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  • Publication . Article . Other literature type . Research . Preprint . 2020
    Open Access English
    Authors: 
    Valerie Domcke; Marco Drewes; Marco Hufnagel; Michele Lucente;
    Publisher: RWTH Aachen University
    Countries: Switzerland, Germany
    Project: EC | NewAve (638528)

    We study the type-I seesaw model with three right-handed neutrinos and Majorana masses below the pion mass. In this mass range, the model parameter space is not only strongly constrained by the requirement to explain the light neutrino masses, but also by experimental searches and cosmological considerations. In the existing literature, three disjoint regions of potentially viable parameter space have been identified. In one of them, all heavy neutrinos decay shortly before big bang nucleosynthesis. In the other two regions, one of the heavy neutrinos either decays between BBN and the CMB decoupling or is quasi-stable. We show that previously unaccounted constraints from photodisintegration of nuclei practically rule out all relevant decays that happen between BBN and the CMB decoupling. Quite remarkably, if all heavy neutrinos decay before BBN, the baryon asymmetry of the universe can be quite generically explained by low-scale leptogenesis, i.e. without further tuning in addition to what is needed to avoid experimental and cosmological constraints. This motivates searches for heavy neutrinos in pion decay experiments. Journal of high energy physics 01(1), 200 (2021). doi:10.1007/JHEP01(2021)200 Published by SISSA, [Trieste]

  • Publication . Article . Preprint . Other literature type . Research . Report . 2018
    Open Access English
    Authors: 
    Marko Dragicevic; Manfred Jeitler; I Kraetschmer; Jochen Schieck; Johannes Wittmann; Claudia-Elisabeth Wulz; Jasper Lauwers; Freya Blekman; Kevin Deroover; Stefaan Tavernier; +449 more
    Countries: Belgium, United States, France, Germany, Croatia, Italy, Italy, France, France, Lithuania ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for charged Higgs boson decaying to a charm and a bottom quark ( $ {\mathrm{H}}^{+}\to \mathrm{c}\overline{\mathrm{b}} $ ) is performed using 19.7 fb$^{−1}$ of pp collision data at $ \sqrt{s}=8 $ TeV. The production mechanism investigated in this search is $ \mathrm{t}\overline{\mathrm{t}} $ pair production in which one top quark decays to a charged Higgs boson and a bottom quark and the other decays to a charged lepton, a neutrino, and a bottom quark. Charged Higgs boson decays to $ \mathrm{c}\overline{\mathrm{b}} $ are searched for, resulting in a final state containing at least four jets, a charged lepton (muon or electron), and missing transverse momentum. A kinematic fit is performed to identify the pair of jets least likely to be the bottom quarks originating from direct top quark decays and the invariant mass of this pair is used as the final observable in the search. No evidence for the presence of a charged Higgs boson is observed and upper limits at 95% confidence level of 0.8–0.5% are set on the branching fraction ℬ(t → H$^{+}$b), assuming ℬ(H$^{+}$ → $ \mathrm{c}\overline{\mathrm{b}} $ ) = 1.0 and ℬ(t → H$^{+}$b) + ℬ(t → Wb) = 1.0, for the charged Higgs boson mass range 90–150 GeV. Journal of high energy physics 1811(11), 115 (2018). doi:10.1007/JHEP11(2018)115 Published by Springer Nature, Cham

  • Publication . Other literature type . Article . Research . Preprint . 2021
    Open Access English
    Authors: 
    Fruehwirth, Rudolf; Wulz, Claudia-Elisabeth; Melo da Costa, Eliza; Brandao Malbouisson, Helena; Tomei, Thiago; de Moraes Gregores, Eduardo; de Souza Lemos, Dener; Garcia Fuentes, Francisco Ignacio; Agram, Jean-Laurent; Brom, Jean-Marie; +279 more
    Publisher: Elsevier
    Countries: Italy, Germany, Belgium, Italy, Turkey, Croatia, United States, Spain, Turkey, Italy ...
    Project: EC | LHCTOPVLQ (752730), EC | INSIGHTS (765710), EC | AMVA4NewPhysics (675440)

