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Strange quark
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<p>The strange quark or s quark (from its symbol, s) is the third lightest of all <a href="/facts/Quark/hwuuVkV5">quarks</a>, a type of <a href="/facts/Elementary_particle/CTFDM97U">elementary particle</a>. Strange quarks are found in <a href="/facts/Subatomic_particle/tMEzcTWQ">subatomic particles</a> called <a href="/facts/Hadron/C0sd1zty">hadrons</a>. Examples of hadrons containing strange quarks include <a href="/facts/Kaon/Yn2w4QlQ">kaons</a> (K), <a href="/facts/Strange_D_meson/o6pW8BLc">strange D mesons</a> (Ds), <a href="/facts/Sigma_baryon/ETeyRRWp">Sigma baryons</a> (Σ), and other <a href="/facts/Strange_particle/SLwkEvDX">strange particles</a>. </p><p>According to the <a href="/facts/IUPAP/ah3BodlS">IUPAP</a>, the symbol s is the official name, while "strange" is to be considered only as a mnemonic. The name sideways has also been used because the s quark (but also the other three remaining quarks) has an <a href="/facts/Isospin/mnksCIaP">I3 value</a> of 0 while the u ("up") and d ("down") quarks have values of +1/2 and −1/2 respectively. </p><p>Along with the <a href="/facts/Charm_quark/RLduBtpL">charm quark</a>, it is part of the <a href="/facts/Generation_(physics)/hAbgvUfV">second generation</a> of matter. It has an <a href="/facts/Electric_charge/xxsBfmlB">electric charge</a> of −+1/3 <a href="/facts/Elementary_charge/lPcj6CoQ"><i>e</i></a> and a <a href="/facts/Bare_mass/2Qh5a7P0">bare mass</a> of 95+9−3 <a href="/facts/Electronvolt/YMT1fqX9">MeV/<i>c</i>2</a>. Like all <a href="/facts/Quark/hwuuVkV5">quarks</a>, the strange quark is an <a href="/facts/Elementary_particle/CTFDM97U">elementary</a> <a href="/facts/Fermion/LEckdDsR">fermion</a> with <a href="/facts/Spin_(physics)/4Jvp7e8P">spin</a> <a href="/facts/Spin-1%2f2/3I929M4X">1/2</a>, and experiences all four <a href="/facts/Fundamental_interaction/WrFEJaFl">fundamental interactions</a>: <a href="/facts/Gravitation/bqAN7DdQ">gravitation</a>, <a href="/facts/Electromagnetism/oAkmALHT">electromagnetism</a>, <a href="/facts/Weak_interaction/f6upmKMs">weak interactions</a>, and <a href="/facts/Strong_interaction/JjRsKcLg">strong interactions</a>. The <a href="/facts/Antiparticle/7Ic43ThI">antiparticle</a> of the strange quark is the strange antiquark (sometimes called <i>antistrange quark</i> or simply <i>antistrange</i>), which differs from it only in that some of its properties have <a href="/facts/Additive_inverse/n8gKUmCf">equal magnitude but opposite sign</a>. </p><p>The first <a href="/facts/Strange_particle/SLwkEvDX">strange particle</a> (a particle containing a strange quark) was discovered by <a href="/facts/George_Rochester/oz8ntg4x">George Rochester</a> and <a href="/facts/Clifford_Butler/9fSP9QlG">Clifford Butler</a> in <a href="/facts/Department_of_Physics_and_Astronomy%2c_University_of_Manchester/nYceCRYk">Department of Physics and Astronomy, University of Manchester</a> in 1947 (<a href="/facts/Kaon/Yn2w4QlQ">kaons</a>), with the existence of the strange quark itself (and that of the <a href="/facts/Up_quark/Aw3Vp3vk">up</a> and <a href="/facts/Down_quark/Nq10ayEE">down quarks</a>) postulated in 1964 by <a href="/facts/Murray_Gell-Mann/7yg75mjR">Murray Gell-Mann</a> and <a href="/facts/George_Zweig/90Ah73xH">George Zweig</a> to explain the <i><a href="/facts/Eightfold_way_(physics)/xDtTrHK2">eightfold way</a></i> classification scheme of <a href="/facts/Hadron/C0sd1zty">hadrons</a>. The first evidence for the existence of quarks came in 1968, in <a href="/facts/Deep_inelastic_scattering/0kB9Leaf">deep inelastic scattering</a> experiments at the <a href="/facts/Stanford_Linear_Accelerator_Center/CzX2afas">Stanford Linear Accelerator Center</a>. These experiments confirmed the existence of up and down quarks, and by extension, strange quarks, as they were required to explain the <i>eightfold way</i>. </p>