CP Violation| CP Violation |
In General > s.a. atomic physics;
early-universe cosmology; matter [antimatter];
neutrino mixing; particle statistics.
* Idea: One of several
possible explanations for the matter-antimatter asymmetry (baryon
asymmetry) observed in the universe.
* Theory: Both strong and
weak interactions can violate CP (charge-parity) symmetry; The effect can be
described in terms of mixing in the CKM matrix (three angles α,
β and γ 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(2β) between 0.66 and 0.84; Violations are likely to
be connected to baryon asymmetry, and maybe neutrino 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 corresponding 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
α and β – although α will require
much more data –, but need Bss
to measure γ; Weak effects are esier to compare with theory.
* In 2+1 dimensions:
P and T are violated by particles with fractional statistics.
> Online resources:
see Wikipedia page.
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 3π) and K2
(+1, short-lived, decays into 2π); K1
found by L Lederman et al.
* 1964: Unexpected, first indirect evidence
found by Fitch & Cronin (CCFT) in K1 meson decay
into 2π [@ news pn(99)mar].
* 1998:
Indications found by CDF in B meson decay.
* 1999: Direct evidence
in K meson decay at Fermilab, ε'/ε = (28
± 4) × 10−4, and CERN,
(18.5 ± 7) × 10−4.
* 2000: RHIC is now online, will
search for violations due to strong interaction, as opposed to weak interactions;
Results from B meson decay give sin(2β) = 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(2β) = 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.
* 2006: The amount of CP
violation observed so far is insufficient to account for matter domination
(there may be more in quark, neutrino, or Higgs physics).
* 2012:
Unexpectedly large violation seen in charmed meson decay.
* 2017: CP violation seen in heavy baryon decays.
* 2019: CP violation seen in the charm sector, D mesons.
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);
Frère CRP(12)-a1201 [rev].
@ Books: Jarlskog 89;
Wolfenstein ed-90;
Castelo Branco et al 99 [r PT(00)aug];
Bigi & Sanda 09;
Sozzi 12.
@ 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];
Ashtekar SHPMP-a1307-conf [new perspective].
@ Lepton sector: Branco & Rebelo NJP(05) [and neutrino mass];
Dita PRD(06)-a1101;
Farzan & Smirnov JHEP(07);
Pascoli et al PRD(07) [and leptogenesis];
Winter PLB(09) [neutrino propagation];
Branco et al RMP(12) [rev];
Fogli et al PRD(12)-a1205 [neutrino masses, mixings and phases];
Miller PT(20)jun [in the neutrino sector];
> s.a. neutrino mixing.
@ 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);
Roney Phys(20) [re observation];
> s.a. Weak Measurements.
@ Experiments:
Abe et al PRL(98),
PRL(98);
Alavi-Harati et KTeV PRL(00)
[KL → π+
π− e+
e− decay];
Abe et Belle PRL(04)
[B0 → π+
π− decay];
Fratina et Belle PRL(07)
[B0 → D+
D− decay];
Nir Phy(12) [D and anti-D charmed meson decay];
news CERN(13)apr [strange meson decay];
news ibt(16)jun [shape of the Radium-224 and Barium-144 nuclei];
LHCb nPhys(17)jan
+ news ns(17)feb [in beauty baryon decay];
news cosmos(19)mar,
Aihara Phy(19) [LHCb experiment, charm sector].
@ 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];
Hadley EPL(11)-a1107
+ news sciblog(11)jul [CP violation as a consequence of frame dragging from galactic rotation];
Piacentino et al a2105-conf.
@ Other theories:
Khalil IJMPA(03) [supersymmetric];
Creutz ht/03,
PRL(04)hl/03,
PRL(04) [strong interactions];
Grzadkowski & Wudka PRL(04)hp [5D QED];
Briere Phy(10)
[new physics beyond the standard model as source of CP violation];
Ellis et al JHEP(10)-a1006 [geometric approach];
Chen & Ratz a1903 [group-theoretical origin];
Keus a2105-conf [in the dark sector].
Related Topics
> s.a. Charge Conjugation; electromagnetism
[dipole moments]; matter [mirror matter]; realism;
uncertainty relations.
* Strong CP problem: The Peccei-Quinn
mechanism is the most popular resolution, with the Nelson-Barr considered the most
viable alternative.
@ Strong CP problem:
Fort & Gambini ht/97 [in loop formulation];
Dine hp/00-ln;
Hsu & Sannino PLB(05);
Mitra hp/05-conf [no problem];
Takahashi PTP(09)-a0804 [anthropic solution];
Peccei AIP(10)-a1005 [history, and spontaneously-broken chiral symmetry];
Swain a1005 [and the existence of black holes];
Lattanzi & Mercuri PRD(10)-a1006 [solution via the Peccei-Quinn mechanism];
Acharya et al JHEP(10) [M-theory solution];
Hook PRL(15)-a1411 [anomalous solutions].
@ 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];
Brauner et al PRL(12)-a1110 [temperature dependence of CP violation effects in the Standard Model].
main page
– abbreviations
– journals – comments
– other sites – acknowledgements
send feedback and suggestions to bombelli at olemiss.edu – modified 19 may 2021