Neutrons| Neutrons |
In General > s.a. experiments
in quantum mechanics; hadrons [structure].
* History: 1932, Discovered
by Chadwick; 1934, Chadwick and Goldhaber determined the mass accurately enough
to determine that a n was not an ep bound
state (as
Rutherford had predicted); 2002, Evidence for neutrinoless double-
decay
reported, and quantum states in gravitational field.
* Mass: mn =
1.6749 ×
10–27 kg.
* Electric dipole moment:
In the standard model, the strong interaction should violate
T-reversal symmetry, and thus CP symmetry; But such a symmetry violation
would result in a neutron electric dipole moment 10 orders of magnitude larger
than the current bound; In 1977, Roberto Peccei
and Helen Quinn discovered a simple dynamical mechanism to enforce strong
CP symmetry which, as Steven Weinberg and Frank Wilczek independently realized,
implies the existence of the axion; 2006,
Currently the best experimental upper bound is 2.9 
10–26 e·cm
(90% c.l.); Soon experiments will do better.
@ History: De Gregorio HSPBS(05)phy
[early 1930s], phy/06.
@ Electric dipole moment:
Fortson et al PT(03)jun;
Baker et al PRL(06)
[upper bound]; Domínguez et al PRD(09)-a0907 [and
QED vacuum fluctuations].
@ n-p mass difference: Feynman & Speisman PR(54);
Dashen & Frautschi
PR(64)
[proved
wrong, see Kim phy/04].
@ Other topics: van den Brand & Huberts PW(96) [charge distribution];
Altschul qp/99 [gravity
and acceleration].
Neutron Interferometry > s.a. experiments
in quantum mechanics; gravitomagnetism; geometric
phase;
quantum equivalence principle.
* And gravity: Gravity-induced phases have already been detected, and they
show that gravity at the quantum level is not a purely geometric effect,
since the
mass
of the employed particles appears explicitly in the interference
expression.
@ General references: Greenberger RMP(83)
[and quantum mechanics, rev]; Rauch HPA(88);
Unnerstall PLA(90)
[comment]; Rauch & Vigier PLA(90);
Rauch FP(93);
Benatti & Floreanini
PLB(99)qp [semigroups
and dissipative evolution]; Felber et al FP(99)
[in space and time]; Rauch & Werner
00 [r PT(02)jun];
Wu et al a0910 [quantum
theory approach].
@ Geometric and quantum phases: Werner CQG(94);
Littrell et al PRA(97);
Allman et al PRA(97);
Bhandari qp/01/PRL;
Rauch et al Nat(02)jun
[confinement-induced].
@ And gravity: Wolf FP(90)
[and quantum gravity]; Werner CQG(94);
Camacho PLA(99)qp,
PLA(99)qp;
Varjú & Ryder AJP(00)may
[general relativistic treatment]; Nandi & Zhang PRD(02)gq [and
equivalence principle]; Camacho & Macías PLB(05)
[and torsion].
@ Related topics: Gähler & Zeilinger AJP(91)apr
[wave phenomena, interference and diffraction].
Other Phenomenology > s.a. CPT
tests; neutron
stars.
@ Quantum states in gravitational field: Nesvizhevsky et al NIM(00), Nat(02)jan;
Schwarzschild PT(02)mar;
Olevik et al qp/02;
Westphal gq/02 [theory];
Nesvizhevsky PRD(03),
comment Hansson et al PRD(03)qp,
reply PRD(03);
> s.a. tests of newtonian gravity.
@ Scattering: news pw(06)dec
[and paper dating]; Alexandrov G&C(08)
[and higher-dimensional gravity]; Furrer et al 09 [in condensed-matter physics].
@ Decay: Klapdor-Kleingrothaus in(02)hp,
et al FP(02)
[neutrinoless
double-];
Klapdor-Kleingrothaus FP(03)
[first evidence].
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send feedback and suggestions to bombelli at olemiss.edu – modified 18
oct 2009