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An Algorithm of City-Level Landmark Mining Based on Internet Forum

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An Algorithm of City-Level Landmark Mining Based on Internet...

International Conference on Network-Based Information Systems (NBIS)

作者： Guang Zhu Xiangyang Luo Fenlin Liu Jingning Chen State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Science and Technology Institute Zhengzhou China

Density and accuracy of network entity landmarks are an important foundation of IP geolocation. For the existing problems of the limited quantity and low reliability of landmarks mined by current landmark mining methods, an algorithm of city-level landmark mining based on Internet forum is proposed in this paper. Firstly, the basic principle of Web-Based landmark mining methods and their existing flaws are analyzed, and then according to existing a huge amount of individual IP addresses in the Internet forums, a technical framework of network entity landmark mining based on the Internet forum is given, Next, the Internet forum selection strategy, IP addresses extraction, IP addresses screening and other major processing steps are described respectively for two major parts of the framework, including landmark extraction algorithm and landmark evaluation algorithm. The classic GeoTrack, a network entity geolocation algorithm, is improved and used for evaluating the candidate landmarks. Finally, the feasibility of our framework and algorithm are studied from 2 aspects: forum selection strategy, and Forum-Based landmark mining algorithm. Experimental results based on 27 Internet forums of 3 types forums in 3 cities show that compared with the classic Web-Based landmark mining methods, the proposed algorithm can not only mine huge amounts of city-level landmarks, but also improve the city-level network entity geolocation accuracy obviously.

关键词： IP networks Geology Web servers Reliability Data mining HTML

Properties of jet fragmentation using charged particles measured with the ATLAS detector in pp collisions at s=13 TeV

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Physical Review D 2019年第5期100卷 052011-052011页

作者： G. Aad B. Abbott D. C. Abbott O. Abdinov A. Abed Abud K. Abeling D. K. Abhayasinghe S. H. Abidi O. S. AbouZeid N. L. Abraham H. Abramowicz H. Abreu Y. Abulaiti B. S. Acharya B. Achkar S. Adachi L. Adam C. Adam Bourdarios L. Adamczyk L. Adamek J. Adelman M. Adersberger A. Adiguzel S. Adorni T. Adye A. A. Affolder Y. Afik C. Agapopoulou M. N. Agaras A. Aggarwal C. Agheorghiesei J. A. Aguilar-Saavedra F. Ahmadov W. S. Ahmed X. Ai G. Aielli S. Akatsuka T. P. A. Åkesson E. Akilli A. V. Akimov K. Al Khoury G. L. Alberghi J. Albert M. J. Alconada Verzini S. Alderweireldt M. Aleksa I. N. Aleksandrov C. Alexa D. Alexandre T. Alexopoulos A. Alfonsi M. Alhroob B. Ali G. Alimonti J. Alison S. P. Alkire C. Allaire B. M. M. Allbrooke B. W. Allen P. P. Allport A. Aloisio A. Alonso F. Alonso C. Alpigiani A. A. Alshehri M. Alvarez Estevez D. Álvarez Piqueras M. G. Alviggi Y. Amaral