    Measurements of the second Fourier harmonic coefficient (v2) of the azimuthal distributions of prompt and nonprompt D0 mesons produced in pp and pPb collisions are presented. Nonprompt D0 mesons come from beauty hadron decays. The data samples are collected by the CMS experiment at nucleon-nucleon center-of-mass energies of 13 and 8.16 TeV, respectively. In high multiplicity pp collisions, v2 signals for prompt charm hadrons are reported for the first time, and are found to be comparable to those for light-flavor hadron species over a transverse momentum (pT) range of 2–6 GeV. Compared at similar event multiplicities, the prompt D0 meson v2 values in pp and pPb collisions are similar in magnitude. The v2 values for open beauty hadrons are extracted for the first time via nonprompt D0 mesons in pPb collisions. For pT in the range of 2–5 GeV, the results suggest that v2 for nonprompt D0 mesons is smaller than that for prompt D0 mesons. These new measurements indicate a positive charm hadron v2 in pp collisions and suggest a mass dependence in v2 between charm and beauty hadrons in the pPb system. These results provide insights into the origin of heavy-flavor quark collectivity in small systems. Individuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 752730, and 765710 (European Union); CERN; the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias. CMS Collaboration: et al. Funded by SCOAP3. Peer reviewed

  • Open Access English
    Authors: 
    Thomas Bergauer; Marko Dragicevic; M. Flechl; Ilse Krätschmer; Dietrich Liko; Thomas Madlener; Jochen Schieck; Robert Schöfbeck; Markus Spanring; Jasper Lauwers; +413 more
    Publisher: Springer Verlag
    Countries: Germany, Germany, United Kingdom, Serbia, France, Italy, Italy, Finland, Switzerland, Italy ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of τ leptons is performed. A data sample of proton-proton collisions collected at s√ = 13 TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb−1. The signal strength is measured relative to the expectation for the standard model Higgs boson, yielding μ = 2.5 − 1.3 + 1.4 . These results are combined with earlier CMS measurements targeting Higgs boson decays to a pair of τ leptons, performed with the same data set in the gluon fusion and vector boson fusion production modes. The combined signal strength is μ = 1.24 − 0.27 + 0.29 (1.00 − 0.23 + 0.24 expected), and the observed significance is 5.5 standard deviations (4.8 expected) for a Higgs boson mass of 125 GeV. Journal of High Energy Physics, 2019 (6) ISSN:1029-8479 ISSN:1126-6708

  • Publication . Article . Other literature type . Preprint . Research . 2022
    Open Access English
    Authors: 
    Tumasyan, Armen; Adam, Wolfgang; Lechner, Lukas; Hensel, Carsten; Kim, Dong Hee; Kim, Gui Nyun; Kim, Jiwoong; Lee, Jeongeun; Lee, Seh Wook; Moon, Chang-Seong; +524 more
    Publisher: SPRINGER
    Countries: Germany, Germany, France, United Kingdom, Turkey, Italy, Finland, Switzerland, United States, Germany ...
    Project: EC | AMVA4NewPhysics (675440), EC | MajorNet (758316)

    Measurements of jet substructure describing the composition of quark- and gluon-initiated jets are presented. Proton-proton (pp) collision data at √s = 13 TeV collected with the CMS detector are used, corresponding to an integrated luminosity of 35.9 fb−1. Generalized angularities are measured that characterize the jet substructure and distinguish quark- and gluon-initiated jets. These observables are sensitive to the distributions of transverse momenta and angular distances within a jet. The analysis is performed using a data sample of dijet events enriched in gluon-initiated jets, and, for the first time, a Z+jet event sample enriched in quark-initiated jets. The observables are measured in bins of jet transverse momentum, and as a function of the jet radius parameter. Each measurement is repeated applying a “soft drop” grooming procedure that removes soft and large angle radiation from the jet. Using these measurements, the ability of various models to describe jet substructure is assessed, showing a clear need for improvements in Monte Carlo generators. Journal of High Energy Physics, 2022 (1) ISSN:1029-8479 ISSN:1126-6708

  • Open Access English
    Authors: 
    Schreiner, Thomas; Kaufmann, Elisabeth; Noachtar, Soheyl; Mehrkens, Jan-Hinnerk; Staudigl, Tobias;
    Country: Germany
    Project: EC | DirectThalamus (802681)

