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Armen Tumasyan

Bio: Armen Tumasyan is an academic researcher from Yerevan Physics Institute. The author has contributed to research in topics: Large Hadron Collider & Lepton. The author has an hindex of 128, co-authored 1189 publications receiving 79408 citations. Previous affiliations of Armen Tumasyan include CERN & Austrian Academy of Sciences.


Papers
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Journal ArticleDOI
TL;DR: In this article, a measurement of the triple-differential cross section of the photon + jets final states using a data sample from proton-proton collisions at 7 TeV is presented.
Abstract: A measurement of the triple-differential cross section, $ {{{{{\mathrm{d}}^3}\sigma }} \left/ {{\left( {\mathrm{d}\mathrm{p}_T^{\gamma}\mathrm{d}{\eta^{\gamma }}\mathrm{d}{\eta^{\mathrm{jet}}}} \right)}} \right.} $ , in photon + jets final states using a data sample from proton-proton collisions at $ \sqrt{s} $ = 7 TeV is presented. This sample corresponds to an integrated luminosity of 2.14 fb$^{−1}$ collected by the CMS detector at the LHC. Photons and jets are reconstructed within a pseudorapidity range of |η| 30 GeV, respectively. The measurements are compared to theoretical predictions from the sherpa leading-order QCD Monte Carlo event generator and the next-to-leading-order perturbative QCD calculation from jetphox. The predictions are found to be consistent with the data over most of the examined kinematic region.

43 citations

Journal ArticleDOI
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam  +2244 moreInstitutions (147)
TL;DR: The authors of as mentioned in this paper acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and======FWO(Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil);MES and CSF (Croatia); MSIP and NRF (Republic of Korea); LAS (Lithuania); BUAP, CINVESTAV, CONACYT, LNS, SEP,
Abstract: we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO(Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil);MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); SENESCYT (Ecuador); MoER, ERC IUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie programme and the European Research Council and EPLANET (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation a la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS programme of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund, the Mobility Plus programme of the Ministry of Science and Higher Education, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2013/11/B/ST2/04202, 2014/13/B/ST2/02543 and 2014/15/B/ST2/03998, Sonata-bis 2012/07/ E/ST2/01406; the Thalis and Aristeia programmes cofinanced by EUESF and the Greek NSRF; the National Priorities Research Program by QatarNationalResearch Fund; the Programa Clarin-COFUND del Principado de Asturias; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its second Century Project Advancement Project (Thailand); and the Welch Foundation, contract C-1845.

42 citations

Journal ArticleDOI
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam  +2360 moreInstitutions (183)
TL;DR: In this paper, the first measurement of the top quark spin asymmetry sensitive to the top-quark polarisation was presented, based on a sample of pp collisions at a center-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb−1.
Abstract: A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb−1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 ± 0.03(stat) ± 0.10(syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.

42 citations

Journal ArticleDOI
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam  +2283 moreInstitutions (141)
TL;DR: In this article, the cross section for ttbar production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 inverse femtobarns.
Abstract: The cross section for ttbar production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 inverse femtobarns. The inclusive cross section is found to be 275.6 +/- 6.1 (stat) +/- 37.8 (syst) +/- 7.2 (lumi) pb. The normalized differential cross sections are measured as a function of the top quark transverse momenta, pt, and compared to predictions from quantum chromodynamics. The results are reported at detector, parton, and particle levels. In all cases, the measured top quark pt spectra are significantly softer than theoretical predictions.

42 citations

Journal ArticleDOI
Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam, Federico Ambrogi  +2304 moreInstitutions (164)
TL;DR: The limits presented in this paper are the best to date in the dijet final state.
Abstract: A search in an all-jet final state for new massive resonances decaying to $$\text{ W }{}{}$$ $$\text{ W }{}{}$$, $$\text{ W }{}{}$$ $$\text{ Z }{}{}$$, or $$\text{ Z }{}{}$$ $$\text{ Z }{}{}$$ boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 $$\,\text {fb}^{-1}$$ recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13 $$\text {Te}\text {V}$$. The search is focussed on potential narrow-width resonances with masses above 1.2 $$\text {Te}\text {V}$$, where the decay products of each $$\text{ W }{}{}$$ or $$\text{ Z }{}{}$$ boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 $${\text {Z}}^{\prime }$$ and $${\text {W}}^{\prime }$$ resonances with masses below 3.5 and 3.8 $$\text {Te}\text {V}$$, respectively, are excluded at 95% confidence level. In a bulk graviton model, upper limits on cross sections are set between 27 and 0.2 $$\,\text {fb}$$ for resonance masses between 1.2 and 5.2 $$\text {Te}\text {V}$$, respectively. The limits presented in this paper are the best to date in the dijet final state.

42 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
Georges Aad1, T. Abajyan2, Brad Abbott3, Jalal Abdallah4  +2964 moreInstitutions (200)
TL;DR: In this article, a search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9.

9,282 citations

Journal ArticleDOI
TL;DR: In this paper, results from searches for the standard model Higgs boson in proton-proton collisions at 7 and 8 TeV in the CMS experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.8 standard deviations.

8,857 citations

Journal ArticleDOI
TL;DR: MadGraph5 aMC@NLO as discussed by the authors is a computer program capable of handling all these computations, including parton-level fixed order, shower-matched, merged, in a unified framework whose defining features are flexibility, high level of parallelisation and human intervention limited to input physics quantities.
Abstract: We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5 aMC@NLO, capable of handling all these computations — parton-level fixed order, shower-matched, merged — in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV e + e − collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

6,509 citations