Affichage des articles dont le libellé est Higgs Boson. Afficher tous les articles
Affichage des articles dont le libellé est Higgs Boson. Afficher tous les articles

mardi 8 octobre 2013

What is the Higgs boson and why is it important?

A proton-proton collision produced in the Large Hadron Collider shows characteristics in line with the decay of a Higgs boson particle.

STORY HIGHLIGHTS
  • Scientists say they've found new evidence the Higgs boson exists
  • The so-called "God particle" is thought to be a building block of the universe
  • The theoretical particle is key to understanding how universe works, experts say

Scientists say they are almost certain they have proven the existence of the Higgs boson -- a never-before-seen subatomic particle long thought to be a fundamental building block of the universe.

Since 2012 researchers have made great strides in the hunt for the so-called "God particle" at the Large Hadron Collider in Geneva, Switzerland, where scientists at the CERN particle physics laboratory are looking for particles that slip into existence when subatomic particles crash into one another at high energies.

Experts say finding the elusive particle would rank as one of the top scientific achievements of the past 50 years.

What is the Higgs boson?

The Standard Model of particle physics lays out the basics of how elementary particles and forces interact in the universe. But the theory crucially fails to explain how particles actually get their mass.Why is the 'God particle' a big deal?

Particles, or bits of matter, range in size and can be larger or smaller than atoms. Electrons, protons and neutrons, for instance, are the subatomic particles that make up an atom.

Scientists believe that the Higgs boson is the particle that gives all matter its mass.

Experts know that elementary particles like quarks and electrons are the foundation upon which all matter in the universe is built. They believe the elusive Higgs boson gives the particles mass and fills in one of the key holes in modern physics.

How does the Higgs boson work?

The Higgs boson is part of a theory first proposed by physicist Peter Higgs and others in the 1960s to explain how particles obtain mass.

The theory proposes that a so-called Higgs energy field exists everywhere in the universe. As particles zoom around in this field, they interact with and attract Higgs bosons, which cluster around the particles in varying numbers.

Imagine the universe like a party. Relatively unknown guests at the party can pass quickly through the room unnoticed; more popular guests will attract groups of people (the Higgs bosons) who will then slow their movement through the room.

The speed of particles moving through the Higgs field works much in the same way. Certain particles will attract larger clusters of Higgs bosons -- and the more Higgs bosons a particle attracts, the greater its mass will be.

Higgs boson is the last missing piece of our current understanding of the most fundamental nature of the universe.
Physicist Martin Archer


Why is finding the Higgs boson so important?

While finding the Higgs boson won't tell us everything we need to know about how the universe works, it will fill in a huge hole in the Standard Model that has existed for more than 50 years, according to experts.

"The Higgs boson is the last missing piece of our current understanding of the most fundamental nature of the universe," Martin Archer, a physicist at Imperial College in London, told CNN.

"Only now with the LHC [Large Hadron Collider] are we able to really tick that box off and say 'This is how the universe works, or at least we think it does'."

"It's not the be all and end all -- but in terms of what can we say practically about the world and how the world is, it actually tells us a lot."

Gordon Kane, director of the Michigan Center for Theoretical Physics, added that finding evidence of the Higgs boson would be a "very wonderful success of science and of people for four centuries."

Why is the Higgs boson called the "God particle?"

The popular nickname for the elusive particle was created for the title of a book by Nobel Prize winning physicist Leon Lederman -- reportedly against his will, as Lederman has said he wanted to call it the "Goddamn Particle" because "nobody could find the thing."

"'God particle' is a nickname I don't really like," says Archer. "It's nothing to do with religion -- the only (theoretical) similarity is you're seeing something that's a field that's everywhere, in all spaces."

How are scientists searching for the Higgs boson?

For the past eighteen months scientists have searched for the Higgs boson by smashing protons together at high energy in the $10 billion Large Hadron Collider (LHC) at CERN in Geneva, Switzerland.

If we don't see [Higgs], it means the universe is more complicated than we thought.
Physicist Martin Archer


Inside the LHC, which is located 328 feet underground in a 17-mile tunnel and is the most powerful particle accelerator ever built, high speed proton collisions generate a range of even smaller particles that scientists sift through in search of a signal in the data suggesting the existence of the Higgs boson.

"You're just hoping that somewhere in these collisions that you see something ... some sort of a statistical bump," says Archer.

If Higgs bosons exist, they are elusive, popping up and then disappearing again quickly. It means, says Archer, that scientists at the LHC will only be able to observe their decaying remnants.

It has taken years for scientists to narrow down the range of mass in which they believed the Higgs boson could exist -- but during the past year a statistical bump suggests they're on the right track.

"Now they're starting to get a bump, the scientists should be able to get that result more and more," says Archer.

What if scientists don't find the Higgs boson?

The general consensus among physics academics is that the Higgs field and boson exists, according to Archer.

"It just makes sense within the framework that we've got everything set up in, given that everything else that we can describe and we can see seems to be described in this simple way," says Archer.

Nearly every scientist believes that the Large Hadron Collider will either prove or disprove the existence of the Higgs boson once and for all -- so if the LHC doesn't find it, it doesn't exist, experts say.

Martin Archer believes a failure to find the Higgs boson would be even more exciting than discovering the elusive particle.

"If we don't see it, it actually means that the universe at the most fundamental level is more complicated than we thought," says Archer, "and therefore maybe the way we've been attacking physics isn't right."

