Search for Higgs boson decays into two new low-mass spin-0 particles in the 4b channel with the ATLAS detector using pp collisions at √s=13  TeV Atlas Collaboration Aguilar Saavedra, Juan Antonio This paper describes a search for beyond the Standard Model decays of the Higgs boson into a pair of new spin-0 particles subsequently decaying into b-quark pairs, H→aa→(b¯b)(b¯b), using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider at center-of-mass energy √s=13  TeV. This search focuses on the range 15  GeV≤ma≤30  GeV, where the decay products are collimated; it is complementary to a previous search in the same final state targeting the range 20  GeV≤ma≤60  GeV, where the decay products are well separated. A novel strategy for the identification of the a→b¯b decays is deployed to enhance the efficiency for topologies with small separation angles. The search is performed with 36  fb−1 of integrated luminosity collected in 2015 and 2016 and sets upper limits on the production cross section of H→aa→(b¯b)(b¯b), where the Higgs boson is produced in association with a Z boson. 2021-03-15T09:22:32Z 2021-03-15T09:22:32Z 2020 journal article Aad, G., Abbott, B., Abbott, D. C., Abud, A. A., Abeling, K., Abhayasinghe, D. K., ... & Balunas, W. K. (2020). Search for Higgs boson decays into two new low-mass spin-0 particles in the 4 b channel with the ATLAS detector using p p collisions at s= 13 TeV. Physical Review D, 102(11), 112006. [DOI: 10.1103/PhysRevD.102.112006] http://hdl.handle.net/10481/67205 10.1103/PhysRevD.102.112006 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España AMER PHYSICAL SOC