CP Violation  

In General > s.a. atomic physics; early-universe cosmology; neutrino mixing; particle statistics.
* Idea, theory: Both strong and weak interactions can violate CP; The effect can be described in terms of mixing in the CKM matrix (three angles , and which form a non-degenerate CKM unitarity triangle–the amount of violation is proportional to the area), but could also be due to other physics; The standard model "predicts" a value of sin(2) between 0.66 and 0.84; Violations are likely to be connected to baryon asymmetry, and maybe oscillations.
* CKM matrix and unitarity: The entries Vij of the CKM matrix, where i = u, c, t, and j = d, s, b, are the amplitudes for the coresponding flavor-changing processes, and must be unitary; The "unitarity triangle" is the expression one obtains when one writes explicitly one of the unitarity conditions, Vub Vud* + Vcb Vcd* + Vtb Vtd* = 0 (so this vanishing of the sum of three complex numbers is one of six such triangles one can get from Vij, but it is the one that contains the two most significant phases).
* Idea, experiment: Can't measure all three CKM angles in the same experiment (BaBar and Belle measure and – although will require much more data –, but need Bs's to measure ; Weak effects are esier to compare with theory; 2006, Amount of CP violation observed so far insufficient to account for matter domination, there may be more effects in quark or neutrino physics, or Higgs boson properties.
* In 2+1 dimensions: P and T are violated by particles with fractional statistics.

History, Status
* 1957: L Landau argues that, although P can be violated, CP should not be; A Pais & M Gell-Mann suggest that the K0 and K0-bar mesons are linear combinations of parity eigenstates K1 (–1, long-lived, decays into 3) and K2 (+1, short-lived, decays into 2); K1 found by L Lederman et al.
* 1964: Unexpected, first indirect evidence found by Fitch & Cronin (CCFT) in K1 meson decay into 2 [@ news pn(99)mar].
* 1998: Indications found by CDF in B meson decay.
* 1999: Direct evidence in K meson decay at Fermilab, '/ = (28 4) 10–4, and CERN, (18.5 7) 10–4.
* 2000: RHIC now online, will search for violations due to strong interaction, as opposed to weak interactions; Results from B meson decay give sin(2) = 0.45 0.44 0.45 (KEK) and 0.45 0.44 0.45 (BaBar at SLAC).
* 2001: Measurements from B meson decays give sin(2) = 0.59 0.14 (BaBar at SLAC) and 0.99 0.14 (Belle at KEK); Aleph and CDF give intermediate values; Strong interaction effects not yet seen.
* 2001: Direct violation – Differences between decays B mesons and their antiparticle equivalents at BaBar.

References > s.a. CPT [including T-reversal]; modified QED; Parity [violation]; theta sectors.
@ Reviews, news: Adair SA(88)feb; news PT(88)oct; Harrison pw(03)jul; news pw(06)apr; Ibrahim & Nath RMP(08); Kobayashi IJMPA(09); Maskawa IJMPA(09).
@ Books: Jarlskog 89; Wolfenstein ed-90; Castelo Branco et al 99 [r PT(00)aug]; Bigi & Sanda 09.
@ General articles: Fitch RMP(81); Cronin RMP(81); Rosner AJP(96)aug [demo]; Rosner & Slezak AJP(01)jan [classical analog]; Sozzi & Mannelli RNC(03) [measurements]; Smit JHEP(04)hp [and standard model effective action]; Gershon pw(07)apr [unitarity triangle].
@ Lepton sector: Branco & Rebelo NJP(05) [and neutrino mass]; Farzan & Smirnov JHEP(07); Pascoli et al PRD(07) [and leptogenesis]; Winter PLB(09) [neutrino propagation].
@ Spontaneous violation: Dorey et al JPA(01) [and supersymmetry]; Frampton IJMPA(02); Balaji et al PLB(04) [dynamical, early universe].
@ B-meson decays: Green & McMahon CP(01); Peruzzi RNC(04); Gronau IJMPA(07).
@ Experiments, specific decays: Abe et al PRL(98), PRL(98); Alavi-Harati et KTeV PRL(00) [KL → + – e+ e– decay]; Abe et Belle PRL(04) [B0 → + – decay]; Fratina et Belle PRL(07) [B0 → D+ D– decay].
@ Gravity: Deser et al PLB(80); Losecco et al PLA(89); Anandan PRL(98)ht/97 [global topology]; Mukhopadhyaya & Sengupta PLB(99)ht/98 [with torsion]; Ahluwalia MPLA(98)hp/99; Kobakhidze a0807 [quantum gravity and discontinuity of CP-conserving limit]; Bargueño & Pérez de Tudela PRD(08) [long-range parity violation].
@ Other theories: Khalil IJMPA(03) [supersymmetric]; Creutz ht/03, PRL(04)hl/03, PRL(04) [strong interactions]; Grzadkowski & Wudka PRL(04)hp [5D QED].

Related Topics > s.a. Charge Conjugation; electromagnetism [dipole moments]; matter [mirror matter]; realism.
@ Strong CP problem: Fort & Gambini ht/97 [in loop formulation]; Hsu & Sannino PLB(05); Mitra hp/05-in [no problem]; Takahashi PTP(09)-a0804 [anthropic solution].
@ Other: Home & Majumdar FP(99)qp [and Bohmian insert]; Huggett PhSc(00)jun [P violation]; Bertlmann et al PLA(01)qp [and Bell inequalities]; Caliceti et al PLA(05)mp/04 [with CPT symmetry].

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send feedback and suggestions to bombelli at olemiss.edu – modified 21 aug 2009