Measurement of π⁰ meson properties through its Dalitz decay channel in pp and p-Pb collisions with the ALICE experiment at the LHC
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, th...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/22440 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/22440 |
| Access Level: | acceso abierto |
| Palabra clave: | 539.12(043.2) Quarks Física nuclear 2207 Física Atómica y Nuclear |
| Sumario: | 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”... |
|---|