Search for Nearly Mass-Degenerate Higgsinos Using Low-Momentum Mildly Displaced Tracks in p p Collisions at s = 13     TeV with the ATLAS Detector

• Published in: Physical review letters 2024-05, Vol.132 (22)
• Main Authors: Acharya, B. S., Agaras, M. N., Ahmadov, F., Baer, T. M., Ballabene, E., Berry, T., Biglietti, M., Biswas, D., Bogdanchikov, A. G., Brown, L. M., Canbay, A. C., Cavaliere, T., Chargeishvili, B., Cherepanova, E., Chitishvili, M., Corpe, L. D., Cueto, A., Dabrowski, W., Dattola, F., David, C., De Santis, F., Deiana, A. M., Delitzsch, C. M., Delsart, P. A., Derendarz, D., Dona, K. M., Drnevich, M., Drozdova, M., Dubovsky, M., Duckeck, G., Earnshaw, Z. O., El Moussaouy, A., Freund, W. S., Gay, C., Gee, C. M., Ghosal, A., Ghosh, A., Giagu, S., Gramstad, E., Guescini, F., Hall, J. J., Hirose, M., Hrabovsky, M., Huffman, T. B., Joshi, R., Kasimi, E., Keeler, R., Kirk, J., Kwan, T., Lankford, A. J., Lanza, A., Longo, R., Maleev, V. P., Mkrtchyan, T., Mosidze, M., Muanza, S., Myagkov, A. G., Norfolk, M. B., Novak, T., Onyisi, P. U. E., Owen, M., Park, K. R., Parzefall, U., Perez Codina, E., Pleskot, V., Qichen, D., Roberts, B. R., Saito, T., Sbrizzi, A., Schaile, D., Schott, M., Serkin, L., Sessa, M., Severini, H., Sickles, A. M., Simpson, L. R., Spiteri, D. P., Standke, M., Ta, D., Taffard, A., Takubo, Y., Tanasini, M., Thielmann, O., Tojo, J., Turk Cakir, I., Valiente Moreno, E., Van Daalen, T. R., Vecchio, V., Wang, R., Ward, R. J., Wei, Y., Wells, C. J., Yang, H. J., Zaid, E., Zakareishvili, T., Zenin, O., Zerwas, D., Zhang, X., Zheng, Z., Zhou, B.
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114

Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is O ( 1     GeV ) . This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140     fb − 1 of proton-proton collision data at s = 13     TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from 0.3 to 0.9 GeV is excluded at 95% confidence level, with a maximum reach of approximately 170 GeV in the Higgsino mass. © 2024 CERN, for the ATLAS Collaboration 2024 CERN