QCD Phenomenology  

In General > s.a. QCD [vacuum].
* Idea: The main strength of QCD is its general structure; It has had many qualitative confirmations but (few quantitative ones since few calculations can be analytically done), and reinforces the belief that elegance and uniqueness are criteria for truth; 2002, Numerical lattice simulations are almost able to make new predictions.
* Experimental evidence: (1) Results from deep inelastic scattering (in the 1960's at SLAC); (2) The behavior of the ratio R of the hadronic over the -pair production in e+e– annihilations; (3) J/ spectroscopy.
* Features: Fragmentation and Jets; Monte Carlo simulation of interactions, using the Lund model.
* Force: Because of confinement, quark behavior can be modeled by a growing potential, e.g., like a spring.
@ General references: Potvin AS(91); Dzierba et al AS(00); Wilczek hp/02-in, AHP(03)phy/02; Klempt & Zaitsev PRP(07) [glueballs, hybrids, multiquarks].
@ Related topics: Lakhina & Swanson PLB(04) [gluonic van der Waals force]; Chandrasekharan & Strouthos PRL(05) [mean field theory, failure for large N]; Cho et al ht/05 [effective potential]; Sorella ht/05-in [gluon dynamical mass]; Acharya ht/06 [mass gap]; > s.a. hadrons [including quarks], Pomeron.

Glueballs
* Idea: Bound states of gluons that can be color singlets.
* 1991: Not confirmed yet; Probably m > mprot, but hard to recognize.
* 1995: Not confirmed yet; Evidence from lattice calculations that lightest one is fJ (1710 MeV).
* 2005: First analytical results for the glueball spectrum in the 3D case by R Leigh et al (> see quantum gauge theories).
@ General references: Ishikawa SA(82)nov; Sexton et al PRL(95) [numerical evidence]; Close CP(97), SA(98)nov; Niemi ht/03-in [as twisted closed strings]; Kondo et al JPA(06) [mass from topological knot soliton in Faddeev model].
@ Spectrum: Morningstar & Peardon PRD(99); Bugg et al PLB(00); Frasca a0704 [strong coupling and lattice calculations].

Quark-Gluon Plasma
* Idea: A hypothetical hot, dense soup of single quarks and gluons obtained at Tc 100–200 MeV/nucleon, last believed to exist naturally in the first millionth of a second after the Big Bang; Subsequently, as the universe expanded and cooled, quarks assembled into mesons and baryons, held together by gluons.
* 2000: Experiment at CERN claims to have produced it, but probably premature.
* 2001: The four detector groups at RHIC (BRAHMS, PHENIX, PHOBOS, and STAR) talk about indications.
* 2004: Many say that Brookhaven's RHIC has "overwhelming" indications, but lab refuses to officially announce.
* 2005: Brookhaven results puzzling (events too explosive), and the consensus interpretation is that the fireball is a (classical) liquid of strongly interacting quarks and gluons, rather than a gas of weakly interacting quarks and gluons [@ news pn(05)apr].
* 2005: BNL's Relativistic Heavy Ion Collider (RHIC) produces more evidence for quark-gluon plasma [@ news pn(06)apr].
@ References: Collins & Reichert SA(00)mar [news from CERN], Quercigh & Rafelski pw(00)oct; Antonov PLB(02)ht [loop space formulation]; Letessier & Rafelski 02; Yagi et al 06; Balakin a0710-in; Davidson a0807 [as ideal classical fluid, and early universe].

Confinement > s.a. Confinement; Gribov Ambiguity; lattice gauge theory; particle models; types of Yang-Mills theories; unified theories.
* Idea: The conjecture that all observable objects are gauge-singlet bound states of quarks and gluons; A non-perturbative feature of non-abelian gauge theories; Not well understood theoretically, but seems to be dominated by an abelian sector; Can be treated in lattice theories; Phenomenologically, seems to be describable by the addition of a |Fiab Fiab|1/2 term to the Lagrangian.
* Question: Is it related to spontaneous breaking of chiral symmetry?
@ Reviews: Fucito ht/97-in [introduction]; Dittmann et al NPPS(02)hl/01 [effective theories]; Greensite PPNP(03)hl [lattice]; Bruckmann a0710-in.
@ General references: Sniatycky & Schwartz RPMP(94) [invariance argument]; Simonov SPU(96); Schaden & Rozenberg PRD(98) [covariant gauge]; Reinhardt NPPS(99)ht/98 [as dual Meißner effect]; Bali ht/98-in; Cho PRD(00)ht/99; Kondo & Taira MPLA(00)ht/99 [SU(3)], PTP(00)ht/99 [SU(N)]; Chaichian & Kobayashi PLB(00); Chernodub et al PLB(00)hp; Frønsdal LMP(01) [as quantization problem]; 't Hooft ht/02-in [perturbative]; Efimov TMP(04) [and stability]; Gogokhia a0704; Tomboulis a0707, comment Ito & Seiler a0711, a0803, reply a0712 [4D SU(2), proof].
@ Phase transition: Langfeld ht/04-in; Ejiri et al PLB(06) [hadronic fluctuations].
@ Related topics: Gaete & Guendelman PLB(04) [Coulomb interaction and screening]; Chernodub JETPL(06)ht/05 [and liquid crystal defects]; Greensite & Olejnik hl/06 [2+1, from gauge invariance].
@ And new physics: Álvarez & Gómez JHEP(00)ht [and strings]; Berman & Parikh PLB(00) [and AdS-cft].

Other Effects > s.a. gravitational wave background; instantons; matter in quantum gravity; phase transitions; Zweig Rule.
* Strangelets: Hypothetical stable or semi-stable particles which contain strange quarks; Theorists have predicted that such entities could survive for long periods inside neutron stars and might be produced in the heavy ion collisions going on at the RHIC machine at Brookhaven; Shown not to lead to dangerous runaway reactions.
@ Quark matter, strange quark nuggets: Dar et al PLB(99); Jaffe et al RMP(00); Madsen PRL(00); Anderson et al ap/02 [and seismic events]; Xiaoping et al NA(06)ap/03 [astrophysics]; Herrin et al PRD(06)ap/05 [seismic search]; Alford et al Nat(07)ap/06 [in compact stars]; Madsen ap/06-in [rev]; > s.a. Quark Stars.
@ Search for fractional charges: LaRue, Phillips & Fairbank PRL(81).
@ And nuclear physics: Schulte et al PRL(01) + pn(01)aug [e's on d]; Beane PRA(04) [rev].
@ Particle propagation: Guhr et al PRL(00) [as disordered system]; Dietrich PRD(05) [gluons in non-trivial backgrounds].
@ High-density / condensed-matter phase: Rajagopal & Shuster PRD(00)hp; Rajagopal & Wilczek hp/00-in, PRL(01)hp/00.
@ Related topics: Haskell et al a0708 [constraints from LIGO]; Gasser et al PRP(08) [hadronic atoms].

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