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Institution

Sofia University

EducationSofia, Bulgaria
About: Sofia University is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 8533 authors who have published 15730 publications receiving 306320 citations. The organization is also known as: University of Sofia & BFUS.


Papers
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Journal ArticleDOI
Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam, Federico Ambrogi  +2292 moreInstitutions (165)
TL;DR: The standard model (SM) production of four top quarks in proton-proton collisions is studied by the CMS Collaboration, with limits set on the production of a heavy scalar or pseudoscalar boson in Type-II two-Higgs-doublet and simplified dark matter models.
Abstract: The standard model (SM) production of four top quarks ($\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $) in proton–proton collisions is studied by the CMS Collaboration. The data sample, collected during the 2016–2018 data taking of the LHC, corresponds to an integrated luminosity of 137$\,\text {fb}^{-1}$ at a center-of-mass energy of 13$\,\text {TeV}$. The events are required to contain two same-sign charged leptons (electrons or muons) or at least three leptons, and jets. The observed and expected significances for the $\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $ signal are respectively 2.6 and 2.7 standard deviations, and the $\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $ cross section is measured to be $12.6^{+5.8}_{-5.2}\,\text {fb} $. The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, $y_{\text {t}}$, yielding a limit of $|y_{\text {t}}/y_{\text {t}}^{\mathrm {SM}} | < 1.7$ at $95\%$ confidence level, where $y_{\text {t}}^{\mathrm {SM}}$ is the SM value of $y_{\text {t}}$. They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, $\hat{H}<0.12$. Limits are set on the production of a heavy scalar or pseudoscalar boson in Type-II two-Higgs-doublet and simplified dark matter models, with exclusion limits reaching 350–470$\,\text {GeV}$ and 350–550$\,\text {GeV}$ for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles.

97 citations

Journal ArticleDOI
TL;DR: In this paper, a key technology for moving toward a promising energy scenario based on renewable (regenerative) energy resources in that wind and solar energy can be stored and stored and...
Abstract: Electrochemical water splitting is a key technology for moving toward a promising energy scenario based on renewable (regenerative) energy resources in that wind and solar energy can be stored and ...

97 citations

Journal ArticleDOI
TL;DR: In this paper, the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t to ch, were presented in terms of the H and A production cross sections times branching fractions.
Abstract: Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of sqrt(s) = 8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. The decays H to hh and A to Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% CL cross section upper limits of approximately 7 pb on sigma times B for H to hh and 2 pb for A to Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t to ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% CL upper limit of 0.56% on B(t to ch).

97 citations

Journal ArticleDOI
TL;DR: The testing of cytotoxic activity suggests that these compounds may be endowed with important antiviral properties, and it is interesting to note that the Pd(II)-benzyl bis(thiosemicarbazone) complex, 2, exhibits a significant activity against acyclovir-resistant viruses R-100 ( HSV 1) and PU (HSV 2) with an in vitro selectivity index (SI) of 8.0.

97 citations

Journal ArticleDOI
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam  +2274 moreInstitutions (154)
TL;DR: In this article, the production yields of quarkonium states are measured through their decays into muon pairs in the CMS detector, in PbPb and pp collisions at the centre-of-mass energy per nucleon pair of 2.76 TeV.

97 citations


Authors

Showing all 8600 results

NameH-indexPapersCitations
Michael Tytgat134144994133
Leander Litov133142492713
Eric Conte132120684593
Georgi Sultanov132149393318
Plamen Iaydjiev131128587958
Anton Dimitrov130123686919
Jordan Damgov129119585490
Borislav Pavlov129124586458
Jean-Laurent Agram128122184423
Cristina Botta128116079070
Jean-Charles Fontaine128119084011
Peicho Petkov128111183495
Muhammad Ahmad128118779758
Roumyana Hadjiiska126100373091
Mircho Rodozov12497270519
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202326
2022141
2021792
2020771
2019769
2018693