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153-613: The Daya Bay Reactor Neutrino Experiment is a China -based multinational particle physics project studying neutrinos , in particular neutrino oscillations . The multinational collaboration includes researchers from China, Chile, the United States, Taiwan (Republic of China), Russia, and the Czech Republic. The US side of the project is funded by the US Department of Energy 's Office of High Energy Physics. It

306-498: A G a μ ν , {\displaystyle {\mathcal {L}}_{\text{QCD}}={\overline {\psi }}i\gamma ^{\mu }D_{\mu }\psi -{\frac {1}{4}}G_{\mu \nu }^{a}G_{a}^{\mu \nu },} where ψ {\displaystyle \psi } is a three component column vector of Dirac spinors , each element of which refers to a quark field with a specific color charge (i.e. red, blue, and green) and summation over flavor (i.e. up, down, strange, etc.)

459-614: A μ ν W μ ν a − 1 4 B μ ν B μ ν , {\displaystyle {\mathcal {L}}_{\text{EW}}={\overline {Q}}_{Lj}i\gamma ^{\mu }D_{\mu }Q_{Lj}+{\overline {u}}_{Rj}i\gamma ^{\mu }D_{\mu }u_{Rj}+{\overline {d}}_{Rj}i\gamma ^{\mu }D_{\mu }d_{Rj}+{\overline {\ell }}_{Lj}i\gamma ^{\mu }D_{\mu }\ell _{Lj}+{\overline {e}}_{Rj}i\gamma ^{\mu }D_{\mu }e_{Rj}-{\tfrac {1}{4}}W_{a}^{\mu \nu }W_{\mu \nu }^{a}-{\tfrac {1}{4}}B^{\mu \nu }B_{\mu \nu },} where

612-577: A failed war in northern Korea provoked widespread unrest. Under the succeeding Tang and Song dynasties , Chinese economy, technology, and culture entered a golden age. The Tang dynasty retained control of the Western Regions and the Silk Road, which brought traders to as far as Mesopotamia and the Horn of Africa , and made the capital Chang'an a cosmopolitan urban center. However, it

765-441: A 50% probability of being sensitive to the neutrino mass hierarchy. Experiments may also be able to probe CP violation among neutrinos. The collaboration produced an updated analysis of their results in 2014, which used the energy spectrum to improve the bounds on the mixing angle: An independent measurement was also published using events from neutrons captured on hydrogen: Daya Bay has used its data to search for signals of

918-401: A climate very suitable for agriculture and the country has been the world's largest producer of rice, wheat, tomatoes, eggplant, grapes, watermelon, spinach, and many other crops. In 2021, 12 percent of global permanent meadows and pastures belonged to China, as well as 8% of global cropland. China is one of 17 megadiverse countries , lying in two of the world's major biogeographic realms :

1071-532: A cultural identity among its populace still remembered in the ethnonym of the modern Han Chinese . The Han expanded the empire's territory considerably , with military campaigns reaching Central Asia, Mongolia , Korea , and Yunnan , and the recovery of Guangdong and northern Vietnam from Nanyue . Han involvement in Central Asia and Sogdia helped establish the land route of the Silk Road , replacing

1224-634: A disputed land border with India and Bhutan . China is additionally involved in maritime disputes with multiple countries over territory in the East and South China Seas , such as the Senkaku Islands and the entirety of South China Sea Islands . The People's Republic of China is a one-party state governed by the Chinese Communist Party (CCP). The CCP is officially guided by socialism with Chinese characteristics , which

1377-730: A far-reaching popular uprising (the May Fourth Movement ). In the late 1920s, the Kuomintang under Chiang Kai-shek was able to reunify the country under its own control with a series of deft military and political maneuverings known collectively as the Northern Expedition . The Kuomintang moved the nation's capital to Nanjing and implemented "political tutelage", an intermediate stage of political development outlined in Sun Yat-sen's Three Principles of

1530-438: A graphical representation of the perturbation theory approximation, invoke "force mediating particles", and when applied to analyze high-energy scattering experiments are in reasonable agreement with the data. However, perturbation theory (and with it the concept of a "force-mediating particle") fails in other situations. These include low-energy quantum chromodynamics, bound states , and solitons . The interactions between all

1683-475: A high density of plant species including numerous rare endemics. Tropical and seasonal rainforests , though confined to Yunnan and Hainan , contain a quarter of all the animal and plant species found in China. China has over 10,000 recorded species of fungi . In the early 2000s, China has suffered from environmental deterioration and pollution due to its rapid pace of industrialization. Regulations such as

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1836-807: A light sterile neutrino, resulting in exclusions of some previous unexplored mass regions. At the Moriond ;2015 physics conference a new best fit for mixing angle and mass difference was presented: On 21 April 2023 (published), Daya Bay's reports the following precision measurements: sin 2 ⁡ ( 2   θ 13 ) = 0.0851 ± 0.0024 , Δ m 32 2 = ( 2.466 ± 0.060 ) × 10 − 3 e V 2 {\displaystyle \sin ^{2}(2\ \theta _{13})=0.0851\pm 0.0024,\qquad \Delta m_{32}^{2}=(2.466\pm 0.060)\times 10^{-3}{\rm {eV}}^{2}} for

1989-497: A major focus, special economic zones (SEZs) were created. Inefficient state-owned enterprises (SOEs) were restructured and some closed. This marked China's transition away from planned economy. China adopted its current constitution on 4 December 1982. In 1989, there were protests such those in Tiananmen Square , and then throughout the entire nation. Zhao Ziyang was put under house arrest for his sympathies to

2142-1043: A member of the group SU(3), and ϕ a ( x ) {\displaystyle \phi ^{a}(x)} is an arbitrary function of spacetime. The electroweak sector is a Yang–Mills gauge theory with the symmetry group U(1) × SU(2) L , L EW = Q ¯ L j i γ μ D μ Q L j + u ¯ R j i γ μ D μ u R j + d ¯ R j i γ μ D μ d R j + ℓ ¯ L j i γ μ D μ ℓ L j + e ¯ R j i γ μ D μ e R j − 1 4 W

2295-546: A new particle with a mass of about 125  GeV/ c (about 133 proton masses, on the order of 10  kg ), which is "consistent with the Higgs boson". On 13 March 2013, it was confirmed to be the searched-for Higgs boson. Technically, quantum field theory provides the mathematical framework for the Standard Model, in which a Lagrangian controls the dynamics and kinematics of the theory. Each kind of particle

2448-465: A non-zero Vacuum expectation value , which generates masses for the Electroweak gauge fields (the Higgs' mechanism), and λ > 0 {\displaystyle \lambda >0} , so that the potential is bounded from below. The quartic term describes self-interactions of the scalar field φ {\displaystyle \varphi } . The minimum of the potential

2601-404: A permanent navy which was supported by the developed shipbuilding industry along with the sea trade. Between the 10th and 11th century CE, the population of China doubled to around 100 million people, mostly because of the expansion of rice cultivation in central and southern China, and the production of abundant food surpluses. The Song dynasty also saw a revival of Confucianism , in response to

2754-457: Is Marxism adapted to Chinese circumstances . The Chinese constitution states that the PRC "is a socialist state governed by a people's democratic dictatorship that is led by the working class and based on an alliance of workers and peasants," that the state institutions "shall practice the principle of democratic centralism ," and that "the defining feature of socialism with Chinese characteristics

