https://doi.org/10.1140/epjc/s10052-020-8102-8
Regular Article - Experimental Physics
Search for a scalar partner of the top quark in the all-hadronic 
plus missing transverse momentum final state at 
TeV with the ATLAS detector
1
Department of Physics, University of Adelaide, Adelaide, Australia
2
Physics Department, SUNY Albany, Albany, NY, USA
3
Department of Physics, University of Alberta, Edmonton, AB, Canada
4
Department of Physics, Ankara University, Ankara, Turkey
5
Istanbul Aydin University, Istanbul, Turkey
6
Division of Physics, TOBB University of Economics and Technology, Ankara, Turkey
7
LAPP, Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS/IN2P3, Annecy, France
8
High Energy Physics Division, Argonne National Laboratory, Argonne, IL, USA
9
Department of Physics, University of Arizona, Tucson, AZ, USA
10
Department of Physics, University of Texas at Arlington, Arlington, TX, USA
11
Physics Department, National and Kapodistrian University of Athens, Athens, Greece
12
Physics Department, National Technical University of Athens, Zografou, Greece
13
Department of Physics, University of Texas at Austin, Austin, TX, USA
14
Bahcesehir University, Faculty of Engineering and Natural Sciences, Istanbul, Turkey
15
Istanbul Bilgi University, Faculty of Engineering and Natural Sciences, Istanbul, Turkey
16
Department of Physics, Bogazici University, Istanbul, Turkey
17
Department of Physics Engineering, Gaziantep University, Gaziantep, Turkey
18
Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan
19
Institut de Física d’Altes Energies (IFAE), Barcelona Institute of Science and Technology, Barcelona, Spain
20
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
21
Physics Department, Tsinghua University, Beijing, China
22
Department of Physics, Nanjing University, Nanjing, China
23
University of Chinese Academy of Science (UCAS), Beijing, China
24
Institute of Physics, University of Belgrade, Belgrade, Serbia
25
Department for Physics and Technology, University of Bergen, Bergen, Norway
26
Physics Division, Lawrence Berkeley National Laboratory and University of California, Berkeley, CA, USA
27
Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany
28
Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland
29
School of Physics and Astronomy, University of Birmingham, Birmingham, UK
30
Facultad de Ciencias y Centro de Investigaciónes, Universidad Antonio Nariño, Bogotá, Colombia
31
Departamento de Física, Universidad Nacional de Colombia, Bogotá, Colombia
32
Dipartimento di Fisica, INFN Bologna and Universita’ di Bologna, Bologna, Italy
33
INFN Sezione di Bologna, Bologna, Italy
34
Physikalisches Institut, Universität Bonn, Bonn, Germany
35
Department of Physics, Boston University, Boston, MA, USA
36
Department of Physics, Brandeis University, Waltham, MA, USA
37
Transilvania University of Brasov, Brasov, Romania
38
Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania
39
Department of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, Romania
40
National Institute for Research and Development of Isotopic and Molecular Technologies, Physics Department, Cluj-Napoca, Romania
41
University Politehnica Bucharest, Bucharest, Romania
42
West University in Timisoara, Timisoara, Romania
43
Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
44
Department of Subnuclear Physics, Institute of Experimental Physics of the Slovak Academy of Sciences, Kosice, Slovak Republic
45
Physics Department, Brookhaven National Laboratory, Upton, NY, USA
46
Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
47
California State University, Long Beach, CA, USA
48
Cavendish Laboratory, University of Cambridge, Cambridge, UK
49
Department of Physics, University of Cape Town, Cape Town, South Africa
50
iThemba Labs, Western Cape, South Africa
51
Department of Mechanical Engineering Science, University of Johannesburg, Johannesburg, South Africa
52
University of South Africa, Department of Physics, Pretoria, South Africa
53
School of Physics, University of the Witwatersrand, Johannesburg, South Africa
54
Department of Physics, Carleton University, Ottawa, ON, Canada
55
Faculté des Sciences Ain Chock, Réseau Universitaire de Physique des Hautes Energies - Université Hassan II, Casablanca, Morocco
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Faculté des Sciences, Université Ibn-Tofail, Kénitra, Morocco
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Faculté des Sciences Semlalia, Université Cadi Ayyad, LPHEA, Marrakech, Morocco
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Faculté des Sciences, Université Mohamed Premier and LPTPM, Oujda, Morocco
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Faculté des sciences, Université Mohammed V, Rabat, Morocco
60
CERN, Geneva, Switzerland
61
Enrico Fermi Institute, University of Chicago, Chicago, IL, USA
62
LPC, Université Clermont Auvergne, CNRS/IN2P3, Clermont-Ferrand, France
63
Nevis Laboratory, Columbia University, Irvington, NY, USA
