Archive for the ‘Fizica particulelor elementare’ Category

http://romanian.ruvr.ru/2013_09_11/LHC-o-mare-realizare-in-lumea-fizicii-particulelor-elementare-1748/

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http://romanian.ruvr.ru/2013_03_17/Particula-descoperita-la-CERN-este-chiar-bosonul-Higgs/

In the communiqué issued by CERN, stating that considering how to split elementary particle yet discovered last summer, this is the Higgs boson!. From experiments ATLAS – A Toroidal LHC Apparatus and CMS – Compact Muon Solenoid, in the Large Hadron Collider – LHC, spanning almost three years, and data analysis by researchers involved in these programs, it is a „strong indication „that the particle discovered much searching Higgs. Certainly in these experiments, to mention a boson, but it really is the Higgs boson?
Richard Feynman, is legendary in the world of physics for his way of seeing and interpreting the world as a whole but also for the enthusiasm with which his students explaining physics. Feynman often said that he does not understand why the media and the public want to know the latest discoveries in physics, although they have no idea about the science, but mostly on discoveries of the past, giving a sense of new discoveries. I will try to provide simplified public current situation in elementary particle physics, and news professionals at CERN, on the Higgs boson, without compromising the truth by distorsioanarea information.
Since the second half of the twentieth century, a series of discoveries and new theories led to a revolution in terms of the concepts in the world of elementary particles, resulting in the Standard Model, which is actually a consensus on the basic constituents of matter and fundamental force describing the interactions between them.
The Standard is a concept formulated and developed in elementary particle that combines quantum electrodynamics, quantum chromodynamics and theories of the weak force. But gravity still has no place in this model. The Standard Model of elementary particles is a theory of three of the four fundamental forces namely the electromagnetic interaction, weak nuclear and strong nuclear interactions and elementary particles that take part in these interactions. These particles of matter and energy, which are described by means of equations, all matter in the universe organized around a basic principle known as local gauge symmetry.
Higgs boson is considered so far, the missing link in the Standard Model of particle physics, which is supposed to have derived all particles with mass.
International scientific community at CERN specialists should be much more cautious because you may not have sufficient evidence to certify that the particle is certainly of Higgs boson!, But we believe that the evidence gathered so far presents the particle as the main candidate for the title. In addition we must consider the events aroused last year and all the fuss surrounding the discovery invalidated researchers at CERN that neutrinos could move the gear speed of light in vacuum, so Einstein can sit quietly famous equation remains form E = mc ², and the speed of light in a vacuum remains a fundamental constant.
The problem currently facing physicists at CERN, is whether the Higgs boson is also prefigured theoretical Standard Model of physics, or not!, Ie if the standard model is correct, or you will have to give up this theory.
One of the ways scientists are trying to prove that complies with the Standard Model of particle discovered particle physics is the study of the ways in which it decomposes. The new type of particle is unstable, decomposing tiny fraction of a second after the other particles. Standard model implies and requires some specific predictions about the type of particles that arise from such a boson decay and how common are decompositions. According to preliminary findings obtained by the team that made CMS experiment, the new particle decays not only other types of bosons, such as photons, but also in a class of particles called fermions, including particulate matter such as quarks which form protons and leptons, which include electrons category.
But CMS has identified that the new boson can only decay into two leptons to your – something that is not covered by the Standard Model of particle physics. But the Higgs is discovered improper presented by the media as „the God particle”. If it looks like a Higgs boson behaves and decomposes according to model predictions, then it probably is the Higgs boson – the particle that gives mass to all other particles.
So far there is insufficient evidence to certify, without any shadow of doubt that the particle discovered in two independent experiments is Higgs boson’s.
Thus, according to the findings of the team that developed the CMS experiment, the new particle decays not only other types of bosons, such as photons, but also in a class of particles called fermions, including particulate matter such as quarks, leptons that make up protons and electrons category they belong. So if independent CMS experiment clearly identified that the new boson can decay into two leptons your – a phenomenon that is not covered by the Standard Model of particle physics.
Higgs boson is postulated and hold certain quantum properties. If ATLAS experiment, the signal value of 125 GeV particle had a level of significance of 3.5 sigma – statistical parameter used to assess the probability that an event will occur other than by chance.
But the 3 sigma is sufficient to prove the possibility of the Higgs boson, but it takes 5-sigma value is reached to confirm actual discovery of this particle. Currently, it is estimated that there are five types of Higgs field – each with an associated Higgs boson. To detect a Higgs boson in the laboratory have created a real one instead of a virtual one!. By colliding particles with antiparticles can be generated very high energy value. Following these interactions result byproduct of subatomic decay, which represents but only evidence of the fact that the Higgs can be created.
Higgs boson is the last particle predicted by the Standard Model of elementary particles. The Standard Model is still over four decades the most accurate theory, uncontradicted by any experiment and whose predictions were all confirmed by further experiments.
Whether the Higgs particle is discovered, leaves open, ie whether it is the Higgs boson of the Standard Model of particle physics, or possibly easier is a particle predicted in other theories that go beyond the Standard Model. However finding the answer to this question will last as long.
And yet … „the old saying of physics say that extraordinary claims require extraordinary evidence.” However if you confirm with certainty, discovering the Higgs boson, it certainly could bring scientists at CERN Nobel Prize.