2907-664: Is "China" ( 中国 ; 中國 ; Zhōngguó ), from zhōng ('central') and guó ('state'), a term which developed under the Western Zhou dynasty in reference to its royal demesne . It was used in official documents as an synonym for the state under the Qing . The name Zhongguo is also translated as 'Middle Kingdom' in English. China is sometimes referred to as " mainland China " or "the Mainland" when distinguishing it from

3060-856: Is bounded by the Bohai , Yellow , East China and South China seas. China connects through the Kazakh border to the Eurasian Steppe . The territory of China lies between latitudes 18° and 54° N , and longitudes 73° and 135° E . The geographical center of China is marked by the Center of the Country Monument at 35°50′40.9″N 103°27′7.5″E  /  35.844694°N 103.452083°E  / 35.844694; 103.452083  ( Geographical center of China ) . China's landscapes vary significantly across its vast territory. In

3213-585: Is commonly agreed that pre-modern China's population experienced two growth spurts, one during the Northern Song period (960–1127), and other during the Qing period (around 1700–1830). By the High Qing era China was possibly the most commercialized country in the world, and imperial China experienced a second commercial revolution by the end of the 18th century. On the other hand, the centralized autocracy

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3366-468: Is conventionally called a " positron ". The Standard Model includes 12 elementary particles of spin 1 ⁄ 2 , known as fermions . Fermions respect the Pauli exclusion principle , meaning that two identical fermions cannot simultaneously occupy the same quantum state in the same atom. Each fermion has a corresponding antiparticle , which are particles that have corresponding properties with

3519-431: Is degenerate with an infinite number of equivalent ground state solutions, which occurs when φ † φ = μ 2 2 λ {\displaystyle \varphi ^{\dagger }\varphi ={\tfrac {\mu ^{2}}{2\lambda }}} . It is possible to perform a gauge transformation on φ {\displaystyle \varphi } such that

3672-412: Is described in terms of a dynamical field that pervades space-time . The construction of the Standard Model proceeds following the modern method of constructing most field theories: by first postulating a set of symmetries of the system, and then by writing down the most general renormalizable Lagrangian from its particle (field) content that observes these symmetries. The global Poincaré symmetry

3825-461: Is home to a variety of forest types. Cold coniferous forests predominate in the north of the country, supporting animal species such as moose and Asian black bear , along with over 120 bird species. The understory of moist conifer forests may contain thickets of bamboo . In higher montane stands of juniper and yew , the bamboo is replaced by rhododendrons . Subtropical forests, which are predominate in central and southern China, support

3978-477: Is implied. The gauge covariant derivative of QCD is defined by D μ ≡ ∂ μ − i g s 1 2 λ a G μ a {\displaystyle D_{\mu }\equiv \partial _{\mu }-ig_{s}{\frac {1}{2}}\lambda ^{a}G_{\mu }^{a}} , where The QCD Lagrangian is invariant under local SU(3) gauge transformations; i.e., transformations of

4131-585: Is in development in the form of the Jiangmen Underground Neutrino Observatory (JUNO) in Kaiping , which will use an acrylic sphere filled with 20,000 tons of liquid scintillator to detect reactor antineutrinos. Groundbreaking began 10 January 2015, with operation expected in 2020. The experiment studies neutrino oscillations and is designed to measure the mixing angle θ 13 using antineutrinos produced by

4284-405: Is mediated by mesons, such as the pion . The color charges inside the nucleon cancel out, meaning most of the gluon and quark fields cancel out outside of the nucleon. However, some residue is "leaked", which appears as the exchange of virtual mesons, that causes the attractive force between nucleons. The (fundamental) strong interaction is described by quantum chromodynamics, which is a component of

4437-404: Is postulated for all relativistic quantum field theories. It consists of the familiar translational symmetry , rotational symmetry and the inertial reference frame invariance central to the theory of special relativity . The local SU(3)×SU(2)×U(1) gauge symmetry is an internal symmetry that essentially defines the Standard Model. Roughly, the three factors of the gauge symmetry give rise to

4590-451: Is protected by law, and as of 2005 , the country has over 2,349 nature reserves , covering a total area of 149.95 million hectares, 15 percent of China's total land area. Most wild animals have been eliminated from the core agricultural regions of east and central China, but they have fared better in the mountainous south and west. The Baiji was confirmed extinct on 12 December 2006. China has over 32,000 species of vascular plants, and

4743-931: Is situated at Daya Bay , approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen . There is an affiliated project in the Aberdeen Tunnel Underground Laboratory in Hong Kong. The Aberdeen lab measures the neutrons produced by cosmic muons which may affect the Daya Bay Reactor Neutrino Experiment. The experiment consists of eight antineutrino detectors, clustered in three locations within 1.9 km (1.2 mi) of six nuclear reactors. Each detector consists of 20 tons of liquid scintillator ( linear alkylbenzene doped with gadolinium ) surrounded by photomultiplier tubes and shielding. A much larger follow-up

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4896-422: Is the third-largest country by total land area. The country is divided into 33 province-level divisions : 22 provinces , five autonomous regions , four municipalities , and two semi-autonomous special administrative regions . Beijing is the country's capital, while Shanghai is its most populous city by urban area and largest financial center . China is considered one of the cradles of civilization :

5049-561: Is the Higgs doublet and φ ~ = i τ 2 φ ∗ {\displaystyle {\tilde {\varphi }}=i\tau _{2}\varphi ^{*}} is its charge conjugate state. The Yukawa terms are invariant under the SU ⁡ ( 2 ) L × U ⁡ ( 1 ) Y {\displaystyle \operatorname {SU} (2)_{\text{L}}\times \operatorname {U} (1)_{\text{Y}}} gauge symmetry of

5202-451: Is the direct ancestor of modern Chinese characters . The Shang were overthrown by the Zhou , who ruled between the 11th and 5th centuries BCE, though the centralized authority of Son of Heaven was slowly eroded by fengjian lords. Some principalities eventually emerged from the weakened Zhou and continually waged war with each other during the 300-year Spring and Autumn period . By

5355-467: Is the electroweak gauge covariant derivative defined above and V ( φ ) {\displaystyle V(\varphi )} is the potential of the Higgs field. The square of the covariant derivative leads to three and four point interactions between the electroweak gauge fields W μ a {\displaystyle W_{\mu }^{a}} and B μ {\displaystyle B_{\mu }} and

5508-401: Is the leadership of the Chinese Communist Party." The PRC officially terms itself as a democracy , using terms such as "socialist consultative democracy", and " whole-process people's democracy ". However, the country is commonly described as an authoritarian one-party state and a dictatorship , with among the heaviest restrictions worldwide in many areas, most notably against freedom of

5661-469: Is the only long-range force in the Standard Model. It is mediated by photons and couples to electric charge. Electromagnetism is responsible for a wide range of phenomena including atomic electron shell structure , chemical bonds , electric circuits and electronics . Electromagnetic interactions in the Standard Model are described by quantum electrodynamics. The weak interaction is responsible for various forms of particle decay , such as beta decay . It

5814-559: Is the world's leading investor in renewable energy and its commercialization , with $ 546 billion invested in 2022; it is a major manufacturer of renewable energy technologies and invests heavily in local-scale renewable energy projects. Long heavily relying on non-renewable energy sources such as coal, China's adaptation of renewable energy has increased significantly in recent years, with their share increasing from 26.3 percent in 2016 to 31.9 percent in 2022. In 2023, 60.5% of China's electricity came from coal (largest producer in