64
Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
65
Dipartimento di Fisica, Università della Calabria, Rende, Italy
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Laboratori Nazionali di Frascati, INFN Gruppo Collegato di Cosenza, Rende, Italy
67
Physics Department, Southern Methodist University, Dallas, TX, USA
68
Physics Department, University of Texas at Dallas, Richardson, TX, USA
69
National Centre for Scientific Research “Demokritos”, Agia Paraskevi, Greece
70
Department of Physics, Stockholm University, Stockholm, Sweden
71
Oskar Klein Centre, Stockholm, Sweden
72
Deutsches Elektronen-Synchrotron DESY, Hamburg and Zeuthen, Germany
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Lehrstuhl für Experimentelle Physik IV, Technische Universität Dortmund, Dortmund, Germany
74
Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
75
Department of Physics, Duke University, Durham, NC, USA
76
SUPA - School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
77
INFN e Laboratori Nazionali di Frascati, Frascati, Italy
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Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
79
II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
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Département de Physique Nucléaire et Corpusculaire, Université de Genève, Geneva, Switzerland
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Dipartimento di Fisica, Università di Genova, Genoa, Italy
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INFN Sezione di Genova, Genoa, Italy
83
II. Physikalisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany
84
SUPA - School of Physics and Astronomy, University of Glasgow, Glasgow, UK
85
LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble INP, Grenoble, France
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Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, MA, USA
87
Department of Modern Physics and State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, China
88
Institute of Frontier and Interdisciplinary Science and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Qingdao, China
89
School of Physics and Astronomy, Shanghai Jiao Tong University, KLPPAC-MoE, SKLPPC, Shanghai, China
90
Tsung-Dao Lee Institute, Shanghai, China
91
Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
92
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Faculty of Applied Information Science, Hiroshima Institute of Technology, Hiroshima, Japan
94
Department of Physics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
95
Department of Physics, University of Hong Kong, Hong Kong, China
96
Department of Physics and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
97
Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
98
IJCLab, Université Paris-Saclay, CNRS/IN2P3, 91405, Orsay, France
99
Department of Physics, Indiana University, Bloomington, IN, USA
100
INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy
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ICTP, Trieste, Italy
102
Dipartimento Politecnico di Ingegneria e Architettura, Università di Udine, Udine, Italy
103
INFN Sezione di Lecce, Lecce, Italy
104
Dipartimento di Matematica e Fisica, Università del Salento, Lecce, Italy
105
INFN Sezione di Milano, Milano, Italy
106
Dipartimento di Fisica, Università di Milano, Milano, Italy
107
INFN Sezione di Napoli, Napoli, Italy
108
Dipartimento di Fisica, Università di Napoli, Napoli, Italy
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INFN Sezione di Pavia, Pavia, Italy
110
Dipartimento di Fisica, Università di Pavia, Pavia, Italy
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INFN Sezione di Pisa, Pisa, Italy
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Dipartimento di Fisica E. Fermi, Università di Pisa, Pisa, Italy
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INFN Sezione di Roma, Roma, Italy
114
Dipartimento di Fisica, Sapienza Università di Roma, Roma, Italy
115
INFN Sezione di Roma Tor Vergata, Roma, Italy
116
Dipartimento di Fisica, Università di Roma Tor Vergata, Roma, Italy
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INFN Sezione di Roma Tre, Roma, Italy
118
Dipartimento di Matematica e Fisica, Università Roma Tre, Roma, Italy
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INFN-TIFPA, Trento, Italy
120
Università degli Studi di Trento, Trento, Italy
121
Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität, Innsbruck, Austria
122
University of Iowa, Iowa City, IA, USA
123
Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
124
Joint Institute for Nuclear Research, Dubna, Russia
125
Departamento de Engenharia Elétrica, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, Brazil
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Universidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro, Brazil
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Universidade Federal de São João del Rei (UFSJ), São João del Rei, Brazil
