Cwarc
Math o ronynnau sylfaenol ydy cwarc (Saesneg: Quarks) ac yn rhan bwysig o'r gynhysgaeth sy'n gwneud mater. Unant gyda'i gilydd i greu gronynnau cyfansawdd a elwir yn hadronau, y mwyaf sefydlog ohonynt, mae'n debyg, yw'r proton a'r niwtron. Y rhain ydy'r unig ronynnau yn y Model Sylfaenol ('Standard Model') sy'n profi grym cryf arnynt, ac felly, nhw ydy'r unig ronynnau sy'n profi'r pedwar grym sylfaenol.[1] Oblegid y ffenomenon hwnnw a elwir yn color confinement, ni cheir byth gwarcs unigol; maen nhw wastad i'w canfod o fewn yr hadron.[2][3] Oherwydd hyn, mae llawer iawn o'r hyn a wyddom am y cwarc yn dod o'n hastudiaeth o'r hadron.
Credid unwaith bod niwtronau, protonau ac electronau yn ronynnau sylfaenol. Ni all gronynnau sylfaenol cael eu torri ymhellach. Darganfuwyd fod hyn yn anghywir yn dilyn defnydd cyflymydd gronynnol.
Er bod electronau yn ronynau sylfaenol, nid yw protonau a niwtronau. Mae'r rhain yn baryonau sy'n cynnwys cwarciau.
Tarddiad y gair
Bathwyd y gair "quark" gan Gell Mann i ddynwared y sŵn a wna hwyaid.[4] Am beth amser roedd yn petruso ynglŷn â'r sillafiad nes y daeth ar draws y gair quark yn llyfr James Joyce's: Finnegans Wake:
Three quarks for Muster Mark!
he has not got much of a bark
And sure any he has it's all beside the mark.[5]
Mae'r odl, felly, yn dweud wrthom mai fel 'a' am 'afal' y dylid ynganu'r gair ac nid fel 'y' am 'ynys'. Ymhelaethodd ynglŷn â'r gair yn ei lyfr The Quark and the Jaguar:[6]
In 1963, when I assigned the name "quark" to the fundamental constituents of the nucleon, I had the sound first, without the spelling, which could have been "kwork". Then, in one of my occasional perusals of Finnegans Wake, by James Joyce, I came across the word "quark" in the phrase "Three quarks for Muster Mark". Since "quark" (meaning, for one thing, the cry of the gull) was clearly intended to rhyme with "Mark", as well as "bark" and other such words, I had to find an excuse to pronounce it as "kwork". But the book represents the dream of a publican named Humphrey Chimpden Earwicker. Words in the text are typically drawn from several sources at once, like the "portmanteau" words in "Through the Looking-Glass". From time to time, phrases occur in the book that are partially determined by calls for drinks at the bar. I argued, therefore, that perhaps one of the multiple sources of the cry "Three quarks for Muster Mark" might be "Three quarts for Mister Mark", in which case the pronunciation "kwork" would not be totally unjustified. In any case, the number three fitted perfectly the way quarks occur in nature.
Roedd yn well gan Zweig y gair 'ace' am y gronyn, ond terminoleg Gell-Mann enillodd unwaith roedd y model wedi'i dderbyn gan y byd gwyddonol.[7]
Cyfeiriadau
- ↑ "Quark (subatomic particle)". Encyclopædia Britannica. Cyrchwyd 2008-06-29.
- ↑ R. Nave. "Confinement of Quarks". HyperPhysics. Georgia State University, Department of Physics and Astronomy. Cyrchwyd 2008-06-29.
- ↑ R. Nave. "Bag Model of Quark Confinement". HyperPhysics. Georgia State University, Department of Physics and Astronomy. Cyrchwyd 2008-06-29.
- ↑ J. Gribbin, M. Gribbin (1997). Richard Feynman: A Life in Science. Penguin Books, tud. 194. ISBN 0-452-27631-4
- ↑ J. Joyce (1939). Finnegans Wake. Penguin Books, tud. 383. LCCN 59-354. ISBN 0-14-00-6286-6
- ↑ M. Gell-Mann (1995). The Quark and the Jaguar: Adventures in the Simple and the Complex, tud. 180. ISBN 978-0805072532
- ↑ J. Gleick (1992). Richard Feynman and modern physics. Little Brown and Company, tud. 390. ISBN 0-316-903167