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  • Open Access English
    Authors: 
    Sirunyan, A. M.; Tumasyan, Armen; Escalante Del Valle, Alberto; Bruno, Giacomo; Ramírez García, Mateo; Sánchez Hernández, Alberto; Carrillo Moreno, Salvador; Oropeza Barrera, Cristina; Vazquez Valencia, Fabiola; Eysermans, Jan; +225 more
    Publisher: APS
    Countries: Germany, France, Switzerland
    Project: EC | AMVA4NewPhysics (675440)

    A search for resonance-like structures in the $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$ invariant mass spectrum is performed using proton-proton collision data collected by the CMS experiment at the LHC at $\sqrt{s} = $ 8 TeV, corresponding to an integrated luminosity of 19.7 fb$^{-1}$. The $\mathrm{B}^{0}_{\mathrm{s}}$ mesons are reconstructed in the decay chain $\mathrm{B}^{0}_{\mathrm{s}} \rightarrow \mathrm{J}/\psi\,\phi$, with $\mathrm{J}/\psi \rightarrow \mu^+\mu^-$ and $\phi\rightarrow\mathrm{K^{+}}\mathrm{K^{-}}$. The $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$ invariant mass distribution shows no statistically significant peaks for different selection requirements on the reconstructed $\mathrm{B}^{0}_{\mathrm{s}}$ and $\pi^{\pm}$ candidates. Upper limits are set on the relative production rates of the X(5568) and $\mathrm{B}^{0}_{\mathrm{s}}$ states times the branching fraction of the decay $\mathrm{X}(5568)^{\pm} \rightarrow \mathrm{B}^{0}_{\mathrm{s}} \pi^{\pm} $. In addition, upper limits are obtained as a function of the mass and the natural width of possible exotic states decaying into $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$. Physical review letters 120(20), 202005 (2018). doi:10.1103/PhysRevLett.120.202005 Published by APS, College Park, Md.

  • Publication . Article . Other literature type . Research . Preprint . 2021
    Open Access English
    Authors: 
    Cole Lindsey; Ayse Polatoz; Alessandro Thea; Sinan Sagir; Soureek Mitra; Ram Krishna Dewanjee; Daniele Fasanella; Robert Hirosky; Santeri Laurila; Austin Baty; +557 more
    Countries: Belgium, Italy, Spain, Turkey, United Kingdom, Italy, Italy, Germany, France, United States ...
    Project: EC | LHCTOPVLQ (752730), EC | INSIGHTS (765710), EC | AMVA4NewPhysics (675440)

    Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at s√ = 13 TeV, corresponding to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC. An excess of events over the back- ground expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at s√ = 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb−1, respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19+0.40−0.39(stat)+0.15−0.14(syst). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date. 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. CMS collaboration: et al. Peer reviewed

  • Publication . Article . Preprint . Other literature type . Research . Report . 2018
    Open Access English
    Authors: 
    Ece Aşılar; Marko Dragicevic; Dietrich Liko; Jochen Schieck; Wolfgang Waltenberger; Claudia-Elisabeth Wulz; Vladimir Chekhovsky; Freya Blekman; Stefaan Tavernier; I. Van Parijs; +450 more
    Publisher: Springer
    Countries: Turkey, Switzerland, Lithuania, Finland, Spain, Italy, Germany, Belgium, Italy, Turkey ...
    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; +193 more
    Publisher: North-Holland Publ.
    Countries: Belgium, Germany, Italy, Switzerland, Italy, Belgium, Belgium, Spain, France, Germany ...
    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

  • Publication . Article . Other literature type . Research . Preprint . 2020
    Open Access
    Authors: 
    Valerie Domcke; Marco Drewes; Marco Hufnagel; Michele Lucente;
    Publisher: SPRINGER
    Countries: Germany, Switzerland
    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]

  • Open Access English
    Authors: 
    Köhler, Mila;
    Publisher: Mannheim: Zentrum für Europäische Wirtschaftsforschung (ZEW)
    Country: Germany
    Project: EC | SIMPATIC (290597)

    In Germany, R&D subsidies are an important tool to support innovation in the private sector. This paper studies the welfare effects of R&D subsidies distributed through the German federal government’s thematic R&D programs between 1994 and 2011. The analysis is based on a structural model of the R&D subsidy process which allows to estimate the benefits of R&D subsides to the German economy. The model takes into account heterogeneous application costs of firms and identifies the effect of the subsidy on the federal government’s utility as well as on firm profits. Assuming a welfare-maximizing federal government, the estimated average social rate of return is 34% for Germany in the period 1994 to 2011. Thereby effects on firm profits are similar to effects on spillovers to the rest of the German economy. Besides results show that the subsidy rate decision in Germany remained remarkably stable over time, and that application costs as well as the marginal profitability of subsidized R&D projects are lower after the year 2000 compared to the years before.