5967-424: Is weak and short-range, due to the fact that the weak mediating particles, W and Z bosons, have mass. W bosons have electric charge and mediate interactions that change the particle type (referred to as flavour) and charge. Interactions mediated by W bosons are charged current interactions . Z bosons are neutral and mediate neutral current interactions, which do not change particle flavour. Thus Z bosons are similar to

6120-702: The Encyclopædia Britannica , to 9,596,961 km (3,705,407 sq mi) according to the UN Demographic Yearbook , and The World Factbook . China has the longest combined land border in the world , measuring 22,117 km (13,743 mi) and its coastline covers approximately 14,500 km (9,000 mi) from the mouth of the Yalu River (Amnok River) to the Gulf of Tonkin . China borders 14 nations and covers

6273-456: The 18th CCP National Congress in 2012. Shortly after his ascension to power, Xi launched a vast anti-corruption crackdown , that prosecuted more than 2 million officials by 2022. During his tenure , Xi has consolidated power unseen since the initiation of economic and political reforms. China's landscape is vast and diverse, ranging from the Gobi and Taklamakan Deserts in the arid north to

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6426-778: The Cultural Revolution , sparking a decade of political recrimination and social upheaval that lasted until Mao's death in 1976. In October 1971, the PRC replaced the ROC in the United Nations, and took its seat as a permanent member of the Security Council. After Mao's death, the Gang of Four was arrested by Hua Guofeng and held responsible for the Cultural Revolution. The Cultural Revolution

6579-564: The GIM mechanism , predicting the charm quark . In 1973 Gross and Wilczek and Politzer independently discovered that non-Abelian gauge theories, like the color theory of the strong force, have asymptotic freedom . In 1976, Martin Perl discovered the tau lepton at the SLAC . In 1977, a team led by Leon Lederman at Fermilab discovered the bottom quark. The Higgs mechanism is believed to give rise to

6732-636: The Kuomintang and the Communists led to the resumption of civil war. Constitutional rule was established in 1947, but because of the ongoing unrest, many provisions of the ROC constitution were never implemented in mainland China. Afterwards, the CCP took control of most of mainland China, and the ROC government retreated offshore to Taiwan . On 1 October 1949, CCP Chairman Mao Zedong formally proclaimed

6885-568: The Northern Chinese Famine of 1876–1879 , in which between 9 and 13 million people died. The Guangxu Emperor drafted a reform plan in 1898 to establish a modern constitutional monarchy , but these plans were thwarted by the Empress Dowager Cixi . The ill-fated anti-foreign Boxer Rebellion of 1899–1901 further weakened the dynasty. Although Cixi sponsored a program of reforms known as the late Qing reforms ,

7038-620: The Palearctic and the Indomalayan . By one measure, China has over 34,687 species of animals and vascular plants, making it the third-most biodiverse country in the world, after Brazil and Colombia . The country is a party to the Convention on Biological Diversity ; its National Biodiversity Strategy and Action Plan was received by the convention in 2010. China is home to at least 551 species of mammals (the third-highest in

7191-744: The RCEP . It is a member of the BRICS , the G20 , APEC , the SCO , and the East Asia Summit . Making up around one-fifth of the world economy, the Chinese economy is the world's largest economy by PPP-adjusted GDP , the second-largest economy by nominal GDP , and the second-wealthiest country , albeit ranking poorly in measures of democracy , human rights and religious freedom . The country has been one of

7344-784: The Republic of China or the PRC's Special Administrative Regions . Archaeological evidence suggests that early hominids inhabited China 2.25 million years ago. The hominid fossils of Peking Man , a Homo erectus who used fire , have been dated to between 680,000 and 780,000 years ago . The fossilized teeth of Homo sapiens (dated to 125,000–80,000 years ago) have been discovered in Fuyan Cave . Chinese proto-writing existed in Jiahu around 6600 BCE, at Damaidi around 6000 BCE, Dadiwan from 5800 to 5400 BCE, and Banpo dating from

7497-700: The Second United Front to fight the Japanese. The Second Sino-Japanese War eventually ended in a Chinese victory; however, the CCP and the KMT resumed their civil war as soon as the war ended. In 1949, the resurgent Communists established control over most of the country, proclaiming the People's Republic of China and forcing the Nationalist government to retreat to the island of Taiwan . The country

7650-531: The Sino-Soviet split , the Shanghai Communiqué in 1972 would precipitate the normalization of relations with the United States . Economic reforms that began in 1978 moved the country away from a socialist planned economy towards an increasingly capitalist market economy , spurring significant economic growth. The corresponding movement for increased democracy and liberalization stalled after

7803-658: The Standard model of particle physics needs improvement. China China , officially the People's Republic of China ( PRC ), is a country in East Asia . With a population exceeding 1.4 billion, it is the second-most populous country after India , representing 17.4% of the world population. China spans the equivalent of five time zones and borders fourteen countries by land . With an area of nearly 9.6 million square kilometers (3,700,000 sq mi), it

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7956-476: The State Council , China's cabinet, composed of four vice premiers, state councilors , and the heads of ministries and commissions. The Chinese People's Political Consultative Conference (CPPCC) is a political advisory body that is critical in China's " united front " system, which aims to gather non-CCP voices to support the CCP. Similar to the people's congresses, CPPCC's exist at various division, with

8109-723: The Tiananmen Square protests and massacre in 1989. China is a unitary one-party socialist republic led by the CCP. It is one of the five permanent members of the UN Security Council ; the UN representative for China was changed from the ROC to the PRC in 1971. It is a founding member of several multilateral and regional organizations such as the AIIB , the Silk Road Fund , the New Development Bank , and

8262-505: The Turpan Depression . China's climate is mainly dominated by dry seasons and wet monsoons , which lead to pronounced temperature differences between winter and summer. In the winter, northern winds coming from high-latitude areas are cold and dry; in summer, southern winds from coastal areas at lower latitudes are warm and moist. A major environmental issue in China is the continued expansion of its deserts , particularly

8415-417: The W and Z bosons with great accuracy. Although the Standard Model is believed to be theoretically self-consistent and has demonstrated some success in providing experimental predictions , it leaves some physical phenomena unexplained and so falls short of being a complete theory of fundamental interactions . For example, it does not fully explain why there is more matter than anti-matter , incorporate

8568-621: The World Trade Organization in 2001. At the 16th CCP National Congress in 2002, Hu Jintao succeeded Jiang as the general secretary. Under Hu, China maintained its high rate of economic growth, overtaking the United Kingdom, France, Germany and Japan to become the world's second-largest economy. However, the growth also severely impacted the country's resources and environment, and caused major social displacement. Xi Jinping succeeded Hu as paramount leader at

8721-719: The Xi , Mekong , Brahmaputra and Amur . To the west sit major mountain ranges, most notably the Himalayas. High plateaus feature among the more arid landscapes of the north, such as the Taklamakan and the Gobi Desert. The world's highest point, Mount Everest (8,848 m), lies on the Sino-Nepalese border. The country's lowest point, and the world's third-lowest, is the dried lake bed of Ayding Lake (−154 m) in

8874-549: The Xinhai Revolution of 1911–1912 ended the Qing dynasty and established the Republic of China . Puyi , the last Emperor, abdicated in 1912 . On 1 January 1912, the Republic of China was established, and Sun Yat-sen of the Kuomintang (KMT) was proclaimed provisional president. In March 1912, the presidency was given to Yuan Shikai , a former Qing general who in 1915 proclaimed himself Emperor of China . In

