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Monday, July 11, 2022

Linguistic discrimination

From Wikipedia, the free encyclopedia

Linguistic discrimination (also called glottophobia, linguicism and languagism) is unfair treatment which is based on use of language and characteristics of speech, including first language, accent, perceived size of vocabulary (whether the speaker uses complex and varied words), modality, and syntax. For example, an Occitan-speaker in France will probably be treated differently from a French-speaker. Based on a difference in use of language, a person may automatically form judgments about another person's wealth, education, social status, character or other traits, which may lead to discrimination.

In the mid-1980s, linguist Tove Skutnabb-Kangas captured the idea of language-based discrimination as linguicism, which was defined as "ideologies and structures which are used to legitimate, effectuate, and reproduce unequal division of power and resources (both material and non-material) between groups which are defined on the basis of language". Although different names have been given to this form of discrimination, they all hold the same definition. It is also important to note that linguistic discrimination is culturally and socially determined due to preference for one use of language over others.

Scholars have analyzed the role of linguistic imperialism in linguicism, with some asserting that speakers of dominant languages gravitate towards discrimination against speakers of other, less dominant languages, while disadvantaging themselves linguistically by remaining monolingual. According to scholar Carolyn McKinley, this phenomenon is most present in Africa, where the majority of the population speaks European languages introduced during the colonial era; African states are also noted as instituting European languages as the main medium of instruction, instead of indigenous languages. UNESCO reports have noted that this has historically benefitted only the African upper class, conversely disadvantaging the majority of Africa's population who hold varying level of fluency in the European languages spoken across the continent. Scholars have also noted impact of the linguistic dominance of English on academic discipline; scholar Anna Wierzbicka has described disciplines such as social science and humanities being "locked in a conceptual framework grounded in English" which prevents academia as a whole from reaching a "more universal, culture-independent perspective".

Linguistic prejudice

It can be noted that speakers with certain accents may experience prejudice. For example, some accents hold more prestige than others depending on the cultural context. However, with so many dialects, it can be difficult to determine which is the most preferable. The best answer linguists can give, such as the authors of Do You Speak American?, is that it depends on the location and the speaker. Research has determined however that some sounds in languages may be determined to sound less pleasant naturally.[6] Also, certain accents tend to carry more prestige in some societies over other accents. For example, in the United States speaking General American (a variety associated with the privileged white middle class) is widely preferred in many contexts such as television journalism. Also, in the United Kingdom, the Received Pronunciation is associated with being of higher class and thus more likable. In addition to prestige, research has shown that certain accents may also be associated with less intelligence, and having poorer social skills. An example can be seen in the difference between Southerners and Northerners in the United States, where people from the North are typically perceived as being less likable in character, and Southerners are perceived as being less intelligent. As sociolinguist, Lippi-Green, argues, "It has been widely observed that when histories are written, they focus on the dominant class... Generally studies of the development of language over time are very narrowly focused on the smallest portion of speakers: those with power and resources to control the distribution of information."

Language and social group saliency

Linguistic discrimination is sometimes linked with belonging to a social group, as in patriotism and nationalism. This poster is propaganda from World War I.

It is natural for human beings to want to identify with others. One way we do this is by categorizing individuals into specific social groups. While some groups may be readily noticeable (such as those defined by ethnicity or gender), other groups are less salient. Linguist Carmen Fought explains how an individual's use of language may allow another person to categorize them into a specific social group that may otherwise be less apparent. For example, in the United States it is common to perceive Southerners as less intelligent. Belonging to a social group such as the South may be less salient than membership to other groups that are defined by ethnicity or gender. Language provides a bridge for prejudice to occur for these less salient social groups.

Linguistic discrimination and colonization

History of linguistic imperialism

The impacts of colonization on linguistic traditions vary based on the form of colonization experienced: trader, settler or exploitation. Congolese-American linguist Salikoko Mufwene describes trader colonization as one of the earliest forms of European colonization. In regions such as the western coast of Africa as well as the Americas, trade relations between European colonizers and indigenous peoples led to the development of pidgin languages. Some of these languages, such as Delaware Pidgin and Mobilian Jargon, were based on Native American languages, while others, such as Nigerian Pidgin and Cameroonian Pidgin, were based on European ones. As trader colonization proceeded mainly via these hybrid languages, rather than the languages of the colonizers, scholars like Mufwene contend that it posed little threat to indigenous languages.