  • Open Access English
    Authors: 
    Sirunyan, Albert M; Tumasyan, Armen; Fruehwirth, Rudolf; Alves, Gilvan; Kim, Tae Jeong; Park, Jiwon; Cho, Sungwoong; Choi, Suyong; Go, Yeonju; Gyun, Dooyeon; +190 more
    Publisher: HAL CCSD
    Countries: Italy, United States, Switzerland, Italy, Italy, Italy, Italy, Germany, France, United Kingdom
    Project: EC | INSIGHTS (765710), EC | LHCTOPVLQ (752730), EC | AMVA4NewPhysics (675440)

    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. The European physical journal / C Particles and fields C 80(3), 237 (2020). doi:10.1140/epjc/s10052-020-7773-5 Published by Springer, Heidelberg

  • Publication . Article . Preprint . Other literature type . Research . 2020
    Open Access English
    Authors: 
    Salvatore Aiola; Simon Akar; Johannes Albrecht; Sandra Amato; G. Andreassi; John Back; Wander Baldini; William Barter; Fedor Baryshnikov; Jan-Marc Basels; +260 more
    Publisher: SpringerOpen
    Countries: Italy, United Kingdom, Netherlands, Italy, United Kingdom, France, Switzerland, Italy, Spain, Italy ...
    Project: EC | pANUCSTR (792684)

    A precision measurement of the $ {B}_c^{+} $ meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb$^{−1}$. The $ {B}_c^{+} $ mesons are reconstructed via the decays $ {B}_c^{+} $→ J/ψπ$^{+}$, $ {B}_c^{+} $→ J/ψπ$^{+}$π$^{−}$π$^{+}$, $ {B}_c^{+}\to J/\psi p\overline{p}{\pi}^{+} $, $ {B}_c^{+}\to J/\psi {D}_s^{+} $, $ {B}_c^{+} $→ J/ψ D$^{0}$K$^{+}$ and $ {B}_c^{+}\to {B}_s^0{\pi}^{+} $. Combining the results of the individual decay channels, the $ {B}_c^{+} $ mass is measured to be 6274.47 ± 0.27 (stat) ± 0.17 (syst) MeV/c$^{2}$. This is the most precise measurement of the $ {B}_c^{+} $ mass to date. The difference between the $ {B}_c^{+} $ and $ {B}_s^0 $ meson masses is measured to be 907.75 ± 0.37 (stat) ± 0.27 (syst) MeV/c$^2.$ Journal of high energy physics 07(7), 123 (1-20) (2020). doi:10.1007/JHEP07(2020)123 Published by SISSA, [Trieste]

  • Open Access English
    Authors: 
    Aaboud, Morad; Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdinov, Ovsat; Abeloos, Baptiste; Aben, Rosemarie; AbouZeid, Ossama; Abraham, Nicola; Abramowicz, Halina; +190 more
    Countries: Italy, Italy, Chile, Switzerland, Sweden, Argentina, United Kingdom, United Kingdom, Italy, Netherlands ...
    Project: SNSF | Teilchenphysik-Experiment... (163402), EC | EPLANET (246806)

    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; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, 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, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex and Idex, ANR, Region Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valenciana, Spain; 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 (Spa This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, H -> aa, where the particle a decays to b-quarks and has a mass in the range of 20-60 GeV. The search is performed in events where the Higgs boson is produced in associationwith aW boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from b-quark decays. The analysis is based on the full dataset of pp collisions at root s = 13 TeV recorded in 2015 by theATLAS detector at theCERNLargeHadron Collider, corresponding to an integrated luminosity of 3.2 fb(-1). No significant excess of events above the Standard Model prediction is observed, and a 95% confidence-level upper limit is derived for the product of the production cross section for pp -> WH times the branching ratio for the decay H -> aa -> 4b. The upper limit ranges from 6.2 pb for an a-boson mass m(a) = 20 GeV to 1.5 pb for m(a) = 60 GeV. info:eu-repo/semantics/publishedVersion

  • Open Access English
    Authors: 
    Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö +205 more
    Countries: France, Italy, Belgium, Switzerland, Germany, United Kingdom, Portugal, Belgium, Italy, Germany ...
    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