9027-471: The atomic nucleus , ultimately constituted of up and down quarks. On the other hand, second- and third-generation charged particles decay with very short half-lives and can only be observed in high-energy environments. Neutrinos of all generations also do not decay, and pervade the universe, but rarely interact with baryonic matter. There are six quarks: up , down , charm , strange , top , and bottom . Quarks carry color charge , and hence interact via

9180-422: The campaigns against Western Xia by Genghis Khan , who also invaded Jin territories . In 1271, the Mongol leader Kublai Khan established the Yuan dynasty , which conquered the last remnant of the Song dynasty in 1279. Before the Mongol invasion, the population of Song China was 120 million citizens; this was reduced to 60 million by the time of the census in 1300. A peasant named Zhu Yuanzhang overthrew

9333-628: The electron , electron neutrino , muon , muon neutrino , tau , and tau neutrino . The leptons do not carry color charge, and do not respond to strong interaction. The main leptons carry an electric charge of -1 e , while the three neutrinos carry a neutral electric charge. Thus, the neutrinos' motion are only influenced by weak interaction and gravity , making them difficult to observe. The Standard Model includes 4 kinds of gauge bosons of spin 1, with bosons being quantum particles containing an integer spin. The gauge bosons are defined as force carriers , as they are responsible for mediating

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9486-438: The fastest-growing major economies and is the world's largest manufacturer and exporter , as well as the second-largest importer . China is a nuclear-weapon state with the world's largest standing army by military personnel and the second-largest defense budget . It is a great power , and has been described as an emerging superpower . China is known for its cuisine and culture, and has 59 UNESCO World Heritage Sites ,

9639-514: The fundamental interactions . The Standard Model explains the four fundamental forces as arising from the interactions, with fermions exchanging virtual force carrier particles, thus mediating the forces. At a macroscopic scale, this manifests as a force . As a result, they do not follow the Pauli exclusion principle that constrains fermions; bosons do not have a theoretical limit on their spatial density . The types of gauge bosons are described below. The Feynman diagram calculations, which are

9792-499: The masses of all the elementary particles in the Standard Model. This includes the masses of the W and Z bosons , and the masses of the fermions , i.e. the quarks and leptons . After the neutral weak currents caused by Z boson exchange were discovered at CERN in 1973, the electroweak theory became widely accepted and Glashow, Salam, and Weinberg shared the 1979 Nobel Prize in Physics for discovering it. The W and Z bosons were discovered experimentally in 1983; and

9945-651: The mn term giving the coupling of the generations m and n , and h.c. means Hermitian conjugate of preceding terms. The fields Q L {\displaystyle Q_{\text{L}}} and ℓ L {\displaystyle \ell _{\text{L}}} are left-handed quark and lepton doublets. Likewise, u R , d R {\displaystyle u_{\text{R}},d_{\text{R}}} and e R {\displaystyle e_{\text{R}}} are right-handed up-type quark, down-type quark, and lepton singlets. Finally φ {\displaystyle \varphi }

10098-399: The second-highest number of any country . The word "China" has been used in English since the 16th century; however, it was not used by the Chinese themselves during this period. Its origin has been traced through Portuguese , Malay , and Persian back to the Sanskrit word Cīna , used in ancient India . "China" appears in Richard Eden 's 1555 translation of the 1516 journal of

10251-585: The strong interaction . The color confinement phenomenon results in quarks being strongly bound together such that they form color-neutral composite particles called hadrons ; quarks cannot individually exist and must always bind with other quarks. Hadrons can contain either a quark-antiquark pair ( mesons ) or three quarks ( baryons ). The lightest baryons are the nucleons : the proton and neutron . Quarks also carry electric charge and weak isospin , and thus interact with other fermions through electromagnetism and weak interaction . The six leptons consist of

10404-422: The subtropical forests in the wetter south. The Himalaya , Karakoram , Pamir and Tian Shan mountain ranges separate China from much of South and Central Asia . The Yangtze and Yellow Rivers, the third- and sixth-longest in the world, respectively, run from the Tibetan Plateau to the densely populated eastern seaboard. China's coastline along the Pacific Ocean is 14,500 km (9,000 mi) long and

10557-440: The 1979 Environmental Protection Law are fairly stringent, though they are poorly enforced, frequently disregarded in favor of rapid economic development. China has the second-highest death toll because of air pollution, after India , with approximately 1 million deaths. Although China ranks as the highest CO 2 emitting country, it only emits 8 tons of CO 2 per capita , significantly lower than developed countries such as

10710-406: The 2010s. In 2020, the Chinese government announced its aims for the country to reach its peak emissions levels before 2030, and achieve carbon neutrality by 2060 in line with the Paris Agreement , which, according to Climate Action Tracker , would lower the expected rise in global temperature by 0.2–0.3 degrees – "the biggest single reduction ever estimated by the Climate Action Tracker". China

10863-405: The 5th millennium BCE. Some scholars have suggested that the Jiahu symbols (7th millennium BCE) constituted the earliest Chinese writing system. According to traditional Chinese historiography , the Xia dynasty was established during the late 3rd millennium BCE, marking the beginning of the dynastic cycle that was understood to underpin China's entire political history. In the modern era,

11016-668: The British under the 1842 Treaty of Nanking , the first of what have been termed as the " unequal treaties ". The First Sino-Japanese War (1894–1895) resulted in Qing China's loss of influence in the Korean Peninsula , as well as the cession of Taiwan to Japan . The Qing dynasty also began experiencing internal unrest in which tens of millions of people died, especially in the White Lotus Rebellion ,

11169-449: The CCP. The NPC is dominated by the CCP, with another eight minor parties having nominal representation under the condition of upholding CCP leadership. The president is elected by the NPC. The presidency is the ceremonial state representative, but not the constitutional head of state. The incumbent president is Xi Jinping, who is also the general secretary of the CCP and the chairman of

11322-638: The Central Military Commission , making him China's paramount leader and supreme commander of the Armed Forces. The premier is the head of government , with Li Qiang being the incumbent. The premier is officially nominated by the president and then elected by the NPC, and has generally been either the second- or third-ranking member of the Politburo Standing Committee (PSC). The premier presides over

11475-450: The Gobi Desert. Although barrier tree lines planted since the 1970s have reduced the frequency of sandstorms , prolonged drought and poor agricultural practices have resulted in dust storms plaguing northern China each spring, which then spread to other parts of East Asia, including Japan and Korea. Water quality, erosion , and pollution control have become important issues in China's relations with other countries. Melting glaciers in

11628-548: The Higgs boson is massive, it must interact with itself. Because the Higgs boson is a very massive particle and also decays almost immediately when created, only a very high-energy particle accelerator can observe and record it. Experiments to confirm and determine the nature of the Higgs boson using the Large Hadron Collider (LHC) at CERN began in early 2010 and were performed at Fermilab 's Tevatron until its closure in late 2011. Mathematical consistency of

11781-1333: The Higgs' mass could not be predicted beforehand and had to be determined experimentally. The Yukawa interaction terms are: L Yukawa = ( Y u ) m n ( Q ¯ L ) m φ ~ ( u R ) n + ( Y d ) m n ( Q ¯ L ) m φ ( d R ) n + ( Y e ) m n ( ℓ ¯ L ) m φ ( e R ) n + h . c . {\displaystyle {\mathcal {L}}_{\text{Yukawa}}=(Y_{\text{u}})_{mn}({\bar {Q}}_{\text{L}})_{m}{\tilde {\varphi }}(u_{\text{R}})_{n}+(Y_{\text{d}})_{mn}({\bar {Q}}_{\text{L}})_{m}\varphi (d_{\text{R}})_{n}+(Y_{\text{e}})_{mn}({\bar {\ell }}_{\text{L}})_{m}{\varphi }(e_{\text{R}})_{n}+\mathrm {h.c.} } where Y u {\displaystyle Y_{\text{u}}} , Y d {\displaystyle Y_{\text{d}}} , and Y e {\displaystyle Y_{\text{e}}} are 3 × 3 matrices of Yukawa couplings, with

