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1.
Johann Zmeskal 《Progress in Particle and Nuclear Physics》2008,61(2):512-550
Strong interaction processes were intensively studied at low energy with exotic atoms, touching one of the fundamental problems in hadron physic today — the still unsolved question of how hadron masses are generated. The question of the origin of the large hadron masses made up of light quarks, the current mass of the up (u) and down (d) quarks (mu,d≈5 MeV) is two orders of magnitude smaller than a typical hadron mass of about 1 GeV, will be discussed in the context with the experimental work done in the field of exotic atoms expanded to exotic nuclei.An overview of the properties of exotic hydrogen atoms made of pions and kaons are presented, using high precision experiments unrevealing the nature of strong interaction physics at low energy. A new field which contributes to the understanding of the origin of the large hadron mass is the study of the mass modification in a nuclear medium. Antikaon mediated bound nuclear systems would be an ideal tool, if they exist, to look for chiral restoration at high density and zero temperature or even more exotic to look for phase transitions. 相似文献
2.
M. Iwasaki H. Bhang J. Chiba S. Choi Y. Fukuda T. Hanaki R.S. Hayano M. Iio T. Ishikawa S. Ishimoto T. Ishiwatari K. Itahashi M. Iwai P. Kienle J.H. Kim Y. Matsuda H. Ohnishi S. Okada H. Outa M. Sato S. Suzuki T. Suzuki D. Tomono E. Widmann T. Yamazaki H. Yim 《Nuclear Physics A》2008,804(1-4):186-196
Very recently, we have performed a couple of experiments, KEK PS-E549/E570, for the detailed study of the strange tribaryon S0(3115) obtained in KEK PS-E471. In contrast to the previous proton spectrum, no narrow (20 MeV) peak structure was found either in the inclusive 4He(stopped K−, p) or in the semi-inclusive 4He(stopped K−, pX±) reaction channel, which is equivalent to the previous E471 event trigger condition. Detailed analysis of the present data and simulation shows that the peak, corresponding to S0(3115), has been an experimental artifact. Present analysis does not exclude the possible existence of a much wider structure. 相似文献
3.
We calculate the leading-order perturbative contribution to γp→MVp, with MV being a Φ or J/Ψ meson, in the kinematic region of large energy and scattering angle. 相似文献
4.
M. Žáková Ch. Geppert A. Herlert H.-J. Kluge R. Sánchez F. Schmidt-Kaler D. Tiedemann C. Zimmermann W. Nörtershäuser 《Hyperfine Interactions》2006,171(1-3):189-195
We propose determination of isotope shifts for radioactive beryllium isotopes using laser cooled ions in a linear radio frequency
(RF) trap. Based on these measurements, combined with precise mass shift calculations, it will be possible to extract model-independent
nuclear charge radii of 7,9,10Be and the one-neutron halo 11Be with precision better than 3%. Radioactive beryllium isotopes produced at ISOLDE and ionized with a laser ion source will
be cooled and bunched in the radio frequency quadrupole buncher of ISOLTRAP. Ion temperatures will be reduced to the mK range
by sympathetic cooling with co-trapped laser cooled ions in a specially designed two-stage linear RF trap. Resonances will
be detected via fluorescence and frequencies measured with a femtosecond frequency comb. 相似文献
5.
The experimentally measurable effects related to extra dimensional gravity in a RS-type brane world are estimated. Two options of the RS framework (with small and large curvature) are considered. It is shown that physical signals of both can be detected by the joint experiment of the CMS and TOTEM Collaborations at the LHC. 相似文献
6.
W. Westphal C. Coppi F. von Feilitzsch C. Isaila J. König W. Potzel W. Rau M. Razeti M. Stark H. Wulandari G. Angloher I. Bavykina P. Christ D. Hauff J. Ninković E. Pantic F. Petricca F. Pröbst W. Seidel L. Stodolsky M. Bauer T. Jagemann J. Jochum K. Rottler S. Scholl C. Bucci C. Cozzini S. Henry H. Kraus B. Majorovits R. McGowan V. Mikhailik A.J.B. Tolhurst Y. Ramachers 《Czechoslovak Journal of Physics》2006,56(5):535-542
The CRESST experiment is looking for non-baryonic particle dark matter via nuclear scattering in CaWO4. The simultaneous measurement of the heat and the scintillation light generated by an event in a CaWO4 single crystal is used to discriminate between electron and nuclear recoils thanks to their different light output. This
allows an efficient suppression of the electron recoil background. The set-up consists of modules with a 300 g CaWO4 crystal mounted in a reflective housing together with a light detector. The heat signal is read out using a superconducting
transition-edge sensor (TES) made of tungsten evaporated directly on to the crystal that is operated at a few mK. Currently
the second phase of the experiment is being set up at the Laboratori Nazionali del Gran Sasso in which it is planned to run
33 detector modules providing a total target mass of 10 kg. First test runs with prototype detectors have been successfully
performed.