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595 Research products, page 1 of 60
  • Open Access English
    Authors: 
    Sirunyan, A. M.; Tumasyan, Armen; Escalante Del Valle, Alberto; Bruno, Giacomo; Ramírez García, Mateo; Sánchez Hernández, Alberto; Carrillo Moreno, Salvador; Oropeza Barrera, Cristina; Vazquez Valencia, Fabiola; Eysermans, Jan; +225 more
    Publisher: APS
    Countries: Germany, France, Switzerland
    Project: EC | AMVA4NewPhysics (675440)

    A search for resonance-like structures in the $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$ invariant mass spectrum is performed using proton-proton collision data collected by the CMS experiment at the LHC at $\sqrt{s} = $ 8 TeV, corresponding to an integrated luminosity of 19.7 fb$^{-1}$. The $\mathrm{B}^{0}_{\mathrm{s}}$ mesons are reconstructed in the decay chain $\mathrm{B}^{0}_{\mathrm{s}} \rightarrow \mathrm{J}/\psi\,\phi$, with $\mathrm{J}/\psi \rightarrow \mu^+\mu^-$ and $\phi\rightarrow\mathrm{K^{+}}\mathrm{K^{-}}$. The $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$ invariant mass distribution shows no statistically significant peaks for different selection requirements on the reconstructed $\mathrm{B}^{0}_{\mathrm{s}}$ and $\pi^{\pm}$ candidates. Upper limits are set on the relative production rates of the X(5568) and $\mathrm{B}^{0}_{\mathrm{s}}$ states times the branching fraction of the decay $\mathrm{X}(5568)^{\pm} \rightarrow \mathrm{B}^{0}_{\mathrm{s}} \pi^{\pm} $. In addition, upper limits are obtained as a function of the mass and the natural width of possible exotic states decaying into $\mathrm{B}^{0}_{\mathrm{s}}\pi^{\pm}$. Physical review letters 120(20), 202005 (2018). doi:10.1103/PhysRevLett.120.202005 Published by APS, College Park, Md.

  • Publication . Article . Other literature type . Research . Preprint . 2021
    Open Access English
    Authors: 
    Cole Lindsey; Ayse Polatoz; Alessandro Thea; Sinan Sagir; Soureek Mitra; Ram Krishna Dewanjee; Daniele Fasanella; Robert Hirosky; Santeri Laurila; Austin Baty; +557 more
    Countries: Belgium, Italy, Spain, Turkey, United Kingdom, Italy, Italy, Germany, France, United States ...
    Project: EC | LHCTOPVLQ (752730), EC | INSIGHTS (765710), EC | AMVA4NewPhysics (675440)

    Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at s√ = 13 TeV, corresponding to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC. An excess of events over the back- ground expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at s√ = 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb−1, respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19+0.40−0.39(stat)+0.15−0.14(syst). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date. 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. CMS collaboration: et al. Peer reviewed

  • Publication . Article . Preprint . Other literature type . Research . Report . 2018
    Open Access English
    Authors: 
    Ece Aşılar; Marko Dragicevic; Dietrich Liko; Jochen Schieck; Wolfgang Waltenberger; Claudia-Elisabeth Wulz; Vladimir Chekhovsky; Freya Blekman; Stefaan Tavernier; I. Van Parijs; +450 more
    Publisher: Springer
    Countries: Turkey, Switzerland, Lithuania, Finland, Spain, Italy, Germany, Belgium, Italy, Turkey ...
    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; +193 more
    Publisher: North-Holland Publ.
    Countries: Belgium, Germany, Italy, Switzerland, Italy, Belgium, Belgium, Spain, France, Germany ...
    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

  • Publication . Article . Other literature type . Research . Preprint . 2020
    Open Access
    Authors: 
    Valerie Domcke; Marco Drewes; Marco Hufnagel; Michele Lucente;
    Publisher: SPRINGER
    Countries: Germany, Switzerland
    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]

  • Open Access English
    Authors: 
    Köhler, Mila;
    Publisher: Mannheim: Zentrum für Europäische Wirtschaftsforschung (ZEW)
    Country: Germany
    Project: EC | SIMPATIC (290597)

    In Germany, R&D subsidies are an important tool to support innovation in the private sector. This paper studies the welfare effects of R&D subsidies distributed through the German federal government’s thematic R&D programs between 1994 and 2011. The analysis is based on a structural model of the R&D subsidy process which allows to estimate the benefits of R&D subsides to the German economy. The model takes into account heterogeneous application costs of firms and identifies the effect of the subsidy on the federal government’s utility as well as on firm profits. Assuming a welfare-maximizing federal government, the estimated average social rate of return is 34% for Germany in the period 1994 to 2011. Thereby effects on firm profits are similar to effects on spillovers to the rest of the German economy. Besides results show that the subsidy rate decision in Germany remained remarkably stable over time, and that application costs as well as the marginal profitability of subsidized R&D projects are lower after the year 2000 compared to the years before.