A photo of students at the Carlisle Indian Industrial School

Trader colonization was often followed by settler colonization, where European colonizers settled in these colonies to build new homes. Hamel, a Mexican linguist, argues that "segregation" and "integration" were two primary ways through which settler colonists engaged with aboriginal cultures. In countries such as Uruguay, Brazil, Argentina, and those in the Caribbean, segregation and genocide decimated indigenous societies. Widespread death due to war and illness caused many indigenous populations to lose their indigenous languages. In contrast, in countries that pursued policies of "integration", such as Mexico, Guatemala and the Andean states, indigenous cultures were lost as aboriginal tribes mixed with colonists. In these countries, the establishment of new European orders led to the adoption of colonial languages in governance and industry. In addition, European colonists also viewed the dissolution of indigenous societies and traditions as necessary for the development of a unified nation state. This led to efforts to destroy tribal languages and cultures: in Canada and the United States, for example, Native children were sent to boarding schools such as Col. Richard Pratt's Carlisle Indian Industrial School. Today, in countries such as the United States, Canada and Australia, which were once settler colonies, indigenous languages are spoken by only a small minority of the populace.

Portrait of Lord Macaulay

Mufwene also draws a distinction between settler colonies and exploitation colonies. In the latter, the process of colonization was focused on the extraction of raw materials needed in Europe. As a result, Europeans were less invested in their exploitation colonies, and few colonists planned to build homes in these colonies. As a result, indigenous languages were able to survive to a greater extent in these colonies compared to settler colonies. In exploitation colonies, colonial languages were often only taught to a small local elite. During the period of British rule in India, for example, Lord Macaulay highlighted the need for "... a class who may be interpreters between us and the millions who govern... a class of persons, Indian in blood and color, but English in taste, in my opinion, in morals and in intellect" in his now-famous "Macaulay minutes", which were written in support of the English Education Act of 1835. The linguistic differences between the local elite and other locals exacerbated class stratification, and also increased inequality in access to education, industry and civic society in postcolonial states.

Linguistic discrimination and culture

Several postcolonial literary theorists have drawn a link between linguistic discrimination and the oppression of indigenous cultures. Prominent Kenyan author Ngugi wa Thiong'o, for example, argues in his book Decolonizing the Mind that language is both a medium of communication, as well as a carrier of culture. As a result, linguistic discrimination resulting from colonization has facilitated the erasure of pre-colonial histories and identities. For example, African slaves were taught English and forbidden to use their indigenous languages. This severed the slaves' linguistic and thus cultural connection to Africa.

Colonial languages and class

In contrast to settler colonies, in exploitation colonies, education in colonial tongues was only accessible to a small indigenous elite. Both the British Macaulay Doctrine, as well as French and Portuguese systems of assimilation, for example, sought to create an "elite class of colonial auxiliaries" who could serve as intermediaries between the colonial government and local populace. As a result, fluency in colonial languages became a signifier of class in colonized lands.

In postcolonial states, linguistic discrimination continues to reinforce notions of class. In Haiti, for example, working-class Haitians predominantly speak Haitian Creole, while members of the local bourgeoise are able to speak both French and Creole. Members of this local elite frequently conduct business and politics in French, thereby excluding many of the working-class from such activities. In addition, D. L. Sheath, an advocate for the use of indigenous languages in India, also writes that the Indian elite associates nationalism with a unitary identity, and in this context, "uses English as a means of exclusion and an instrument of cultural hegemony”.

Linguistic discrimination in education

Photo of school children in Haiti

Class disparities in postcolonial nations are often reproduced through education. In countries such as Haiti, schools attended by the bourgeoisie are usually of higher quality and use colonial languages as their means of instruction. On the other hand, schools attended by the rest of the population are often taught in Haitian Creole. Scholars such as Hebblethwaite argue that Creole-based education will improve learning, literacy and socioeconomic mobility in a country where 95% of the population are monolingual in Creole. However, resultant disparities in colonial language fluency and educational quality can impede social mobility.

On the other hand, areas such as French Guiana have chosen to teach colonial languages in all schools, often to the exclusion of local indigenous languages. As colonial languages were viewed by many as the "civilized" tongues, being "educated" often meant being able to speak and write in these colonial tongues. Indigenous language education was often seen as an impediment to achieving fluency in these colonial languages, and thus deliberately suppressed.

