92 research outputs found
Whole body counter surveys of Miharu-town school children for four consecutive years after the Fukushima NPP accident
Comprehensive whole-body counter surveys of Miharu town school children have
been conducted for four consecutive years, in 2011-2014. This represents the
only long-term sampling-bias-free study of its type conducted after the
Fukushima Dai-ichi accident. For the first time in 2014, a new device called
the Babyscan, which has a low Cs MDA of Bq/body, was used to
screen the children shorter than 130 cm. No child in this group was found to
have detectable level of radiocesium. Using the MDAs, upper limits of daily
intake of radiocesium were estimated for each child. For those screened with
the Babyscan, the upper intake limits were found to be <1 Bq/day for
Cs. Analysis of a questionnaire filled out by the children's parents
regarding their food and water consumption shows that the majority of Miharu
children regularly consume local and/or home-grown rice and vegetables. This
however does not increase the body burden.Comment: 11 pages, 10 figure
Hadron properties in the nuclear medium
The QCD vacuum shows the dynamical breaking of chiral symmetry. In the
hot/dense QCD medium, the chiral order parameter such as is
expected to change as function of temperature and density of the
medium, and its experimental detection is one of the main challenges in modern
hadron physics. In this article, we discuss theoretical expectations for the
in-medium hadron spectra associated with partial restoration of chiral symmetry
and the current status of experiments with an emphasis on the measurements of
properties of mesons produced in near-ground-state nuclei.Comment: 40 pages, submitted to Reviews of Modern Physic
Hyperfine structure measurements of antiprotonic helium and antihydrogen
This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of α-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may— through comparison with these theories— determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and apositron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting , which for hydrogen is one of the most accurately measuredp hysical quantities, will directly yielda precise value for , andalso compare the internal structure of proton andan tiproton through the contribution of the magnetic size of the
Spectroscopy of eta'-nucleus bound states at GSI-SIS
The eta' meson mass may be reduced due to partial restoration of chiral
symmetry. If this is the case, an eta'-nucleus system may form a nuclear bound
state. We plan to carry out a missing-mass spectroscopy with the 12C(p,d)
reaction at GSI-SIS. Peak structures corresponding to such a bound state may be
observed even in an inclusive measurement, if the decay width is narrow enough.Comment: 4 pages, 2 figures, to appear in the proceedings of MESON2012 (12th
International Workshop on Meson Production, Properties and Interaction),
Krakow, Polan
Microwave spectroscopic study of the hyperfine structure of antiprotonic helium-3
In this work we describe the latest results for the measurements of the
hyperfine structure of antiprotonic helium-3. Two out of four measurable
super-super-hyperfine SSHF transition lines of the (n,L)=(36,34) state of
antiprotonic helium-3 were observed. The measured frequencies of the individual
transitions are 11.12548(08) GHz and 11.15793(13) GHz, with an increased
precision of about 43% and 25% respectively compared to our first measurements
with antiprotonic helium-3 [S. Friedreich et al., Phys. Lett. B 700 (2011)
1--6]. They are less than 0.5 MHz higher with respect to the most recent
theoretical values, still within their estimated errors. Although the
experimental uncertainty for the difference of 0.03245(15) GHz between these
frequencies is large as compared to that of theory, its measured value also
agrees with theoretical calculations. The rates for collisions between
antiprotonic helium and helium atoms have been assessed through comparison with
simulations, resulting in an elastic collision rate of gamma_e = 3.41 +- 0.62
MHz and an inelastic collision rate of gamma_i = 0.51 +- 0.07 MHz.Comment: 15 pages, 9 figures. arXiv admin note: substantial text overlap with
arXiv:1102.528
Feasibility Study of Observing eta' Mesic Nuclei with (p,d) Reaction
A novel method is proposed to measure eta'(958) meson bound states in 11C
nuclei by missing mass spectroscopy of the 12C(p,d) reaction near the eta'
production threshold. It is shown that peak structures will be observed
experimentally in an inclusive measurement in case that the in-medium eta' mass
reduction is sufficiently large and that the decay width of eta' mesic states
is narrow enough. Such a measurement will be feasible with the intense proton
beam supplied by the SIS synchrotron at GSI combined with the good energy
resolution of the fragment separator FRS.Comment: 12 pages, 6 figures, accepted for publication in Progress of
Theoretical Physic
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