FBFlorian Urs Bernlochner

Florian Urs Bernlochner

University of Bonn
*This is an algorithmically generated author record based on publicly available information.
See Latest Publications
See Most Cited Publications
SciProfiles
ORCID Profile
Google Scholar

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Research Subjects

Florian Urs Bernlochner has a total of 1000 co-authors. Here are the top co-authors by number of shared publications:

Latest Publications

  • Website
    Google Scholar
    Open Access

    Measurements of longitudinal flow decorrelations in p p and Xe + Xe collisions with the ATLAS detector

    by G. Aad, B. Abbott, K. Abeling, N. J. Abicht, S. H. Abidi, A. Aboulhorma, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, et al.

    Measurements of longitudinal flow decorrelations in 13-TeV p p and 5.44-TeV Xe + Xe collisions with the ATLAS detector are presented. The measurements are performed using the two-particle correlation method, combining charged-particle tracks within | η | < 2.5 with either calorimeter energy clusters or towers within 4.0 < | η | < 4.9 . A template-based subtraction procedure is used to remove nonflow effects in both the p p and the Xe + Xe analyses. The dependence of the longitudinal flow decorrelations on the pseudorapidity separation between the particles is characterized via the slope parameter F n for the elliptic ( n = 2 ) and triangular ( n = 3 ) harmonic moments. The results are reported as a function of charged-particle multiplicity for the p p and Xe + Xe collision systems. Comparing the data to a color string-based model of the initial geometry indicates that in p p and peripheral Xe + Xe collisions, subnucleonic structure, and fluctuations in longitudinal energy deposition are needed to describe the data.

  • Website
    Google Scholar
    Open Access

    Measurement of J/ψ-jet correlations in pp and Pb+Pb collisions at $ \sqrt{s_{\mathrm{NN}}}=5.02 $ TeV with the ATLAS detector

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N. J. Abicht, S. H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

    A bstract: Yields of charmonia, bound states of $$ c\overline{c} $$ c c ¯ quarks, are observed to be strongly suppressed in heavy-ion collisions relative to proton-proton collisions as a result of their interaction with the quark-gluon plasma produced in such collisions. Understanding the mechanisms responsible for this suppression requires a detailed understanding of charmonium production. To constrain the production mechanisms, it is essential to quantify how charmonium production correlates with jet activity. Measurements of J/ψ production in the dimuon decay channel are presented for inclusive J/ψ mesons and for J/ψ mesons that are either isolated or not isolated from jets, separately for prompt and non-prompt production. Non-isolated J/ψ mesons are defined by matching J/ψ candidates to anti- k t jets with R = 0 . 2 and p T > 20 GeV, reconstructed without signal from the J/ψ meson, allowing the quantification of jet activity accompanying J/ψ production. The analysis uses Pb+Pb and pp collisions at $$ \sqrt{s_{\mathrm{NN}}}=5.02 $$ s NN = 5.02 TeV recorded by the ATLAS experiment at the LHC, corresponding to integrated luminosities of 1 . 82 nb − 1 and 0 . 26 fb − 1 , respectively. The J/ψ yields in Pb+Pb, cross sections in pp , and nuclear modification factors are presented for non-isolated, isolated, and inclusive J/ψ up to p T = 60 GeV. Isolated fractions and non-prompt fractions are reported in both pp and Pb+Pb collisions. Strong J/ψ suppression is observed to persist up to the highest measured p T values, with differences observed between non-isolated, isolated, and inclusive J/ψ . These results provide new constraints on charmonium production mechanisms and their in-medium suppression.

  • Website
    Google Scholar
    Open Access

    First Measurement of the Masses of the ϒ 1 ( 1 D ) and ϒ 3 ( 1 D ) States and the Energy Dependence of the Cross Sections for e + e − → ϒ J ( 1 D ) η and e + e − → ϒ J <mo...

    by M. Abumusabh, I. Adachi, K. Adamczyk, A. Aggarwal, H. Ahmed, Y. Ahn, M. Akdag, N. Akopov, S. Alghamdi, M. Alhakami, et al.