Coutinho A. Ambler L. Ambroz C. Amelung D. Amidei S. P. Amor Dos Santos S. Amoroso C. S. Amrouche F. An C. Anastopoulos N. Andari T. Andeen C. F. Anders J. K. Anders A. Andreazza V. Andrei C. R. Anelli S. Angelidakis A. Angerami A. V. Anisenkov A. Annovi C. Antel M. T. Anthony M. Antonelli D. J. A. Antrim F. Anulli M. Aoki J. A. Aparisi Pozo L. Aperio Bella G. Arabidze J. P. Araque V. Araujo Ferraz R. Araujo Pereira C. Arcangeletti A. T. H. Arce F. A. Arduh J-F. Arguin S. Argyropoulos J.-H. Arling A. J. Armbruster A. Armstrong O. Arnaez H. Arnold A. Artamonov G. Artoni S. Artz S. Asai N. Asbah E. M. Asimakopoulou L. Asquith K. Assamagan R. Astalos R. J. Atkin M. Atkinson N. B. Atlay H. Atmani K. Augsten G. Avolio R. Avramidou M. K. Ayoub A. M. Azoulay G. Azuelos M. J. Baca H. Bachacou K. Bachas M. Backes F. Backman P. Bagnaia M. Bahmani H. Bahrasemani A. J. Bailey V. R. Bailey J. T. Baines M. Bajic C. Bakalis O. K. Baker P. J. Bakker D. Bakshi Gupta S. Balaji E. M. Baldin P. Balek F. Balli W. K. Balunas J. Balz E. Banas A. Bandyopadhyay Sw. Banerjee A. A. E. Bannoura L. Barak W. M. Barbe E. L. Barberio D. Barberis M. Barbero T. Barillari M-S. Barisits CPPM Aix-Marseille Université CNRS/IN2P3 Marseille France Homer L. Dodge Department of Physics and Astronomy University of Oklahoma Norman Oklahoma USA Department of Physics University of Massachusetts Amherst Massachusetts USA Institute of Physics Azerbaijan Academy of Sciences Baku Azerbaijan INFN Sezione di Pavia Italy Dipartimento di Fisica Università di Pavia Pavia Italy II. Physikalisches Institut Georg-August-Universität Göttingen Göttingen Germany Department of Physics Royal Holloway University of London Egham United Kingdom Department of Physics University of Toronto Toronto Ontario Canada Niels Bohr Institute University of Copenhagen Copenhagen Denmark Department of Physics and Astronomy University of Sussex Brighton United Kingdom Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv Israel Department of Physics Technion Israel Institute of Technology Haifa Israel High Energy Physics Division Argonne National Laboratory Argonne Illinois USA INFN Gruppo Collegato di Udine Sezione di Trieste Udine Italy ICTP Trieste Italy International Center for Elementary Particle Physics and Department of Physics University of Tokyo Tokyo Japan Institut für Physik Universität Mainz Mainz Germany LAL Université Paris-Sud CNRS/IN2P3 Université Paris-Saclay Orsay France AGH University of Science and Technology Faculty of Physics and Applied Computer Science Krakow Poland Department of Physics Northern Illinois University DeKalb Illinois USA Fakultät für Physik Ludwig-Maximilians-Universität München München Germany Department of Physics Bogazici University Istanbul Turkey Département de Physique Nucléaire et Corpusculaire Université de Genève Genève Switzerland Particle Physics Department Rutherford Appleton Laboratory Didcot United Kingdom Santa Cruz Institute for Particle Physics University of California Santa Cruz Santa Cruz California USA LPC Université Clermont Auvergne CNRS/IN2P3 Clermont-Ferran

