|Standard Model of Particle Physics|
In General > s.a. cosmological
standard model; history of particle physics; particle
* Particles: Classified by representations of the symmetry group SU(3) × SU(2) × U(1); Presently known particles can be divided into quarks (u, d; c, s; t, d) (each in 3 colors), leptons (e, νe; μ, νμ; τ, ντ), and gauge bosons (graviton, 8 gluons, W ±, Z); Others are predicted by various extensions, like Higgs scalars (from spontaneous gauge symmetry breaking), gravitinos (> see supergravity), etc; Cosmology puts an upper bound of 4 on the number of generations.
* Interactions: Four of them explain all presently known phenomena.
|Interaction||Strength||Range||Exchange particles||Theory||See also|
|gravitational||10–40||∞||graviton||> general relativity||> other theories, quantum gravity|
|weak||10–15||10–15 cm||W ±, Z||> electroweak|
|electromagnetic||10–2||∞||photon||> electroweak||> other theories, QED|
|strong||1||10–13 cm||gluons||> QCD|
The weak and electromagnetic interactions have in fact been unified by
the Weinberg-Salam electroweak theory, which has been experimentally tested;
aka hypercharge force;
There could be additional forces (> see fifth force).
* Theoretical problems: Why do weak interactions couple differently to left-handed and right-handed particles? The theoretical basis for the Cabibbo-Kobayashi-Maskawa matrix (too many parameters); The standard model is not enough to account for baryogenesis (GUTs or supersymmetry of some type are needed); > s.a. Landau Pole and Hierarchy Problem.
@ General references: Leader & Predazzi 95; Cahn RMP(96) [18 parameters]; Herrero hp/98-ln; Riles CP(98) [tests]; Bertin et al RNC(00) [CKM matrix]; Quigg AIP(00)hp; Rosner AJP(03)apr [RL]; Particle Data Group PLB(04) [reference]; Morii et al 04; Oerter 05 [I]; Burgess & Moore 06; Cottingham & Greenwood 07; McCabe ed-PFP(07) [structure and interpretation]; Mann 09; Langacker 09; Perović SHPMP(11) [missing experimental challenges]; Robinson 11 [introduction]; Schwartz 13, Han 14 [and qft]; Becchi & Ridolfi 14 [II]; Donoghue et al 14; Kibble a1412-conf [rev]; Butterworth PTRS(16)-a1601-conf [successes and challenges]; Maiani & Rolandi ed-16; 't Hooft IJMPA(16).
@ Number of generations: van der Bij PRD(07) [three generations and the topology of the universe]; Gould a1011 [anthropic argument for three generations]; Kaplan & Sun PRL(12) [spacetime as a topological insulator]; He et al a1408 [algebraic geometry and the phenomenology of generations]; > s.a. beyond the standard model [beyond three generations].
Theoretical Aspects > s.a. group
renormalization of gauge theories; unified theories.
* Isospin: A quantum number associated with an SU(2) group, related to a transformation between the u and d quarks; The isospin SU(2) is a symmetry group for strong interactions, but is broken when electromagnetic interactions are turned on, since Q = \(1\over2\)B + I3, so [Q, I1,2] ≠ 0; Usually though Hem \(\ll\) Hstrong, and the breaking is small.
* Cabibbo angle: The parameter θC that allows to obtain the weakly interacting eigenstates as linear combinations of the quark mass eigenstates, like
d' = d cos θC + s sin θC, s' = –d sin θC + s cos θC .
@ General references: Iliopoulos a1101-conf [Cabibbo angle, history].
@ Hamiltonian / Dirac treatment: Lusanna NPPS(97)ht, ht/97-conf; Lusanna & Valtancoli IJMPA(98)ht/97.
@ Other theoretical aspects: Grigore a1506-conf [perturbation theory up to second order (in the causal approach)].
> Related topics: see Calabi-Yau Spaces; CKM Matrix; clifford algebra; conformal symmetry; fine-structure constant [variation]; Fine Tuning; Krajewski Diagrams; PMNS Matrix.
Phenomenology and Experiment > s.a. experimental physics and particle physics / early-universe
* And experiment: 1989, So far seems to be ok with experiment down to 10–16 cm; Some predictions confirmed to 10–12; No problem including a fourth family, and can accommodate ν oscillations; Possible problems include same sign dileptons; The decay Z0 → l+ l– γ, and, Where is the Higgs particle? 2002, The experimental value of the CP violation parameter sin 2β approaches prediction, but the g–2 problem remains.
@ Cosmology: Kusenko & Langacker PLB(97) [vacuum]; Bjorken PRD(01) [and Λ], PRD(03)ht/02; > s.a. vacuum phenomenology.
@ Particle physics: Froggatt et al NPB(94) [fermion masses]; Dolgov NPB(97) [mass corrections in expanding universe]; Gynther & Vepsäläinen JHEP(06) [high-T, pressure]; Mangano IJMPA(08)-a0802-in [LHC preview]; news symm(11)jul [Ξb discovery by CDF]; Blümlein a1205-proc [perturbative precision calculations]; > s.a. astrophysics; atomic physics; electroweak theory [including W and Z bosons, Higgs particle]; higgs field; Regge Trajectory; Sum Rules.
Variations / Generalizations > s.a. physics beyond
the standard model [including non-commutative geometry].
@ Variations: Spaans gq/97 [topological]; Lombardo hp/01-ln [at finite temperature, phase transitions]; Srivastava & Brodsky PRD(02) [light front]; Blaha ht/02 [as quantum computer]; Davoudiasl et al PLB(05)hp/04 [new minimal model]; Ziino MPLA(07) [with neutrino masses and oscillations]; Zubkov PLB(07) [extra discrete symmetry]; Grinstein et al PRD(08)-a0704 [Lee-Wick, with Higgs mass stabilization]; Alberghi et al a0804 [vacuum energy and additional particles]; Sannino MPLA(11) [as the magnetic dual of a gauge theory with only fermionic matter]; Masina & Sannino a1110 [dark-sector modifications]; Senjanović MPLA(17)-a1610-proc [left-right symmetric theory].
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