Hadrons| Hadrons |
In General
> s.a. atomic physics [exotic atoms]; Bag Model;
constants; lattice theories [masses in lattice QCD];
particle physics; Skyrme Model.
* Idea: Mesons and baryons (and
pentaquarks), which are strongly-interacting many-body systems consisting of
quarks and gluons, with a size of about 1 fm.
@ General references: Chew et al SA(64)feb;
Alkofer & von Smekal PRP(01) [IR Green functions];
Gogohia PLB(05)ht/04,
ht/06 [mass gap];
Belotsky et al hp/04 [4th generation, bounds];
Afonin IJMPA(07) [parity doubling];
Close CP(08) ["Rumsfeld hadrons"].
@ Hadron structure: Rajeev ht/99 [structure functions];
Jaffe AIP(01)hp [spin distribution];
Drechsel & Walcher RMP(08) [at low Q2];
Hägler PRP(10) [from lattice QCD];
Alexandrou et al RMP(12) [the shape of hadrons];
Hobbs a1408-PhD [non-perturbative].
Types of Hadrons
> s.a. neutron; proton.
* Types and classification: The
known mesons (singlets and octets) and baryons (singlets, octets and decuplets)
belong to representations which are explained as made up from the fundamental
representation of flavor SU(6):
q-\(\bar q\) = 3 ⊗ 3bar = 1 ⊕ 8 ; qqq = 3 ⊗ 3 ⊗ 3 = 1 ⊕ 8 ⊕ 8 ⊕ 10 .
* Pions, π: The isovector
fundamental representation of isospin SU(2); The "mesons" postulated by
H Yukawa in 1935, discovered by C Powell in emulsions exposed to cosmic rays in 1947.
* Kaons, K:
Mesons containing strange quarks; > s.a. CP
violation; CPT symmetry.
* Baryons: Hadrons composed of three
(valence) quarks; They include p, n, and the heavier, unstable ones,
or hyperons; In the large-Nc limit of
QCD, baryons can be modeled as solitons, for instance, as Skyrmions.
* Tetraquarks: Evidence has been reported
several times since 2003; 2013, Is the Zc(3900)
a tetraquark, a hadron molecule, or something different? 2014, The strongest evidence yet
is the Z(4430) at the LHC.
* Pentaquarks: 2002–2003, Discovered
in Japan and confirmed by others, thought to be made up of five quarks; 2004–2005,
More claimed detections [@ news pw(04)mar,
charmed], but not seen in further, higher-energy experiments, and considered by some
to be a mistake; 2015, Two resonant states of the p and the J/Ψ seen
by LHCb; 2019, A pentaquark is a bound state of a baryon and a meson.
@ Mesons: Particle Data Group PLB(04);
Choi et al PRL(05)
+ pw(05)may [hybrid];
Swanson PRP(06) [new heavy];
Cirigliano et al RMP(12) [kaon decays in the standard model, comprehensive overview];
Blum et al PRL(12)
+ news bnl(12)mar [kaon to decay into two π mesons, lattice QCD];
Aaij et al PRL(13)
+ news PhysOrg(13)mar [D-meson oscillations];
Bernstein & Holstein RMP(13) [history of the π0, and the QCD chiral anomaly];
news sn(14)oct
[discovery of the Ds3*(2860)–];
> s.a. dynamical wave-function collapse [flavor oscillations].
@ Baryons:
Particle Data Group PLB(04);
Cherman & Cohen JHEP(06)ht [and large-Nc limit];
news pn(06)oct,
png(06) [periodic table];
news SFN(06)nov
[Σb discovered by CDF, heaviest baryons known];
Klempt & Richard RMP(10) [survey of baryon spectroscopy];
Aaij et LHCb PRL(15)
[obervation of Ξb];
Gal et al a2003 [from mesons].
@ Tetraquarks: Choi et Belle PRL(03)he
+ news pw(03)nov [X(3872) mystery meson?];
Gupta IJMPA(05);
news pw(07)nov;
news pw(10)apr [evidence grows];
Swanson Phy(13),
news wired(13)jun [Zc(3900)];
news ns(14)apr,
Aaij et LHCb PRL(14) [Z(4430) confirmed];
Olsen PT(14)sep [particles with four or more quarks];
D0 Collaboration PRL(16)-a1602
+ news pw(16)feb [X(5568) as a ubds bound state],
news pw(16)mar [CERN fails to confirm];
Ablikim et al PRL(17)
[spin and parity of the Zc(3900)];
news pw(17)dec [stable tetraquark prediction];
news sn(20)jul [with 4 charm quarks];
Sonnenschein & Weissman a2008;
Ablikim et BESIII PRL(21) [observation
in e+e− collisions].