Les scientifiques de l’espoir Grand collisionneur de hadrons va produire un voyage hypothétique à travers le temps pour détecter les effets du boson de Higgs. Les chercheurs Thomas Weiler de l’Université Vanderbilt et Ho Chui, considèrent que l’atome pourrait être en mesure d’émettre une particule de Higgs singulet doit apparaître juste avant la collision qui l’a produit, écrit  Singulet de Higgs particule est liée à une autre hypothèse, qui est l’espoir d’être découverts, notamment le boson de Higgs, les deux physiciens croient que le LHC pourrait éventuellement transmettre le message dans le passé et l’avenir, sans briser les lois de la physique, selon des articles publiés sur le site Live Science et sites arXiv.org. Avec le LHC, les physiciens espèrent les deux seront en mesure de trouver le boson de Higgs et le singulet peuvent être produites simultanément.

Cela va créer des conditions de «faire bouillir plasma quark-gluon» qui étaient supposées exister 13,7 milliards d’années, à une fraction de seconde après le Big Bang. Ils croient que les détecteurs ATLAS et CMS peut voir l’influence du boson de Higgs, dans le temps.Au centre de leurs spéculations, il ya des modèles et des théories physiques comme Kaluza-Klein espace-temps que la géométrie est le nombre de dimensions spatiales est supérieure à 3 M et la théorie des cordes à 11 dimensions. Certaines des dernières théories de Randall et Sundrum – RS 1999, estime que notre univers serait comme une membrane ou flottant dans l’espace.  Certains physiciens pensent que, bien que laborieux calculs des deux chercheurs repose sur plusieurs hypothèses physiques pourraient être corrects dans leurs spéculations ne survivra pas clairement les données actuelles et futures expériences.
Quel que soit le monde est sur le point de révolutionner la compréhension profonde rereferitor structure de données et les processus de l’univers qui a eu lieu après le Big Bang conduisant à l’apparition de la vie sur Terre.
Naissance de l’Univers est encore un mystère troublant de constater que les chercheurs «cosmique» et «terrestre» dans la même mesure, l’énigme qui dure une vingtaine d’années. Tout commence à l’astronome américain Hubble, qui a traité ses observations sur les spectres des galaxies lointaines est parvenu à une conclusion que les galaxies les unes des autres et de l’univers observable est en expansion uniforme. La théorie d’Einstein, la théorie de la relativité générale avec une déclaration publiée par Aleksandrovici Alexander Fridman, prévoir une éventuelle extension de l’univers similaire, mais dit que l’expansion de l’univers pourrait cesser d’être capable de compresser et redémarrez à nouveau pour démarrer l’expansion . Ainsi, l’univers peut vibrer, et la durée de ces impulsions est des milliards d’années. Mais la théorie d’Einstein ne peut pas expliquer les causes de telles impulsions. Nous croyons qu’il a commencé la chasse pour tous les spécialistes dans le domaine de confirmation et / ou boson règle générale, la découverte de nouvelles particules peuvent être à sa fin?
… il semble… NON!.
Einstein lutté toute sa vie à créer une théorie unifiée de tous les champs et les particules, mais a échoué. Son objectif pour les années se sont révélées si géant, mais inaccessible, et que l’esprit brillant de la physique moderne qu’il ne pouvait pas faire face. Les tentatives se multiplient chaque année, mais de nouvelles théories effondrement sous le poids de nouvelles découvertes ou de violation des lois de la physique. Je viens de les paroles de la grande montagne Niels Bohr à l’occasion de discussions avec deux autres titans de la physique Heissenberg Pauli, sur la théorie de Heissenberg, reste célèbre phrase:!. „Nous sommes tous d’accord que votre théorie est folle La question qui dérange nous est de savoir si il est assez fou pour pouvoir se tenir debout et équitable. ”
Nous sommes convaincus aujourd’hui que les particules élémentaires qui constituent la matière commune, tels que les leptons, les photons, les particules W, Z, les quarks et les gluons sont bien décrites par le modèle standard, une fusion de la théorie électrofaible avec la chromodynamique quantique. Mais cette synthèse n’est pas la solution définitive aux problèmes existentiels de l’univers. Une restriction claire de ce modèle est qu’il ne comprend pas la gravité, ce qui est très difficile à traiter dans la théorie quantique. Théorie est la théorie des supercordes, étant définie dans un hyperespace avec 10 dimensions, peut-être pourrait fournir une réponse aux questions restées sans réponse sur l’univers si loin.