    We study the processes e + e − → ϒ J ( 1 D ) η and e + e − → ϒ J ( 1 D ) π + π − at center-of-mass energies s = ( 10.73 − 11.02 ) GeV using a 142.5 fb − 1 data sample, including 122 fb − 1 near the ϒ ( 10860 ) peak ( s = 10.866 GeV ), collected with the Belle detector at the KEKB asymmetric-energy e + e − collider. From the peak sample, the products of Born cross section times branching fraction are obtained for σ Born ( e + e − → ϒ J ( 1 D ) η ) or σ Born ( e + e − → ϒ J ( 1 D ) π + π − ) and B ( ϒ J ( 1 D ) → χ b 1 γ ) or B ( ϒ J ( 1 D ) → χ b 2 γ ) for each ϒ J ( 1 D ) state. The corresponding branching fractions for ϒ ( 10860 ) decays are also obtained. The significances of the ϒ 1 ( 1 D ) , ϒ 2 ( 1 D ) , and ϒ 3 ( 1 D ) signals are 4.8 σ , > 10 σ , and 3.0 σ , respectively, including systematic uncertainties. The mass for ϒ 2 ( 1 D ) is measured to be ( 10167.0 ± 1.0 ± 0.2 ) MeV / c 2 , where the first and second uncertainties are statistical and systematic. The mass splittings Δ m 12 = m ( ϒ 2 ( 1 D ) ) − m ( ϒ 1 ( 1 D ) ) and Δ m 23 = m ( ϒ 3 ( 1 D ) ) − m ( ϒ 2 ( 1 D ) ) are ( 11.8 ± 1.5 ± 0.4 ) MeV / c 2 and ( 7.6 ± 2.4 ± 0.6 ) MeV / c 2 , respectively. We determine the energy dependence of the cross sections for e + e − → ϒ J ( 1 D ) η and e + e − → ϒ J ( 1 D ) π + π − for the ϒ 1 ( 1 D ) , ϒ 2 ( 1 D ) , and ϒ 3 ( 1 D ) states, combined.

  • Website
    Google Scholar
    Open Access

    First Search for Quirks at the LHC with FASER

    by FASER Collaboration, Roshan Mammen Abraham, Xiaocong Ai, Saul Alonso Monsalve, John Anders, Emma Kate Anderson, Akitaka Ariga, Tomoko Ariga, Jeremy Atkinson, Florian U. Bernlochner, et al.

    We present the first LHC search for quirks, particles with standard model and QCD-like infracolor (IC) interactions. The analysis uses data collected in 2022–2024 by FASER, with a 186 fb − 1 integrated luminosity of proton-proton collisions at a center-of-mass energy s = 13.6 TeV . Scintillator charge and timing information are used to search for slow pairs of quirks with no QCD color and electric charge ± 1 . No events are seen in this nearly background-free search, resulting in the first exclusion of quirks with masses above the weak scale for IC confinement scales in the broad range of 300 eV < Λ < 100 keV .

  • Website
    Google Scholar
    Open Access

    Search for dark photons from Higgs boson decays in the gluon-gluon fusion channel in proton-proton collisions at $ \sqrt{s}=13.6 $ TeV with the ATLAS detector

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N. J. Abicht, S. H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