Presented by W. Westphal at the Workshop on calculation of double-beta-decay matrix elements (MEDEX’05), Corfu, Greece, September
26–29, 2005. 相似文献
7.
Ternary and quaternary fission produced in silver and bromine nuclei have been studied withK5 nuclear emulsion exposed to 1.8 GeV/cK
− beams. The frequency of the ternary events is found to be ∼0.08 of that of the binary events produced in the same volume
of the emulsion. The range ratio and range distribution of the fission fragments are studied and the angles between each pair
of the fragments are determined. Ranges are found to vary from 5 to 40μ with a maximum number lying between 5 and 10μ. The angles between the fission fragments are found to form a broad distribution extending from 40° to 180°. A few of the
events have also been analysed to give them a possible identity. A possible case of quaternary fission has also been reported.
This paper was presented at the Symposium on 3rd High Energy Physics held at Bhubaneswar during November 1976. 相似文献
8.
The study of nuclear decay modes reveals a large panel of nuclear structure phenomena and allows us to investigate the behaviour of the atomic nucleus with an extreme imbalance of the number of neutrons and protons with respect to stable nuclei. In the present paper, we review certain aspects of β-delayed decay modes, of one- and two-proton radioactivity, and of the experimental techniques which allowed us to get deep insights into the organisation of the atomic nucleus. In most cases, the study of these decay modes is the only means to obtain the information searched for. The investigation of nuclear decay modes is shown to be a powerful tool to study the most proton-rich nuclei and their nuclear structure. 相似文献
9.
G. Lévai J. Cseh P. Van Isacker 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):305-308
A supersymmetry scheme is proposed for nuclear cluster systems. The bosonic sector of the superalgebra describes the relative
motion of the clusters, while its fermionic sector is associated with their internal structure. An example of core + α configurations
is discussed in which the core is a p-shell nucleus and the underlying superalgebra is U(4|12). The α-cluster states of the nuclei 20Ne and 19F are analyzed and correlations between their spectra, electric quadrupole transitions, and one-nucleon transfer reactions
are interpreted in terms of U(4|12) supersymmetry.
Received: 14 September 2001 / Accepted: 26 October 2001 相似文献
10.
The cluster state is an indispensable resource for one-way quantum computing (1WQC). We propose a practical scheme for constructing cluster states among nuclear spins in nitrogen-vacancy defect centres (NV centres) in different diamonds. The entanglement of nuclear spins within an NV centre is made by hyperfine coupling via electron spin, and the entanglement between remote NV centres is accomplished using the parity projection of emitted photons. We discus the possibility to build large-scale nuclear-spin cluster states with diamonds. 相似文献
11.
S. P. Tretyakova 《Radiation measurements》1995,25(1-4):279-282
The last results of studying radioactive decay of heavy nuclei 232Th, 236U, 236Pu and 242Cm using different dielectric detector types and methods of their development have presented. 相似文献
12.
Beyond mean field approach to the beta decay of medium mass nuclei relevant for nuclear astrophysics
The Gamow-Teller strength distributions for the β decay of the ground state as well as the lowest excited states of the rp-process waiting point nuclei 68Se and 72Kr are obtained within the complex Excited Vampir variational approach using realistic effective interactions and a rather large model space. The shape mixing is consistently described for both the states in the even-even parent and the states in the odd-odd daugther nucleus. The influence of the shape mixing accounted by the different effective interactions used and comparison with the available data are presented. The possible influence of the decay of the lowest excited states of the parent nuclei in the astrophysical environment of X-ray bursts is discussed.Gamow-Teller strength distributions, β-decay half-lives, and β-delayed neutron emission probabilities for neutron-rich Zr nuclei are investigated for the first time within the complex Excited Vampir approach using a large model space. Comparison with available data and predictions relevant for the astrophysical r process are presented. 相似文献
13.