    A hallmark of non-rapid eye movement (NREM) sleep is the coordinated interplay of slow oscillations (SOs) and sleep spindles. Traditionally, a cortico-thalamo-cortical loop is suggested to coordinate these rhythms: neocortically-generated SOs trigger spindles in the thalamus that are projected back to neocortex. Here, we used direct intrathalamic recordings from human epilepsy patients to test this canonical interplay. We show that SOs in the anterior thalamus precede neocortical SOs, whereas concurrently-recorded SOs in the mediodorsal thalamus are led by neocortical SOs. Furthermore, sleep spindles, detected in both thalamic nuclei, preceded their neocortical counterparts and were initiated during early phases of thalamic SOs. Our findings indicate an active role of the anterior thalamus in organizing the cardinal sleep rhythms in the neocortex and highlight the functional diversity of specific thalamic nuclei in humans. The concurrent coordination of sleep oscillations by the thalamus could have broad implications for the mechanisms underlying memory consolidation.

  • Open Access English
    Authors: 
    Ece Aşılar; Marko Dragicevic; Martin Flechl; Ilse Krätschmer; Thomas Madlener; Navid Rad; Jochen Schieck; Robert Schöfbeck; Wolfgang Waltenberger; Claudia-Elisabeth Wulz; +470 more
    Publisher: Springer
    Countries: France, Italy, Croatia, Belgium, Italy, Switzerland, Belgium, Portugal, United States, Italy ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for the pair production of the lightest supersymmetric partner of the top quark (t~1) is presented. The search focuses on a compressed scenario where the mass difference between the top squark and the lightest supersymmetric particle, often considered to be the lightest neutralino (χ~01), is smaller than the mass of the W boson. The proton-proton collision data were recorded by the CMS experiment at a centre-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 35.9 fb−1. In this search, two decay modes of the top squark are considered: a four-body decay into a bottom quark, two additional fermions, and a χ~01; and a decay via an intermediate chargino. Events are selected using the presence of a high-momentum jet, significant missing transverse momentum, and a low transverse momentum electron or muon. Two analysis techniques are used, targeting different decay modes of the t~1: a sequential selection and a multivariate technique. No evidence for the production of top squarks is found, and mass limits at 95% confidence level are set that reach up to 560 GeV, depending on the m(t~1)−m(χ~01) mass difference and the decay mode. Journal of High Energy Physics, 2018 (9) ISSN:1029-8479 ISSN:1126-6708

  • Publication . Article . Preprint . Research . Other literature type . 2020
    Open Access English
    Authors: 
    Thomas Bergauer; Marko Dragicevic; A. Escalante Del Valle; Jochen Schieck; Wolfgang Waltenberger; Freya Blekman; Emil Sørensen Bols; Stefaan Tavernier; Barbara Clerbaux; Amandeep Kaur Kalsi; +492 more
    Publisher: Springer
    Countries: United States, Italy, Belgium, Germany, Belgium, Italy, Italy, Italy, Serbia, Spain ...
    Project: EC | LHCTOPVLQ (752730), EC | AMVA4NewPhysics (675440), EC | INSIGHTS (765710)

    Decays of the 125 GeV Higgs boson into a Z boson and a ρ0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at s√ = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb−1. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels. Individuals have received support from the Marie-Curie programme and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 752730, and 765710 (European Union); the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias. Article funded by SCOAP3. CMS collaboration: et al. Peer reviewed

  • Open Access English
    Authors: 
    Georges Aad; Brad Abbott; A. Abed Abud; Kira Abeling; Syed Haider Abidi; Halina Abramowicz; Baida Achkar; Lennart Adam; C. Adam Bourdarios; Leszek Adamczyk; +1,420 more
    Publisher: Springer
    Countries: France, Denmark, United Kingdom, United Kingdom, United Kingdom, Norway, Argentina, France, Italy, Spain ...
    Project: EC | LightAtLHC (864950)