This paper presents a measurement of quantities related to the formation of jets from high-energy quarks and gluons (fragmentation). Jets with transverse momentum 100 GeV 500 MeV and |η|<2.5 are used to probe the detailed structure of the jet. The fragmentation properties of the more forward and the more central of the two leading jets from each event are studied. The data are unfolded to correct for detector resolution and acceptance effects. Comparisons with parton shower Monte Carlo generators indicate that existing models provide a reasonable description of the data across a wide range of phase space, but there are also significant differences. Furthermore, the data are interpreted in the context of quark- and gluon-initiated jets by exploiting the rapidity dependence of the jet flavor fraction. A first measurement of the charged-particle multiplicity using model-independent jet labels (topic modeling) provides a promising alternative to traditional quark and gluon extractions using input from simulation. The simulations provide a reasonable description of the quark-like data across the jet pT range presented in -this measurement, but the gluon-like data have systematically fewer charged particles than the simulation.

关键词： Quark & gluon jets

Studies of charm and beauty hadron long-range correlations in pp and pPb collisions at LHC energies

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arXiv 2020年

作者： Sirunyan, A.M. Tumasyan, A. Adam, W. Ambrogi, F. Bergauer, T. Dragicevic, M. Erö, J. Escalante Del Valle, A. Flechl, M. Frühwirth, R. Jeitler, M. Krammer, N. Krätschmer, I. Liko, D. Madlener, T. Mikulec, I. Rad, N. Schieck, J. Schöfbeck, R. Spanring, M. Waltenberger, W. Wulz, C.-E. Zarucki, M. Drugakov, V. Mossolov, V. Suarez Gonzalez, J. Darwish, M.R. de Wolf, E.A. Di Croce, D. Janssen, X. Kello, T. Lelek, A. Pieters, M. Rejeb Sfar, H. van Haevermaet, H. van Mechelen, P. van Putte, S. van Remortel, N. Blekman, F. Bols, E.S. Chhibra, S.S. D’Hondt, J. de Clercq, J. Lontkovskyi, D. Lowette, S. Marchesini, I. Moortgat, S. Python, Q. Tavernier, S. van Doninck, W. van Mulders, P. Beghin, D. Bilin, B. Clerbaux, B. de Lentdecker, G. Delannoy, H. Dorney, B. Favart, L. Grebenyuk, A. Kalsi, A.K. Moureaux, L. Popov, A. Postiau, N. Starling, E. Thomas, L. Vander Velde, C. Vanlaer, P. Vannerom, D. Cornelis, T. Dobur, D. Khvastunov, I. Niedziela, M. Roskas, C. Skovpen, K. Tytgat, M. Verbeke, W. Vermassen, B. Vit, M. Bruno, G. Caputo, C. David, P. Delaere, C. Delcourt, M. Giammanco, A. Lemaitre, V. Prisciandaro, J. Saggio, A. Vischia, P. Zobec, J. Alves, G.A. Correia Silva, G. Hensel, C. Moraes, A. Belchior Batista Das Chagas, E. Carvalho, W. Chinellato, J. Coelho, E. da Costa, E.M. da Silveira, G.G. de Jesus Damiao, D. de Oliveira Martins, C. Fonseca De Souza, S. Malbouisson, H. Martins, J. Matos Figueiredo, D. Medina Jaime, M. Melo De Almeida, M. Mora Herrera, C. Mundim, L. Nogima, H. Prado Da Silva, W.L. Rebello Teles, P. Sanchez Rosas, L.J. Santoro, A. Sznajder, A. Thiel, M. Tonelli Manganote, E.J. Torres Da Silva De Araujo, F. Vilela Pereira, A. Bernardes, C.A. Calligaris, L. Fernandez Perez Tomei, T.R. Gregores, E.M. Lemos, D.S. Mercadante, P.G. Novaes, S.F. Padula, Sandra S. Aleksandrov, A. Antchev, G. Hadjiiska, R. Iaydjiev, P. Misheva, M. Rodozov, M. Shopova, M. Sultanov, G. Bonchev, M. Dimitrov, A. Ivanov, T. Litov, L. Pavlov, B. Petkov, P. Petrov, A. Fang, W. Gao, X. Yuan, L. Ahmad, M. Hu, Z. Wang, Y. Chen, G.M. Yerevan Physics Institute Yerevan Armenia Institut für Hochenergiephysik Wien Austria Institute for Nuclear Problems Minsk Belarus Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Université Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Université Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista São Paulo Brazil Universidade Federal do ABC São Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Beihang University Beijing China Department of Physics Tsinghua University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Zhejiang University Hangzhou China Universidad de Los Andes Bogota Colombia Universidad de Antioquia Medellin Colombia University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Split Croatia University of Split Faculty of Science Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Escuela Politecnica Nacional Quito Ecuador Universidad San Francisco de Quito Quito Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt Egyptian Network of High Energy Physics Cairo Egypt National Institute of Chemical Physics and Biophysics Tallinn Estonia Department of Physics University of Helsinki Helsinki Finland Helsinki Institute of Physics Helsinki Finland Lappeenranta University of Technology Lappeenranta Finland IRFU CEA Université Paris-Saclay Gif-sur-Yvette France Laboratoire Leprince-Ringuet CNRS/IN2P3 Ecole Polytechnique Institut Polytechnique de Paris Palaiseau France Université de Str

Measurements of the second Fourier harmonic coefficient (v2) of the azimuthal distributions of prompt and nonprompt D0 mesons (the latter coming from beauty hadron decays) produced in pp and pPb collisions are presented. 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 are smaller than those 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. Copyright © 2020, The Authors. All rights reserved.

关键词： Hadrons

First measurement of the cross section for top quark pair production with additional charm jets using dileptonic final states in pp collisions at √s = 13 TeV