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Instituto de Física, Universidade de São Paulo, São Paulo, Brazil
129
KEK, High Energy Accelerator Research Organization, Tsukuba, Japan
130
Graduate School of Science, Kobe University, Kobe, Japan
131
AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow, Poland
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Marian Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland
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Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
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Faculty of Science, Kyoto University, Kyoto, Japan
135
Kyoto University of Education, Kyoto, Japan
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Research Center for Advanced Particle Physics and Department of Physics, Kyushu University, Fukuoka, Japan
137
Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina
138
Physics Department, Lancaster University, Lancaster, UK
139
Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK
140
Department of Experimental Particle Physics, Jožef Stefan Institute and Department of Physics, University of Ljubljana, Ljubljana, Slovenia
141
School of Physics and Astronomy, Queen Mary University of London, London, UK
142
Department of Physics, Royal Holloway University of London, Egham, UK
143
Department of Physics and Astronomy, University College London, London, UK
144
Louisiana Tech University, Ruston, LA, USA
145
Fysiska institutionen, Lunds universitet, Lund, Sweden
146
Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules (IN2P3), Villeurbanne, France
147
Departamento de Física Teorica C-15 and CIAFF, Universidad Autónoma de Madrid, Madrid, Spain
148
Institut für Physik, Universität Mainz, Mainz, Germany
149
School of Physics and Astronomy, University of Manchester, Manchester, UK
150
CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
151
Department of Physics, University of Massachusetts, Amherst, MA, USA
152
Department of Physics, McGill University, Montreal, QC, Canada
153
School of Physics, University of Melbourne, Victoria, Australia
154
Department of Physics, University of Michigan, Ann Arbor, MI, USA
155
Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
156
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus
157
Research Institute for Nuclear Problems of Byelorussian State University, Minsk, Belarus
158
Group of Particle Physics, University of Montreal, Montreal, QC, Canada
159
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia
160
National Research Nuclear University MEPhI, Moscow, Russia
161
D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
162
Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany
163
Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany
164
Nagasaki Institute of Applied Science, Nagasaki, Japan
165
Graduate School of Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya, Japan
166
Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
167
Institute for Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen/Nikhef, Nijmegen, Netherlands
168
Nikhef National Institute for Subatomic Physics and University of Amsterdam, Amsterdam, Netherlands
169
Department of Physics, Northern Illinois University, DeKalb, IL, USA
170
Budker Institute of Nuclear Physics and NSU, SB RAS, Novosibirsk, Russia
171
Novosibirsk State University Novosibirsk, Novosibirsk, Russia
172
Institute for High Energy Physics of the National Research Centre Kurchatov Institute, Protvino, Russia
173
Institute for Theoretical and Experimental Physics named by A.I. Alikhanov of National Research Centre “Kurchatov Institute”, Moscow, Russia
174
Department of Physics, New York University, New York, NY, USA
175
Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo, Japan
176
Ohio State University, Columbus, OH, USA
177
Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK, USA
178
Department of Physics, Oklahoma State University, Stillwater, OK, USA
179
Palacký University, RCPTM, Joint Laboratory of Optics, Olomouc, Czech Republic
180
Institute for Fundamental Science, University of Oregon, Eugene, OR, USA
181
Graduate School of Science, Osaka University, Osaka, Japan
182
Department of Physics, University of Oslo, Oslo, Norway
183
Department of Physics, Oxford University, Oxford, UK
184
LPNHE, Sorbonne Université, Université de Paris, CNRS/IN2P3, Paris, France
185
Department of Physics, University of Pennsylvania, Philadelphia, PA, USA
186
Konstantinov Nuclear Physics Institute of National Research Centre “Kurchatov Institute”, PNPI, St. Petersburg, Russia
187
Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA
188
Laboratório de Instrumentação e Física Experimental de Partículas - LIP, Lisboa, Portugal
189
Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
190
Departamento de Física, Universidade de Coimbra, Coimbra, Portugal
191
Centro de Física Nuclear da Universidade de Lisboa, Lisboa, Portugal
