| 词条 | Z(4430) |
| 释义 |
| name = Z(4430) | image = | caption = | num_types = | classification = Exotic meson | composition = {{Subatomic particle|Charm quark|link=yes}}{{Subatomic particle|Charm antiquark|link=yes}}{{Subatomic particle|Down quark|link=yes}}{{Subatomic particle|Up antiquark|link=yes}} | statistics = | group = | generation = | interaction = | particle = | antiparticle = | status = | theorised = | theorized = | discovered = | symbol = | mass = | mean_lifetime = | width = | decay_particle = | electric_charge = | charge_radius = | electric_dipole_moment = | electric_polarisability = | electric_polarizability = | magnetic_moment = | magnetic_polarisability = | magnetic_polarizability = | colour_charge = | color_charge = | spin = | num_spin_states = | lepton_number = | baryon_number = | strangeness = | charm = | bottomness = | topness = | isospin = | weak_isospin = | weak_isospin_3 = | hypercharge = | weak_hypercharge = | chirality = | B-L = | X_charge = | parity = | g_parity = | c_parity = | r_parity = | condensed_symmetries = }} Z(4430) is a mesonic resonance discovered by the Belle experiment.[1][2] It has a mass of {{val|4430|ul=MeV/c2}}. The resonant nature of the peak has been confirmed by the LHCb experiment with a significance of at least 13.9 σ.[3] The particle is charged and is thought to have a quark content of {{Subatomic particle|Charm quark|link=yes}}{{Subatomic particle|Charm antiquark|link=yes}}{{Subatomic particle|Down quark|link=yes}}{{Subatomic particle|Up antiquark|link=yes}},[3] making it a tetraquark candidate. It has the spin-parity quantum numbers JP = 1+. The particle joins the X(3872), Zc(3900) and Y(4140) as exotic hadron candidates observed by multiple experiments, although it is the first to be confirmed as a resonance.[4][5] See also
References1. ^{{cite journal |last1=Choi | first1=S.-K. |author2=Belle Collaboration |title=Observation of a resonance-like structure in the {{Subatomic particle|Pion+-}}Ψ′ mass distribution in exclusive B→K{{Subatomic particle|Pion+-}}Ψ′ decays |year=2007 |doi=10.1103/PhysRevLett.100.142001 | pmid=18518023 |journal=Physical Review Letters |volume=100 |issue=14 | pages=142001 |arxiv=0708.1790|bibcode = 2008PhRvL.100n2001C |display-authors=etal}} 2. ^{{cite press |url=http://www.kek.jp/intra-e/press/2007/BellePress11e.html |title=Belle Discovers a New Type of Meson |publisher=KEK |year=2007 |accessdate=2009-06-20}} 3. ^1 {{cite journal |last=LHCb collaboration |arxiv=1404.1903 |title=Observation of the resonant character of the Z(4430)− state |year=2014 |version= |doi=10.1103/PhysRevLett.112.222002 |pmid=24949760 |volume=112 |issue=22 |pages=222002 |journal=Physical Review Letters |bibcode=2014PhRvL.112v2002A}} 4. ^{{cite web|url=http://home.web.cern.ch/about/updates/2014/04/lhcb-confirms-existence-exotic-hadrons|title=LHCb confirms existence of exotic hadrons|publisher=CERN|author=Cian O'Luanaigh|date=9 April 2014}} 5. ^{{cite web|url=http://lhcb-public.web.cern.ch/lhcb-public/Welcome.html#Z(4430)|title=Unambiguous observation of an exotic particle which cannot be classified within the traditional quark model|date=9 April 2014|publisher=European Organization for Nuclear Research}} External links
2 : Mesons|2014 in science |
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