Search for long-lived charginos based on a disappearing-track signature using 136 fb$^{-1}$ of pp collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2022-01, Vol.82 (7)
• Main Authors: Aad, Georges, Abbott, Braden Keim, Abbott, Dale, Abed Abud, Adam, Abeling, Kira, Abhayasinghe, Deshan Kavishka, Abidi, Haider, Abramowicz, Halina, Abreu, Henso, Abulaiti, Yiming, Abusleme Hoffman, A.C., Acharya, Bobby Samir, Achkar, Baida, Adam, Lennart, Adam Bourdarios, Claire, Adamczyk, Leszek, Adamek, Lukas, Adelman, Jahred, Adiguzel, Aytul, Adorni Braccesi Chiassi, Sofia, Adye, Tim, Affolder, A.A., Affolder, Tony, Afik, Yoav, Agapopoulou, Christina, Agaras, Merve Nazlim, Agarwala, Jinky, Aggarwal, Anamika, Agheorghiesei, Catalin, Aguilar Saavedra, Juan Antonio, Ahmad, Ammara, Ahmadov, Faig, Ahmed, Waleed Syed, Ai, Xiaocong, Aielli, Giulio, Akatsuka, Shunichi, Akbiyik, Melike, Akesson, Torsten, Akimov, Andrei, Al Khoury, Konie, Alberghi, Gian Luigi, Albert, Justin, Alconada Verzini, M.J., Alderweireldt, Sara, Aleksa, Martin, Aleksandrov, I.N., Alexa, Calin, Alexopoulos, Theodoros, Alfonsi, Alice, Alfonsi, Fabrizio, Alhroob, Muhammad, Ali, Babar, Ali, Shahzad, Aliev, Malik, Alimonti, Gianluca, Allaire, Corentin, Allbrooke, Benedict, Allport, Philip Patrick, Aloisio, Alberto, Alonso, Francisco, Alpigiani, Cristiano, Alunno Camelia, Elio, Alvarez Estevez, Manuel, Alviggi, Mariagrazia, Do Amaral Coutinho, Yara, Ambler, Alessandro, Ambroz, Luca, Amelung, Christoph, Amidei, Dante, Amor dos Santos, Susana Patricia, Amoroso, Simone, Amrouche, Cherifa Sabrina, Anastopoulos, Christos, Andari, Nansi, Andeen, Timothy Robert, Anders, John Kenneth, Andrean, Stefio Yosse, Andreazza, Attilio, Andrei, Victor, Angelidakis, Stylianos, Angerami, Aaron, Anisenkov, Alexey, Annovi, Alberto, Antel, Claire, Anthony, Matthew Thomas, Antipov, Egor, Antonelli, Mario, Antrim, Daniel Joseph, Anulli, Fabio, Aoki, Masato, Aparisi Pozo, Javier Alberto, Aparo, Marco, Aperio Bella, Ludovica, Aranzabal Barrio, Nordin, Araujo Ferraz, Victor, Arcangeletti, Chiara, Arce, Ayana Tamu, Arena, Eloisa, Arguin, Jean-Francois, Argyropoulos, Spyros
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-022-10489-5

A search for long-lived charginos produced either directly or in the cascade decay of heavy prompt gluino states is presented. The search is based on proton–proton collision data collected at a centre-of-mass energy of $\sqrt{s}$ = 13 T$\text {eV}$ between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 136 fb$^{-1}$. Long-lived charginos are characterised by a distinct signature of a short and then disappearing track, and are reconstructed using at least four measurements in the ATLAS pixel detector, with no subsequent measurements in the silicon-microstrip tracking volume nor any associated energy deposits in the calorimeter. The final state is complemented by a large missing transverse-momentum requirement for triggering purposes and at least one high-transverse-momentum jet. No excess above the expected backgrounds is observed. Exclusion limits are set at 95% confidence level on the masses of the chargino and gluino for different chargino lifetimes. Chargino masses up to 660 (210) G$\text {eV}$ are excluded in scenarios where the chargino is a pure wino (higgsino). For charginos produced during the cascade decay of a heavy gluino, gluinos with masses below 2.1 T$\text {eV}$ are excluded for a chargino mass of 300 G$\text {eV}$ and a lifetime of 0.2 ns.