PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/5

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Citation - Scopus: 2
Evidence for Similar Collectivity of High Transverse-Momentum Particles in P-Pb and Pb-Pb Collisions
(American Physical Society, 2025) Chekhovsky, V.; Hayrapetyan, A.; Makarenko, V.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Druzhkin, D.
Charged hadron elliptic anisotropies (v(2)) are presented over a wide transverse momentum (p(T)) range for proton-lead (pPb) and lead-lead (PbPb) collisions at nucleon-nucleon center-of-mass energies of 8.16 and 5.02 TeV, respectively. The data were recorded by the CMS experiment and correspond to integrated luminosities of 186 and 0.607 nb(-1) for the pPb and PbPb systems, respectively. A four-particle cumulant analysis is performed using subevents separated in pseudorapidity to effectively suppress noncollective effects. At high pT (p(T) > 8 GeV), significant positive v(2) values that are similar between pPb and PbPb collisions at comparable charged particle multiplicities are observed. This observation suggests a common origin for the multiparticle collectivity for high-p(T) particles in the two systems.
Citation - WoS: 47
Citation - Scopus: 52
Evidence for the Higgs Boson Decay To a Z Boson and a Photon at the Lhc
(American Physical Society, 2024) Aad, G.; Abbott, B.; Abeling, K.; Abicht, N.J.; Abidi, S.H.; Aboulhorma, A.; Abramowicz, H.
The first evidence for the Higgs boson decay to a Formula Presented boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around Formula Presented for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is Formula Presented times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations. © 2024 CERN, for the ATLAS and CMSs Collaboration.
Citation - WoS: 7
Citation - Scopus: 8
Measurement of the Dependence of the Hadron Production Fraction Ratios Fs/Fu and Fd/Fu on B Meson Kinematic Variables in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
The dependence of the ratio between the B s 0 and B + hadron production fractions, f s / f u , on the transverse momentum ( p T ) and rapidity of the B mesons is studied using the decay channels B s 0 → J / ψ ϕ and B + → J / ψ K + . The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6 fb - 1 . The f s / f u ratio is observed to depend on the B p T and to be consistent with becoming asymptotically constant at large p T . No rapidity dependence is observed. The ratio of the B 0 to B + meson production fractions, f d / f u , is also measured, for the first time in proton-proton collisions, using the B 0 → J / ψ K * 0 decay channel. The result is found to be within 1 standard deviation of unity and independent of p T and rapidity, as expected from isospin invariance. © 2023 CERN, for the CMS Collaboration.
Measurement of Wwz and Zh Production Cross Sections at √s=13 and 13.6 TeV
(American Physical Society, 2025) Hayrapetyan, A.; Makarenko, V.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Choi, J.
A measurement is presented of the cross section in proton-proton collisions for the production of two W bosons and one Z boson. It is based on data recorded by the CMS experiment at the CERN LHC at center-of-mass energies root s = 13 and 13.6 TeV, corresponding to an integrated luminosity of 200 fb(-1). Events with four charged leptons (electrons or muons) in the final state are selected. Both nonresonant WWZ production and ZH production, with the Higgs boson decaying into two W bosons, are reported. For the first time, the two processes are measured separately in a simultaneous fit. Combining the two modes, signal strengths relative to the standard model (SM) predictions of 0.75(-0.29)(+0.34) and 1.74(-0.60)(+0.71) are measured for root s = 13 and 13.6 TeV, respectively. The observed (expected) significance for the triboson signal is 3.8 (2.5) standard deviations for root s = 13.6 TeV, thus providing the first evidence for triboson production at this center-of-mass energy. Combining the two modes and the two center-of-mass energies, the inclusive signal strength relative to the SM prediction is measured to be 1.03(-0.28)(+0.31), with an observed (expected) significance of 4.5 (5.0) standard deviations.