Photo of a school in Uganda

Certain Commonwealth nations such as Uganda and Kenya have historically had a policy of teaching in indigenous languages and only introducing English in the upper grades. This policy was a legacy of the "dual mandate" as conceived by Lord Lugard, a British colonial administrator in Nigeria. However, by the post-war period, English was increasingly viewed as necessary skill for accessing professional employment and better economic opportunities. As a result, there was increasing support amongst the populace for English-based education, which Kenya's Ministry of Education adopted post-independence, and Uganda following their civil war. Later on, members of the Ominde Commission in Kenya expressed the need for Kiswahili in promoting a national and pan-African identity. Kenya therefore began to offer Kiswahili as a compulsory, non-examinable subject in primary school, but it remained secondary to English as a medium of instruction.

While the mastery of colonial languages may provide better economic opportunities, the Convention against Discrimination in Education and the UN Convention on the Rights of the Child also states that minority children have the right to "use [their] own [languages]". The suppression of indigenous languages within the education system appears to contravene this treaty. In addition, children who speak indigenous languages can also be disadvantaged when educated in foreign languages, and often have high illiteracy rates. For example, when the French arrived to "civilize" Algeria, which included imposing French on local Algerians, the literacy rate in Algeria was over 40%, higher than that in France at the time. However, when the French left in 1962, the literacy rate in Algiers was at best 10-15%.

Linguistic discrimination in governance

As colonial languages are used as the languages of governance and commerce in many colonial and postcolonial states, locals who only speak indigenous languages can be disenfranchised. For example, when representative institutions were introduced to the Algoma region in what is now modern-day Canada, the local returning officer only accepted the votes of individuals who were enfranchised, which required indigenous peoples to "read and write fluently... [their] own and another language, either English or French". This caused political parties to increasingly identify with settler perspectives rather than indigenous ones.

Even today, many postcolonial states continue to use colonial languages in their public institutions, even though these languages are not spoken by the majority of their residents. For example, the South African justice system still relies primarily on English and Afrikaans as its primary languages, even though most South Africans, particularly Black South Africans, speak indigenous languages. In these situations, the use of colonial languages can present barriers to participation in public institutions.

Examples

Linguistic discrimination is often defined in terms of prejudice of language. It is important to note that although there is a relationship between prejudice and discrimination, they are not always directly related. Prejudice can be defined as negative attitudes towards a person based on their membership of a social group, whereas discrimination can be seen as the acts towards them. The difference between the two should be recognized because prejudice may be held against someone, but it may not be acted on. The following are examples of linguistic prejudice which may result in discrimination.

Linguistic prejudice and minority groups

While, theoretically, any speaker may be the victim of linguicism regardless of social and ethnic status, oppressed and marginalized social minorities are often the most consistent targets, due to the fact that the speech varieties that come to be associated with such groups have a tendency to be stigmatized.

In Canada

Francophones in Canada

The Canadian federation and provinces have historically discriminated against their French-speaking population, treating them as second-class citizens in some time periods, in favor of the powerful English-speaking population. This discrimination has resulted in or contributed to many developments in Canadian history, including the Quebec sovereignty movement, Quebecois nationalism, the Lower Canada Rebellion, the Red River Rebellion, a proposed Acadia province, extreme poverty and low socio-economic status of the French Canadian population, low francophone graduation rates as a result of the outlawing of francophone schools across Canada, differences in average earnings between francophones and anglophones in the same positions, lowered chances of being hired or promoted for francophones, and many other things.

Anglophones in Quebec

The Charter of the French Language, first established in 1977 and amended several times since, has been accused of being discriminatory by English-speakers.[citation needed] The law makes French the official language of Quebec and mandates its use (with exceptions) in government offices and communiques, schools, and in commercial public relations. The law is a way of preventing linguistic discrimination against the majority francophone population of Quebec who were for a very long time controlled by the English minority of the province. The law also seeks to protect French against the growing social and economic dominance of English. Though the English-speaking population had been shrinking since the 1960s, it was hastened by the law, and the 2006 census showed a net loss of 180,000 native English-speakers. Despite this, speaking English at work continues to be strongly correlated with higher earnings, with French-only speakers earning significantly less. The law is credited with successfully raising the status of French in a predominantly English-speaking economy, and it has been influential in countries facing similar circumstances. However, amendments have made it less powerful and thus less effective than it was in the past.

In Europe

Linguistic disenfranchisement rate

The linguistic disenfranchisement rate in the EU can significantly vary across countries. For residents in two EU-countries that are either native speakers of English or proficient in English as a foreign language the disenfranchisement rate is equal to zero. In his study "Multilingual communication for whom? Language policy and fairness in the European Union" Michele Gazzola comes to the conclusion that the current multilingual policy of the EU is not in the absolute the most effective way to inform Europeans about the EU; in certain countries, additional languages may be useful to minimize linguistic exclusion.

