Search for a Higgs Portal Scalar Decaying to Electron-Positron Pairs in the MicroBooNE Detector Abratenko, P. García Gámez, Diego MicroBooNE Collaboration This document was prepared by the MicroBooNE collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359. MicroBooNE is supported by the following: the U.S. Department of Energy, Office of Science, Offices of High Energy Physics and Nuclear Physics; the U.S. National Science Foundation; the Swiss National Science Foundation; the Science and Technology Facilities Council (STFC), part of the United Kingdom Research and Innovation; and The Royal Society (United Kingdom). Additional support for the laser calibration system and cosmic ray tagger was provided by the Albert Einstein Center for Fundamental Physics, Bern, Switzerland. Participation of individual researchers in this project is supported by funds from the European Unions Horizon 2020 Research and Innovation Programme under the Marie SklodowskaCurie Grant Agreement No. 752309. We thank Brian Batell, Joshua Berger, and Ahmed Ismail for outlining the search strategy. We present a search for the decays of a neutral scalar boson produced by kaons decaying at rest, in the context of the Higgs portal model, using the MicroBooNE detector. We analyze data triggered in time with the Fermilab NuMI neutrino beam spill, with an exposure of 1.93 x 10(20) protons on target. We look for monoenergetic scalars that come from the direction of the NuMI hadron absorber, at a distance of 100 m from the detector, and decay to electron-positron pairs. We observe one candidate event, with a standard model background prediction of 1.9 +/- 0.8. We set an upper limit on the scalar-Higgs mixing angle of theta < (3.3 - 4.6) x 10(-4) at the 95% confidence level for scalar boson masses in the range (100-200) MeV/c(2). We exclude, at the 95% confidence level, the remaining model parameters required to explain the central value of a possible excess of K-L(0) -> pi(0)nu(nu) over bar decays reported by the KOTO collaboration. We also provide a model-independent limit on a new boson X produced in K -> pi X decays and decaying to e(+)e(-). 2021-11-05T08:06:04Z 2021-11-05T08:06:04Z 2021-10-06 info:eu-repo/semantics/article P. Abratenko... [et al.]. Search for a Higgs Portal Scalar Decaying to Electron-Positron Pairs in the MicroBooNE Detector. PHYSICAL REVIEW LETTERS 127, 151803 (2021). DOI: [10.1103/PhysRevLett.127.151803] http://hdl.handle.net/10481/71299 10.1103/PhysRevLett.127.151803 eng info:eu-repo/grantAgreement/EC/H2020/752309 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España American Physical Society