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arXiv 2020年

作者： Sirunyan, A.M. Tumasyan, A. Adam, W. Ambrogi, F. Asilar, E. Bergauer, T. Brandstetter, J. Brondolin, E. Dragicevic, M. Erö, J. Escalante Del Valle, A. Flechl, M. Frühwirth, R. Ghete, V.M. Hrubec, J. Jeitler, M. Krammer, N. Krätschmer, I. Liko, D. Madlener, T. Mikulec, I. Rad, N. Rohringer, H. Schieck, J. Schöfbeck, R. Spanring, M. Spitzbart, D. Taurok, A. Waltenberger, W. Wittmann, J. Wulz, C.-E. Zarucki, M. Chekhovsky, V. Mossolov, V. Suarez Gonzalez, J. De Wolf, E.A. Di Croce, D. Janssen, X. Lauwers, J. Pieters, M. Van De Klundert, M. Van Haevermaet, H. Van Mechelen, P. Van Remortel, N. Abu Zeid, S. Blekman, F. D'Hondt, J. De Bruyn, I. De Clercq, J. Deroover, K. Flouris, G. Lontkovskyi, D. Lowette, S. Marchesini, I. Moortgat, S. Moreels, L. Python, Q. Skovpen, K. Tavernier, S. Van Doninck, W. Van Mulders, P. Van Parijs, I. Beghin, D. Bilin, B. Brun, H. Clerbaux, B. De Lentdecker, G. Delannoy, H. Dorney, B. Fasanella, G. Favart, L. Goldouzian, R. Grebenyuk, A. Kalsi, A.K. Lenzi, T. Luetic, J. Postiau, N. Starling, E. Thomas, L. Vander Velde, C. Vanlaer, P. Vannerom, D. Wang, Q. Cornelis, T. Dobur, D. Fagot, A. Gul, M. Khvastunov, I. Poyraz, D. Roskas, C. Trocino, D. Tytgat, M. Verbeke, W. Vermassen, B. Vit, M. Zaganidis, N. Bakhshiansohi, H. Bondu, O. Brochet, S. Bruno, G. Caputo, C. David, P. Delaere, C. Delcourt, M. Francois, B. Giammanco, A. Krintiras, G. Lemaitre, V. Magitteri, A. Mertens, A. Musich, M. Piotrzkowski, K. Saggio, A. Vidal Marono, M. Wertz, S. Zobec, J. Alves, F.L. Alves, G.A. Brito, L. Correia Silva, G. Hensel, C. Moraes, A. Pol, M.E. Rebello Teles, P. Belchior Batista Das Chagas, E. Carvalho, W. Chinellato, J. Coelho, E. Da Costa, E.M. Da Silveira, G.G. De Jesus Damiao, D. De Oliveira Martins, C. Fonseca De Souza, S. Malbouisson, H. Matos Figueiredo, D. Melo De Almeida, M. Mora Herrera, C. Mundim, L. Nogima, H. Prado Da Silva, W.L. Sanchez Rosas, L.J. Santoro, A. Sznajder, A. Thiel, M. Tonelli Manganote, E.J. Torres Da Silva De Araujo, F. Vilela Pereira, A. Ahuja, S. Bernardes, C.A. Calligari Yerevan Physics Institute Yerevan Armenia Institut für Hochenergiephysik Wien Austria Institute for Nuclear Problems Minsk Belarus Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Université Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Université Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista São Paulo Brazil Universidade Federal do ABC São Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Beihang University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Tsinghua University Beijing China Universidad de Los Andes Bogota Colombia University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Split Croatia University of Split Faculty of Science Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Escuela Politecnica Nacional Quito Ecuador Universidad San Francisco de Quito Quito Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt Egyptian Network of High Energy Physics Cairo Egypt National Institute of Chemical Physics and Biophysics Tallinn Estonia Department of Physics University of Helsinki Helsinki Finland Helsinki Institute of Physics Helsinki Finland Lappeenranta University of Technology Lappeenranta Finland IRFU CEA Université Paris-Saclay Gif-sur-Yvette France Laboratoire Leprince-Ringuet Ecole polytechnique CNRS/IN2P3 Université Paris-Saclay Palaiseau France Université de Strasbourg CNRS IPHC UMR 7178 StrasbourgF-67000 France Centre de Calcul de l'Institut National de Physique Nucl

The first measurement of the inclusive cross section for top quark pairs (tt) produced in association with two additional charm jets is presented. The analysis uses the dileptonic final states of tt events produced in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 41.5 fb−1, recorded by the CMS experiment at the LHC. A new charm jet identification algorithm provides input to a neural network that is trained to distinguish among tt events with two additional charm (ttcc), bottom (ttbb), and light-flavour or gluon (ttLL) jets. By means of a template fitting procedure, the inclusive ttcc, ttbb, and ttLL cross sections are simultaneously measured, together with their ratios to the inclusive tt + two jets cross section. This provides measurements of the ttcc and ttbb cross sections of 10.1 ±1.2 (stat) ±1.4 (syst) pb and 4.54 ±0.35 (stat) ±0.56 (syst) pb, respectively, in the full phase space. The results are compared and found to be consistent with predictions from two different matrix element generators with next-to-leading order accuracy in quantum chromodynamics, interfaced with a parton shower simulation. © 2020, CC BY.