  • Open Access English
    Authors: 
    Sirunyan, Albert M; Tumasyan, Armen; Fruehwirth, Rudolf; Alves, Gilvan; Kim, Tae Jeong; Park, Jiwon; Cho, Sungwoong; Choi, Suyong; Go, Yeonju; Gyun, Dooyeon; +190 more
    Publisher: HAL CCSD
    Countries: Italy, United States, Switzerland, Italy, Italy, Italy, Italy, Germany, France, United Kingdom
    Project: EC | INSIGHTS (765710), EC | LHCTOPVLQ (752730), EC | AMVA4NewPhysics (675440)

    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. The European physical journal / C Particles and fields C 80(3), 237 (2020). doi:10.1140/epjc/s10052-020-7773-5 Published by Springer, Heidelberg

  • Publication . Article . Preprint . Other literature type . Research . 2020
    Open Access English
    Authors: 
    Salvatore Aiola; Simon Akar; Johannes Albrecht; Sandra Amato; G. Andreassi; John Back; Wander Baldini; William Barter; Fedor Baryshnikov; Jan-Marc Basels; +260 more
    Publisher: SpringerOpen
    Countries: Italy, United Kingdom, Netherlands, Italy, United Kingdom, France, Switzerland, Italy, Spain, Italy ...
    Project: EC | pANUCSTR (792684)

    A precision measurement of the $ {B}_c^{+} $ meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb$^{−1}$. The $ {B}_c^{+} $ mesons are reconstructed via the decays $ {B}_c^{+} $→ J/ψπ$^{+}$, $ {B}_c^{+} $→ J/ψπ$^{+}$π$^{−}$π$^{+}$, $ {B}_c^{+}\to J/\psi p\overline{p}{\pi}^{+} $, $ {B}_c^{+}\to J/\psi {D}_s^{+} $, $ {B}_c^{+} $→ J/ψ D$^{0}$K$^{+}$ and $ {B}_c^{+}\to {B}_s^0{\pi}^{+} $. Combining the results of the individual decay channels, the $ {B}_c^{+} $ mass is measured to be 6274.47 ± 0.27 (stat) ± 0.17 (syst) MeV/c$^{2}$. This is the most precise measurement of the $ {B}_c^{+} $ mass to date. The difference between the $ {B}_c^{+} $ and $ {B}_s^0 $ meson masses is measured to be 907.75 ± 0.37 (stat) ± 0.27 (syst) MeV/c$^2.$ Journal of high energy physics 07(7), 123 (1-20) (2020). doi:10.1007/JHEP07(2020)123 Published by SISSA, [Trieste]

  • Open Access English
    Authors: 
    Aaboud, Morad; Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdinov, Ovsat; Abeloos, Baptiste; Aben, Rosemarie; AbouZeid, Ossama; Abraham, Nicola; Abramowicz, Halina; +190 more
    Countries: Italy, Italy, Chile, Switzerland, Sweden, Argentina, United Kingdom, United Kingdom, Italy, Netherlands ...
    Project: SNSF | Teilchenphysik-Experiment... (163402), EC | EPLANET (246806)

    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; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, 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, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex and Idex, ANR, Region Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valenciana, Spain; 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 (Spa This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, H -> aa, where the particle a decays to b-quarks and has a mass in the range of 20-60 GeV. The search is performed in events where the Higgs boson is produced in associationwith aW boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from b-quark decays. The analysis is based on the full dataset of pp collisions at root s = 13 TeV recorded in 2015 by theATLAS detector at theCERNLargeHadron Collider, corresponding to an integrated luminosity of 3.2 fb(-1). No significant excess of events above the Standard Model prediction is observed, and a 95% confidence-level upper limit is derived for the product of the production cross section for pp -> WH times the branching ratio for the decay H -> aa -> 4b. The upper limit ranges from 6.2 pb for an a-boson mass m(a) = 20 GeV to 1.5 pb for m(a) = 60 GeV. info:eu-repo/semantics/publishedVersion

  • Open Access English
    Authors: 
    Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö +205 more
    Countries: France, Italy, Belgium, Switzerland, Germany, United Kingdom, Portugal, Belgium, Italy, Germany ...
    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

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