11934-717: The Himalayas could potentially lead to water shortages for hundreds of millions of people. According to academics, in order to limit climate change in China to 1.5 °C (2.7 °F) electricity generation from coal in China without carbon capture must be phased out by 2045. With current policies, the GHG emissions of China will probably peak in 2025, and by 2030 they will return to 2022 levels. However, such pathway still leads to three-degree temperature rise. Official government statistics about Chinese agricultural productivity are considered unreliable, due to exaggeration of production at subsidiary government levels. Much of China has

12087-705: The Kuomintang and the CCP. Japanese forces committed numerous war atrocities against the civilian population; as many as 20 million Chinese civilians died. An estimated 40,000 to 300,000 Chinese were massacred in Nanjing alone during the Japanese occupation. China, along with the UK, the United States, and the Soviet Union , were recognized as the Allied " Big Four " in the Declaration by United Nations . Along with

12240-598: The National Committee of the CPPCC being chaired by Wang Huning , fourth-ranking member of the PSC. Standard model The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic , weak and strong interactions – excluding gravity ) in the universe and classifying all known elementary particles . It was developed in stages throughout

12393-648: The PRC initially allied closely with the Soviet Union , the relations between the two communist nations gradually deteriorated , leading China to develop an independent industrial system and its own nuclear weapons . The Chinese population increased from 550 million in 1950 to 900 million in 1974. However, the Great Leap Forward , an idealistic massive industrialization project, resulted in an estimated 15 to 55 million deaths between 1959 and 1961, mostly from starvation. In 1964, China detonated its first atomic bomb. In 1966, Mao and his allies launched

12546-949: The People program for transforming China into a modern democratic state. The Kuomintang briefly allied with the Chinese Communist Party (CCP) during the Northern Expedition, though the alliance broke down in 1927 after Chiang violently suppressed the CCP and other leftists in Shanghai, marking the beginning of the Chinese Civil War . The CCP declared areas of the country as the Chinese Soviet Republic (Jiangxi Soviet) in November 1931 in Ruijin , Jiangxi . The Jiangxi Soviet

12699-535: The People's Republic of China in Tiananmen Square , Beijing . In 1950, the PRC captured Hainan from the ROC and annexed Tibet . However, remaining Kuomintang forces continued to wage an insurgency in western China throughout the 1950s. The CCP consolidated its popularity among the peasants through the Land Reform Movement , which included the state-tolerated executions of between 1 and 2 million landlords by peasants and former tenants. Though

12852-573: The Portuguese explorer Duarte Barbosa . Barbosa's usage was derived from Persian Chīn ( چین ), which in turn derived from Sanskrit Cīna ( चीन ). Cīna was first used in early Hindu scripture, including the Mahabharata (5th century BCE) and the Laws of Manu (2nd century BCE). In 1655, Martino Martini suggested that the word China is derived ultimately from

13005-510: The Standard Model and generate masses for all fermions after spontaneous symmetry breaking. The Standard Model describes three of the four fundamental interactions in nature; only gravity remains unexplained. In the Standard Model, such an interaction is described as an exchange of bosons between the objects affected, such as a photon for the electromagnetic force and a gluon for the strong interaction. Those particles are called force carriers or messenger particles . Despite being perhaps

13158-479: The Standard Model requires that any mechanism capable of generating the masses of elementary particles must become visible at energies above 1.4  TeV ; therefore, the LHC (designed to collide two 7 TeV proton beams) was built to answer the question of whether the Higgs boson actually exists. On 4 July 2012, two of the experiments at the LHC ( ATLAS and CMS ) both reported independently that they had found

13311-510: The Standard Model was driven by theoretical and experimental particle physicists alike. The Standard Model is a paradigm of a quantum field theory for theorists, exhibiting a wide range of phenomena, including spontaneous symmetry breaking , anomalies , and non-perturbative behavior. It is used as a basis for building more exotic models that incorporate hypothetical particles , extra dimensions , and elaborate symmetries (such as supersymmetry ) to explain experimental results at variance with

13464-500: The Standard Model, such as the existence of dark matter and neutrino oscillations. In 1928, Paul Dirac introduced the Dirac equation which implied the existence of antimatter . In 1954, Yang Chen-Ning and Robert Mills extended the concept of gauge theory for abelian groups , e.g. quantum electrodynamics , to nonabelian groups to provide an explanation for strong interactions . In 1957, Chien-Shiung Wu demonstrated parity

13617-488: The United States (16.1), Australia (16.8) and South Korea (13.6). Greenhouse gas emissions by China are the world's largest . The country has significant water pollution problems; only 89.4% of China's national surface water was graded suitable for human consumption by the Ministry of Ecology and Environment in 2023. China has prioritized clamping down on pollution, bringing a significant decrease in air pollution in

13770-556: The Xia is the earliest for which there are both contemporary written records and undisputed archaeological evidence. The Shang ruled much of the Yellow River valley until the 11th century BCE, with the earliest hard evidence dated c.  1300 BCE . The oracle bone script , attested from c.  1250 BCE but generally assumed to be considerably older, represents the oldest known form of written Chinese , and

13923-513: The Xia's historicity came under increasing scrutiny, in part due to the earliest known attestation of the Xia being written millennia after the date given for their collapse. In 1958, archaeologists discovered sites belonging to the Erlitou culture that existed during the early Bronze Age ; they have since been characterized as the remains of the historical Xia, but this conception is often rejected. The Shang dynasty that traditionally succeeded

14076-681: The Yuan in 1368 and founded the Ming dynasty as the Hongwu Emperor . Under the Ming dynasty, China enjoyed another golden age, developing one of the strongest navies in the world and a rich and prosperous economy amid a flourishing of art and culture. It was during this period that admiral Zheng He led the Ming treasure voyages throughout the Indian Ocean, reaching as far as East Africa. In

14229-465: The addition of fermion mass terms into the electroweak Lagrangian is forbidden, since terms of the form m ψ ¯ ψ {\displaystyle m{\overline {\psi }}\psi } do not respect U(1) × SU(2) L gauge invariance. Neither is it possible to add explicit mass terms for the U(1) and SU(2) gauge fields. The Higgs mechanism is responsible for the generation of

14382-820: The bulk of East Asia, bordering Vietnam , Laos , and Myanmar in Southeast Asia; India , Bhutan , Nepal , Pakistan and Afghanistan in South Asia; Tajikistan , Kyrgyzstan and Kazakhstan in Central Asia; and Russia, Mongolia , and North Korea in Inner Asia and Northeast Asia . It is narrowly separated from Bangladesh and Thailand to the southwest and south, and has several maritime neighbors such as Japan , Philippines , Malaysia , and Indonesia . China has resolved its land borders with 12 out of 14 neighboring countries, having pursued substantial compromises in most of them. China currently has

14535-462: The country in the late 19th century to various European powers by a series of unequal treaties . After decades of Qing China on the decline, the 1911 Revolution overthrew the Qing dynasty and the monarchy and the Republic of China (ROC) was established the following year. The country under the nascent Beiyang government was unstable and ultimately fragmented during the Warlord Era , which

