Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions at sqrt(s) = 8 TeV

A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fb−1. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at 95% confidence level for a W′-boson with the same couplings as that of the standard model W-boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza–Klein WKK(2) states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W-boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W′-boson and the standard model W-boson and for a compositeness model.

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Muhammad Ahmad, Georgios Anagnostou, Konstantin Androsov, Alexandre Aubin, Giovanni Bianchi, Roberto Castello, Yixing Chen, Tian Cheng, Giuseppe Codispoti, Alessandro Degano, Charles Dietz, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Yifei Guo, Ruchi Gupta, Csaba Hajdu, Alexis Kalogeropoulos, Ji Hyun Kim, Donghyun Kim, Vineet Kumar, Ajay Kumar, Sanjeev Kumar, Ekaterina Kuznetsova, Wei Li, Ho Ling Li, Shuai Liu, Hao Liu, Werner Lustermann, Matteo Marone, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Ashish Sharma, Varun Sharma, Lesya Shchutska, Muhammad Shoaib, Michal Simon, Gurpreet Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, Paul Turner, Joao Varela, Rui Wang, Zheng Wang, Xiao Wang, Jian Wang, Qian Wang, Matthias Weber, Matthias Wolf, Fan Yang, Yong Yang, Kai Yi, Lei Zhang, Yu Zheng
2015
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https://infoscience.epfl.ch/record/274771?ln=fr

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Search for new phenomena in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum in pp collisions at $ \sqrt{s}=13 $ TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Michele Bianco, Roberto Castello, Yixing Chen, Xin Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Alessandro Degano, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Daniel Gonzalez, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Alexis Kalogeropoulos, Viktor Khristenko, Donghyun Kim, Ji Hyun Kim, Vineet Kumar, Ajay Kumar, Sanjeev Kumar, Ekaterina Kuznetsova, Wei Li, Ho Ling Li, Hao Liu, Shuai Liu, Zhen Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Amr Mohamed, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Ashish Sharma, Varun Sharma, Lesya Shchutska, Muhammad Shoaib, Gurpreet Singh, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Jian Wang, Yi Wang, Mingkui Wang, Zheng Wang, Qian Wang, Hui Wang, Siyuan Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Zhirui Xu, Yong Yang, Kai Yi

Search results are presented for physics beyond the standard model in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb

^{−1}

of proton-proton collisions at

\sqrt{s}=13

TeV collected with the CMS detector at the LHC in 2016. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. The search for a kinematic edge targets production of particles sensitive to the strong force, while the resonance search targets both strongly and electroweakly produced new physics. The observed yields are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry. In a gauge mediated supersymmetry breaking (GMSB) model of gluino pair production with decay chains including Z bosons, gluino masses up to 1500–1770 GeV are excluded at the 95% confidence level depending on the lightest neutralino mass. In a model of electroweak chargino-neutralino production, chargino masses as high as 610 GeV are excluded when the lightest neutralino is massless. In GMSB models of electroweak neutralino-neutralino production, neutralino masses up to 500-650 GeV are excluded depending on the decay mode assumed. Finally, in a model with bottom squark pair production and decay chains resulting in a kinematic edge in the dilepton invariant mass distribution, bottom squark masses up to 980–1200 GeV are excluded depending on the mass of the next-to-lightest neutralino.

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Search for heavy resonances decaying into two Higgs bosons or into a Higgs boson and a W or Z boson in proton-proton collisions at 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Michele Bianco, Roberto Castello, Xin Chen, Yixing Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Alessandro Degano, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Daniel Gonzalez, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Alexis Kalogeropoulos, Viktor Khristenko, Ji Hyun Kim, Donghyun Kim, Vineet Kumar, Sanjeev Kumar, Ajay Kumar, Ekaterina Kuznetsova, Ho Ling Li, Jing Li, Wei Li, Shuai Liu, Zhen Liu, Hao Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Varun Sharma, Ashish Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Gurpreet Singh, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Yi Wang, Mingkui Wang, Jian Wang, Siyuan Wang, Hui Wang, Qian Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Wenjing Wu, Fan Xia, Meng Xiao, Zhirui Xu, Yong Yang, Kai Yi

A search is presented for massive narrow resonances decaying either into two Higgs bosons, or into a Higgs boson and a W or Z boson. The decay channels considered are

\mathrm{H}\mathrm{H}\to \mathrm{b}\overline{\mathrm{b}}{\tau}^{+}{\tau}^{-}

and

\mathrm{V}\mathrm{H}\to \mathrm{q}\overline{\mathrm{q}}{\tau}^{+}{\tau}^{-}

, where H denotes the Higgs boson, and V denotes the W or Z boson. This analysis is based on a data sample of proton-proton collisions collected at a center-of-mass energy of 13 TeV by the CMS Collaboration, corresponding to an integrated luminosity of 35.9 fb

^{−1}

. For the TeV-scale mass resonances considered, substructure techniques provide ways to differentiate among the hadronization products from vector boson decays to quarks, Higgs boson decays to bottom quarks, and quark- or gluon-induced jets. Reconstruction techniques are used that have been specifically optimized to select events in which the tau lepton pair is highly boosted. The observed data are consistent with standard model expectations and upper limits are set at 95% confidence level on the product of cross section and branching fraction for resonance masses between 0.9 and 4.0 TeV. Exclusion limits are set in the context of bulk radion and graviton models:spin-0 radion resonances are excluded below a mass of 2.7 TeV at 95% confidence level. In the spin-1 heavy vector triplet framework, mass-degenerate W′ and Z′ resonances with dominant couplings to the standard model gauge bosons are excluded below a mass of 2.8 TeV at 95% confidence level. These are the first limits for massive resonances at the TeV scale with these decay channels at

\sqrt{s}=13

TeV.

Springer2019

Chargement

Search for the Higgs boson decaying to two muons in proton-proton collisions at $\sqrt{s} =$ 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Michele Bianco, Yixing Chen, Xin Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Daniel Gonzalez, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Alexis Kalogeropoulos, Viktor Khristenko, Ji Hyun Kim, Donghyun Kim, Sanjeev Kumar, Vineet Kumar, Ajay Kumar, Ekaterina Kuznetsova, Ho Ling Li, Wei Li, Jing Li, Zhen Liu, Shuai Liu, Hao Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Varun Sharma, Ashish Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Gurpreet Singh, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Hui Wang, Mingkui Wang, Jian Wang, Qian Wang, Yi Wang, Zheng Wang, Siyuan Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Zhirui Xu, Yong Yang

A search for the Higgs boson decaying to two oppositely charged muons is presented using data recorded by the CMS experiment at the CERN LHC in 2016 at a center-of-mass energy s=13 TeV, corresponding to an integrated luminosity of 35.9 fb-1. Data are found to be compatible with the predicted background. For a Higgs boson with a mass of 125.09 GeV, the 95% confidence level observed (background-only expected) upper limit on the production cross section times the branching fraction to a pair of muons is found to be 3.0 (2.5) times the standard model expectation. In combination with data recorded at center-of-mass energies s=7 and 8 TeV, the background-only expected upper limit improves to 2.2 times the standard model value with a standard model expected significance of 1.0 standard deviation. The corresponding observed upper limit is 2.9 with an observed significance of 0.9 standard deviation. This corresponds to an observed upper limit on the standard model Higgs boson branching fraction to muons of 6.4×10-4 and to an observed signal strength of 1.0±1.0(stat)±0.1(syst).

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Chargement