关键词： Phase space methods

Measurement of the Υ(1S) pair production cross section and search for resonances decaying to Υ(1S)µ+µ− in proton-proton collisions at √s = 13 TeV

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arXiv 2020年

The fiducial cross section for Υ(1S) pair production in proton-proton collisions at a center-of-mass energy of 13 TeV in the region where both Υ(1S) mesons have an absolute rapidity below 2.0 is measured to be 79 ±11 (stat) ±6 (syst) ±3 (B) pb assuming the mesons are produced unpolarized. The last uncertainty corresponds to the uncertainty in the Υ(1S) meson dimuon branching fraction. The measurement is performed in the final state with four muons using proton-proton collision data collected in 2016 by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. This process serves as a standard model reference in a search for narrow resonances decaying to Υ(1S)µ+µ− in the same final state. Such a resonance could indicate the existence of a tetraquark that is a bound state of two b quarks and two b antiquarks. The tetraquark search is performed for masses in the vicinity of four times the bottom quark mass, between 17.5 and 19.5 GeV, while a generic search for other resonances is performed for masses between 16.5 and 27 GeV. No significant excess of events compatible with a narrow resonance is observed in the data. Limits on the production cross section times branching fraction to four muons via an intermediate Υ(1S) resonance are set as a function of the resonance mass. Copyright © 2020, The Authors. All rights reserved.

关键词： Hadrons

Study of excited L0 b states decaying to L0 bp+p in proton-proton collisions at p s = 13 TeV the CMS Collaboration

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arXiv 2020年

作者： Sirunyan, A.M. Tumasyan, A. Adam, W. Ambrogi, F. Bergauer, T. Dragicevic, M. Ero, J. Escalante Del Valle, A. Flechl, M. Fruhwirth, R. Jeitler, M. Krammer, N. Kratschmer, I. Liko, D. Madlener, T. Mikulec, I. Rad, N. Schieck, J. Schofbeck, R. Spanring, M. Waltenberger, W. Wulz, C.-E. Zarucki, M. Drugakov, V. Mossolov, V. J. Suarez Gonzalez Darwish, M.R. De Wolf, E.A. Di Croce, D. Janssen, X. Kello, T. Lelek, A. Pieters, M. Rejeb Sfar, H. Van Haevermaet, H. Van Mechelen, P. Van Putte, S. Van Remortel F. Blekman, N. Bols, E.S. Chhibra, S.S. D'Hondt, J. De Clercq, J. Lontkovskyi, D. Lowette, S. Marchesini, I. Moortgat, S. Python, Q. Tavernier, S. Van Doninck, W. Van Mulders, P. Beghin, D. Bilin, B. Clerbaux, B. De Lentdecker, G. Delannoy, H. Dorney, B. Favart, L. Grebenyuk, A. Kalsi, A.K. Moureaux, L. Popov, A. Postiau, N. Starling, E. Thomas, L. Vander Velde, C. Vanlaer, P. Vannerom, D. Cornelis, T. Dobur, D. Khvastunov, I. Niedziela, M. Roskas, C. Skovpen, K. Tytgat, M. Verbeke, W. Vermassen, B. Vit, M. Bondu, O. Bruno, G. Caputo, C. David, P. Delaere, C. Delcourt, M. Giammanco, A. Lemaitre, V. Prisciandaro, J. Saggio, A. Vidal Marono, M. Vischia, P. Zobec, J. Alves, G.A. Correia Silva, G. Hensel, C. Moraes, A. Belchior Batista Das Chagas, E. Carvalho, W. Chinellato, J. Coelho, E. Da Costa, E.M. Da Silveira, G.G. De Jesus Damiao, D. De Oliveira Martins, C. Fonseca De Souza, S. Malbouisson, H. Martins, J. Matos Figueiredo, D. Medina Jaime, M. Melo De Almeida, M. Mora Herrera, C. Mundim, L. Nogima, H. Prado Da Silva, W.L. Rebello Teles, P. Sanchez Rosas, L.J. Santoro, A. Sznajder, A. Thiel, M. Tonelli Manganote, E.J. Torres Da Silva De Araujo, F. Vilela Pereira, A. Bernardesa, C.A. Calligarisa, L. Fernandez Perez Tomeia, T.R. Gregoresb, E.M. Lemos, D.S. Mercadanteb, P.G. Novaes, S.F. Padula, Sandra S. Aleksandrov, A. Antchev, G. Hadjiiska, R. Iaydjiev, P. Misheva, M. Rodozov, M. Shopova, M. Sultanov, G. Bonchev, M. Dimitrov, A. Ivanov, T. Litov, L. Pavlov, B. Petkov, P. Petrov, A. Fang, W. Gao, X. Yuan, L. Chen, G.M. Yerevan Physics Institute Yerevan Armenia Institut fur Hochenergiephysik Wien Australia Institute for Nuclear Problems Minsk Belarus Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Universite Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Universite Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade Do Estado Do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista Universidade Federal Do Abc Sao Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Beihang University Beijing China Department of Physics Tsinghua University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Zhejiang University Hangzhou China Universidad de Los Andes Bogota Colombia Universidad de Antioquia Medellin Colombia University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Split Croatia University of Split Faculty of Science Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Escuela Politecnica Nacional Quito Ecuador Universidad San Francisco de Quito Quito Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt Network of High Energy Physics Cairo Egypt National Institute of Chemical Physics and Biophysics Tallinn Estonia Department of Physics University of Helsinki Helsinki Finland Helsinki Institute of Physics Helsinki Finland Lappeenranta University of Technology Lappeenranta Finland Irfu Cea Universite Paris-Saclay Gif-sur-Yvette France Laboratoire Leprince-Ringuet CNRS/IN2P3 Ecole Polytechnique Universite de Strasbourg Cnrs Iphc Umr 7178 Strasbourg France Centre de Calcul de L'Institu

