- published: 22 Oct 2015
- views: 4454
The eta (η) and eta prime meson (η′) are mesons made of a mixture of up, down and strange quarks and their antiquarks. The charmed eta meson (η
c) and bottom eta meson (η
b) are forms of quarkonium; they have the same spin and parity as the light eta but are made of charm quarks and bottom quarks respectively. The top quark is too heavy to form a similar meson, due to its very fast decay.
The eta was discovered in pion-nucleon collisions at the Bevatron in 1961 by A. Pevsner et al. at a time when the proposal of the Eightfold Way was leading to predictions and discoveries of new particles from symmetry considerations.
The difference between the mass of the η and that of the η' is larger than the quark model can naturally explain. This " η-η' puzzle" can be resolved by the 't Hooft instanton mechanism, whose 1/N realization is also known as Witten-Veneziano mechanism.
The η particles belong to the "pseudo-scalar" nonet of mesons which have spin J = 0 and negative parity, and η and η′ have zero total isospin, I, and zero strangeness and hypercharge. Each quark which appears in an η particle is accompanied by its antiquark (the particle overall is "flavourless") and all the main quantum numbers are zero.
Eta (uppercase Η, lowercase η; Ancient Greek: ἦτα êta or Modern Greek: ήτα íta) is the seventh letter of the Greek alphabet. Originally denoting a consonant /h/, its sound value in the classical Attic dialect of Ancient Greek was a long vowel [ɛː], raised to [i] in medieval Greek, a process known as iotacism.
In the system of Greek numerals it has a value of 8. It was derived from the Phoenician letter heth . Letters that arose from Eta include the Latin H and the Cyrillic letter И.
The letter shape 'H' was originally used in most Greek dialects to represent the sound /h/, a voiceless glottal fricative. In this function, it was borrowed in the 8th century BC by the Etruscan and other Old Italic alphabets, which were based on the Euboean form of the Greek alphabet. This also gave rise to the Latin alphabet with its letter H.
Other regional variants of the Greek alphabet (epichoric alphabets), in dialects that still preserved the sound /h/, employed various glyph shapes for consonantal Heta side by side with the new vocalic Eta for some time. In the southern Italian colonies of Heracleia and Tarentum, the letter shape was reduced to a "half-heta" lacking the right vertical stem (Ͱ). From this sign later developed the sign for rough breathing or spiritus asper, which brought back the marking of the /h/ sound into the standardized post-classical (polytonic) orthography.Dionysius Thrax in the second century BC records that the letter name was still pronounced heta (ἥτα), correctly explaining this irregularity by stating "in the old days the letter Η served to stand for the rough breathing, as it still does with the Romans."
La historia de ETA - Los Años de Plomo - Madrid como objetivo
UPDATE: The BBC are reporting that a video has been passed exclusively to them that allegedly shows the start of a process of complete ETA disarmament. Find out more here: http://bbc.in/1dbnrua For 40 years the militant group ETA carried out a bloody campaign for independence in the regions of Spain and France known as Basque country. 800 people lost their lives in the campaign with countless others injured. More than two years ago ETA announced a unilateral, permanent ceasefire in favour of a political agreement but the Spanish government maintains it won't enter talks with the group until it admits defeat and surrenders unconditionally. But now ETA is expected to announce that it will hand over its weapons and bomb-making equipment. We take a closer look. Subscribe to our channel: ht...
Desde que el 20 de octubre de 2011 ETA anunciase el cese definitivo de su actividad armada, varios centenares de personas que han estado involucradas en la organización terrorista han querido volver. Volver al País Vasco pero también volver a una vida normal tras años de clandestinidad. Cinco años después del fin del terrorismo algunos ya se han atrevido a retornar a Euskadi pero otros siguen del otro lado de la frontera por miedo a ser detenidos y llevados ante los tribunales. VICE News ha estado con varias de estas personas. El reportaje también cuenta con la intervención del fiscal jefe de la Audiencia Nacional, Javier Zaragoza, quien asegura que la justicia española no puede dejar de actuar contra aquellas personas que tengan causas pendientes. Un recorrido vital desde la huida y...
Los primeros años de la historia de ETA. Durante la dictadura franquista, el 31 de julio de 1959, un grupo de jóvenes nacionalistas agrupados en EKIN crearon Euskadi Ta Askatasuna, ETA. En 1974 ETA Militar se escindió. Visita nuestra web http://www.eitb.com/ Más vídeos interesantes en http://www.youtube.com/eitbcom/ Televisión a la carta http://www.eitb.tv/es/ Suscríbete el canal de vídeos de EiTB en Youtube http://www.youtube.com/eitbcom
Part 1-https://youtu.be/dfMA9GOpMXw Starring; Toyin Aimaku Johnson,Adeniyi Johnson, Afeez Eniola and many other favourites This is the concluding Part you have been waiting for. What really happened to Eta and her two sisters at the end. Lets find out. Eta resumes work but not as herself as she resonate an entirely different personality, this makes her PA and her fiancé suspicious. They team up to find out who eta really is... Starring: Toyin Aimakhu, Niyi Johnson. Link to our channel page: https://www.youtube.com/user/Yorubac For more interesting movies on our playlist https://www.youtube.com/playlist?list=PLUHuM0g065aocY3vdroyN5otKOrzb8vn6 Please click here to watch more of our interesting Yoruba cinema movieshttps://www.youtube.com/watch?v=qpoOLDF5FUQv=JiSGgY8_4Z4&list;=PLUHuM0g065aq...
Spain's crackdown on members of the Basque separatist organisation ETA is continuing - even though the group has announced a permanent ceasefire. Just why is ETA making this move now? Has it given up its fight for a Basque independent homeland?
Canada will introduce a mandatoey new entrey requirment for all travels who don't require a Canadian Visa to enter Canada, This does not include American citizens and permanit Residents of Canada.
Three identical ladies born on the same day to the same parents, each exhibit distinct interesting characters. But amongst the three Eta seem like the only individual who fits normally into the society and her two sisters wouldn't like to be taken for granted either. Starring: Toyin Aimakhu J, Niyi Johnson. This Free African Nigerian Nollywood Yoruba movie is a must watch for all lovers of Nigerian Yoruba movies. To watch Free African, Nigerian Nollywood Yoruba movies, please freely subscribe to Yoruba5star by clicking on this link: http://www.youtube.com/subscription_center?add_user=Yoruba5star Powered by AFOREVO. Brought to you by Yoruba5star. Propulsé par AFOREVO. Apporté à vous par Yoruba5star.
I need to tell this secret be sure to keep it down
If this gets out I don't know what I'll do
I've held it in through many heartaches and all you did was smile
Cna't you see I've fallen in love wiht you, with you
Apology accepted, erase what's in the past
You need me you don't need them
And in spite of my mistakes, I've learned there's so much I can take
I can't believe what I'm saying
Don't walk away so quickly I haven't lost it yet
I just need to be honest with myself
And all the times I've used my shoulder to wipe away the tears
I vowed to see you with nobody else, or else
Apology accepted, erase what's in the past
You need me you don't need them
And in spite of my mistakes, I've learned there's so much more I can take
I can't believe what I'm saying
Then it hits me, fooled again
Into thinking, we'd be more than friends
The messages you left for me, will all go unreturned
I need some time to think about the facts
I opened up my heart to you and you hid yours away
So silence is the best way to react, react
Apology accepted, erase what's in the past
You need me you don't need them
And in spite of my mistkes there's only so much I can take
I can't believe what I'm saying, I'm saying, I'm saying