Citation - WoS: 69
Citation - Scopus: 90
New Structures in the Formula Presented Mass Spectrum in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Gürpınar Güler, Emine; Güler, Yalçın
A search is reported for near-threshold structures in the Formula Presented invariant mass spectrum produced in proton-proton collisions at Formula Presented from data collected by the CMS experiment, corresponding to an integrated luminosity of Formula Presented. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of Formula Presented. Another structure with even higher significance is found at a mass of Formula Presented, which is consistent with the Formula Presented resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.7 standard deviations, is found at a mass of Formula Presented. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference. © 2024 CERN, for the CMS Collaboration.
Citation - Scopus: 17
Observation of Same-Sign Ww Production From Double Parton Scattering in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
The first observation of the production of Formula Presented bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of Formula Presented recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign Formula Presented bosons decaying leptonically is Formula Presented, whereas the measured fiducial cross section is Formula Presented. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis. © 2023 CERN, for the CMS Collaboration.
Observation of the Charged-Particle Multiplicity Dependence of Σψ(2s)/Σj in P-Pb Collisions at 8.16 TeV
(American Physical Society, 2025) Chekhovsky, V.; Hayrapetyan, A.; Makarenko, V.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Dutta, S.
Bound states of charm and anticharm quarks, known as charmonia, have a rich spectroscopic structure that can be used to probe the dynamics of hadron production in high-energy hadron collisions. Here, the cross section ratio of excited (psi(2S)) and ground state (J/psi) vector mesons is measured as a function of the charged-particle multiplicity in proton-lead (pPb) collisions at a center-of-mass (CM) energy per nucleon pair of 8.16 TeV. The data corresponding to an integrated luminosity of 175 nb(-1) were collected using the CMS detector. The ratio is measured separately for prompt and nonprompt charmonia in the transverse momentum range 6.5 < p(T) < 30 GeV and in four rapidity ranges spanning -2.865 < y(CM) < 1.935. For the first time, a statistically significant multiplicity dependence of the prompt cross section ratio is observed in proton-nucleus collisions. There is no clear rapidity dependence in the ratio. The prompt measurements are compared with a theoretical model which includes interactions with nearby particles during the evolution of the system. These results provide additional constraints on hadronization models of heavy quarks in nuclear collisions.
Citation - WoS: 6
Citation - Scopus: 15
Observation of the Rare Decay of the Η Meson To Four Muons
(American Physical Society, 2023) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Gürpınar Güler, Emine; Güler, Yalçın
A search for the rare Formula Presented double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of Formula Presented. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the Formula Presented decay as normalization, the branching fraction Formula Presented is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions. © 2023 CERN, for the CMS Collaboration.
Citation - WoS: 12
Citation - Scopus: 10
Observation of the Γ(3s) Meson and Suppression of Γ States in Pb-Pb Collisions at √sNN=5.02 TeV
(American Physical Society, 2024) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Zhokin, A.
The production of gamma(2S) and gamma(3S) mesons in lead-lead (Pb-Pb) and proton-proton (pp) collisions is studied in their dimuon decay channel using the CMS detector at the LHC. The gamma(3S) meson is observed for the first time in Pb-Pb collisions, with a significance above 5 standard deviations. The ratios of yields measured in Pb-Pb and pp collisions are reported for both the gamma(2S) and gamma(3S) mesons, as functions of transverse momentum and Pb-Pb collision centrality. These ratios, when appropriately scaled, are significantly less than unity, indicating a suppression of gamma yields in Pb-Pb collisions. This suppression increases from peripheral to central Pb-Pb collisions. Furthermore, the suppression is stronger for gamma(3S) mesons compared to gamma(2S) mesons, extending the pattern of sequential suppression of quarkonium states in nuclear collisions previously seen for the J/psi, psi(2S), gamma(1S), and gamma(2S) mesons.
Observation of Λ Hyperon Local Polarization in P-Pb Collisions at √snn=8.16 Tev
(American Physical Society, 2025) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Bergauer, T.; Druzhkin, D.
