Department of Physics annual report 2000 - Fysiikan laitos - Helsinki.fi

On topic (a) the strangeness mag-
vector mesons to the resonances. A
Accelerator Laboratory of the Univer-
netic moment as well as the strange-
model for the resonance widths in terms
sity of Jyväskylä. The work has fo-
ness form factors were calculated us-
of 5-quark admixtures in the wave func-
cussed on in-beam and decay spec-
ing the chiral quark model. These form
tions was formulated.
troscopy of exotic nuclei in the lead
factors have recently been measured
On topic (c) the form factors of the
and translead region. During the past
by the SAMPLE and HAPPEX collab-
nucleon were calculated with the ab
year the first experiments to comple-
orations. The model suggests very
initio quantized Skyrme model. The
ment the pioneering in-beam gamma-
small values for these observables,
possibility for dibaryons was studied
ray studies of 252,254 No by in-beam
which is consistent with the most re-
with the rational map ansatz to the
electron spectroscopy using the new
cent results. The model was also
consistently quantized Skyrme model.
SACRED electron spectrometer were
shown to lead to very small values for
On topic (d) the contribution of
successfully accomplished by interna-
the anapole moment of the proton.
the two-nucleon mechanisms that are
tional collaboration. More conventional
On topic (b) the heavy-light mes-
associated with the short range compo-
studies of new exotic α-decay emitters
ons were described as interacting two-
nents of the nucleon-nucleon interac-
have concentrated on 195,196 Rn.
particle systems formed of light consist-
tion to the cross section for emission of
The nuclei 102,103 Sn close to the
ent quarks and heavy antiquarks.
η mesons in proton-proton collisions
double magic nucleus 100 Sn are studied
A model for the scalar confining and
near the production threshold was
through in beam measurements both
hyperfine interaction between the quark
calculated and shown to be significant.
with the GASP and Euroball detector
and antiquark was developed and fitted
For articles, see list of publications in
setups. Preparations for g-factor meas-
10
to the spectra. The electromagnetic M1
and pionic decay rates were calculated.
Appendices.
urements of isomeric states in the 100 Sn
region are also in progress. In-beam
Large two-quark contributions were
noted. Finally the hadronic decays of
the nucleon resonances were calculated
▼ Experimental Nuclear Physics
K a r i E s k o l a
measurements on light Tl-nuclei using
the recoil decay tagging method are
also performed and more experiments
in the chiral quark model for the deter-
Experiments in nuclear physics have
are planned.
mination of the transition couplings of
centered at the RITU facility at the
▼ Didactical Physics
(didactical.physics.helsinki.fi/)
H e i m o S a a r i k k o
The main developments in didactical
physics in 2000 can be summarized as
follows: 1) study of learning processes
based on the empirical-constructive
approach, 2) increased international
cooperation and 3) learning to utilize
modern education technology. The
group has continued its project on the
perceptional approach, i.e. search for
constructive principles of teaching
based on the conceptual and processual
structure of physics, and on devel-