different between particle vs helicity

English

Etymology

From Middle French particule, and its source, Latin particula (“small part, particle”), diminutive of pars (“part, piece”).

Pronunciation

• (Received Pronunciation) IPA^(key): /?p??t?k(?)l/
• (General American) IPA^(key): /?p??t?k?l/
• Rhymes: -??(?)t?k?l

Noun

particle (plural particles)

1. A very small piece of matter, a fragment; especially, the smallest possible part of something. [from 14th c.]
2. (physics) Any of various physical objects making up the constituent parts of an atom; an elementary particle or subatomic particle. [from 19th c.]
   • 2011, Brian Cox & Jeff Forshaw, The Quantum Universe, Allen Lane 2011, p. 55:

     What, he asked himself, does quantum theory have to say about the familiar properties of particles such as position?
3. (linguistics) A word that has a particular grammatical function but does not obviously belong to any particular part of speech, such as the word to in English infinitives or O as a vocative particle.

   • In English there is no grammatical device to differentiate predicational judgments from nonpredicational descriptions. This distinction does cast a shadow on the grammatical sphere to some extent, but recognition of it must generally be made in semantic terms. It is maintained here that in Japanese, on the other hand, the distinction is grammatically realized through the use of the two particles wa and ga.

   • Traditional grammar typically recognises a number of further categories: for example, in his Reference Book of Terms in Traditional Grammar for Language Students, Simpson (1982) posits two additional word-level categories which he refers to as Particle, and Conjunction. Particles include the italicised words in (58) below:

     (58)

     (a) He put his hat on

     (b) If you pull too hard, the handle will come off

     (c) He was leaning too far over the side, and fell out

     (d) He went up to see the manager

4. (linguistics) A part of speech which cannot be inflected: an adverb, preposition, conjunction or interjection.
   • 1844, E. A. Andrews: First Lessions in Latin; or Introduction to Andrews and Stoddard's Latin Grammar. (6th edition, Boston), p.91 (at books.google)

     322. The parts of speech which are neither declined nor conjugated, are called by the general name of particles. 323. They are adverbs, prepositions, conjunctions, and interjections.

   • 1894 (2008), B. L. Gildersleeve & G. Lodge: Gildersleeve's Latin Grammar (reprint of the 3rd edition by Dover, 2008), p.9. (at books.google)

     The Parts of Speech are the Noun (Substantive and Adjective), the Pronoun, the Verb, and the Particles (Adverb, Preposition, and Conjunction)[.]

5. (Christianity) In the Roman Catholic church, a crumb of consecrated bread; also the smaller breads used in the communion of the laity.

Synonyms

• see Thesaurus:particle
• p-word

Hyponyms

Derived terms

• charged-particle
• multiparticle

Related terms

Translations

References

• particle on Wikipedia.Wikipedia

Anagrams

• crepital, preictal, prelatic

English

Noun

helicity (countable and uncountable, plural helicities)

1. The quality of being helical.
2. (physics, fluid mechanics, electrodynamics) Any of certain measures of the extent to which vortex lines (in fluid flow) or field lines (in a magnetic or electromagnetic field) kink and twist and/or link and coil around one another.
   • 1991, E. Levich, L. Shtilman, Helicity Fluctuations and Coherence in Developed Turbulence, D. Schertzer, S. Lovejoy (editors), Non-Linear Variability in Geophysics: Scaling and Fractals, Kluwer Academic Publishers, page 18,

     The conjecture made in Tsinober and Levich (1983) was that coherent structures should possess a significant coherent helicity.

   • 1995, G. E. Marsh, 2: Helicity and Electrodynamic Field Topology, Terence William Barrett, Dale M. Grimes (editors), Advanced Electromagnetism: Foundations, Theory and Applications, World Scientific, page 62,

     The helicity associated with the writhing number is obtained by observing that a torus with twist number ±1 may be distorted into a figure-8 configuration which appears untwisted. […] Note that at each step the total helicity, consisting of the sum of twist, kink, and link helicities, is conserved.

   • 2001, Mitchell A. Berger, Measures of Topological Structure in Magnetic Fields, Renzo L. Ricca (editor), An Introduction to the Geometry and Topology of Fluid Flows, Springer, page 249,

     Thus the total helicity H equals the sum of the entries in a matrix H_ij. If N is large then there will be many more mutual helicity terms. In this case ignoring the self helicities (if they are difficult to observe) may only give a small error.

   • 2016, Eric G. Blackman, Magnetic Helicity and Large Scale Magnetic Fields: A Primer, Andre Balogh, Andrei Bykov, Jonathan Eastwood, Jelle Kaastra (editors), Multi-scale Structure Formation and Dynamics in Cosmic Plasmas, Springer, page 72,

     Now conservation of helicity is maintained: the writhe of the loops in the second panel is compensated for by the opposite sign of the twist helicity along the loops.

3. (physics, quantum mechanics) The quantized spin component of a moving particle along the direction of its motion.
   • 1989, John Taylor, 17: Gauge theories in particle physics, Paul Davies, The New Physics, Cambridge University Press, 1992, 1st Paperback Edition, page 467,

     To understand this name, note that the helicity is, roughly speaking, the spin in the direction of motion.

   • 1999, Gustavo Castelo Branco, Luís Lavoura, João Paulo Silva, CP Violation, Oxford University Press, page 12,

     The experiment was particularly ingenious because, as the neutrino hardly interacts with matter, some way of indirectly measuring its helicity had to be devised.

   • 2010, Franz Mandl, Graham Shaw, Quantum Field Theory, Wiley, page 151,

     Interpreted in terms of helicity, this means that if the incident electron has positive helicity, then the outgoing electron has positive helicity for forward scattering, and negative helicity for backward scattering.

Derived terms

• hydrodynamical helicity
• magnetic helicity

Translations

See also

• chirality
• linking number
• vorticity