A study of excited L0 b baryons is reported, based on a data sample collected in 2016- 2018 with the CMS detector at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of up to 140 fb1. The existence of four excited L0 b states: Lb(5912)0, Lb(5920)0, Lb(6146)0, and Lb(6152)0 in the L0 bp+p mass spectrum is confirmed, and their masses are measured. The L0 bp+p mass distribution exhibits a broad excess of events in the region of 6040- 6100MeV, whose origin cannot be discerned with the present data. Copyright © 2020, The Authors. All rights reserved.

关键词： Mass spectrometry

Performance of the CMS Level-1 trigger in proton-proton collisions at √s = 13 TeV

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arXiv 2020年

作者： Sirunyan, A.M. Tumasyan, A. Adam, W. Ambrogi, F. Bergauer, T. Dragicevic, M. Erö, J. Escalante Del Valle, A. Flechl, M. Frühwirth, R. Jeitler, M. Krammer, N. Krätschmer, I. Liko, D. Madlener, T. Mikulec, I. Rad, N. Schieck, J. Schöfbeck, R. Spanring, M. Waltenberger, W. Wulz, C.-E. Zarucki, M. Drugakov, V. Mossolov, V. Suarez Gonzalez, J. Darwish, M.R. de Wolf, E.A. Di Croce, D. Janssen, X. Kello, T. Lelek, A. Pieters, M. Rejeb Sfar, H. van Haevermaet, H. van Mechelen, P. van Putte, S. van Remortel, N. Blekman, F. Bols, E.S. Chhibra, S.S. D’Hondt, J. de Clercq, J. Lontkovskyi, D. Lowette, S. Marchesini, I. Moortgat, S. Python, Q. Tavernier, S. van Doninck, W. van Mulders, P. Beghin, D. Bilin, B. Clerbaux, B. de Lentdecker, G. Delannoy, H. Dorney, B. Favart, L. Grebenyuk, A. Kalsi, A.K. Moureaux, L. Popov, A. Postiau, N. Starling, E. Thomas, L. Vander Velde, C. Vanlaer, P. Vannerom, D. Cornelis, T. Dobur, D. Khvastunov, I. Niedziela, M. Roskas, C. Skovpen, K. Tytgat, M. Verbeke, W. Vermassen, B. Vit, M. Bruno, G. Caputo, C. David, P. Delaere, C. Delcourt, M. Giammanco, A. Lemaitre, V. Prisciandaro, J. Saggio, A. Vischia, P. Zobec, J. Alves, G.A. Correia Silva, G. Hensel, C. Moraes, A. Belchior Batista Das Chagas, E. Carvalho, W. Chinellato, J. Coelho, E. da Costa, E.M. da Silveira, G.G. de Jesus Damiao, D. de Oliveira Martins, C. Fonseca De Souza, S. Malbouisson, H. Martins, J. Matos Figueiredo, D. Medina Jaime, M. Melo De Almeida, M. Mora Herrera, C. Mundim, L. Nogima, H. Prado Da Silva, W.L. Rebello Teles, P. Sanchez Rosas, L.J. Santoro, A. Sznajder, A. Thiel, M. Tonelli Manganote, E.J. Torres Da Silva De Araujo, F. Vilela Pereira, A. Bernardes, C.A. Calligaris, L. Fernandez Perez Tomei, T.R. Gregores, E.M. Lemos, D.S. Mercadante, P.G. Novaes, S.F. Padula, Sandra S. Aleksandrov, A. Antchev, G. Hadjiiska, R. Iaydjiev, P. Misheva, M. Rodozov, M. Shopova, M. Sultanov, G. Bonchev, M. Dimitrov, A. Ivanov, T. Litov, L. Pavlov, B. Petkov, P. Petrov, A. Fang, W. Gao, X. Yuan, L. Ahmad, M. Hu, Z. Yuan, A. Chen, G.M. Yerevan Physics Institute Yerevan Armenia Institut für Hochenergiephysik Wien Austria Institute for Nuclear Problems Minsk Belarus Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Université Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Université Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista São Paulo Brazil Universidade Federal do ABC São Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Beihang University Beijing China Department of Physics Tsinghua University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Zhejiang University Hangzhou China Universidad de Los Andes Bogota Colombia Universidad de Antioquia Medellin Colombia University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Split Croatia University of Split Faculty of Science Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Escuela Politecnica Nacional Quito Ecuador Universidad San Francisco de Quito Quito Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt Egyptian Network of High Energy Physics Cairo Egypt National Institute of Chemical Physics and Biophysics Tallinn Estonia Department of Physics University of Helsinki Helsinki Finland Helsinki Institute of Physics Helsinki Finland Lappeenranta University of Technology Lappeenranta Finland IRFU CEA Université Paris-Saclay Gif-sur-Yvette France Laboratoire Leprince-Ringuet CNRS/IN2P3 Ecole Polytechnique Institut Polytechnique de Paris Paris France Université de Strasbo