In the 24 countries examined, an English-only language policy would exclude 51% to 90% of adult residents. A language regime based on English, French and German would disenfranchise 30% to 56% of residents, whereas a regime based on six languages would bring the shares of excluded population down to 9–22%. After Brexit, the rates of linguistic exclusion associated with a monolingual policy and with a trilingual and a hexalingual regime are likely to increase.

Linguistic discrimination towards languages in the Celtic nations

  • During the period of British rule in Ireland, the Irish language was not taught in schools and held no official status until the establishment of the Republic of Ireland in 1921.
  • In Wales, English was seen as the language of progress and the speaking of Welsh was discouraged in schools, and the Welsh Not was used in some places to help with this during the 18th and 19th centuries.
  • Scottish Gaelic had no official status until 2005; it was not taught in the educational system due to being "one of the chief, principal causes of barbarity and incivility" in the words of one statute.
  • Scots was in 1946 not considered "a suitable medium of education or culture".

Other examples

"I will not speak Basque" punishment in the exercise book of a schoolchild during Franco's dictatorial regime

In the United States

Perpetuation of discriminatory practices through terminology

Here and elsewhere the terms 'standard' and 'non-standard' make analysis of linguicism difficult. These terms are used widely by linguists and non-linguists when discussing varieties of American English that engender strong opinions, a false dichotomy which is rarely challenged or questioned. This has been interpreted by linguists Nicolas Coupland, Rosina Lippi-Green, and Robin Queen (among others) as a discipline-internal lack of consistency which undermines progress; if linguists themselves cannot move beyond the ideological underpinnings of 'right' and 'wrong' in language, there is little hope of advancing a more nuanced understanding in the general population.

Black Americans

Because some black Americans speak a particular non-standard variety of English which is often seen as substandard, they are often targets of linguicism. AAVE is often perceived by members of mainstream American society as indicative of low intelligence or limited education, and as with many other non-standard dialects and especially creoles, it is usually called "lazy" or "bad" English.

The linguist John McWhorter has described this particular form of linguicism as particularly problematic in the United States, where non-standard linguistic structures are often deemed "incorrect" by teachers and potential employers in contrast to other countries such as Morocco, Finland and Italy where diglossia (the ability to switch between two or more dialects or languages) is an accepted norm, and non-standard usage in conversation is seen as a mark of regional origin, not of intellectual capacity or achievement.

In the 1977 Ann Arbor court case, AAVE was compared against standard English to determine how much of an education barrier existed for children that had been primarily raised with AAVE. The assigned linguists determined that the differences, stemming from a history of racial segregation, were significant enough for the children to receive supplementary teaching to better understand standard English.

For example, a black who uses a typical AAVE sentence such as "He be comin' in every day and sayin' he ain't done nothing" may be judged as having a deficient command of grammar, whereas, in fact, such a sentence is constructed based on a complex grammar which is different from that of standard English, not a degenerate form of it. A listener may misjudge the user of such a sentence to be unintellectual or uneducated. The speaker may be intellectually capable, educated, and proficient in standard English, but chose to say the sentence in AAVE for social and sociolinguistic reasons such as the intended audience of the sentence, a phenomenon known as code switching.

Hispanic Americans and linguicism

Another form of linguicism is evidenced by the following: in some parts of the United States, a person who has a strong Spanish accent and uses only simple English words may be thought of as poor, poorly educated, and possibly an undocumented immigrant. However, if the same person has a diluted accent or no noticeable accent at all and can use a myriad of words in complex sentences, they are likely to be perceived as more successful, better educated, and a "legitimate citizen".

American Sign Language users

Users of American Sign Language (ASL) have faced linguistic discrimination based on the perception of the legitimacy of signed languages compared to spoken languages. This attitude was explicitly expressed in the Milan Conference of 1880 which set precedence for public opinion of manual forms of communication, including ASL, creating lasting consequences for members of the Deaf community. The conference almost unanimously (save a handful of allies such as Thomas Hopkins Gallaudet), reaffirmed the use of oralism, instruction conducted exclusively in spoken language, as the preferred education method for Deaf individuals. These ideas were outlined in eight resolutions which ultimately resulted in the removal of Deaf individuals from their own educational institutions, leaving generations of Deaf persons to be educated single-handedly by hearing individuals.

