Michaelson Morley Experiment

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• Präzisions-Physik mit Neutronen
• Neutronenquellen
• Physik mit Neutronen, allgemein
• Neutronen-Experimente jenseits SM
• Theorie Standard Modell
• Neutronen-Experimente diesseits SM
• Theorie n-Zerfall
• D. Dubbers
• U. Heidelberg

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Neutronenquellen1.1 Reaktor Neutronenquellen1.
2 Spallations-Neutronenquellen1.3 Ultrakalte
Neutronen
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Physik mit Neutronen allgemein 2.1
Neutronen-Streuung2.3 Angewandte Neutronenphysik
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Besonderheiten des Neutrons

• Neutronen
• sehen besonders gut die leichten Atome (z.B.
  Wasserstoff-Brücken)
• sehen einzelne Isotope (Kontrastvariation)
• sehen Magnetismus (Spintronik)
• sehen Bewegungen der Moleküle, Spins, (auch sehr
  langsame)
• separat für alle Längenskalen
• (En Anregungsenergien des Festkörpers,
• ?n Gitterkonstante des Festkörpers)
• sehen getrennt kohärente und inkohärente Prozesse
  
• (Paar- und Autokorrelations-Funktionen)
• machen wenig Vielfachstreuung
• sind meist sehr durchdringend

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Neutronen-Experimente jenseits des SM3.1
Einführung3.2 Einige Experimente
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3.1 Einführung
History of the universe a succession of phase
transitions
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The Standard Model of particle physics

• small input SYMMETRIES Gauge principle ?'(x)
  ei?(x) ?(x)
• ('principia') applied to U(1)SU(2)SU(3),
• ( Lorentz x' Lx, CPT etc. invariances,
  )
• rich output INTERACTIONS
• basis for
• ? equations of motion Maxwell,
  technology,
• Schrödinger, chemistry,
• Dirac, molec. biology,
• solar/nuclear power,
• ? existence of photons, gluons, W, Z0
  ( carriers of interaction)
• ? conservation of charges (
  sources of interaction)
• ? generation of masses

is very successful ...
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but is only part of the picture

• Unsolved problems
• 3 particle families
• 12 masses ?
• 4 quark-phases 4 lepton-phases
• gravitation and quantum mechanics
• baryon-asymmetry of universe ?
• mass-energy content of universe
• Test all laws of physics with the highest
  possible precision
• (including energy conservation, Lorentz-,
  CPT-invariance, ).
• To be tested, laws must be well known
• this is the case mostly in the electroweak and
  the gravitational sector.

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Particle physics at the lowest energies
Mx
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Precision reached in low-energy work

• in energy dE lt 10-23 eV 0.000 000 000 000
  000 000 000 01 eV
• reached in high-precision ultracold neutron
  and atom work
• in momentum dp/p lt 10-11 1Å/10m p
• reached in state-of-the-art neutron optics
  dp
• in mass dm/m 10-11
• reached in atomic mass spectrometry
• in time dt/t 10-16
• reached with atomic clocks
• in spin-polariz. dP lt 10-7
• reached in polarized neutron work

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Low energy mostly 1st family

• quarks leptons
• 3rd b t t ?t
• 2nd s c µ ?µ
• 1st d u e ?e
• first family is
• - abundant,
• - long-lived,
• - useful.

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3.2 Einige Experimente 1. Why is charge
quantized?
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Theory of charge quantization
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2. Why has so much matter survived the Big Bang?
Big Bang theory baryon density 10-18 photon
density baryon density antibaryon
density Observation baryon density 10-9
photon density baryon density gtgt antibaryon
density possible explanation Violation of
'CP-symmetry' Experimentum crucis Electric
Dipole Moment dn of the neutron if
'CP' explanation is right dn 10-27 ? 1 e
cm value required to explain our existence
if 'CP' explanation is wrong dn
10-32 ? 1 e cm value predicted by the
Standard Model Meas.time t from uncertainty rel.
N ?f 1 with ?f ?Bohr t dnE/h t,
i.e. error ?N ?f N
½ ??Bohr t (?UCNV)½ ?dnE t 1 1
Bohr-period/year 10-23 eV
60 years of instrument development
M.v.d. Grinten, K. Jungmann, Sa vorm., S. Paul,
Di abend
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3. Are there extra spatial dimensions?
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Neutron quantization in the earth's gravitational
field
Ultracold neutrons (UCNs) probe Newton's law in
the µ-meter and the pico-eV range, set limits on
such extra forces.
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UCN gravitational levels

• Neutron density above the mirror measured with a
  position-sensitive detector with spatial
  resolution of 1.5 µm

Measurement of neutron transmission as a function
of the height of the absorber above the neutron
mirror.
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Experimental limits on non-Newtonian gravity
Ph. Schmidt-Wellenburg, Sa Vorm. Schleching 2006
Difficulties of AFM Electrostatics, geometry,
roughness, lateral Casimir force, theory
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4. Neutron oscillations
a) Is baryon number conserved?

• Neutrinos oscillate ?e? ?µ , etc. ?m
• Lepton number oscillations Le ? Lµ, etc. 0.05
  eV
• Kaons oscillate K ? K'
• Strangeness oscillations S ? ? S 10-18
  eV
• Do neutrons oscillate? n ? nbar
• Baryon-number oscillations B ? ? B ?
• Neutron oscillations allowed in various
  Grand-Unified Theories

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The ILL neutron oscillation experiment
The magnetically shielded beam lt 5 nT
The antineutron detector
'Appearence experiment' Experimental limit tn
nbar gt 0.86108 s (90 c.l.) ?mc2
ltnHnbargt lt 10-23 eV probes 105 GeV range
(model dependent) Heidelberg-ILL-Padova-Pavia
collaboration (M. Baldo-Ceolin et al., 1994)
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b) Is Dark Matter from a mirror world?

• Is there a sterile mirror world?
• Mohapatra, 2005 n ? nmirror
• can neutrons spontaneously disappear into
  sterile,
• i.e. unobservable mirror neutrons?
• Search for neutron - mirror-neutron oscillations
• Experiment U. Schmidt, spring 2007
• using zero-field spin-echo apparatus at FRM2, and
  ultrafast 'CASCADE' n-detector
• 'disappearence experiment' - experimental limit
• NBgt0/NB0 1.00002(3) ? tn-nmirror gt 2.7 s
  (90 c.l.)
• September 2007 New limit from ILL, Serebrov et
  al. tn-nmirror gt 400 s (90 c.l.)

K. Kirch, Mo Abend?
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Summary low-energy neutron physics beyond S.M.

• Why is charge quantized? (qn)
• Why is so much matter and so little antimatter
  in the universe? (EDM)
• Are there hidden dimensions of space-time?
  (n-free fall)
• Can matter oscillate into antimatter?
  (n-nbar)
• Is there a sterile mirror world?
  (n-nmirror)
• (Paul Di Abend)