 

O echipa de cercetatori care lucreaza in cadrul experimentului ALPHA la CERN, au realizat primele masuratori spectroscopice in cazul unui atom de antimaterie. Experimentul reprezinta un pas important spre intelegerea universului si a raporturilor dintre materie si antimaterie care guverneaza simetria spatio temporala, scrie <a href=”http://physicsworld.com/cws/article/news/48871” target=”_blank”>Physicsworld<a>. Atomul de antihidrogen este alcatuit dintr-un pozitron si un antiproton. In 1995 au fost produsi artificial primii atomi de antimaterie in cardul unor experimente la CERN, dar acestia s-au anihilat rapid in contact cu materia inconjuratoare, inainte de a fi examinati in detaliu. In 2009 au fost capturati 38 de atomi de antihidrogen pentru o cincime de secunda, apoi in 2010 peste 1.000 de particule de antimaterie. Antihidrogenul rece a fost captat in capcane magnetice de tip Penning pentru prima oara in 2010. Cercetatorii din cadrul proiectului ALPHA au reusit sondarea pentru prima oara a structurii interne a atomului de antihidrogen, realizand astfel prima tentativa de a analiza spectrele de frecventa si structura antimateriei, studiul fiind publicat in recent in revista de specialitate <a href=”http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10942.html” target=”_blank”>Nature</a>. Echipa din cadrul experimentului ATLAS a realizat sase serii de experimente, reusind sa observe tranzitii cuantice intre atomii de antimaterie prinsi in capcana magnetica si comparand astfel spetrele hidrogenului si ale antihidrogenului. Astfel specialistii cauta sa observe diferentele de structura dintre atomi, si antiatomii corespunzatori, incercand sa gaseasca explicatii referitoare la evolutia universului si la raporturile dintre materie si antimaterie, inclusiv a simetriei dintre cele doua componente.

 

 

Idei ciudate in fizica: Cristalele de timp traduc simetria si in timp

 

Fizica in general este definta prin simetriile sale, pornind de la legile termodinamicii, privind conservarea masei si a energie, si pana la principiul conform caruia universul este in esenta acelasi peste tot.

Fizicienii, Frank Wilczek de la MIT – laureat al Premiului Nobel in 2004 si Alfred Shapere de la Universitatea din Kentucky, au scris doua lucrari despre o idee cel putin bizara, cristalele de timp, clasice si cuantice,  precizeaza <a href=”http://www.physorg.com/news/2012-02-crystals-perpetual-motion-machines.html” target=”_blank”>Physorg</a>.

Conform celor doi fizicieni, teoretic este posibil ca un sistem aflat in starea de energie minima, prezinta o miscare periodica, sistemul fiind echivalent temporal cu un cristal definit prin periodicitatea sa spatiala.

Wilczek si Shapere au efectuat calcule matematice complexe, care au relevat faptul ca un sistem in starea de minima energie, s-ar putea muta intr-o miscare periodica, cum ar fi o bucla sau o orbita, miscarea fiind de tip perpetuum mobile.
Definitia unui cristal este destul de simpla –  orice solid ale carui parti componente sunt aranjate intr-un model ordonat, repetand extinderea in toate cele trei dimensiuni spatiale. Desi cristale in sine sunt definite prin dispunerea lor simetrica, ele reprezinta de fapt o forma a ceea ce este cunoscut sub numele de rupere spontana de simetrie in sisteme inchise.
In cazul in care simetrie generala spatiala a fost distrusa, periodicitatea care defineste structura de cristal nu a fost pierduta in intregime. Cei doi fizicieni sustin ca simetria poate fi tradusa si in timp, in cazul cristalelor de timp. Desi nu a fost demonstrata existenta lor, fizicienii cred ca astfel de cristale ar putea exista in cazul supraconductorilor.
Wilczek, considera ca ideea cristalelor de timp, este dificila si din punct de vedere matematic, dar indiferent daca acestea ar exista sau nu in mod natural, ele reprezinta pana la urma o stare a materiei supusa unor tranzitii de faza. Conform celor doua studii cristalele de timp s-ar putea sa se deplaseze periodic pentru totdeauna, definind de fapt o miscare perpetua, fapt care ar conduce la obtinerea unei energii eterne.

Posibilitatea existentei cristalelor de timp, incita deja comunitatea stiintifica din domeniu, oamenii de stiinta planuind sa investigheze existenta lor in viitor.

 

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Big Bounce in loc de Big Bang – si un experiment indraznet al fizicienilor pentru confirmarea gravitatiei cuantice

Teoria gravitatie cuantice nu a fost pana acum testata, fizicienii spera sa descopere semnaturi ale unor radiatii studiind evaporarea unei gauri negre.

Big Bounce vs. Big Bang - experiment pentru confirmarea gravitatiei cuantice

Big Bounce vs. Big Bang – experiment pentru confirmarea gravitatiei cuantice

Teoria gravitatiei cuantice nu a fost pana acum testata, iar fizicienii spera sa descopere semnaturi ale unor radiatii, studiind evaporarea unei gauri negre. Fizicienii francezi si americani propun un experiment senzational – sondarea in cazul evaporarii unei gauri negre – care poate…

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06.01.2012