Observation of quantum entanglement in top quark pair production in proton-proton collisions at V¯s = 13 TeV

Entanglement is an intrinsic property of quantum mechanics and is predicted to be exhibited in the particles produced at the Large Hadron Collider. A measurement of the extent of entanglement in top quark-antiquark (t¯t) events produced in proton-proton collisions at a center-of-mass energy of 13 Te...

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Autores: Hayrapetyan, A., Bhowmik, Sandeep, Blanco Fernández, Sergio, Brochero Cifuentes, Javier Andrés|||0000-0003-2093-7856, Cabrillo Bartolomé, José Ibán, Calderón Tazón, Alicia|||0000-0002-7205-2040, Duarte Campderros, Jorge|||0000-0003-0687-5214, Fernández García, Marcos|||0000-0002-4824-1087, Gómez Gramuglio, Gervasio|||0000-0002-1077-6553, Lasaosa García, Clara, López Ruiz, Rubén, Martínez Rivero, Celso, Martínez Ruiz del Árbol, Pablo|||0000-0002-7737-5121, Matorras Weinig, Francisco|||0000-0003-4295-5668, Matorras Cuevas, Pablo|||0000-0001-7481-7273, Navarrete Ramos, Efrén|||0000-0002-5180-4020, Piedra Gómez, Jonatan|||0000-0002-9157-1700, Scodellaro, Luca|||0000-0002-4974-8330, Vila Álvarez, Iván|||0000-0002-6797-7209, Vizán García, Jesús Manuel|||0000-0002-6823-8854
Tipo de recurso: artículo
Fecha de publicación:2024
País:España
Institución:Universidad de Cantabria (UC)
Repositorio:UCrea Repositorio Abierto de la Universidad de Cantabria
Idioma:inglés
OAI Identifier:oai:repositorio.unican.es:10902/38733
Acceso en línea:https://hdl.handle.net/10902/38733
Access Level:acceso abierto
Palabra clave:CMS
Top quark
Entanglement
Descripción
Sumario:Entanglement is an intrinsic property of quantum mechanics and is predicted to be exhibited in the particles produced at the Large Hadron Collider. A measurement of the extent of entanglement in top quark-antiquark (t¯t) events produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed with the data recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 36.3 fb-1. The events are selected based on the presence of two leptons with opposite charges and high transverse momentum. An entanglement-sensitive observable D is derived from the top quark spin-dependent parts of the t¯t production density matrix and measured in the region of the t¯t production threshold. Values of D < -1/3 are evidence of entanglement and D is observed (expected) to be -0.480+0.026 -0.029 (-0.467+0.026-0.029) at the parton level. With an observed significance of 5.1 standard deviations with respect to the non-entangled hypothesis, this provides observation of quantum mechanical entanglement within t¯t pairs in this phase space. This measurement provides a new probe of quantum mechanics at the highest energies ever produced.