inequalities, increase dependence on automated systems for cognitive tasks, and disrupt established economic paradigms. We emphasize the critical need for strong governance and ethical guidelines to tackle these issues, urging the academic community to actively participate in creating policies that ensure the benefits of artificial intelligence are shared fairly and its risks are managed effectively.

physics.soc-ph↗

arXiv2024

Investigating the soft and hard limits in transverse momentum spectra in pp collisions

The transverse momentum spectra and their multiplicity dependence serve as key tools for extracting parameters to be compared with theoretical models. Over the past decade, the scientific community has extensively studied the possibility of a system analogous to quark-gluon plasma, predicted in heavy nuclei collisions, also existing in collisions involving light nuclei and protons. We have reanalysed the data published by the ALICE Collaboration at the LHC. We present the dependence of the mean transverse momenta obtained in the soft and soft+hard (mixed) parts. Finally, we also discuss possible refinements of the analyses concerning the use of statistical parameters of higher order, aimed at a more detailed way of comparing the models with data.

hep-ph↗

arXiv2024

Measurement of muon flux variations with scintillators in Mexico City and their correlation to solar activity

In this work we report the variations of the atmospheric muons flux in Mexico City. The measurements were performed from September to December 2023 at at the Institute of Nuclear Sciences of UNAM, located at coordinates 19.32$^{\circ}$N 99.18$^{\circ}$W, with an altitude of 2274 meters above see level and a cutoff rigidity of 8.24 GV. The experimental setup consists of a pair of scintillators, with dimensions of 50cm x 1m. To compensate for fluctuations in air pressure, we calculate the barometric coefficient using data, which is determined to be -0.21%/mb. The observed muon flux corresponds to $98.3 \pm 2.6$ m$^{-2}$ s$^{-1}$ sr$^{-1}$, and is consistent with other measurements at the same location. We have identified three variations in the pressure-corrected muon flux that exhibit a pattern similar to those observed by a neutron cosmic ray detector at UNAM. Through an extensive analysis of the publicly available geomagnetic data, we have correlated these variations with a phenomenon known as a Forbush decrease.

physics.ins-det↗

arXiv2021

Treatment of top-quark backgrounds in extreme phase spaces: the "top $p_{T}$ reweighting" and novel data-driven estimations in ATLAS and CMS

The top quark plays an important role in searches for physics beyond the SM, both as a dominant background and as a key signature for the signal. The most notable feature found in the top physics analyses in both ATLAS and CMS Collaborations: the disagreement between simulation and data of the top quark $p_{T}$ spectrum - is highlighted. A reweighting procedure which significantly improves the agreement between simulation and data, also known as the "top $p_{T}$ reweighting", is summarised. Commonly raised points concerning the reweighting to fixed-order predictions are discussed, and several refined approaches are mentioned. An overview of several data-driven methods developed and used to estimate the $t\bar{t}$ background in regions with large jet and b-jet multiplicities and/or high top quark $p_{T}$ is presented.

hep-ex↗

arXiv2019

Top quarks and exotics at ATLAS and CMS

An overview of recent searches with top quarks in the final state using up to 36 fb$^{-1}$ of pp collision data at $\sqrt{s}$ = 13 TeV collected with the ATLAS and CMS experiments at the LHC is presented. In particular, searches for heavy resonances decaying into third generation quarks, searches for production of vector-like quarks and searches for dark-matter produced in association with top quarks are summarised. No significant excess over the SM prediction is found and 95% CL exclusion limits are set in a variety of models.

hep-ex↗

arXiv2017

Search for the SM Higgs boson produced in association with top quarks at $\sqrt{s}$ = 13 TeV with the ATLAS detector at the LHC

A review of the searches for the SM Higgs boson produced in association with a pair of top quarks, ${t\bar{t}H}$, using up to 13.3 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector at the LHC is presented. Searches in the diphoton, multilepton and $b\bar{b}$ decay channels are summarised. The combination of these searches yields a measured (expected) significance for the observation of the ${t\bar{t}H}$ production process of $2.8 σ$ ($1.8 σ$).

hep-ex↗