The polarization of the Lambda and (Lambda) over bar hyperons along the beam direction has been measured in proton-lead (p-Pb) collisions at a center-of-mass energy per nucleon pair of 8.16 TeV. The data were obtained with the CMS detector at the LHC and correspond to an integrated luminosity of 186.0 +/- 6.5 nb(-1). A significant azimuthal dependence of the hyperon polarization, characterized by the second-order Fourier sine coefficient P-z,P-s2, is observed. The P-z,P-s2 values decrease as a function of charged particle multiplicity, but increase with transverse momentum. A hydrodynamic model that describes the observed P-z,P-s2 values in nucleus-nucleus collisions by introducing vorticity effects does not reproduce either the sign or the magnitude of the p-Pb results. These observations pose a challenge to the current theoretical implementation of spin polarization in heavy ion collisions and offer new insights into the origin of spin polarization in hadronic collisions at LHC energies.
Citation - WoS: 27
Citation - Scopus: 34
Observation of Τ Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
We present an observation of photon-photon production of Formula Presented lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of Formula Presented collected by the CMS experiment at a center-of-mass energy per nucleon pair of Formula Presented. The Formula Presented process is observed for Formula Presented events with a muon and three charged hadrons in the final state. The measured fiducial cross section is Formula Presented, where the second (third) term corresponds to the statistical (systematic) uncertainty in Formula Presented in agreement with leading-order QED predictions. Using Formula Presented, we estimate a model-dependent value of the anomalous magnetic moment of the Formula Presented lepton of Formula Presented. © 2023 CERN, for the CMS Collaboration.
Citation - Scopus: 1
Probing Gluon Fluctuations in Nuclei With the First Energy-Dependent Measurement of Incoherent J/Ψ Photoproduction in Ultraperipheral PbPb Collisions
(American Physical Society, 2025) Chekhovsky, V.; Hayrapetyan, A.; Makarenko, V.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Lee, J.
Incoherent J/psi photoproduction in heavy ion ultraperipheral collisions (UPCs) provides a sensitive probe of localized, fluctuating gluonic structures within heavy nuclei. This Letter reports the first measurement of the photon-nucleon center-of-mass energy (W-gamma N) dependence of this process in PbPb UPCs at a nucleon-nucleon center-of-mass energy of 5.02 TeV, using 1.52 nb(-1) of data recorded by the CMS experiment. The measurement covers a wide W-gamma N range of approximate to 40-400 GeV, probing gluons carrying a fraction x of nucleon momentum down to an unexplored regime of 6.5 x 10(-5). Compared to baseline predictions neglecting nuclear effects, the measured cross sections exhibit significantly greater suppression at lower x. Additionally, the ratio of incoherent to coherent photoproduction is found to be constant across the probed W-gamma N and x range, disfavoring the establishment of the black disk limit. This Letter provides critical insights into the x-dependent evolution of fluctuating gluonic structures within nuclei and calls for further advancements in theoretical models incorporating nuclear shadowing and gluon saturation.
Citation - WoS: 17
Citation - Scopus: 27
Probing Heavy Majorana Neutrinos and the Weinberg Operator Through Vector Boson Fusion Processes in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision dataset recorded at s = 13 TeV , collected with the CMS detector and corresponding to a total integrated luminosity of 138 fb − 1 . The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μ μ Majorana neutrino mass of 10.8 GeV. © 2023 CERN, for the CMS Collaboration.
Citation - WoS: 30
Citation - Scopus: 43
Probing Small Bjorken-X Nuclear Gluonic Structure Via Coherent J=ψ Photoproduction in Ultraperipheral Pb-Pb Collisions at √snn = 5.02 Tev
(American Physical Society, 2023) Tumasyan A.; Adam W.; Andrejkovic J.W.; Bergauer T.; Chatterjee S.; Damanakis K.; Dragicevic M.; Gürpınar Güler, Emine; Güler, Yalçın
Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J=ψ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (WPbγN) over a wide range of 40 < WPbγN < 400 GeV. Results are obtained using data at the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 1.52 nb−1. The cross section is observed to rise rapidly at low WPbγN, and plateau above WPbγN ≈ 40 GeV, up to 400 GeV, entering a new regime of small Bjorken-x (≈6 × 10−5) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models. © 2023 CERN, for the CMS Collaboration.