Due to misconceptions about ASL, it was not recognized as its own, fully functioning language until recently. In the 1960s, linguist William Stokoe proved ASL to be its own language based on its unique structure and grammar, separate from that of English. Before this, ASL was thought to be merely a collection of gestures used to represent English. Because of its use of visual space, it was mistakenly believed that its users are of a lesser mental capacity. The misconception that ASL users are incapable of complex thought was prevalent, although this has decreased as further studies about its recognition of a language have taken place. For example, ASL users faced overwhelming discrimination for the supposedly "lesser" language that they use and were met with condescension especially when using their language in public. Another way discrimination against ASL is evident is how, despite research conducted by linguists like Stokoe or Clayton Valli and Cecil Lucas of Gallaudet University, ASL is not always recognized as a language. Its recognition is crucial both for those learning ASL as an additional language, and for prelingually-deaf children who learn ASL as their first language. Linguist Sherman Wilcox concludes that given that it has a body of literature and international scope, to single ASL out as unsuitable for a foreign language curriculum is inaccurate. Russel S. Rosen also writes about government and academic resistance to acknowledging ASL as a foreign language at the high school or college level, which Rosen believes often resulted from a lack of understanding about the language. Rosen and Wilcox's conclusions both point to discrimination ASL users face regarding its status as a language, that although decreasing over time is still present.

In the medical community, there is immense bias against deafness and ASL. This stems from the belief that spoken languages are superior to sign languages. Because 90% of deaf babies are born to hearing parents, who are usually unaware of the existence of the Deaf Community, they often turn to the medical community for guidance. Medical and audiological professionals, who are typically biased against sign languages, encourage parents to get a cochlear implant for their deaf child in order for the child to use spoken language. Research shows, however, that deaf kids without cochlear implants acquire ASL with much greater ease than deaf kids with cochlear implants acquire spoken English. In addition, medical professionals discourage parents from teaching ASL to their deaf kid to avoid compromising their English although research shows that learning ASL does not interfere with a child's ability to learn English. In fact, the early acquisition of ASL proves to be useful to the child in learning English later on. When making a decision about cochlear implantation, parents are not properly educated about the benefits of ASL or the Deaf Community. This is seen by many members of the Deaf Community as cultural and linguistic genocide.

In Africa

  • Anglophone Cameroonians: the central Cameroonian government has pushed francophonization in the English-speaking regions of the country despite constitutional stipulations on bilingualism. Measures include appointing French-speaking teachers and judges (in regions with Common Law) despite local desires.
  • South Africa: Carolyn McKinley is highly critical of the language policy in the South African educational system, which she describes as 'anglonormatif', because the increasing anglicisation becomes 'normative' in the education system. The universities of Pretoria, Free State and Unisa want to anglicise completely.

In the Middle East

  • At the turn of the eighth century, the Umayyad caliph Abd al-Malik ibn Marwan decreed that Arabic would replace Medieval Greek and the Coptic language as the administrative language of the empire. Coptic gradually declined within a few hundred years and suffered violent persecutions, especially under the Mamluke Sultanate of Cairo, leading to its virtual extinction by the 17th century.
  • The Kurdish languages are under pressure in many countries where they are spoken. Publishing materials in Kurdish in Syria is forbidden, though this prohibition is not enforced any more due to the Syrian civil war. Until 2002, Turkey placed severe restrictions on the use of Kurdish, including a ban on its use in education and broadcast media. Many mayors were tried for issuing public documents in Kurdish language. The Kurdish alphabet is not recognized in Turkey, and prior to 2013 the use of Kurdish names containing the letters Q, W, and X, which do not exist in the Turkish alphabet, was not allowed. Turkey began to allow private television channels to broadcast in Kurdish on a limited basis in 2006, with most restrictions lifted by 2009. The state-run Turkish Radio and Television Corporation (TRT) started its 24-hour Kurdish television station in 2009, with full use of the letters Q, W, and X. In 2010, Kurdish municipalities in the southeast began printing marriage certificates, water bills, construction and road signs, as well as emergency, social and cultural notices in Kurdish alongside Turkish. Also, Imams began to deliver Friday sermons in Kurdish and Esnaf price tags in Kurdish. In 2012, Kurdish-language lessons became an elective subject in public schools. Previously, Kurdish education had only been possible in private institutions.

