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General: EL BOSON DE HIGGS, EL GRIAL DE LOS FISICOS
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El bosón de Higgs, un grial para los físicos
La 'partícula de Dios' es la pieza que falta en el rompecabezas de la teoría más fundamental de la física, el Modelo Estándar, para explicar por qué los objetos tienen masa
MICHELE CATANZARO
1. ¿Por qué este elemento es tan importante?
La partícula más buscada por los físicos, el bosón de Higgs, es esencial para entender por qué los objetos tienen masa y es la pieza que falta para que se aguante la teoría más fundamental de la física actual, el Modelo Estándar. Fue el premio Nobel Leon Lederman quien la apodó "la partícula de Dios", para resaltar su importancia para la ciencia. Aunque parezca mentira, la existencia de la masa (la propiedad que, junto con la aceleración de gravedad, hace que los objetos tengan peso) sigue siendo un misterio. El Modelo Estándar describe con precisión el funcionamiento de las partículas más pequeñas de la materia y de sus interacciones, pero paradójicamente esta teoría funciona bien solo si se asume que todas las partículas tienen masa nula. Para arreglar este fallo, en 1960 el físico británico Peter Higgs sugirió la existencia de una partícula cuya acción generaría la masa. Los bosones de Higgs crearían un campo que, interactuando con las otras partículas, les daría la propiedad de tener masa. Si esta partícula no existiera, el Modelo Estándar se debería revisar completamente.
Uno de los grandes aparatos utilizados en la búsqueda del bosón de Higgs. DENIS BALIBOUSE | REUTERS
2 ¿Cómo se detecta una partícula de este tipo?
Si el bosón de Higgs existe, se debería observar entre los productos de las colisiones entre partículas que se producen en el Gran Colisionador de Hadrones (LHC) de Ginebra. En este aparato, se producen colisiones de protones, partículas de carga positiva que se hallan en el núcleo atómico y forman parte de una familia de partículas llamadas hadrones. Dos haces de protones son acelerados con energías altísimas y corren en sentidos contrarios en el anillo de 27 kilómetros del LHC. En diversos puntos, los haces se encuentran, las partículas se rompen en el choque y sus constituyentes más pequeños salen disparados. Los científicos observan estos productos de la colisión para detectar partículas desconocidas. La especialidad del LHC es que produce choques con alta densidad de energía en el minúsculo espacio ocupado por los protones. Esta es una situación parecida a la de pocas milésimas de segundo después del 'big bang'. Hacen falta 100 millones de millones de colisiones para que se produzca un solo bosón de Higgs, por eso es tan difícil confirmar su existencia.
3 ¿Cuáles son las aplicaciones de estos estudios?
Televisores, transistores, ordenadores y aparatos médicos no existirían sin los estudios de rayos X, catódicos, alfa y beta, es decir, las investigaciones que han desembocado en el LHC y la búsqueda del bosón de Higgs. El descubrimiento de esta partícula no tendría aplicaciones inmediatas en la tecnología o en la salud; sin embargo, algunos de los descubrimientos clave del siglo pasado han sido efectos colaterales de la investigación de las propiedades fundamentales de la materia. Entre otros, el World Wide Web, el sistema que se utiliza para navegar en Internet, se inventó en el CERN, durante un experimento anterior que utilizaba el mismo túnel del LHC. Para los experimentos actuales se ha desarrollado el GRID, una especie de internet de élite a la que de momento se conectan centros especializados, pero que en un futuro se podría abrir al público. En 1977, el CERN obtuvo la primera imagen de tomografía por emisión de positrones (PET), una técnica que hoy se usa en miles de hospitales para visualizar el cerebro humano y que nació para alcanzar objetivos de investigación abstracta.
4. ¿Cómo puede cambiar la ciencia a partir de ahora?
Ahora se deben investigar en profundidad los detalles de la partícula, y si presentara propiedades anómalas se debería revisar la teoría básica. En todo caso, el cometido del LHC no se acaba con el bosón de Higgs. Las partículas supersimétricas son otro objetivo de los experimentos: estos objetos, nunca observados, podrían ser los constituyentes de la materia oscura cuya existencia se ha detectado en el universo. Otro asunto son las dimensiones extra: según las teorías físicas más atrevidas, puede que el Universo tenga unas dimensiones no detectadas que explicarían fenómenos anómalos.