@ Pentaquarks:
Diakonov et al ZPA(97) [prediction];
Nakano et al PRL(03)
+ pw(03)jul [evidence];
Zhu PRL(03) [in QCD],
IJMPA(04) [rev];
Carlson et al PLB(04);
Jaffe & Wilczek EPJC(04)hp-conf,
news pw(04)mar;
Close pw(05)feb;
news Nat(05)apr [doubts];
Karliner IJMPA(05);
Stancu IJMPA(05);
Hicks IJMPA(05);
Seth IJMPA(05) [status];
Wei et al JHEP(05) [spin-3/2];
Close CP(06) [rev];
Liu et al IJMPA(14) [search status];
news pw(15)jul,
pt(15)jul [best evidence yet];
Aaij et al PRL(15)
+ Hicks Phys(15)
[charmonium-pentaquark states observed at LHCb];
news Phy(16) [confirmation by LHCb];
Aaij et LHCb Collaboration PRL(19)
+ news sn(19)jun [structure].
Parton Models > s.a. QCD phenomenology.
* Parton models: Treat
hadrons as composite particles; Feynman came up with the idea, but in the
currently accepted QCD picture, the partons are Gell-Mann's quarks.
@ General references: Kogut & Susskind PRP(73);
Drell & Yan AP(00) [high-energy physics applications];
Kim & Noz qp/02-proc [relating quarks and Feynman's partons];
Kancheli hp/02 [and trans-planckian collisions];
Diehl PRP(03),
Belitsky & Radyushkin PRP(05) [generalized parton distributions];
Blümlein MPLA(10)-a1007-in [nucleon parton distributions].
@ Phenomenology: Bashindzhagyan & Korotkova a1601 [search for fractional charges in cosmic rays].
Quarks
> s.a. astronomical objects [quark stars]; HEP
experiments [search for fractional charges]; QCD [including gluons];
QCD phenomenology.
* Idea: Basic building blocks of
hadronic matter, which interact by exchange of gluons (and gammas, gravitons, ...).
* History: The first indications
of hadron properties that led to the idea of quarks was the isospin symmetry,
under an SU(2) that was to become a subgroup of SU(n); The
proposal of the first three quarks was made by Gell-Mann in 1964, as
mathematical objects belonging to the fundamental (triplet) representation
of (flavor) SU(3), an (approximate) symmetry of strong interactions; 1979:
Discovery of gluons at DESY; 1996, It is believed that there are 6 flavors,
that fill the fundamental representation of flavor SU(6) (not a symmetry)
and physically make up hadrons.
* Top: Discovered in 1995;
m = 177 GeV (CDF) or 172 GeV (D0) in 1997; 2004, 178.0 ±
4.3 GeV, from D0 results.
* Mass: It is subtle to define,
since quark confinement does not allow the measurement in isolation; The
short-distance (current algebra) mass is the one appearing in the fundamental
Lagrangian, and the long-distance (constituent) mass is the relevant one
for hadron-mass calculations; 2010, Supercomputer simulations give \(m_u
= 2.01 \pm 0.14\) MeV and \(m_d = 4.79 \pm 0.16\) MeV; 2014, Combined LHC
results give \(m_t = 173.34 \pm 0.76\) MeV.
@ General references: Gell-Mann PL(64);
Zweig pr(64);
Mermin PT(93)dec [pronunciation];
Arkhipov conf(94)-a1410 [quark-quark forces];
Albrow CP(95) [top];
Campagnari & Franklin RMP(97),
Liss & Tipton SA(97)sep [top];
Particle Data Group PLB(04);
Schiff IJTP(11)-a1012 [classical quark-like particle model];
Fritzsch & Gell-Mann ed-15.
@ Masses: Maity et al IJTP(83) [model];
Chandra Raju & Chintalapati IJTP(05) [in terms of standard model parameters];
Jaffe et al PRD(09)-a0809;
news sci(10)apr [more precise values for masses of u and d quarks];
Domínguez IJMPA(10),
MPLA(11) [determination in QCD];
Castillo-Felisola et al PRD(13)-a1310 [from the condensation of a fourth family, through torsion];
news hp(14)mar [combined LHC top mass];
> s.a. mass.
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send feedback and suggestions to bombelli at olemiss.edu – modified 15 mar 2021