Probing top-antitop resonances with tt scattering at LHC14

We explore the sensitivity of the LHC at 14 TeV centre -of -mass energy (LHC14) to the single production and decay of top-antitop resonances in the four -top final state. We focus on the same -sign dilepton channel, and work within a simplified model with a vector boson coupling to the Standard Model only via its interactions with right-handed top quarks. We find it is possible to discover (exclude) such a vector boson with 30011D-1 of integrated luminosity up to a mass of 1.2 (1.6) TeV for a modest coupling to tops of gp = 2. We present our results as an exclusion limit on the cross-section x branching ratio for ease of recasting, and interpret them in the context of the gauge -singlet vector boson px present in many simple Composite Higgs theories.

Measurement of the Properties of a Higgs Boson in the Four-Lepton Final State

Muhammad Ahmad, Georgios Anagnostou, Konstantin Androsov, Giovanni Bianchi, Roberto Castello, Yixing Chen, Jie Chen, Tian Cheng, Giuseppe Codispoti, Alessandro Degano, Charles Dietz, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Yu Fu, Yifei Guo, Ruchi Gupta, Csaba Hajdu, Alexis Kalogeropoulos, Donghyun Kim, Ji Hyun Kim, Ajay Kumar, Sanjeev Kumar, Vineet Kumar, Ekaterina Kuznetsova, Wei Li, Hao Liu, Shuai Liu, Werner Lustermann, Matteo Marone, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Varun Sharma, Ashish Sharma, Lesya Shchutska, Muhammad Shoaib, Michal Simon, Gurpreet Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, Paul Turner, Joao Varela, Qian Wang, Xiao Wang, Mingkui Wang, Jian Wang, Zheng Wang, Matthias Weber, Matthias Wolf, Wenjing Wu, Yong Yang, Fan Yang, Kai Yi, Lei Zhang, Yu Zheng

The properties of a Higgs boson candidate are measured in the H→ZZ→4ℓ decay channel, with ℓ=e, μ, using data from pp collisions corresponding to an integrated luminosity of 5.1 fb−1 at the center-of-mass energy of s=7 TeV and 19.7 fb-1 at s=8 TeV, recorded with the CMS detector at the LHC. The new boson is observed as a narrow resonance with a local significance of 6.8 standard deviations, a measured mass of 125.6±0.4(stat)±0.2(syst) GeV, and a total width ≤3.4 GeV at the 95% confidence level. The production cross section of the new boson times its branching fraction to four leptons is measured to be 0.93-0.23+0.26(stat)-0.09+0.13(syst) times that predicted by the standard model. Its spin-parity properties are found to be consistent with the expectations for the standard-model Higgs boson. The hypotheses of a pseudoscalar and all tested spin-1 boson hypotheses are excluded at the 99% confidence level or higher. All tested spin-2 boson hypotheses are excluded at the 95% confidence level or higher.

2014

Combined measurements of Higgs boson couplings in proton–proton collisions at $\sqrt{s}=13\,\text {Te}\text {V} $

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, 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, Wei Li, Jing Li, Lei Li, Ho Ling Li, Zhen Liu, Hao Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Ashish Sharma, Varun Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Gurpreet Singh, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Yi Wang, Zheng Wang, Qian Wang, Siyuan Wang, Jian Wang, Mingkui Wang, Hui Wang, Xiao Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Zhirui Xu, Yong Yang

Combined measurements of the production and decay rates of the Higgs boson, as well as its couplings to vector bosons and fermions, are presented. The analysis uses the LHC proton–proton collision data set recorded with the CMS detector in 2016 at

\sqrt{s}=13\,\text {Te}\text {V}

, corresponding to an integrated luminosity of 35.9

{\,\text {fb}^{-1}}

. The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a

\mathrm {W}

\mathrm {Z}

boson, or a top quark-antiquark pair) and the following decay modes:

\mathrm {H} \rightarrow \gamma \gamma

\mathrm {Z}\mathrm {Z}

\mathrm {W}\mathrm {W}

\mathrm {\tau }\mathrm {\tau }

\mathrm {b} \mathrm {b}

, and

\mathrm {\mu }\mathrm {\mu }

. Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be

\mu =1.17\pm 0.10

, assuming a Higgs boson mass of

125.09\,\text {Ge}\text {V}

. Additional results are given for various assumptions on the scaling behavior of the production and decay modes, including generic parametrizations based on ratios of cross sections and branching fractions or couplings. The results are compatible with the standard model predictions in all parametrizations considered. In addition, constraints are placed on various two Higgs doublet models.

Springer2019

Combined measurements of Higgs boson couplings in proton–proton collisions at $\sqrt{s}=13\,\text {Te}\text {V} $

\sqrt{s}=13\,\text {Te}\text {V}

, corresponding to an integrated luminosity of 35.9

{\,\text {fb}^{-1}}

. The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a

\mathrm {W}

\mathrm {Z}

boson, or a top quark-antiquark pair) and the following decay modes:

\mathrm {H} \rightarrow \gamma \gamma

\mathrm {Z}\mathrm {Z}

\mathrm {W}\mathrm {W}

\mathrm {\tau }\mathrm {\tau }

\mathrm {b} \mathrm {b}

, and

\mathrm {\mu }\mathrm {\mu }

. Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be

\mu =1.17\pm 0.10

, assuming a Higgs boson mass of

125.09\,\text {Ge}\text {V}

Springer2019

Probing top-antitop resonances with tt scattering at LHC14

Measurement of the Properties of a Higgs Boson in the Four-Lepton Final State

Search for associated production of a Higgs boson and a single top quark in proton-proton collisions at $\sqrt{s} =$ TeV

Combined measurements of Higgs boson couplings in proton–proton collisions at $\sqrt{s}=13\,\text {Te}\text {V} $

Combined measurements of Higgs boson couplings in proton–proton collisions at $\sqrt{s}=13\,\text {Te}\text {V} $

Measurement of the Properties of a Higgs Boson in the Four-Lepton Final State

Search for associated production of a Higgs boson and a single top quark in proton-proton collisions at $\sqrt{s} =$ TeV