At the start of Run 2 in 2015, the LHC delivered proton-proton collisions at a center-of-mass energy of 13 TeV. During Run 2 (years 2015–2018) the LHC eventually reached a luminosity of 2.1 × 1034 cm−2 s−1, almost three times that reached during Run 1 (2009–2013) and a factor of two larger than the LHC design value, leading to events with up to a mean of about 50 simultaneous inelastic proton-proton collisions per bunch crossing (pileup). The CMS Level-1 trigger was upgraded prior to 2016 to improve the selection of physics events in the challenging conditions posed by the second run of the LHC. This paper describes the performance of the CMS Level-1 trigger upgrade during the data taking period of 2016–2018. The upgraded trigger implements pattern recognition and boosted decision tree regression techniques for muon reconstruction, includes pileup subtraction for jets and energy sums, and incorporates pileup-dependent isolation requirements for electrons and tau leptons. In addition, the new trigger calculates high-level quantities such as the invariant mass of pairs of reconstructed particles. The upgrade reduces the trigger rate from background processes and improves the trigger efficiency for a wide variety of physics signals. Copyright © 2020, The Authors. All rights reserved.

关键词： Pattern recognition

The production of isolated photons in PbPb and pp collisions at √sNN= 5.02 TeV

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arXiv 2020年

作者： Sirunyan, A.M. Tumasyan, A. Adam, W. Ambrogi, F. Bergauer, T. Brandstetter, J. Dragicevic, M. Erö, J. Escalante Del Valle, A. Flechl, M. Frühwirth, R. Jeitler, M. Krammer, N. Krätschmer, I. Liko, D. Madlener, T. Mikulec, I. Rad, N. Rohringer, H. Schieck, J. Schöfbeck, R. Spanring, M. Waltenberger, W. Wulz, C.-E. Zarucki, M. Chekhovsky, V. Mossolov, V. Suarez Gonzalez, J. Darwish, M.R. De Wolf, E.A. Di Croce, D. Janssen, X. Kello, T. Lelek, A. Pieters, M. Rejeb Sfar, H. Van Haevermaet, H. Van Mechelen, P. Van Putte, S. Van Remortel, N. Blekman, F. Bols, E.S. Chhibra, S.S. D'Hondt, J. De Clercq, J. Lontkovskyi, D. Lowette, S. Marchesini, I. Moortgat, S. Python, Q. Tavernier, S. Van Doninck, W. Van Mulders, P. Beghin, D. Bilin, B. Brun, H. Clerbaux, B. De Lentdecker, G. Delannoy, H. Dorney, B. Fasanella, G. Favart, L. Goldouzian, R. Grebenyuk, A. Kalsi, A.K. Lenzi, T. Luetic, J. Postiau, N. Starling, E. Thomas, L. Vander Velde, C. Vanlaer, P. Vannerom, D. Wang, Q. Cornelis, T. Dobur, D. Fagot, A. Gul, M. Khvastunov, I. Poyraz, D. Roskas, C. Trocino, D. Tytgat, M. Verbeke, W. Vermassen, B. Vit, M. Zaganidis, N. Bakhshiansohi, H. Bondu, O. Brochet, S. Bruno, G. Caputo, C. David, P. Delaere, C. Delcourt, M. Giammanco, A. Krintiras, G. Lemaitre, V. Magitteri, A. Mertens, A. Musich, M. Piotrzkowski, K. Saggio, A. Vidal Marono, M. Wertz, S. Zobec, J. Alves, F.L. Alves, G.A. Correa Martins, M. Correia Silva, G. Hensel, C. Moraes, A. Pol, M.E. Rebello Teles, P. Das Chagas, E. Belchior Batista Carvalho, W. Chinellato, J. Coelho, E. Da Costa, E.M. Da Silveira, G.G. De Jesus Damiao, D. De Oliveira Martins, C. De Souza, S. Fonseca Malbouisson, H. Matos Figueiredo, D. De Almeida, M. Melo Mora Herrera, C. Mundim, L. Nogima, H. Prado Da Silva, W.L. Sanchez Rosas, L.J. Santoro, A. Sznajder, A. Thiel, M. Tonelli Manganote, E.J. Da Silva De Araujo, F. Torres Vilela Pereira, A. Ahuja, S. Bernardes, C.A. Calligaris, L. Fernandez Perez Tomei, T.R. Gregores, E.M. Mercadante, P.G. Novaes, S.F. Padula, Sandra S. Aleksandrov, A. Hadjiiska, Yerevan Physics Institute Yerevan Armenia Institut Fr Hochenergiephysik Wien Austria