14688-610: The earlier path over the Himalayas to India. Han China gradually became the largest economy of the ancient world. Despite the Han's initial decentralization and the official abandonment of the Qin philosophy of Legalism in favor of Confucianism , Qin's legalist institutions and policies continued to be employed by the Han government and its successors. After the end of the Han dynasty , a period of strife known as Three Kingdoms followed, at

14841-537: The early Ming dynasty, China's capital was moved from Nanjing to Beijing. With the budding of capitalism, philosophers such as Wang Yangming critiqued and expanded Neo-Confucianism with concepts of individualism and equality of four occupations . The scholar-official stratum became a supporting force of industry and commerce in the tax boycott movements, which, together with the famines and defense against Japanese invasions of Korea (1592–1598) and Later Jin incursions led to an exhausted treasury. In 1644, Beijing

14994-737: The east, along the shores of the Yellow Sea and the East China Sea, there are extensive and densely populated alluvial plains , while on the edges of the Inner Mongolian plateau in the north, broad grasslands predominate. Southern China is dominated by hills and low mountain ranges, while the central-east hosts the deltas of China's two major rivers, the Yellow River and the Yangtze River. Other major rivers include

15147-656: The end of which Wei was swiftly overthrown by the Jin dynasty . The Jin fell to civil war upon the ascension of a developmentally disabled emperor ; the Five Barbarians then rebelled and ruled northern China as the Sixteen States . The Xianbei unified them as the Northern Wei , whose Emperor Xiaowen reversed his predecessors' apartheid policies and enforced a drastic sinification on his subjects . In

15300-626: The exception of opposite charges . Fermions are classified based on how they interact, which is determined by the charges they carry, into two groups: quarks and leptons . Within each group, pairs of particles that exhibit similar physical behaviors are then grouped into generations (see the table). Each member of a generation has a greater mass than the corresponding particle of generations prior. Thus, there are three generations of quarks and leptons. As first-generation particles do not decay, they comprise all of ordinary ( baryonic ) matter. Specifically, all atoms consist of electrons orbiting around

15453-473: The face of popular condemnation and opposition from his own Beiyang Army , he was forced to abdicate and re-establish the republic in 1916. After Yuan Shikai's death in 1916, China was politically fragmented. Its Beijing-based government was internationally recognized but virtually powerless; regional warlords controlled most of its territory. During this period , China participated in World War I and saw

15606-555: The failed Taiping Rebellion that ravaged southern China in the 1850s and 1860s and the Dungan Revolt (1862–1877) in the northwest. The initial success of the Self-Strengthening Movement of the 1860s was frustrated by a series of military defeats in the 1880s and 1890s. In the 19th century, the great Chinese diaspora began. Losses due to emigration were added to by conflicts and catastrophes such as

15759-475: The first human inhabitants in the region arrived during the Paleolithic . By the late 2nd millennium BCE, the earliest dynastic states had emerged in the Yellow River basin. The 8th–3rd centuries BCE saw a breakdown in the authority of the Zhou dynasty , accompanied by the emergence of administrative and military techniques, literature , philosophy , and historiography . In 221 BCE, China

15912-486: The form ψ → ψ ′ = U ψ {\displaystyle \psi \rightarrow \psi '=U\psi } , where U = e − i g s λ a ϕ a ( x ) {\displaystyle U=e^{-ig_{s}\lambda ^{a}\phi ^{a}(x)}} is 3 × 3 {\displaystyle 3\times 3} unitary matrix with determinant 1, making it

16065-414: The full theory of gravitation as described by general relativity , or account for the universe's accelerating expansion as possibly described by dark energy . The model does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology . It also does not incorporate neutrino oscillations and their non-zero masses. The development of

16218-913: The gauge boson masses, and the fermion masses result from Yukawa-type interactions with the Higgs field. In the Standard Model, the Higgs field is an SU ⁡ ( 2 ) L {\displaystyle \operatorname {SU} (2)_{\text{L}}} doublet of complex scalar fields with four degrees of freedom: φ = ( φ + φ 0 ) = 1 2 ( φ 1 + i φ 2 φ 3 + i φ 4 ) , {\displaystyle \varphi ={\begin{pmatrix}\varphi ^{+}\\\varphi ^{0}\end{pmatrix}}={\frac {1}{\sqrt {2}}}{\begin{pmatrix}\varphi _{1}+i\varphi _{2}\\\varphi _{3}+i\varphi _{4}\end{pmatrix}},} where

16371-428: The ground state is transformed to a basis where φ 1 = φ 2 = φ 4 = 0 {\displaystyle \varphi _{1}=\varphi _{2}=\varphi _{4}=0} and φ 3 = μ λ ≡ v {\displaystyle \varphi _{3}={\tfrac {\mu }{\sqrt {\lambda }}}\equiv v} . This breaks

16524-612: The growth of Buddhism during the Tang, and a flourishing of philosophy and the arts, as landscape art and porcelain were brought to new levels of complexity. However, the military weakness of the Song army was observed by the Jin dynasty . In 1127, Emperor Huizong of Song and the capital Bianjing were captured during the Jin–Song wars . The remnants of the Song retreated to southern China . The Mongol conquest of China began in 1205 with

16677-400: The informal paramount leader . The current general secretary is Xi Jinping , who took office on 15 November 2012. At the local level, the secretary of the CCP committee of a subdivision outranks the local government level; CCP committee secretary of a provincial division outranks the governor while the CCP committee secretary of a city outranks the mayor. The government in China is under

16830-614: The interactions between quarks and gluons, which is a Yang–Mills gauge theory with SU(3) symmetry, generated by T a = λ a / 2 {\displaystyle T^{a}=\lambda ^{a}/2} . Since leptons do not interact with gluons, they are not affected by this sector. The Dirac Lagrangian of the quarks coupled to the gluon fields is given by L QCD = ψ ¯ i γ μ D μ ψ − 1 4 G μ ν

16983-409: The largest importer of Russian crude oil in 2022. China is the third-largest country in the world by land area after Russia , and the third- or fourth-largest country in the world by total area. China's total area is generally stated as being approximately 9,600,000 km (3,700,000 sq mi). Specific area figures range from 9,572,900 km (3,696,100 sq mi) according to

17136-457: The latter half of the 20th century, through the work of many scientists worldwide, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks . Since then, proof of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and

17289-642: The left-handed doublet and right-handed singlet lepton fields. The electroweak gauge covariant derivative is defined as D μ ≡ ∂ μ − i g ′ 1 2 Y W B μ − i g 1 2 τ → L W → μ {\displaystyle D_{\mu }\equiv \partial _{\mu }-ig'{\tfrac {1}{2}}Y_{\text{W}}B_{\mu }-ig{\tfrac {1}{2}}{\vec {\tau }}_{\text{L}}{\vec {W}}_{\mu }} , where Notice that

17442-408: The massive spin-zero particle, was proposed as the Higgs boson , and is a key building block in the Standard Model. It has no intrinsic spin , and for that reason is classified as a boson with spin-0. The Higgs boson plays a unique role in the Standard Model, by explaining why the other elementary particles, except the photon and gluon , are massive. In particular, the Higgs boson explains why

17595-415: The most familiar fundamental interaction, gravity is not described by the Standard Model, due to contradictions that arise when combining general relativity, the modern theory of gravity, and quantum mechanics. However, gravity is so weak at microscopic scales, that it is essentially unmeasurable. The graviton is postulated to be the mediating particle, but has not yet been proved to exist. Electromagnetism

