330 research outputs found
correlations from the stopped reaction on He
We have investigated correlations of coincident pairs from the
stopped reaction on He, and clearly observed and
branches of the two-nucleon absorption process in the
invariant mass spectra. In addition, non-mesonic reaction channels, which
indicate possible exotic signals for the formation of strange multibaryon
states, have been identified.Comment: 5 pages, 3 figures, submitted to Physical Review Letter
ANALYSIS OF THE EFECTS OF AN AC ELECTROMAGNETIC FIELD EXPOSURE IN MICROCIRCULATION OF HUMANS BY USING A 2D LASER SPECKLE FLOWMETRY
To date, there are only a few reports evaluating non-thermal alternating current electromagnetic exposure for medical therapeutic applications. Here, we analyzed the acute effects of hand and forearm exposure to a 50 Hz electromagnetic field (EMF; peak magnetic flux density Bmax 180 mT, Brms 127 mT, 15-min duration of exposure) on cutaneous microcirculation in 11 healthy human subjects (10 males and 1 female, age betwen 22-57 years). The blood flow volume values in the back of the hand were monitored and analyzed using a 2D laser speckle flowmetry. Regional blood flow volume values in sham control exposure were significantly reduced from baseline values during resting conditions. In contrast, the EMF exposure did not significantly decreased the blood flow volume from the baseline values during and after the EMF exposure period. There were significant differences between the EMF and sham exposure groups. Therefore, the EMF exposure significantly prevented the reduction of blood flow volume. Thus, the EMF could improve blood flow volume in cutaneous tissue under ischemic conditions. These findings imply that the physiological role of an EMF-enhanced blood circulation might help eliminate the metabolic waste products including endogenous pain producing substances inducing muscle hardness and pain
Line shape of the muH(3p - 1s) hyperfine transitions
The (3p - 1s) X-ray transition to the muonic hydrogen ground state was
measured with a high resolution crystal spectrometer. A Doppler effect
broadening of the X-ray line was established which could be attributed to
different Coulomb de-excitation steps preceding the measured transition. The
assumption of a statistical population of the hyperfine levels of the muonic
hydrogen ground state was directly confirmed by the experiment and measured
values for the hyperfine splitting can be reported. The results allow a
decisive test of advanced cascade model calculations and establish a method to
extract fundamental strong-interaction parameters from pionic hydrogen
experiments.Comment: Submitted to Physical Review Letter
Line shape analysis of the K transition in muonic hydrogen
The K transition in muonic hydrogen was measured with a
high-resolution crystal spectrometer. The spectrum is shown to be sensitive to
the ground-state hyperfine splitting, the corresponding triplet-to-singlet
ratio, and the kinetic energy distribution in the state. The hyperfine
splitting and triplet-to-singlet ratio are found to be consistent with the
values expected from theoretical and experimental investigations and,
therefore, were fixed accordingly in order to reduce the uncertainties in the
further reconstruction of the kinetic energy distribution. The presence of
high-energetic components was established and quantified in both a
phenomenological, i.e. cascade-model-free fit, and in a direct deconvolution of
the Doppler broadening based on the Bayesian approach.Comment: 22 pages, 21 figure
The VIP Experiment
The Pauli Exclusion Principle (PEP) is a basic principle of Quantum
Mechanics, and its validity has never been seriously challenged. However, given
its importance, it is very important to check it as thoroughly as possible.
Here we describe the VIP (Violation of PEP) experiment, an improved version of
the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990)
438); VIP shall be performed at the Gran Sasso underground laboratories, and
aims to test the Pauli Exclusion Principle for electrons with unprecedented
accuracy, down to Comment: 7 pages, 5 figures, PDF only, presented by Edoardo Milotti to the
conference "Quantum Theory: reconsideration of foundations-3", Vaxjo
(Sweden), June, 6-11 200
A New Measurement of Kaonic Hydrogen X rays
The system at threshold is a sensitive testing ground for low
energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we
have measured the -series x rays of kaonic hydrogen atoms at the DANE
electron-positron collider of Laboratori Nazionali di Frascati, and have
determined the most precise values of the strong-interaction energy-level shift
and width of the atomic state. As x-ray detectors, we used large-area
silicon drift detectors having excellent energy and timing resolution, which
were developed especially for the SIDDHARTA experiment. The shift and width
were determined to be eV and
eV, respectively. The new
values will provide vital constraints on the theoretical description of the
low-energy interaction.Comment: 5 figures, submitted to Physics Letters
High sensitivity tests of the Pauli Exclusion Principle with VIP2
The Pauli Exclusion Principle is one of the most fundamental rules of nature
and represents a pillar of modern physics. According to many observations the
Pauli Exclusion Principle must be extremely well fulfilled. Nevertheless,
numerous experimental investigations were performed to search for a small
violation of this principle. The VIP experiment at the Gran Sasso underground
laboratory searched for Pauli-forbidden X-ray transitions in copper atoms using
the Ramberg-Snow method and obtained the best limit so far. The follow-up
experiment VIP2 is designed to reach even higher sensitivity. It aims to
improve the limit by VIP by orders of magnitude. The experimental method,
comparison of different PEP tests based on different assumptions and the
developments for VIP2 are presented.Comment: 6 pages, 3 figures, Proceedings DISCRETE2014 Conferenc
Precision X-ray spectroscopy of kaonic atoms as a probe of low-energy kaon-nucleus interaction
In the exotic atoms where one atomic electron is replaced by a ,
the strong interaction between the and the nucleus introduces an energy
shift and broadening of the low-lying kaonic atomic levels which are determined
by only the electromagnetic interaction. By performing X-ray spectroscopy for
Z=1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the
shift and width for the state of and the state of kaonic
helium-3 and kaonic helium-4. These results provided unique information of the
kaon-nucleus interaction in the low energy limit.Comment: 4 pages, 1 figure, proceedings for oral presentation at the ICNFP2015
conference, Kolymbari, Cret
- …