    We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRT, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; JINR; MES of Russia and NRC KI, Russian Federation; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, CANARIE, Compute Canada, CRC and IVADO, Canada; Beijing Municipal Science & Technology Commission, China; COST, ERC, ERDF, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union; Investissements d’Avenir Labex, Investissements d’Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and GIF, Israel; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelse, Sweden; The Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (U.K.) and BNL (U.S.A.), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in ref. This paper describes a measurement of light-by-light scattering based on Pb+Pb collision data recorded by the ATLAS experiment during Run 2 of the LHC. The study uses 2.2 nb(-1) of integrated luminosity collected in 2015 and 2018 at root sNN = 5.02TeV. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy E-T(gamma) > 2.5 GeV, pseudorapidity vertical bar eta(gamma)vertical bar 5 GeV, and with small diphoton transverse momentum and diphoton acoplanarity. The integrated and differential fiducial cross sections are measured and compared with theoretical predictions. The diphoton invariant mass distribution is used to set limits on the production of axion-like particles. This result provides the most stringent limits to date on axion-like particle production for masses in the range 6-100 GeV. Cross sections above 2 to 70 nb are excluded at the 95% CL in that mass interval. Swiss National Science Foundation (SNSF) Canton of Bern, Switzerland Canton of Geneva, Switzerland Ministry of Education, Youth & Sports - Czech Republic Czech Republic Government Netherlands Organization for Scientific Research (NWO) Netherlands Government Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Departamento Administrativo de Ciencia, Tecnologia e Innovacion Colciencias National Council for Scientific and Technological Development (CNPq) Natural Sciences and Engineering Research Council of Canada (NSERC) German-Israeli Foundation for Scientific Research and Development Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) Ministry of Science and Higher Education, Poland NCN, Poland National Natural Science Foundation of China (NSFC) Centre National de la Recherche Scientifique (CNRS) Beijing Municipal Science & Technology Commission Portuguese Foundation for Science and Technology PROMETEO Programme Generalitat Valenciana, Spain Ministry of Energy & Natural Resources - Turkey CERCA Programme Generalitat de Catalunya, Spain Federal Ministry of Education & Research (BMBF) Science & Technology Facilities Council (STFC) Azerbaijan National Academy of Sciences (ANAS) Marie Sklodowska-Curie Actions, European Union Russian Federation NRC KI, Russian Federation Istituto Nazionale di Fisica Nucleare (INFN) GenT Programme Generalitat Valenciana, Spain Ministry of Science and Technology, Taiwan Japan Society for the Promotion of Science SRC, Sweden Wallenberg Foundation, Sweden Ministry of Science and Technology, China United States Department of Energy (DOE) Danish Natural Science Research Council Herakleitos programme - EU-ESF, Greece French National Research Agency (ANR) Slovenian Research Agency - Slovenia Aristeia programme - EU-ESF, Greece Goran Gustafssons Stiftelse, Sweden Greek Ministry of Development-GSRT La Caixa Banking Foundation, Spain National Science Foundation (NSF) Alexander von Humboldt Foundation Thales programme - EU-ESF, Greece German Research Foundation (DFG) Canada Foundation for Innovation European Research Council (ERC) UK Research & Innovation (UKRI) Horizon 2020, European Union Australian Research Council Austrian Science Fund (FWF) Chinese Academy of Sciences Israel Science Foundation CRC, Canada IVADO, Canada Royal Society of London Benoziyo Center, Israel Compute Canada, Canada DST/NRF, South Africa ERDF, European Union Hong Kong SAR, China COST, European Union CEA-DRF/IRFU, France European Commission Greek NSRF, Greece Max Planck Society Spanish Government SERI, Switzerland Leverhulme Trust MNE/IFA, Romania SRNSFG, Georgia BSF-NSF, Israel CANARIE, Canada YerPhI, Armenia MSSR, Slovakia BMWFW, Austria CNRST, Morocco MIZS, Slovenia BCKDF, Canada DNRF, Denmark MESTD, Serbia SSTC, Belarus HGF, Germany RCN, Norway NRC, Canada ANID, Chile RGC, China ANPCyT CERN JINR

  • Open Access English
    Authors: 
    Henrikus, Sarah S.; Tassis, Konstantinos; Zhang, Lei; Velde, Jasper H. M. van der; Gebhardt, Christian; Herrmann, Andreas; Jung, Gregor; Cordes, Thorben;
    Country: Germany
    Project: EC | SM-IMPORT (638536)