Institute for Nuclear Problems Minsk Belarus Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Universit Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Universit Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade Do Estado Do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista So Paulo Brazil Universidade Federal Do ABC So Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Beihang University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Tsinghua University Beijing China Universidad de Los Andes Bogota Colombia Universidad de Antioquia Medellin Colombia University of Split Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture Split Croatia University of Split Faculty of Science Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Escuela Politecnica Nacional Quito Ecuador Universidad San Francisco de Quito Quito Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt Egyptian Network of High Energy Physics Cairo Egypt National Institute of Chemical Physics and Biophysics Tallinn Estonia Department of Physics University of Helsinki Helsinki Finland Helsinki Institute of Physics Helsinki Finland Lappeenranta University of Technology Lappeenranta Finland IRFU CEA Universit Paris-Saclay Gif-sur-Yvette France Laboratoire Leprince-Ringuet Ecole Polytechnique CNRS IN2P3 Universit Paris-Saclay Palaiseau France Universit de Strasbourg CNRS IPHC UMR 7178 Strasbourg France Centre de Calcul de l'Inst

The transverse energy (EγT) spectra of photons isolated from other particles are measured using proton-proton (pp) and lead-lead (PbPb) collisions at the LHC at √sNN= 5.02 TeV with integrated luminosities of 27.4 pb-1and 404 μb-1for pp and PbPb data, respectively. The results are presented for photons with 25 γT Copyright © 2020, The Authors. All rights reserved.

关键词： Photons

Search for long-lived particles using displaced jets in proton-proton collisions at √s = 13 TeV

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arXiv 2020年

An inclusive search is presented for long-lived particles using displaced jets. The search uses a data sample collected with the CMS detector at the CERN LHC in 2017 and 2018, from proton-proton collisions at a center-of-mass energy of 13 TeV. The results of this search are combined with those of a previous search using a data sample collected with the CMS detector in 2016, yielding a total integrated luminosity of 132 fb−1. The analysis searches for the distinctive topology of displaced tracks and displaced vertices associated with a dijet system. For a simplified model, where pair-produced long-lived neutral particles decay into quark-antiquark pairs, pair production cross sections larger than 0.07 fb are excluded at 95% confidence level (CL) for long-lived particle masses larger than 500 GeV and mean proper decay lengths between 2 and 250 mm. For a model where the standard model-like Higgs boson decays to two long-lived scalar particles that each decays to a quark-antiquark pair, branching fractions larger than 1% are excluded at 95% CL for mean proper decay lengths between 1 mm and 340 mm. A group of supersymmetric models with pair-produced long-lived gluinos or top squarks decaying into various final-state topologies containing displaced jets is also tested. Gluino masses up to 2500 GeV and top squark masses up to 1600 GeV are excluded at 95% CL for mean proper decay lengths between 3 and 300 mm. The highest lower bounds on mass reach 2600 GeV for long-lived gluinos and 1800 GeV for long-lived top squarks. These are the most stringent limits to date on these models. © 2020, CC BY.

关键词： Bosons