    A bstract: This paper presents a search for semi-visible Higgs boson decays in final states with a photon ( γ ) and missing transverse momentum $$ {p}_{\mathrm{T}}^{\mathrm{miss}} $$ p T miss . The analysis is optimised for the gluon-gluon fusion production channel and exploits a novel trigger deployed in 2023, with reduced thresholds down to 50 GeV on the photon transverse momentum ( $$ {p}_{\mathrm{T}}^{\gamma } $$ p T γ ) and 70 GeV on the $$ {p}_{\mathrm{T}}^{\mathrm{miss}} $$ p T miss , in combination with a selection on the transverse mass of the $$ {p}_{\mathrm{T}}^{\mathrm{miss}} $$ p T miss -γ system ( m T ) above 80 GeV. The results are interpreted in terms of Higgs boson decays into a γ and a dark photon γ d ( H → γγ d ). The analysis is performed using 135 fb − 1 of Run 3 data collected by ATLAS in 2023 and 2024. A boosted decision tree is used to identify events with misreconstructed primary vertices, which can affect the $$ {p}_{\mathrm{T}}^{\mathrm{miss}} $$ p T miss calculation. Data-driven methods are employed to estimate the backgrounds from jets and electrons misidentified as photons, while the backgrounds with genuine photons are taken from Monte Carlo simulations, normalised to data in control regions with muons. A binned maximum-likelihood fit to the m T distribution is performed to evaluate the compatibility of the observed data with the Standard Model expectation. No significant excess is observed over the Standard Model prediction, and an observed (expected) upper limit on the branching ratio of H → γγ d of 1.4% (1.2%) is obtained at 95% confidence level. Combining this result with previous Run 2 searches improves the observed (expected) upper limit to 0.9% (0.9%).

  • Website
    Google Scholar
    Open Access

    Measurement of isolated photon plus two-jet correlations in Pb+Pb and pp collisions at 5.02 TeV with ATLAS

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N.J. Abicht, S.H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

  • Website
    Google Scholar
    Open Access

    Search for $ t\overline{t} $ resonances in final states with exactly one or two leptons using 140 fb−1 of pp collision data at $ \sqrt{s}=13 $ TeV with the ATLAS experiment

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N. J. Abicht, S. H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

    A bstract: A search for heavy spin-1 and spin-2 resonances decaying into a top-antitop-quark pair has been performed with 140 fb − 1 of proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a centre-of-mass energy of $$ \sqrt{s}=13 $$ s = 13 TeV. Final states with either exactly one electron or muon, or exactly two leptons ( ee , μμ or eμ ), large missing transverse momentum, and two jets, at least one of which must be identified as likely containing a b -hadron decay, are considered. The search targets resonances with both narrow and broad widths relative to the detector resolution, and with masses in the range of 0.4–5.0 TeV. No significant deviation from the Standard Model prediction is observed. Exclusion limits are set on the production cross-section times branching ratio for hypothetical Z′ bosons, Kaluza-Klein gravitons, and Kaluza-Klein gluons that decay into top-quark pairs.

  • Website
    Google Scholar
    Open Access

    Publisher Correction: Calibration of the jet energy scale and resolution of small-radius jets using semileptonic $t\bar{t}$ events with the ATLAS detector

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N. J. Abicht, S. H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

  • Website
    Google Scholar
    Open Access

    Search for soft unclustered energy patterns containing muons in the final state in pp collisions at $ \sqrt{s}=13 $ TeV with the ATLAS detector

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N. J. Abicht, S. H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

    A bstract: Soft unclustered energy patterns (SUEPs) refer to high-multiplicity, isotropic distributions of low-momentum particles that could arise in strongly-coupled hidden sector theories. A search for SUEPs whose decay products contain muons in the final state is presented using 140 fb − 1 of proton–proton collision data at $$ \sqrt{s}=13 $$ s = 13 TeV collected by the ATLAS detector at the Large Hadron Collider during 2015–2018. The analysis targets SUEP signatures via gluon–gluon fusion production of a scalar mediator in Hidden Valley scenarios. No significant excess over the Standard Model expectation is observed. Exclusion limits are set on the product of the mediator production cross section and the branching fraction for its decay into a SUEP, down to 0.05 fb for a mediator mass of m S = 750 GeV, 0.4 fb for m S = 400 GeV, and 70 fb for m S = 125 GeV; the last value, when identifying the mediator with the Standard Model Higgs boson, translates to an upper limit on the branching fraction of around 0.2%.

  • Website
    Google Scholar
    Open Access

    Search for a leptoquark in events with a hadronically decaying τ-lepton and missing transverse momentum using pp collisions at s=13TeV with the ATLAS detector

    by G. Aad, E. Aakvaag, B. Abbott, S. Abdelhameed, K. Abeling, N.J. Abicht, S.H. Abidi, M. Aboelela, A. Aboulhorma, H. Abramowicz, et al.

Show all