Barak Liron, Bloch Itay M, Botti Ana M, Cababie Mariano, Cancelo Gustavo, Cervantes-Vergara Brenda A, Chaplinsky Luke, Crisler Michael, Drlica-Wagner Alex, Essig Rouven, Estrada Juan, Etzion Erez, Moroni Guillermo Fernandez, Holland Stephen E, Korn Yaron, Lawson Ian, Luoma Steffon, Munagavalasa Sravan, Orly Aviv, Perez Santiago E, Rodrigues Dario, Saffold Nathan A, Scorza Silvia, Singal Aman, Haro Miguel Sofo, Stefanazzi Leandro, Stifter Kelly, Tiffenberg Javier, Uemura Sho, Volansky Tomer, Yu Tien-Tien, Harnik Roni, Liu Zhen, Plestid Ryan
School of Physics and Astronomy, <a href="https://ror.org/04mhzgx49">Tel-Aviv University</a>, Tel-Aviv 69978, Israel.
Berkeley Center for Theoretical Physics, <a href="https://ror.org/01an7q238">University of California</a>, Berkeley, California 94720, USA.
Phys Rev Lett. 2024 Aug 16;133(7):071801. doi: 10.1103/PhysRevLett.133.071801.
Millicharged particles appear in several extensions of the standard model, but have not yet been detected. These hypothetical particles could be produced by an intense proton beam striking a fixed target. We use data collected in 2020 by the SENSEI experiment in the MINOS cavern at the Fermi National Accelerator Laboratory to search for ultrarelativistic millicharged particles produced in collisions of protons in the NuMI beam with a fixed graphite target. The absence of any ionization events with 3 to 6 electrons in the SENSEI data allow us to place world-leading constraints on millicharged particles for masses between 30 to 380 MeV. This work also demonstrates the potential of utilizing low-threshold detectors to investigate new particles in beam-dump experiments, and motivates a future experiment designed specifically for this purpose.