In Asia

  • Suppression of Korean during Japanese rule in Korea, 1910 to 1945.
  • Anti-Chinese legislation in Indonesia
  • The brutality and linguicism against Tamils in Sri Lanka which took thousands of Tamil lives because of their language. This was rooted from "The Sinhala Only Act", formerly the Official Language Act No. 33 of 1956, that was passed in the Parliament of Ceylon in 1956. Black July was the peak of the violence against Tamils in 1983.
  • China: In the 2000s the Chinese government began promoting the use of Mandarin Chinese in areas where Cantonese is spoken. In 2010 this gave rise to the Guangzhou Television Cantonese controversy. This has also been a point of contention with Hong Kong, which is located in the general area where Cantonese is spoken. Cantonese has become a means of asserting Hong Kong's political identity as separate from mainland China.
  • After the Kuomintang retreated to Taiwan following the Chinese Civil War, the Nationalist government promoted Mandarin and banned the public use of Taiwanese and other native languages as part of a deliberate political repression, especially in schools and broadcast media. In 1964 use of Taiwanese in schools or official settings was forbidden, and transgression in schools punished with beatings, fines and humiliation. This discrimination started to decrease and ended when martial law ended in 1987.
  • Bengali language movement occurred in a move to recognise Bengali as an official language in the then-Dominion of Pakistan of 1947.
  • Kannada supremacism widely known as "activism" is common in Karnataka and enjoys political support. It forces all residents including those from outside Karnataka to speak Kannada.
  • Marathi superamacy in Maharashtra (mainly Mumbai) perpuated by ultranationalist regional nativist parties like Shiv Sena and MNS which labelled immigrants as 'job stealers' and 'outsiders', with South Indian Kannadigas and Tuluvas becoming the target of Bal Thackeray's racist slurs and attack by Marathi goons who prided on their 'Marathi Manoos'  status. Subsequently Bihari, Gujarati and other North Indian communities were targeted and attacked resulting in an exodus in 2008. Till date, there have been sporadic attacks and discrimination towards non-Marathi communities in Mumbai.
  • Imposition of Hindi by the Indian Government on non-Hindi speaking states, especially that of South India has led to anti Hindi agitations in states like Karnataka and Tamil Nadu. The prioritization of Hindi in non-Hindi speaking states has led to discrimination towards people who do not know Hindi.

Texts

Linguicism applies to written, spoken, or signed languages. The quality of a book or article may be judged by the language in which it is written. In the scientific community, for example, those who evaluated a text in two language versions, English and the national Scandinavian language, rated the English-language version as being of higher scientific content.

The Internet operates a great deal using written language. Readers of a web page, Usenet group, forum post, or chat session may be more inclined to take the author seriously if the language is written in accordance with the standard language.

Music

A catalog of contemporary episodes of linguistic bigotry reported in the media has been assembled by critical applied linguist Steven Talmy, and can be found here.

Prejudice

In contrast to the previous examples of linguistic prejudice, linguistic discrimination involves the actual treatment of individuals based on use of language. Examples may be clearly seen in the workplace, in marketing, and in education systems. For example, some workplaces enforce an English-only policy, which is part of an American political movement that pushes for English to be accepted as the official language. In the United States, the federal law, Titles VI and VII of the Civil Rights Act of 1964 protects non-native speakers from discrimination in the workplace based on their national origin or use of dialect. There are state laws which also address the protection of non-native speakers, such as the California Fair Employment and Housing Act. However, industries often argue in retrospect that clear, understandable English is often needed in specific work settings in the U.S.

Antiparticle

From Wikipedia, the free encyclopedia
 
Diagram illustrating the particles and antiparticles of electron, neutron and proton, as well as their "size" (not to scale). It is easier to identify them by looking at the total mass of both the antiparticle and particle. On the left, from top to bottom, is shown an electron (small red dot), a proton (big blue dot), and a neutron (big dot, black in the middle, gradually fading to white near the edges). On the right, from top to bottom, are shown the anti electron (small blue dot), anti proton (big red dot) and anti neutron (big dot, white in the middle, fading to black near the edges).
Illustration of electric charge of particles (left) and antiparticles (right). From top to bottom; electron/positron, proton/antiproton, neutron/antineutron.

In particle physics, every type of particle is associated with an antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron is the positron (also known as an antielectron). While the electron has a negative electric charge, the positron has a positive electric charge, and is produced naturally in certain types of radioactive decay. The opposite is also true: the antiparticle of the positron is the electron.

Some particles, such as the photon, are their own antiparticle. Otherwise, for each pair of antiparticle partners, one is designated as the normal particle (the one that occurs in matter usually interacted with in daily life). The other (usually given the prefix "anti-") is designated the antiparticle.

Particle–antiparticle pairs can annihilate each other, producing photons; since the charges of the particle and antiparticle are opposite, total charge is conserved. For example, the positrons produced in natural radioactive decay quickly annihilate themselves with electrons, producing pairs of gamma rays, a process exploited in positron emission tomography.