    Genetically encodable fluorescent proteins have revolutionized biological imaging in vivo and in vitro. Since there are no other natural fluorescent tags with comparable features, the impact of fluorescent proteins for biological research cannot be overemphasized. Despite their importance, their photophysical properties, i.e., brightness, count-rate and photostability, are relatively poor compared to synthetic organic fluorophores or quantum dots. Intramolecular photostabilizers were recently rediscovered as an effective approach to improve photophysical properties. The approach uses direct conjugation of photostablizing compounds such as triplet-state quenchers or redox-active substances to an organic fluorophore, thereby creating high local concentrations of photostabilizer. Here, we introduce an experimental strategy to screen for the effects of covalently-linked photostabilizers on fluorescent proteins. We recombinantly produced a double cysteine mutant (A206C/L221C) of α-GFP for attachment of photostabilizer-maleimides on the ß-barrel in close proximity to the chromophore. Whereas labelling with photostabilizers such as Trolox, Nitrophenyl, and Cyclooctatetraene, which are often used for organic fluorophores, had no effect on α-GFP-photostability, a substantial increase of photostability was found upon conjugation of α-GFP to an azobenzene derivative. Although the mechanism of the photostabilizing effects remains to be elucidated, we speculate that the higher triplet-energy of azobenzene might be crucial for triplet-quenching of fluorophores in the near-UV and blue spectral range. Our study paves the way towards the development and design of a second generation of fluorescent proteins with photostabilizers placed directly in the protein barrel by methods such as unnatural amino acid incorporation.

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420 Research products, page 1 of 42
  • Publication . Article . Other literature type . Research . Preprint . 2020
    Open Access English
    Authors: 
    Valerie Domcke; Marco Drewes; Marco Hufnagel; Michele Lucente;
    Publisher: RWTH Aachen University
    Countries: Switzerland, Germany
    Project: EC | NewAve (638528)

    We study the type-I seesaw model with three right-handed neutrinos and Majorana masses below the pion mass. In this mass range, the model parameter space is not only strongly constrained by the requirement to explain the light neutrino masses, but also by experimental searches and cosmological considerations. In the existing literature, three disjoint regions of potentially viable parameter space have been identified. In one of them, all heavy neutrinos decay shortly before big bang nucleosynthesis. In the other two regions, one of the heavy neutrinos either decays between BBN and the CMB decoupling or is quasi-stable. We show that previously unaccounted constraints from photodisintegration of nuclei practically rule out all relevant decays that happen between BBN and the CMB decoupling. Quite remarkably, if all heavy neutrinos decay before BBN, the baryon asymmetry of the universe can be quite generically explained by low-scale leptogenesis, i.e. without further tuning in addition to what is needed to avoid experimental and cosmological constraints. This motivates searches for heavy neutrinos in pion decay experiments. Journal of high energy physics 01(1), 200 (2021). doi:10.1007/JHEP01(2021)200 Published by SISSA, [Trieste]

  • Publication . Article . Preprint . Other literature type . Research . Report . 2018
    Open Access English
    Authors: 
    Marko Dragicevic; Manfred Jeitler; I Kraetschmer; Jochen Schieck; Johannes Wittmann; Claudia-Elisabeth Wulz; Jasper Lauwers; Freya Blekman; Kevin Deroover; Stefaan Tavernier; +449 more
    Countries: Belgium, United States, France, Germany, Croatia, Italy, Italy, France, France, Lithuania ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for charged Higgs boson decaying to a charm and a bottom quark ( $ {\mathrm{H}}^{+}\to \mathrm{c}\overline{\mathrm{b}} $ ) is performed using 19.7 fb$^{−1}$ of pp collision data at $ \sqrt{s}=8 $ TeV. The production mechanism investigated in this search is $ \mathrm{t}\overline{\mathrm{t}} $ pair production in which one top quark decays to a charged Higgs boson and a bottom quark and the other decays to a charged lepton, a neutrino, and a bottom quark. Charged Higgs boson decays to $ \mathrm{c}\overline{\mathrm{b}} $ are searched for, resulting in a final state containing at least four jets, a charged lepton (muon or electron), and missing transverse momentum. A kinematic fit is performed to identify the pair of jets least likely to be the bottom quarks originating from direct top quark decays and the invariant mass of this pair is used as the final observable in the search. No evidence for the presence of a charged Higgs boson is observed and upper limits at 95% confidence level of 0.8–0.5% are set on the branching fraction ℬ(t → H$^{+}$b), assuming ℬ(H$^{+}$ → $ \mathrm{c}\overline{\mathrm{b}} $ ) = 1.0 and ℬ(t → H$^{+}$b) + ℬ(t → Wb) = 1.0, for the charged Higgs boson mass range 90–150 GeV. Journal of high energy physics 1811(11), 115 (2018). doi:10.1007/JHEP11(2018)115 Published by Springer Nature, Cham

