TY  - JOUR
AU  - Sirunyan, A.
AU  - Tumasyan, A.
AU  - Adam, W.
AU  - Ambrogi, F.
AU  - Bergauer, T.
AU  - Adžić, Petar
AU  - Ćirković, Predrag
AU  - Đorđević, Miloš
AU  - Milenović, Predrag
AU  - Milošević, Jovan
AU  - Stojanović, Milan
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9986
AB  - The ratios of the production cross sections between the excited ϒ(2S) and ϒ(3S) mesons and the ϒ(1S) ground state, detected via their decay into two muons, are studied as a function of the number of charged particles in the event. The data are from proton-proton collisions at s = 7 TeV, corresponding to an integrated luminosity of 4.8 fb−1, collected with the CMS detector at the LHC. Evidence of a decrease in these ratios as a function of the particle multiplicity is observed, more pronounced at low transverse momentum pTμμ. For ϒ(nS) mesons with pTμμ> 7 GeV, where most of the data were collected, the correlation with multiplicity is studied as a function of the underlying event transverse sphericity and the number of particles in a cone around the ϒ(nS) direction. The ratios are found to be multiplicity independent for jet-like events. The mean pTμμ values for the ϒ(nS) states as a function of particle multiplicity are also measured and found to grow more steeply as their mass increases.
T2  - Journal of High Energy Physics
T1  - Investigation into the event-activity dependence of ϒ(nS) relative production in proton-proton collisions at √s = 7 TeV
VL  - 2020
IS  - 11
SP  - 1
EP  - 39
DO  - 10.1007/JHEP11(2020)001
ER  - 

@article{
author = "Sirunyan, A. and Tumasyan, A. and Adam, W. and Ambrogi, F. and Bergauer, T. and Adžić, Petar and Ćirković, Predrag and Đorđević, Miloš and Milenović, Predrag and Milošević, Jovan and Stojanović, Milan",
year = "2020",
abstract = "The ratios of the production cross sections between the excited ϒ(2S) and ϒ(3S) mesons and the ϒ(1S) ground state, detected via their decay into two muons, are studied as a function of the number of charged particles in the event. The data are from proton-proton collisions at s = 7 TeV, corresponding to an integrated luminosity of 4.8 fb−1, collected with the CMS detector at the LHC. Evidence of a decrease in these ratios as a function of the particle multiplicity is observed, more pronounced at low transverse momentum pTμμ. For ϒ(nS) mesons with pTμμ> 7 GeV, where most of the data were collected, the correlation with multiplicity is studied as a function of the underlying event transverse sphericity and the number of particles in a cone around the ϒ(nS) direction. The ratios are found to be multiplicity independent for jet-like events. The mean pTμμ values for the ϒ(nS) states as a function of particle multiplicity are also measured and found to grow more steeply as their mass increases.",
journal = "Journal of High Energy Physics",
title = "Investigation into the event-activity dependence of ϒ(nS) relative production in proton-proton collisions at √s = 7 TeV",
volume = "2020",
number = "11",
pages = "1-39",
doi = "10.1007/JHEP11(2020)001"
}

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Adžić, P., Ćirković, P., Đorđević, M., Milenović, P., Milošević, J.,& Stojanović, M.. (2020). Investigation into the event-activity dependence of ϒ(nS) relative production in proton-proton collisions at √s = 7 TeV. in Journal of High Energy Physics, 2020(11), 1-39.
https://doi.org/10.1007/JHEP11(2020)001

Sirunyan A, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Adžić P, Ćirković P, Đorđević M, Milenović P, Milošević J, Stojanović M. Investigation into the event-activity dependence of ϒ(nS) relative production in proton-proton collisions at √s = 7 TeV. in Journal of High Energy Physics. 2020;2020(11):1-39.
doi:10.1007/JHEP11(2020)001 .

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Adžić, Petar, Ćirković, Predrag, Đorđević, Miloš, Milenović, Predrag, Milošević, Jovan, Stojanović, Milan, "Investigation into the event-activity dependence of ϒ(nS) relative production in proton-proton collisions at √s = 7 TeV" in Journal of High Energy Physics, 2020, no. 11 (2020):1-39,
https://doi.org/10.1007/JHEP11(2020)001 . .

TY  - JOUR
AU  - Sirunyan, A.
AU  - Tumasyan, A.
AU  - Adam, W.
AU  - Ambrogi, F.
AU  - Bergauer, T.
AU  - Adžić, Petar
AU  - Ćirković, Predrag
AU  - Devetak, Damir
AU  - Đorđević, Miloš
AU  - Milenović, Predrag
AU  - Milošević, Jovan
AU  - Stojanović, Milan
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10142
AB  - The standard model (SM) production of four top quarks (t t ¯ t 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 137fb-1 at a center-of-mass energy of 13TeV. 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 t t ¯ t t ¯ signal are respectively 2.6 and 2.7 standard deviations, and the t t ¯ t t ¯ cross section is measured to be 12.6-5.2+5.8fb. The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, yt, yielding a limit of |yt/ytSM|<1.7 at 95 % confidence level, where ytSM is the SM value of yt. They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, 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 350–470GeV and 350–550GeV for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles.
T2  - European Physical Journal C. Particles and Fields
T1  - Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at √s=13TeV
VL  - 80
IS  - 2
SP  - 75
DO  - 10.1140/epjc/s10052-019-7593-7
ER  - 

@article{
author = "Sirunyan, A. and Tumasyan, A. and Adam, W. and Ambrogi, F. and Bergauer, T. and Adžić, Petar and Ćirković, Predrag and Devetak, Damir and Đorđević, Miloš and Milenović, Predrag and Milošević, Jovan and Stojanović, Milan",
year = "2020",
abstract = "The standard model (SM) production of four top quarks (t t ¯ t 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 137fb-1 at a center-of-mass energy of 13TeV. 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 t t ¯ t t ¯ signal are respectively 2.6 and 2.7 standard deviations, and the t t ¯ t t ¯ cross section is measured to be 12.6-5.2+5.8fb. The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, yt, yielding a limit of |yt/ytSM|<1.7 at 95 % confidence level, where ytSM is the SM value of yt. They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, 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 350–470GeV and 350–550GeV for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles.",
journal = "European Physical Journal C. Particles and Fields",
title = "Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at √s=13TeV",
volume = "80",
number = "2",
pages = "75",
doi = "10.1140/epjc/s10052-019-7593-7"
}

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Adžić, P., Ćirković, P., Devetak, D., Đorđević, M., Milenović, P., Milošević, J.,& Stojanović, M.. (2020). Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at √s=13TeV. in European Physical Journal C. Particles and Fields, 80(2), 75.
https://doi.org/10.1140/epjc/s10052-019-7593-7

Sirunyan A, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Adžić P, Ćirković P, Devetak D, Đorđević M, Milenović P, Milošević J, Stojanović M. Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at √s=13TeV. in European Physical Journal C. Particles and Fields. 2020;80(2):75.
doi:10.1140/epjc/s10052-019-7593-7 .

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Adžić, Petar, Ćirković, Predrag, Devetak, Damir, Đorđević, Miloš, Milenović, Predrag, Milošević, Jovan, Stojanović, Milan, "Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at √s=13TeV" in European Physical Journal C. Particles and Fields, 80, no. 2 (2020):75,
https://doi.org/10.1140/epjc/s10052-019-7593-7 . .