The laws of nature are very nearly symmetrical with respect to particles and antiparticles. For example, an antiproton and a positron can form an antihydrogen atom, which is believed to have the same properties as a hydrogen atom. This leads to the question of why the formation of matter after the Big Bang resulted in a universe consisting almost entirely of matter, rather than being a half-and-half mixture of matter and antimatter. The discovery of charge parity violation helped to shed light on this problem by showing that this symmetry, originally thought to be perfect, was only approximate.

Because charge is conserved, it is not possible to create an antiparticle without either destroying another particle of the same charge (as is for instance the case when antiparticles are produced naturally via beta decay or the collision of cosmic rays with Earth's atmosphere), or by the simultaneous creation of both a particle and its antiparticle, which can occur in particle accelerators such as the Large Hadron Collider at CERN.

Although particles and their antiparticles have opposite charges, electrically neutral particles need not be identical to their antiparticles. The neutron, for example, is made out of quarks, the antineutron from antiquarks, and they are distinguishable from one another because neutrons and antineutrons annihilate each other upon contact. However, other neutral particles are their own antiparticles, such as photons, Z0 bosons,
π0
 mesons, and hypothetical gravitons and some hypothetical WIMPs.

History

Experiment

In 1932, soon after the prediction of positrons by Paul Dirac, Carl D. Anderson found that cosmic-ray collisions produced these particles in a cloud chamber— a particle detector in which moving electrons (or positrons) leave behind trails as they move through the gas. The electric charge-to-mass ratio of a particle can be measured by observing the radius of curling of its cloud-chamber track in a magnetic field. Positrons, because of the direction that their paths curled, were at first mistaken for electrons travelling in the opposite direction. Positron paths in a cloud-chamber trace the same helical path as an electron but rotate in the opposite direction with respect to the magnetic field direction due to their having the same magnitude of charge-to-mass ratio but with opposite charge and, therefore, opposite signed charge-to-mass ratios.

The antiproton and antineutron were found by Emilio Segrè and Owen Chamberlain in 1955 at the University of California, Berkeley. Since then, the antiparticles of many other subatomic particles have been created in particle accelerator experiments. In recent years, complete atoms of antimatter have been assembled out of antiprotons and positrons, collected in electromagnetic traps.

Dirac hole theory

... the development of quantum field theory made the interpretation of antiparticles as holes unnecessary, even though it lingers on in many textbooks.

Steven Weinberg

Solutions of the Dirac equation contain negative energy quantum states. As a result, an electron could always radiate energy and fall into a negative energy state. Even worse, it could keep radiating infinite amounts of energy because there were infinitely many negative energy states available. To prevent this unphysical situation from happening, Dirac proposed that a "sea" of negative-energy electrons fills the universe, already occupying all of the lower-energy states so that, due to the Pauli exclusion principle, no other electron could fall into them. Sometimes, however, one of these negative-energy particles could be lifted out of this Dirac sea to become a positive-energy particle. But, when lifted out, it would leave behind a hole in the sea that would act exactly like a positive-energy electron with a reversed charge. These holes were interpreted as "negative-energy electrons" by Paul Dirac and mistakenly identified with protons in his 1930 paper A Theory of Electrons and Protons However, these "negative-energy electrons" turned out to be positrons, and not protons.

This picture implied an infinite negative charge for the universe—a problem of which Dirac was aware. Dirac tried to argue that we would perceive this as the normal state of zero charge. Another difficulty was the difference in masses of the electron and the proton. Dirac tried to argue that this was due to the electromagnetic interactions with the sea, until Hermann Weyl proved that hole theory was completely symmetric between negative and positive charges. Dirac also predicted a reaction
e
 + 
p+
 → 
γ
 + 
γ
, where an electron and a proton annihilate to give two photons. Robert Oppenheimer and Igor Tamm, however, proved that this would cause ordinary matter to disappear too fast. A year later, in 1931, Dirac modified his theory and postulated the positron, a new particle of the same mass as the electron. The discovery of this particle the next year removed the last two objections to his theory.

Within Dirac's theory, the problem of infinite charge of the universe remains. Some bosons also have antiparticles, but since bosons do not obey the Pauli exclusion principle (only fermions do), hole theory does not work for them. A unified interpretation of antiparticles is now available in quantum field theory, which solves both these problems by describing antimatter as negative energy states of the same underlying matter field i.e. particles moving backwards in time.

