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Measurement of π⁰ meson properties through its Dalitz decay channel in pp and p-Pb collisions with the ALICE experiment at the LHC
Medida de propiedades de π⁰ usando la desintegración Dalitz en el experimento ALICE del LHC en colisiones pp y p-Pb

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González Zamora, Pedro (2017) Measurement of π⁰ meson properties through its Dalitz decay channel in pp and p-Pb collisions with the ALICE experiment at the LHC. [Thesis]

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Abstract

Quarks and gluons are elementary particles described in the Standard Model of particle physics which have never been observed free in nature. Quarks are always bound with other quarks through gluons (which are the force carriers of the strong force) forming other particles named hadrons. However, the Quantum Chromodynamics theory (QCD), which is the theory that describes the strong force, predicts that at extreme conditions of temperature and density quarks and gluons behave as quasifree particles. The phase transition from hadronic matter to a state of free quarks and gluons is known as Quark-Gluon Plasma (QGP) and is believed to have existed shortly after the Big Bang. Ultra-relativistic Heavy-ion Collisions is the field of Physics that allows to study the QGP in the laboratory since extreme conditions of temperature and energy are expected to occur in such collisions. The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has a circumference of 27 km and is located at the border between Switzerland and France, close to Geneva. Although the LHC has been designed to study the Physics of the Higgs Boson, it also includes a program of ultra-relativistic heavy-ion collisions (Pb–Pb). The experiment installed at the LHC optimized for the study of the QGP is called ALICE (A Large Ion Collider Experiment). The QGP formed in ultra-relativistic heavy-ion collisions has a lifetime so short that it is not possible to observe it directly. Instead, it is studied by analyzing the properties of the thousands of particles produced during the collision. Within the variety of observables proposed as signatures of the QGP, there is one known as “jet quenching”. The phenomenon of jet quenching refers to a hadron suppression at intermediate and high transverse momentum (pT) in nucleus-nucleus collisions with respect to their production in nucleon-nucleon collisions at the same center-of-mass collision energy and was first observed at the RHIC experiments. The first measurements on charged hadrons and neutral mesons ( 0) production in Pb–Pb collisions at psNN = 2.76 TeV reported by ALICE, have also shown a suppression in their production at pT > 2 GeV=c. In order to give a definitive conclusion of what was observed, one has to be sure that the hadron suppression is due to effects of the QGP formation (also known as final-state effects) and not due to initial-state effects also known as cold nuclear matter (CNM) effects. The CNM effects can be studied in pp and p–Pb collisions by computing the so-called “nuclear modification factor R 0 pPb”...

Resumen (otros idiomas)

Los quarks y los gluones son partículas elementales descritas en el modelo estándar de la física de partículas que nunca han sido observadas libres en la naturaleza. Los quarks siempre están unidos a otros quarks por medio de gluones (quienes actúan como portadores de la interacción nuclear fuerte) formando otra clase de partículas llamadas hadrones. Sin embargo, la teoría de la Cromodinámica Cuántica (la teoría que describe la interacción nuclear fuerte), predice que en condiciones extremas de temperatura y densidad los quarks y los gluones se comportan como partículas casi libres. La transición de fase de la materia hadrónica al estado de quarks y gluones libres se conoce como Plasma de Quarks y Gluones (QGP, por sus siglas en inglés) y ésta pudo haber existido poco después del Bing Bang. Las propiedades del QGP pueden estudiarse en el laboratorio mediante colisiones de iones pesados ultra-relativistas. Esto es debido a que en dichas colisiones se alcanzan condiciones de extrema temperatura y densidad, condiciones necesarias para la formación del QGP. El Gran Colisionador de Hadrones (LHC, por sus siglas en inglés) es el acelerador de partículas más potente que existe en el mundo actualmente. El LHC tiene una forma circular y un diámetro de aproximadamente 27 kilómetros y se encuentra ubicado entre la frontera suiza y francesa, cerca de la ciudad de Ginebra. Aunque el LHC fue diseñado para estudiar la física del Bosón de Higgs, también incluye dentro de su programa colisiones de iones pesados (Pb–Pb). El experimento diseñado para el estudio del QGP en el LHC se llama ALICE (A Large Ion Collider Experiment)...

Item Type:Thesis
Additional Information:

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física Atómica, Molecular y Nuclear, leída el 22/07/2016

Directors:
DirectorsDirector email
Marín García, Ana María
Ladrón de Guevara Montero, Pedro
Uncontrolled Keywords:Quarks
Palabras clave (otros idiomas):Quarks
Subjects:Sciences > Physics > Nuclear physics
ID Code:44172
Deposited On:01 Aug 2017 10:04
Last Modified:10 Dec 2018 14:57

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