Search for direct pair production of supersymmetric partners to the $${\uptau }_{}^{}$$ lepton in proton–proton collisions at $$\sqrt{s}=13\,\text {TeV} $$
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi, T. Bergauer, J. Brandstetter, M. Dragicevic, J. Erö, A. Escalante Del Valle, M. Flechl, R. Frühwirth, M. Jeitler, N. Krammer, I. Krätschmer, D. Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck, R. Schöfbeck, M. Spanring, D. Spitzbart, W. Waltenberger, C.-E. Wulz, M. Zarucki, V. Drugakov, V. Mossolov, J. Suarez Gonzalez, M. R. Darwish, E. A. De Wolf, D. Di Croce, X. Janssen, A. Lelek, M. Pieters, H. Rejeb Sfar, H. Van Haevermaet, P. Van Mechelen, S. Van Putte, N. Van Remortel, F. Blekman, E. S. Bols, S. S. Chhibra, J. D’Hondt, J. De Clercq, D. Lontkovskyi, S. Lowette, I. Marchesini, S. Moortgat, L. Moreels, Q. Python, K. Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders, I. Van Parijs, John C. Beghin, B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorney, L. Favart, A. Grebenyuk, A. K. Kalsi, A. Popov, N. Postiau, E. Starling, L. Thomas, C. Vander Velde, P. Vanlaer, D. Vannerom, T. Cornelis, D. Dobur, I. Khvastunov, M. Niedziela, C. Roskas, D. Trocino, M. Tytgat, W. Verbeke, B. Vermassen, M. Vit, N. Zaganidis, O. Bondu, G. Bruno, C. Caputo, P. David, C. Delaere, M. Delcourt, A. Giammanco, V. Lemaitre, A. Magitteri, J. Prisciandaro, A. Saggio, M. Vidal Marono, P. Vischia, J. Zobec, F. L. Alves, G. A. Alves, G. Correia Silva
Abstract
Abstract A search is presented for $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton pairs produced in proton–proton collisions at a center-of-mass energy of 13 $$\,\text {TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>TeV</mml:mtext></mml:mrow></mml:math> . The search is carried out in events containing two $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> leptons in the final state, on the assumption that each $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton decays primarily to a $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> lepton and a neutralino. Events are considered in which each $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> lepton decays to one or more hadrons and a neutrino, or in which one of the $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> leptons decays instead to an electron or a muon and two neutrinos. The data, collected with the CMS detector in 2016 and 2017, correspond to an integrated luminosity of 77.2 $$\,\text {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:msup><mml:mtext>fb</mml:mtext><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> . The observed data are consistent with the standard model background expectation. The results are used to set 95% confidence level upper limits on the cross section for $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton pair production in various models for $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton masses between 90 and 200 $$\,\text {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>GeV</mml:mtext></mml:mrow></mml:math> and neutralino masses of 1, 10, and 20 $$\,\text {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>GeV</mml:mtext></mml:mrow></mml:math> . In the case of purely left-handed $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton production and decay to a $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> lepton and a neutralino with a mass of 1 $$\,\text {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>GeV</mml:mtext></mml:mrow></mml:math> , the strongest limit is obtained for a $${\uptau }_{}^{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow/><mml:mrow/></mml:msubsup></mml:math> slepton mass of 125 $$\,\text {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>GeV</mml:mtext></mml:mrow></mml:math> at a factor of 1.14 larger than the theoretical cross section.