Particle–antiparticle annihilation

Feynman diagram of a kaon oscillation. A straight red line suddenly turns purple, showing a kaon changing into an antikaon. A medallion is show zooming in on the region where the line changes color. The medallion shows that the line is not straight, but rather that at the place the kaon changes into an antikaon, the red line breaks into two curved lines, corresponding the production of virtual pions, which rejoin into the violet line, corresponding to the annihilation of the virtual pions.
An example of a virtual pion pair that influences the propagation of a kaon, causing a neutral kaon to mix with the antikaon. This is an example of renormalization in quantum field theory— the field theory being necessary because of the change in particle number.

If a particle and antiparticle are in the appropriate quantum states, then they can annihilate each other and produce other particles. Reactions such as
e
 + 
e+
 → 
γ

γ
(the two-photon annihilation of an electron-positron pair) are an example. The single-photon annihilation of an electron-positron pair,
e
 + 
e+
 → 
γ
, cannot occur in free space because it is impossible to conserve energy and momentum together in this process. However, in the Coulomb field of a nucleus the translational invariance is broken and single-photon annihilation may occur. The reverse reaction (in free space, without an atomic nucleus) is also impossible for this reason. In quantum field theory, this process is allowed only as an intermediate quantum state for times short enough that the violation of energy conservation can be accommodated by the uncertainty principle. This opens the way for virtual pair production or annihilation in which a one particle quantum state may fluctuate into a two particle state and back. These processes are important in the vacuum state and renormalization of a quantum field theory. It also opens the way for neutral particle mixing through processes such as the one pictured here, which is a complicated example of mass renormalization.

Properties

Quantum states of a particle and an antiparticle are interchanged by the combined application of charge conjugation , parity and time reversal . and are linear, unitary operators, is antilinear and antiunitary, . If denotes the quantum state of a particle with momentum and spin whose component in the z-direction is , then one has

where denotes the charge conjugate state, that is, the antiparticle. In particular a massive particle and its antiparticle transform under the same irreducible representation of the Poincaré group which means the antiparticle has the same mass and the same spin.

If , and can be defined separately on the particles and antiparticles, then

where the proportionality sign indicates that there might be a phase on the right hand side.

As anticommutes with the charges, , particle and antiparticle have opposite electric charges q and -q.

Quantum field theory

One may try to quantize an electron field without mixing the annihilation and creation operators by writing

where we use the symbol k to denote the quantum numbers p and σ of the previous section and the sign of the energy, E(k), and ak denotes the corresponding annihilation operators. Of course, since we are dealing with fermions, we have to have the operators satisfy canonical anti-commutation relations. However, if one now writes down the Hamiltonian

then one sees immediately that the expectation value of H need not be positive. This is because E(k) can have any sign whatsoever, and the combination of creation and annihilation operators has expectation value 1 or 0.

So one has to introduce the charge conjugate antiparticle field, with its own creation and annihilation operators satisfying the relations

where k has the same p, and opposite σ and sign of the energy. Then one can rewrite the field in the form

where the first sum is over positive energy states and the second over those of negative energy. The energy becomes

where E0 is an infinite negative constant. The vacuum state is defined as the state with no particle or antiparticle, i.e., and . Then the energy of the vacuum is exactly E0. Since all energies are measured relative to the vacuum, H is positive definite. Analysis of the properties of ak and bk shows that one is the annihilation operator for particles and the other for antiparticles. This is the case of a fermion.

This approach is due to Vladimir Fock, Wendell Furry and Robert Oppenheimer. If one quantizes a real scalar field, then one finds that there is only one kind of annihilation operator; therefore, real scalar fields describe neutral bosons. Since complex scalar fields admit two different kinds of annihilation operators, which are related by conjugation, such fields describe charged bosons.

Feynman–Stueckelberg interpretation

By considering the propagation of the negative energy modes of the electron field backward in time, Ernst Stueckelberg reached a pictorial understanding of the fact that the particle and antiparticle have equal mass m and spin J but opposite charges q. This allowed him to rewrite perturbation theory precisely in the form of diagrams. Richard Feynman later gave an independent systematic derivation of these diagrams from a particle formalism, and they are now called Feynman diagrams. Each line of a diagram represents a particle propagating either backward or forward in time. In Feynman diagrams, anti-particles are shown traveling backwards in time relative to normal matter, and vice versa. This technique is the most widespread method of computing amplitudes in quantum field theory today.

Since this picture was first developed by Stueckelberg, and acquired its modern form in Feynman's work, it is called the Feynman–Stueckelberg interpretation of antiparticles to honor both scientists.

Inequality (mathematics)

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