192
Departamento de Física, Universidade do Minho, Braga, Portugal
193
Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada, Spain
194
Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
195
Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
196
Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic
197
Czech Technical University in Prague, Prague, Czech Republic
198
Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic
199
Particle Physics Department, Rutherford Appleton Laboratory, Didcot, UK
200
IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
201
Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz, CA, USA
202
Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile
203
Universidad Andres Bello, Department of Physics, Santiago, Chile
204
Instituto de Alta Investigación, Universidad de Tarapacá, Santiago, Chile
205
Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile
206
Department of Physics, University of Washington, Seattle, WA, USA
207
Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
208
Department of Physics, Shinshu University, Nagano, Japan
209
Department Physik, Universität Siegen, Siegen, Germany
210
Department of Physics, Simon Fraser University, Burnaby, BC, Canada
211
SLAC National Accelerator Laboratory, Stanford, CA, USA
212
Physics Department, Royal Institute of Technology, Stockholm, Sweden
213
Departments of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
214
Department of Physics and Astronomy, University of Sussex, Brighton, UK
215
School of Physics, University of Sydney, Sydney, Australia
216
Institute of Physics, Academia Sinica, Taipei, Taiwan
217
E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia
218
High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia
219
Department of Physics, Technion, Israel Institute of Technology, Haifa, Israel
220
Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
221
Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
222
International Center for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan
223
Graduate School of Science and Technology, Tokyo Metropolitan University, Tokyo, Japan
224
Department of Physics, Tokyo Institute of Technology, Tokyo, Japan
225
Tomsk State University, Tomsk, Russia
226
Department of Physics, University of Toronto, Toronto, ON, Canada
227
TRIUMF, Vancouver, BC, Canada
228
Department of Physics and Astronomy, York University, Toronto, ON, Canada
229
Division of Physics and Tomonaga Center for the History of the Universe, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
230
Department of Physics and Astronomy, Tufts University, Medford, MA, USA
231
Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
232
Department of Physics and Astronomy, University of Uppsala, Uppsala, Sweden
233
Department of Physics, University of Illinois, Urbana, IL, USA
234
Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia - CSIC, Valencia, Spain
235
Department of Physics, University of British Columbia, Vancouver, BC, Canada
236
Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
237
Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
238
Department of Physics, University of Warwick, Coventry, UK
239
Waseda University, Tokyo, Japan
240
Department of Particle Physics, Weizmann Institute of Science, Rehovot, Israel
241
Department of Physics, University of Wisconsin, Madison, WI, USA
242
Fakultät für Mathematik und Naturwissenschaften, Fachgruppe Physik, Bergische Universität Wuppertal, Wuppertal, Germany
243
Department of Physics, Yale University, New Haven, CT, USA
244
CERN, 1211, Geneva 23, Switzerland
* e-mail: atlas.publications@cern.ch
Received:
29
April
2020
Accepted:
31
May
2020
Published online:
13
August
2020
A search for direct pair production of scalar partners of the top quark (top squarks or scalar third-generation up-type leptoquarks) in the all-hadronic plus missing transverse momentum final state is presented. The analysis of 139 
of 
TeV proton–proton collision data collected using the ATLAS detector at the LHC yields no significant excess over the Standard Model background expectation. To interpret the results, a supersymmetric model is used where the top squark decays via 
, with 
denoting an on-shell (off-shell) top quark and 
the lightest neutralino. Three specific event selections are optimised for the following scenarios. In the scenario where 
, top squark masses are excluded in the range 400–1250 GeV for masses below 200 GeV at 95% confidence level. In the situation where 
, top squark masses in the range 300–630 GeV are excluded, while in the case where 
(with 
GeV), considered for the first time in an ATLAS all-hadronic search, top squark masses in the range 300–660 GeV are excluded. Limits are also set for scalar third-generation up-type leptoquarks, excluding leptoquarks with masses below 1240 GeV when considering only leptoquark decays into a top quark and a neutrino.
© CERN for the benefit of the ATLAS collaboration, 2020
