Search for dark photons in decays of Higgs bosons produced in association with Z bosons in proton-proton collisions at $ \sqrt{s} $ = 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Alessandro Caratelli, Xin Chen, Yixing Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Sebastiana Gianì, 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, Ajay Kumar, Sanjeev Kumar, Ekaterina Kuznetsova, Lei Li, Jing Li, Yiming Li, Wei Li, Zhen Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Amr Mohamed, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Ashish Sharma, Varun Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Yi Wang, Zheng Wang, Mingkui Wang, Qian Wang, Jian Wang, Siyuan Wang, Hui Wang, Xiao Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang, Yi Zhang
Springer, 2019
Article

Résumé

A search is presented for a Higgs boson that is produced in association with a Z boson and that decays to an undetected particle together with an isolated photon. The search is performed by the CMS Collaboration at the Large Hadron Collider using a data set corresponding to an integrated luminosity of 137 fb $^{−}^{1}$ recorded at a center-of-mass energy of 13 TeV. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for associated Higgs and Z boson production and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a mass of 125 GeV, assuming the standard model production cross section, this corresponds to an observed (expected) upper limit on this branching fraction of 4.6 (3.6)% at 95% confidence level. These are the first limits on Higgs boson decays to final states that include an undetected massless dark photon.

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https://infoscience.epfl.ch/record/275119?ln=fr

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Springer2019