By Nick Thompson, CNN
October 8, 2013 -- Updated 0940 GMT (1740 HKT)

http://edition.cnn.com/2011/12/13/world/europe/higgs-boson-q-and-a/index.html

dimanche 6 octobre 2013

The Higgs, The Dilaton & The Big Bang



fromquarkstoquasars:

The world of particle physics was vindicated upon the discovery of the Higgs Boson (the long-sought after particle that plays a crucial role in granting elementary particles mass). Obviously, the Higgs is a key component in tackling the nature of matter itself, but now it appears as if the Higgs my provide valuable insight to the expansion of the universe and the events that came after the big bang.

To read the full article, see: http://www.fromquarkstoquasars.com/the-higgs-the-dilaton-the-big-bang/

image credit: NASA / WMAP Science Team

Oct 6, 2013 3:31 pm by: kenobi-wan-obi

http://scinerds.tumblr.com/post/63299715014/fromquarkstoquasars-the-higgs-the-dilaton

Le Boson de Higgs à l'Origine de la Matière Noire et de l'Asymétrie Matière-Antimatière ?

Et si le boson de Higgs était à l'origine de deux grandes énigmes actuelles de la physique : la matière noire et l'asymétrie entre matière et antimatière ? C'est ce que suggèrent deux physiciens qui publient une nouvelle théorie audacieuse dans Physical Review Letters.

Tout part de la suggestion par Sean Tulin, de l'University of Michigan et Géraldine Servant de l'institut Catalan de recherches avancées de Barcelone, qu'il aurait pu exister une asymétrie entre le boson de Higgs et son antiparticule dans l'Univers primordial.
On pense actuellement que le boson de Higgs ne possède pas d'antiparticule, mais le modèle standard de la cosmologie permet qu'il y ait eu à la fois des bosons de Higgs et des anti-bosons de Higgs quand l'Univers était très jeune. Le boson de Higgs interagit avec la matière ordinaire, et une éventuelle asymétrie entre bosons et anti-bosons de Higgs peut se transmettre d'une certaine manière en provoquant une asymétrie entre matière et antimatière...


Cette idée a été appelée l'Higgsogénèse par les auteurs, en référence à la baryogénèse, qui est la phase de production des baryons (protons et neutrons) en plus grande quantité que les antibaryons.

Tulin et Servant montrent que si le boson de Higgs interagit également avec la matière noire, par exemple en produisant des particules de matière noire lors de sa désintégration, il peut créer une quantité de matière noire telle que le ratio matière noire/matière visible est exactement ce que nos observons aujourd'hui...

Une conséquence, et non des moindres, de ce concept serait l'existence d'un test très simple pour l'existence de la matière noire, qui a tant de mal à être mise en évidence directement. Ici, quand le boson de Higgs se désintègre en d'autres particules dans le LHC au CERN, il produirait également des particules de matière noire, indétectables, mais que l'on pourrait déduire à partir des autres produits de la désintégration.

Les désintégrations de bosons de Higgs n'ont pour le moment pas encore été étudiées avec suffisamment de détails pour dire si un tel phénomène a lieu, mais cela pourrait être fait assez facilement dans le futur proche...

Et d'autres groupes de recherche s'intéressent aussi à l'Higgsogénèse, comme par exemple la physicienne théoricienne Sacha Davidson, de l'Institut de Physique Nucléaire de Lyon, et ses collègues, qui ont publié en juillet dernier sur arxiv.org une étude cherchant quels sont les prérequis pour produire l'asymétrie originelle entre Higgs et anti-Higgs à l'origine de tout le processus. Et ils trouvent qu'une théorie relativement simple peut produire une asymétrie du type de celle que proposent Tulin et Servant aujourd'hui.
Dans ce modèle, le modèle standard de la physique des particules inclut bien sûr toutes les particules existantes, mais y incorpore aussi deux bosons de Higgs, plus une troisième particule 'Higgs-like' qui resterait inobservable...

Ce qui rend ces modèles théoriques très intéressants, c'est qu'ils parviennent à mettre ensemble trois faits empiriques assez éloignés a priori : l'existence prouvée du boson de Higgs (nobélisé dans quelques jours), d'une matière noire, et d'une asymétrie matière-antimatière.

Références :
Higgsogenesis
Servant, G. & Tulin, S. 4
Preprint : http://arxiv.org/abs/1304.3464 (2013).
à paraître dans Phys. Rev. Lett.

Davidson, et al.
Baryogenesis through split Higgsogenesis
Preprint : http://arxiv.org/abs/1307.6218 (2013).

vendredi 4 octobre 2013

samedi 25 mai 2013

What is the Higgs Boson? An Animated Explanation



So, here it is – everything you ever wanted to know about the Higgs Boson but were way too intimidated by the science to ask. Particle physics is something of a mystery to me and so it was great to watch this animation and be able to get something of a grasp on the Higgs Boson and what it actually is (and isn’t). This is (I am guessing!) a simplified explanation of what the Higgs Boson is and why it is so important (nothing would exist if it didn’t, effectively!).

This animation was created by James Sutton for part of his final year studying graphic design. The soundtrack is provided by christ. There has to be some irony in that.

Friday, May 24, 2013

http://www.kuriositas.com/2013/05/what-is-higgs-boson-animation.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Kuriositas+%28Kuriositas%29