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Different cyclotron size: a) Lawrence ́s first one, b) Venezuela First one (courtesy of Dorly Coehlo), c) Fermi National Laboratory at CERN. And size matters, and Cyclotrons win as best hospital candidates due to Reactors are bigger, harder and difficult to be set in a hospital installation. Can you imagine a nuclear reactor inside a health installation? Radiation Protection Program will consume all the budget available. Size, controlled reactions, electrical control, made cyclotrons easy to install, and baby cyclotrons come selfshielded so hospital don ́t need to spend money in a extremely large bunker. Now on, we are going to talk about our first experience with the set up of a baby cyclotron for medical uses inside the first PET installation in Latin America. “Baby” means its acceleration “D” diameters are suitable to be set inside a standard hospital room dimensions, with all its needs to be safetly shielded for production transmision and synthetized for human uses for imaging in Nuclear Medicine PET routine. When we ask why Cyclotrons are better than reactors for radioisotopes production to be used in Medicine, we also have to have in mind that they has: 1. Less radioactive waste 2. Less harmful debris
https://www.researchgate.net/figure/Different-cyclotron-size-a-Lawrence-s-first-one-b-Venezuela-First-one-courtesy-of_fig3_221906035
 
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Particle of God, The famous Higgs Boson
What is the Higgs boson?
The Higgs boson is a type of elementary particle that is believed to have a fundamental role in the mechanism by which the mass of elementary particles originates. Without mass, the Universe would be a very different place. If the electron had no mass there would be no atoms, which would not exist as we know it, so there would be no chemistry, no biology, and we would not exist. To explain why some particles have mass and others do not, several physicists, among them the British Peter Higgs, postulated in the 60s of the 20th century a mechanism known as the "Higgs field". Just as the photon is the fundamental component of light, the Higgs field requires the existence of a particle that composes it, which physicists call the "Higgs boson". This is the last piece missing to complete the Standard Model of Particle Physics, which describes everything we know about the elementary particles that make up everything we see and how they interact with each other.
Why is the Higgs boson so important?
Because it is the only particle predicted by the Standard Model of Particle Physics that has not yet been discovered. The standard model perfectly describes the elementary particles and their interactions, but an important part remains to be confirmed, precisely the one that responds to the origin of the mass. Without mass, the Universe would be a very different place. If the electron had no mass there would be no atoms, which would not exist as we know it, so there would be no chemistry, no biology, and we would not exist. To explain this, several physicists, including the British Peter Higgs, postulated in the 60s of the twentieth century a mechanism known as the Higgs field. Just as the photon is the fundamental component of the electromagnetic field and light, the Higgs field requires the existence of a particle that composes it, which physicists call the Higgs boson.
History of a search
The search for the Higgs boson began decades ago in particle accelerators such as LEP from CERN or Tevatron from FERMILAB (United States), both already closed. Because the theory does not establish the mass of the Higgs boson, but a wide range of possible values, very powerful accelerators are required to explore this new territory of Physics. The LHC is the culmination of an "energy escalation" aimed at discovering the Higgs boson in the particle accelerators, which has allowed until now to exclude that it has a mass smaller than the equivalent to approximately 115 times that of the proton.
What is a boson?
Subatomic particles are divided into two types: fermions and bosons. Fermions are particles that makeup matter, and bosons carry forces or interactions. The components of the atom (electrons, protons, and neutrons) are fermions, while the photons, the gluons and the W and Z bosons, responsible respectively for electromagnetic nuclear forces, strong and weak nuclear, are bosons.
Wikimedia, Public Domain
How can the Higgs boson be detected?
The Higgs boson can not be detected directly, because once it is produced it disintegrates almost instantaneously giving rise to other more familiar elementary particles. What you can see are your "fingerprints", those other particles that can be detected in the LHC. Within the accelerator ring, the protons collide with each other at a speed close to that of light. When collisions occur at strategic points where large detectors are located, the energy of the movement is released and is available to generate other particles. The greater the energy of the particles that collide, the more mass that will result, according to the famous Einstein E2 equation.
The Higgs boson points the way to the New Physics
New results obtained at the European Organization for Nuclear Research (CERN) have shown how the Higgs boson, the heaviest known elementary particle, interacts not only with massive particles but also with particles devoid of mass. It was observed due to the disintegration of the Higgs boson in two photons, which are massless particles. According to quantum mechanics, the Higgs boson can fluctuate for a brief moment in a top quark and a top antiquark, which cancel each other rapidly forming a pair of photons. The top quark is an elementary particle that belongs to the third generation of quarks, the only elementary particles that interact with the four fundamental forces: nuclear, electromagnetic, weak and gravity. Quarks not only form nuclear matter but also sometimes subatomic particles such as protons and neutrons. Quarks exist with their corresponding antiparticles. The top quark is the most massive of the quarks discovered to date. It is a very unstable particle, so it does not have time to merge with other quarks and form new particles known as hadrons. Its antiparticle is the top antiquark. The Higgs boson or Higgs particle is an elementary particle proposed in the standard model of particle physics. It has no spin, electric charge or color, is very unstable and disintegrates quickly: its half-life is of the order of one billionth of a second (zeptosecond).
Wikimedia, Public Domain
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