17748-502: The most precise measurement of θ 13 {\displaystyle \theta _{13}} in the foreseeable future and be crucial to the investigation of the mass hierarchy and CP violation in neutrino oscillation." Daya Bay Collaboration measured the anti-neutrino energy spectrum, and found that anti-neutrinos at an energy of around 5 MeV are in excess relative to theoretical expectations. This unexpected disagreement between observation and predictions suggested that

17901-715: The multiple consultation mechanisms that exist in Chinese government. According to the CCP constitution , its highest body is the National Congress held every five years. The National Congress elects the Central Committee , who then elects the party's Politburo , Politburo Standing Committee and the general secretary ( party leader ), the top leadership of the country. The general secretary holds ultimate power and authority over party and state and serves as

18054-720: The name of the Qin dynasty (221–206 BCE). Although use in Indian sources precedes this dynasty, this derivation is still given in various sources. The origin of the Sanskrit word is a matter of debate. Alternative suggestions include the names for Yelang and the Jing or Chu state. The official name of the modern state is the "People's Republic of China" ( simplified Chinese : 中华人民共和国 ; traditional Chinese : 中華人民共和國 ; pinyin : Zhōnghuá rénmín gònghéguó ). The shorter form

18207-560: The normal mass ordering or Δ m 32 2 = − ( 2.571 ± 0.060 ) × 10 − 3 e V 2 {\displaystyle \Delta m_{32}^{2}=-(2.571\pm 0.060)\times 10^{-3}{\rm {eV}}^{2}} , for the inverted mass ordering. The Daya Bay collaboration suggests, "The reported sin 2 ⁡ ( 2   θ 13 ) {\displaystyle \sin ^{2}(2\ \theta _{13})} will likely remain

18360-472: The other three great powers, China was one of the four major Allies of World War II , and was later considered one of the primary victors in the war. After the surrender of Japan in 1945, Taiwan, including the Penghu , was handed over to Chinese control ; however, the validity of this handover is controversial. China emerged victorious but war-ravaged and financially drained. The continued distrust between

18513-427: The particles described by the Standard Model are summarized by the diagrams on the right of this section. The Higgs particle is a massive scalar elementary particle theorized by Peter Higgs ( and others ) in 1964, when he showed that Goldstone's 1962 theorem (generic continuous symmetry, which is spontaneously broken) provides a third polarisation of a massive vector field. Hence, Goldstone's original scalar doublet,

18666-431: The photon has no mass, while the W and Z bosons are very heavy. Elementary-particle masses and the differences between electromagnetism (mediated by the photon) and the weak force (mediated by the W and Z bosons) are critical to many aspects of the structure of microscopic (and hence macroscopic) matter. In electroweak theory , the Higgs boson generates the masses of the leptons (electron, muon, and tau) and quarks. As

18819-423: The photon, aside from them being massive and interacting with the neutrino. The weak interaction is also the only interaction to violate parity and CP . Parity violation is maximal for charged current interactions, since the W boson interacts exclusively with left-handed fermions and right-handed antifermions. In the Standard Model, the weak force is understood in terms of the electroweak theory, which states that

18972-553: The press , freedom of assembly , free formation of social organizations , freedom of religion and free access to the Internet . China has consistently been ranked amongst the lowest as an "authoritarian regime" by the Economist Intelligence Unit 's Democracy Index , ranking at 148th out of 167 countries in 2023. Other sources suggest that terming China as "authoritarian" does not sufficiently account for

19125-417: The protests and was replaced by Jiang Zemin . Jiang continued economic reforms, closing many SOEs and trimming down " iron rice bowl " (life-tenure positions). China's economy grew sevenfold during this time. British Hong Kong and Portuguese Macau returned to China in 1997 and 1999 , respectively, as special administrative regions under the principle of one country, two systems . The country joined

19278-450: The ratio of their masses was found to be as the Standard Model predicted. The theory of the strong interaction (i.e. quantum chromodynamics , QCD), to which many contributed, acquired its modern form in 1973–74 when asymptotic freedom was proposed (a development which made QCD the main focus of theoretical research) and experiments confirmed that the hadrons were composed of fractionally charged quarks. The term "Standard Model"

19431-726: The reactors of the Daya Bay Nuclear Power Plant and the Ling Ao Nuclear Power Plant . Scientists are also interested in whether neutrinos violate Charge-Parity conservation . On 8 March 2012, the Daya Bay collaboration announced a 5.2σ discovery of θ 13 ≠ 0, with This significant result represents a new type of oscillation and is surprisingly large. It is consistent with earlier, less significant results by T2K , MINOS and Double Chooz . With θ 13 so large, NOνA has about

19584-649: The scalar field φ {\displaystyle \varphi } . The scalar potential is given by V ( φ ) = − μ 2 φ † φ + λ ( φ † φ ) 2 , {\displaystyle V(\varphi )=-\mu ^{2}\varphi ^{\dagger }\varphi +\lambda \left(\varphi ^{\dagger }\varphi \right)^{2},} where μ 2 > 0 {\displaystyle \mu ^{2}>0} , so that φ {\displaystyle \varphi } acquires

19737-689: The scale of electroweak physics. This is the only dimensional parameter of the Standard Model and has a measured value of ~ 246 GeV/ c . After symmetry breaking, the masses of the W {\displaystyle {\text{W}}} and Z {\displaystyle {\text{Z}}} are given by m W = 1 2 g v {\displaystyle m_{\text{W}}={\frac {1}{2}}gv} and m Z = 1 2 g 2 + g ′ 2 v {\displaystyle m_{\text{Z}}={\frac {1}{2}}{\sqrt {g^{2}+g'^{2}}}v} , which can be viewed as predictions of

19890-637: The sole control of the CCP. The CCP controls appointments in government bodies, with most senior government officials being CCP members. The National People's Congress (NPC), with nearly 3,000-members, is constitutionally the " highest organ of state power ", though it has been also described as a " rubber stamp " body. The NPC meets annually, while the NPC Standing Committee , around 150 members elected from NPC delegates, meets every couple of months. Elections are indirect and not pluralistic, with nominations at all levels being controlled by

20043-761: The south, the general Liu Yu secured the abdication of the Jin in favor of the Liu Song . The various successors of these states became known as the Northern and Southern dynasties , with the two areas finally reunited by the Sui in 581. The Sui restored the Han to power through China, reformed its agriculture, economy and imperial examination system, constructed the Grand Canal , and patronized Buddhism . However, they fell quickly when their conscription for public works and

20196-657: The standardization of Chinese characters, measurements , road widths, and currency . His dynasty also conquered the Yue tribes in Guangxi , Guangdong , and Northern Vietnam . The Qin dynasty lasted only fifteen years, falling soon after the First Emperor's death. Following widespread revolts during which the imperial library was burned , the Han dynasty emerged to rule China between 206 BCE and 220 CE, creating

20349-430: The strong force becomes weaker, as the energy scale increases. The strong force overpowers the electrostatic repulsion of protons and quarks in nuclei and hadrons respectively, at their respective scales. While quarks are bound in hadrons by the fundamental strong interaction, which is mediated by gluons, nucleons are bound by an emergent phenomenon termed the residual strong force or nuclear force . This interaction

20502-522: The subscript j {\displaystyle j} sums over the three generations of fermions; Q L , u R {\displaystyle Q_{L},u_{R}} , and d R {\displaystyle d_{R}} are the left-handed doublet, right-handed singlet up type, and right handed singlet down type quark fields; and ℓ L {\displaystyle \ell _{L}} and e R {\displaystyle e_{R}} are