  • Publication . Other literature type . Article . Research . Preprint . 2021
    Open Access English
    Authors: 
    Fruehwirth, Rudolf; Wulz, Claudia-Elisabeth; Melo da Costa, Eliza; Brandao Malbouisson, Helena; Tomei, Thiago; de Moraes Gregores, Eduardo; de Souza Lemos, Dener; Garcia Fuentes, Francisco Ignacio; Agram, Jean-Laurent; Brom, Jean-Marie; +279 more
    Publisher: Elsevier
    Countries: Italy, Germany, Belgium, Italy, Turkey, Croatia, United States, Spain, Turkey, Italy ...
    Project: EC | LHCTOPVLQ (752730), EC | INSIGHTS (765710), EC | AMVA4NewPhysics (675440)

    Measurements of the second Fourier harmonic coefficient (v2) of the azimuthal distributions of prompt and nonprompt D0 mesons produced in pp and pPb collisions are presented. Nonprompt D0 mesons come from beauty hadron decays. The data samples are collected by the CMS experiment at nucleon-nucleon center-of-mass energies of 13 and 8.16 TeV, respectively. In high multiplicity pp collisions, v2 signals for prompt charm hadrons are reported for the first time, and are found to be comparable to those for light-flavor hadron species over a transverse momentum (pT) range of 2–6 GeV. Compared at similar event multiplicities, the prompt D0 meson v2 values in pp and pPb collisions are similar in magnitude. The v2 values for open beauty hadrons are extracted for the first time via nonprompt D0 mesons in pPb collisions. For pT in the range of 2–5 GeV, the results suggest that v2 for nonprompt D0 mesons is smaller than that for prompt D0 mesons. These new measurements indicate a positive charm hadron v2 in pp collisions and suggest a mass dependence in v2 between charm and beauty hadrons in the pPb system. These results provide insights into the origin of heavy-flavor quark collectivity in small systems. Individuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 752730, and 765710 (European Union); CERN; the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias. CMS Collaboration: et al. Funded by SCOAP3. Peer reviewed

  • Open Access English
    Authors: 
    Thomas Bergauer; Marko Dragicevic; M. Flechl; Ilse Krätschmer; Dietrich Liko; Thomas Madlener; Jochen Schieck; Robert Schöfbeck; Markus Spanring; Jasper Lauwers; +413 more
    Publisher: Springer Verlag
    Countries: Germany, Germany, United Kingdom, Serbia, France, Italy, Italy, Finland, Switzerland, Italy ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of τ leptons is performed. A data sample of proton-proton collisions collected at s√ = 13 TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb−1. The signal strength is measured relative to the expectation for the standard model Higgs boson, yielding μ = 2.5 − 1.3 + 1.4 . These results are combined with earlier CMS measurements targeting Higgs boson decays to a pair of τ leptons, performed with the same data set in the gluon fusion and vector boson fusion production modes. The combined signal strength is μ = 1.24 − 0.27 + 0.29 (1.00 − 0.23 + 0.24 expected), and the observed significance is 5.5 standard deviations (4.8 expected) for a Higgs boson mass of 125 GeV. Journal of High Energy Physics, 2019 (6) ISSN:1029-8479 ISSN:1126-6708

  • Publication . Article . Other literature type . Preprint . Research . 2022
    Open Access English
    Authors: 
    Tumasyan, Armen; Adam, Wolfgang; Lechner, Lukas; Hensel, Carsten; Kim, Dong Hee; Kim, Gui Nyun; Kim, Jiwoong; Lee, Jeongeun; Lee, Seh Wook; Moon, Chang-Seong; +524 more
    Publisher: SPRINGER
    Countries: Germany, Germany, France, United Kingdom, Turkey, Italy, Finland, Switzerland, United States, Germany ...
    Project: EC | AMVA4NewPhysics (675440), EC | MajorNet (758316)