M. Aliotta 《The European physical journal. Special topics》2007,150(1):201-206
Reactions involving unstable nuclei play an important role in many astrophysical sites. Radioactive ion beams provide a unique
tool to investigate the structure of such unstable nuclei as well as the cross sections for many reactions of astrophysical
relevance. This paper provides a brief survey of some recent results in experimental nuclear astrophysics with Radioactive
Ion Beams, particularly for processes which take place during explosive hydrogen burning in novae and X-ray bursts. Some prospects
for future studies at next generation facilities are also briefly discussed. 相似文献
14.
L Satpathy 《Pramana》1989,32(4):319-330
The ground-state energy of an atomic nucleus with asymmetryβ is considered to be equivalent to the energy of a perfect sphere made up of the infinite nuclear matter of the same asymmetry
plus a residual energyη called the local energy,η represents the energy due to shell, deformation, diffuseness and exchange Coulomb effect etc. Using this picture and the
generalized Hugenholtz- Van Hove theorem of many-body theory a new mass formula has been developed. Based on this, a mass
table containing the mass excesses of 3481 nuclei in the range 18 ⩽A ⩽ 267 has been made. This mass formula is compared with other mass models. 相似文献
15.
J S Yadav A P Sharma G N Flerov V O Perelygin S G Stetsenko P Pellas C Perron R Antanasijevich B Jakupi Y Todorovich 《Pramana》1983,20(4):287-292
A study is made for the search of superheavy nuclei in Marjalahti, Eagle Station and in other pallasite olivines. The olivine
crystals are calibrated for heavy ion track lengths by using heavy ion beams from cyclotrons. The calibration for ultra heavy
ions which are presently not available with sufficient energy to produce volume tracks in olivine crystals, is based on Katz
and Kobetich model of track formation. The length spectrum of volume tracks, revealed by puncturing them with focussed Nd-glass
laser beam, is measured and the abundances of different nuclei groups are calculated. Partial annealing has been used at 430°C
for 32 hr which eliminates the interfering tracks due to nuclei of atomic numberS ≤ 50. During the scanning 4 cm3 olivine crystals, about 360 long tracks of uranium group as well as two very long tracks have been found. If these tracks
belong to superheavy nuclei, the relative abundance of super heavies is found to be 6 × 10−11 in galactic cosmic rays. 相似文献
16.
17.
The expressions for baryon number violating nuclear partial decay widths are derived from the interactions as predicted by
grand unified theories. Theory predicts that the baryon number violating proton decay inside the nucleus is hindered relative
to the free proton decay rate. In the case of closed shell nuclei, the meson spin-isospin dependence of the partial width
is the same as that for the nucleon decay. The branching ratios of decay amplitudes depend on the nuclear binding energies.
Nuclear structure introduces lepton energy spread of ±49.5 MeV for light closed shell nuclei, while it does not affect the
back to back emission of lepton-meson pair. 相似文献
18.
V M Strutinsky 《Pramana》1989,33(1):21-32
Some new aspects in the theory of heavy nuclei emerging from studies of nuclear shell structure in the nuclear-fission process
are described. Specific subjects cover general understanding of shell structure, the significance of macroscopic modes and
the droplet model. 相似文献
19.
Quantifying larval infestation with an acoustical sensor array and cluster analysis of cross-correlation outputs 总被引:2,自引:0,他引:2
An automated, computer-based system was designed to quantify infestation of internally feeding larvae in a grain sample by obtaining data correlated with the location of sound sources. Information related to the relative arrival times of insect feeding sounds to an array of acoustic sensors is obtained despite the low signal to noise ratios and the differential distortion induced by sound propagation through the non-uniform grain medium to the different sensors. This is achieved by employing parallel acquisition of all sensor outputs and cross-correlation analyses of all adjacent sensor pairs in the vicinity of the sensor with the largest signal. The peak location times of the resulting cross-correlograms cluster together for multiple sounds produced by the same insect but otherwise are more broadly distributed. A cluster analysis algorithm was developed to group sounds with similar ‘fingerprints’ (i.e. patterns of peak locations across several cross-correlograms). Each sufficiently large group of matching sounds indicates the presence of an insect. 相似文献
20.
In a high-temperature approximation, theoretical consideration is given to dynamic polarization of nuclei within the framework
of the EPR spin-temperature concept. We show that the maximum polarization of nuclei can be attained at a certain value of
the detuning of an SHF-field if the intensity of the latter is fixed. The possibility of determining some relaxation parameters
of the system by the value of this detuning at a high value of the saturating field is shown. In the presence of a trial field,
the effect of a nuclear Zeeman subsystem on the time of transverse relaxation T2 is evaluated.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 404–406, May–June, 2000. 相似文献