20655-782: The superscripts + and 0 indicate the electric charge Q {\displaystyle Q} of the components. The weak hypercharge Y W {\displaystyle Y_{\text{W}}} of both components is 1. Before symmetry breaking, the Higgs Lagrangian is L H = ( D μ φ ) † ( D μ φ ) − V ( φ ) , {\displaystyle {\mathcal {L}}_{\text{H}}=\left(D_{\mu }\varphi \right)^{\dagger }\left(D^{\mu }\varphi \right)-V(\varphi ),} where D μ {\displaystyle D_{\mu }}

20808-451: The symmetry of the ground state. The expectation value of φ {\displaystyle \varphi } now becomes ⟨ φ ⟩ = 1 2 ( 0 v ) , {\displaystyle \langle \varphi \rangle ={\frac {1}{\sqrt {2}}}{\begin{pmatrix}0\\v\end{pmatrix}},} where v {\displaystyle v} has units of mass and sets

20961-473: The theory. The photon remains massless. The mass of the Higgs Boson is m H = 2 μ 2 = 2 λ v {\displaystyle m_{\text{H}}={\sqrt {2\mu ^{2}}}={\sqrt {2\lambda }}v} . Since μ {\displaystyle \mu } and λ {\displaystyle \lambda } are free parameters,

21114-434: The three fundamental interactions. The fields fall into different representations of the various symmetry groups of the Standard Model (see table). Upon writing the most general Lagrangian, one finds that the dynamics depends on 19 parameters, whose numerical values are established by experiment. The parameters are summarized in the table (made visible by clicking "show") above. The quantum chromodynamics (QCD) sector defines

21267-576: The time of the Warring States period of the 5th–3rd centuries BCE, there were seven major powerful states left. The Warring States period ended in 221 BCE after the state of Qin conquered the other six states, reunited China and established the dominant order of autocracy . King Zheng of Qin proclaimed himself the Emperor of the Qin dynasty , becoming the first emperor of a unified China. He enacted Qin's legalist reforms, notably

21420-546: The weak and electromagnetic interactions become united into a single electroweak interaction at high energies. The strong nuclear force is responsible for hadronic and nuclear binding . It is mediated by gluons, which couple to color charge. Since gluons themselves have color charge, the strong force exhibits confinement and asymptotic freedom . Confinement means that only color-neutral particles can exist in isolation, therefore quarks can only exist in hadrons and never in isolation, at low energies. Asymptotic freedom means that

21573-485: The world), 1,221 species of birds (eighth), 424 species of reptiles (seventh) and 333 species of amphibians (seventh). Wildlife in China shares habitat with, and bears acute pressure from, one of the world's largest population of humans. At least 840 animal species are threatened, vulnerable or in danger of local extinction , due mainly to human activity such as habitat destruction, pollution and poaching for food, fur and traditional Chinese medicine . Endangered wildlife

21726-428: The world), 13.2% from hydroelectric power (largest), 9.4% from wind (largest), 6.2% from solar energy (largest), 4.6% from nuclear energy (second-largest), 3.3% from natural gas (fifth-largest), and 2.2% from bioenergy (largest); in total, 31% of China's energy came from renewable energy sources. Despite its emphasis on renewables, China remains deeply connected to global oil markets and next to India, has been

21879-709: Was wiped out by the KMT armies in 1934, leading the CCP to initiate the Long March and relocate to Yan'an in Shaanxi . It would be the base of the communists before major combat in the Chinese Civil War ended in 1949. In 1931, Japan invaded and occupied Manchuria . Japan invaded other parts of China in 1937, precipitating the Second Sino-Japanese War (1937–1945), a theater of World War II . The war forced an uneasy alliance between

22032-406: Was captured by a coalition of peasant rebel forces led by Li Zicheng . The Chongzhen Emperor committed suicide when the city fell. The Manchu Qing dynasty , then allied with Ming dynasty general Wu Sangui , overthrew Li's short-lived Shun dynasty and subsequently seized control of Beijing, which became the new capital of the Qing dynasty. The Qing dynasty, which lasted from 1644 until 1912,

22185-523: Was devastated and weakened by the An Lushan rebellion in the 8th century. In 907, the Tang disintegrated completely when the local military governors became ungovernable. The Song dynasty ended the separatist situation in 960, leading to a balance of power between the Song and the Liao dynasty . The Song was the first government in world history to issue paper money and the first Chinese polity to establish

22338-399: Was ended upon the Northern Expedition conducted by the Kuomintang (KMT) to reunify the country. The Chinese Civil War began in 1927, when KMT forces purged members of the rival Chinese Communist Party (CCP), who proceeded to engage in sporadic fighting against the KMT-led Nationalist government . Following the country's invasion by the Empire of Japan in 1937, the CCP and KMT formed

22491-590: Was introduced by Abraham Pais and Sam Treiman in 1975, with reference to the electroweak theory with four quarks. Steven Weinberg , has since claimed priority, explaining that he chose the term Standard Model out of a sense of modesty and used it in 1973 during a talk in Aix-en-Provence in France. The Standard Model includes members of several classes of elementary particles, which in turn can be distinguished by other characteristics, such as color charge . All particles can be summarized as follows: Notes : [†] An anti-electron ( e )

22644-508: Was not conserved in the weak interaction . In 1961, Sheldon Glashow combined the electromagnetic and weak interactions . In 1964, Murray Gell-Mann and George Zweig introduced quarks and that same year Oscar W. Greenberg implicitly introduced color charge of quarks. In 1967 Steven Weinberg and Abdus Salam incorporated the Higgs mechanism into Glashow's electroweak interaction , giving it its modern form. In 1970, Sheldon Glashow, John Iliopoulos, and Luciano Maiani introduced

22797-408: Was rebuked, with millions rehabilitated. Deng Xiaoping took power in 1978, and instituted large-scale political and economic reforms , together with the " Eight Elders ", most senior and influential members of the party. The government loosened its control and the communes were gradually disbanded. Agricultural collectivization was dismantled and farmlands privatized. While foreign trade became

22950-463: Was split, with both sides claiming to be the sole legitimate government of China . Following the implementation of land reforms , further attempts by the PRC to realize communism failed: the Great Leap Forward was largely responsible for the Great Chinese Famine that ended with millions of Chinese people having died, and the subsequent Cultural Revolution was a period of social turmoil and persecution characterized by Maoist populism. Following

23103-492: Was strengthened in part to suppress anti-Qing sentiment with the policy of valuing agriculture and restraining commerce, like the Haijin during the early Qing period and ideological control as represented by the literary inquisition , causing some social and technological stagnation. In the mid-19th century, the Opium Wars with Britain and France forced China to pay compensation, open treaty ports, allow extraterritoriality for foreign nationals, and cede Hong Kong to

23256-422: Was the last imperial dynasty of China. The Ming-Qing transition (1618–1683) cost 25 million lives, but the Qing appeared to have restored China's imperial power and inaugurated another flowering of the arts. After the Southern Ming ended, the further conquest of the Dzungar Khanate added Mongolia, Tibet and Xinjiang to the empire. Meanwhile, China's population growth resumed and shortly began to accelerate. It

23409-418: Was unified under an emperor , ushering in more than two millennia of imperial dynasties including the Qin , Han , Tang , Yuan , Ming , and Qing . With the invention of gunpowder and paper , the establishment of the Silk Road , and the building of the Great Wall , Chinese culture flourished and has heavily influenced both its neighbors and lands further afield. However, China began to cede parts of

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