Citation - Scopus: 19
Search for Exotic Higgs Boson Decays Formula Presented With Events Containing Two Merged Diphotons in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
We present the first direct search for exotic Higgs boson decays Formula Presented, Formula Presented in events with two photonlike objects. The hypothetical particle Formula Presented is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at Formula Presented corresponding to an integrated luminosity of Formula Presented. No excess above the estimated background is found. We set upper limits on the branching fraction Formula Presented of Formula Presented at 95% confidence level for masses of Formula Presented in the range 0.1-1.2 GeV. © 2023 CERN, for the CMS Collaboration.
Citation - WoS: 37
Citation - Scopus: 46
Search for Higgs Boson Decay To a Charm Quark-Antiquark Pair in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H → c c ¯ , produced in association with a leptonically decaying V ( W or Z ) boson is presented. The search is performed with proton-proton collisions at s = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb - 1 . Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z → c c ¯ in V Z events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ ( V H ) B ( H → c c ¯ ) is 0.94 ( 0.50 - 0.15 + 0.22 )pb at 95% confidence level (C.L.), corresponding to 14 ( 7.6 - 2.3 + 3.4 ) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κ c , the observed (expected) 95% C.L. interval is 1.1 < | κ c | < 5.5 ( | κ c | < 3.4 ), the most stringent constraint to date. © 2023 CERN, for the CMS Collaboration.
Citation - WoS: 41
Citation - Scopus: 51
Search for Higgs Boson Pair Production in the Four B Quark Final State in Proton-Proton Collisions at S =13 Tev
(American Physical Society, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Güler, Yalçın; The CMS Collaboration
A search for pairs of Higgs bosons produced via gluon and vector boson fusion is presented, focusing on the four b quark final state. The data sample consists of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, and corresponds to an integrated luminosity of 138 fb-1. No deviation from the background-only hypothesis is observed. A 95% confidence level upper limit on the Higgs boson pair production cross section is observed at 3.9 times the standard model prediction for an expected value of 7.8. Constraints are also set on the modifiers of the Higgs field self-coupling, ??, and of the coupling of two Higgs bosons to two vector bosons, ?2 V. The observed (expected) allowed intervals at the 95% confidence level are -2.3
Citation - WoS: 8
Citation - Scopus: 5
Search for Inelastic Dark Matter in Events With Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at √s=13 Tev
(American Physical Society, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Gürpınar Güler, Emine; Güler, Yalçın
A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138 fb-1 of protonproton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016.2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp → A′ → χ1χ2) and the decay branching fraction ℬ(χ2 → χ1μ+μ-), where A′ is a dark photon and +++χ1 and χ2 are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter. © 2024 American Physical Society. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 3
Search for Narrow Trijet Resonances in Proton-Proton Collisions at Formula Presented
(American Physical Society, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Gürpınar Güler, Emine; Güler, Yalçın
The first search for singly produced narrow resonances decaying to three well-separated hadronic jets is presented. The search uses proton-proton collision data corresponding to an integrated luminosity of Formula Presented at Formula Presented, collected at the CERN LHC. No significant deviations from the background predictions are observed between 1.75 and 9.00 TeV. The results provide the first mass limits on a right-handed boson Formula Presented decaying to three gluons and on an excited quark decaying via a vector boson to three quarks, as well as updated limits on a Kaluza-Klein gluon decaying via a radion to three gluons. © 2024 CERN, for the CMS Collaboration.
Search for New Physics in Jet Multiplicity Patterns of Multilepton Events at (Formula Presented)
(American Physical Society, 2025) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Makarenko, V.
A first search for beyond the standard model physics in jet multiplicity patterns of multilepton events is presented, using a data sample corresponding to an integrated luminosity of (Formula presented) of 13 TeV proton-proton collisions recorded by the CMS detector at the LHC. The search uses observed jet multiplicity distributions in one-, two-, and four-lepton events to explore possible enhancements in jet production rate in three-lepton events with and without bottom quarks. The data are found to be consistent with the standard model expectation. The results are interpreted in terms of supersymmetric production of electroweak chargino-neutralino superpartners with cascade decays terminating in prompt hadronic (Formula presented)-parity violating interactions. © 2025 CERN, for the CMS Collaboration.

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