    Measurements of jet substructure describing the composition of quark- and gluon-initiated jets are presented. Proton-proton (pp) collision data at √s = 13 TeV collected with the CMS detector are used, corresponding to an integrated luminosity of 35.9 fb−1. Generalized angularities are measured that characterize the jet substructure and distinguish quark- and gluon-initiated jets. These observables are sensitive to the distributions of transverse momenta and angular distances within a jet. The analysis is performed using a data sample of dijet events enriched in gluon-initiated jets, and, for the first time, a Z+jet event sample enriched in quark-initiated jets. The observables are measured in bins of jet transverse momentum, and as a function of the jet radius parameter. Each measurement is repeated applying a “soft drop” grooming procedure that removes soft and large angle radiation from the jet. Using these measurements, the ability of various models to describe jet substructure is assessed, showing a clear need for improvements in Monte Carlo generators. Journal of High Energy Physics, 2022 (1) ISSN:1029-8479 ISSN:1126-6708

  • Open Access English
    Authors: 
    Schreiner, Thomas; Kaufmann, Elisabeth; Noachtar, Soheyl; Mehrkens, Jan-Hinnerk; Staudigl, Tobias;
    Country: Germany
    Project: EC | DirectThalamus (802681)

    A hallmark of non-rapid eye movement (NREM) sleep is the coordinated interplay of slow oscillations (SOs) and sleep spindles. Traditionally, a cortico-thalamo-cortical loop is suggested to coordinate these rhythms: neocortically-generated SOs trigger spindles in the thalamus that are projected back to neocortex. Here, we used direct intrathalamic recordings from human epilepsy patients to test this canonical interplay. We show that SOs in the anterior thalamus precede neocortical SOs, whereas concurrently-recorded SOs in the mediodorsal thalamus are led by neocortical SOs. Furthermore, sleep spindles, detected in both thalamic nuclei, preceded their neocortical counterparts and were initiated during early phases of thalamic SOs. Our findings indicate an active role of the anterior thalamus in organizing the cardinal sleep rhythms in the neocortex and highlight the functional diversity of specific thalamic nuclei in humans. The concurrent coordination of sleep oscillations by the thalamus could have broad implications for the mechanisms underlying memory consolidation.

  • Open Access English
    Authors: 
    Ece Aşılar; Marko Dragicevic; Martin Flechl; Ilse Krätschmer; Thomas Madlener; Navid Rad; Jochen Schieck; Robert Schöfbeck; Wolfgang Waltenberger; Claudia-Elisabeth Wulz; +470 more
    Publisher: Springer
    Countries: France, Italy, Croatia, Belgium, Italy, Switzerland, Belgium, Portugal, United States, Italy ...
    Project: EC | AMVA4NewPhysics (675440)

    A search for the pair production of the lightest supersymmetric partner of the top quark (t~1) is presented. The search focuses on a compressed scenario where the mass difference between the top squark and the lightest supersymmetric particle, often considered to be the lightest neutralino (χ~01), is smaller than the mass of the W boson. The proton-proton collision data were recorded by the CMS experiment at a centre-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 35.9 fb−1. In this search, two decay modes of the top squark are considered: a four-body decay into a bottom quark, two additional fermions, and a χ~01; and a decay via an intermediate chargino. Events are selected using the presence of a high-momentum jet, significant missing transverse momentum, and a low transverse momentum electron or muon. Two analysis techniques are used, targeting different decay modes of the t~1: a sequential selection and a multivariate technique. No evidence for the production of top squarks is found, and mass limits at 95% confidence level are set that reach up to 560 GeV, depending on the m(t~1)−m(χ~01) mass difference and the decay mode. Journal of High Energy Physics, 2018 (9) ISSN:1029-8479 ISSN:1126-6708

  • Publication . Article . Preprint . Research . Other literature type . 2020
    Open Access English
    Authors: 
    Thomas Bergauer; Marko Dragicevic; A. Escalante Del Valle; Jochen Schieck; Wolfgang Waltenberger; Freya Blekman; Emil Sørensen Bols; Stefaan Tavernier; Barbara Clerbaux; Amandeep Kaur Kalsi; +492 more