Effect of selenite on 86Rb uptake by rat lens
The effect was observed in vitro of selenite on the uptake of 86Rb by the lens in two weeks old and adult rats. Also measured was the uptake of 86Rb by the lens in vitro in 30-days old rats with cataracts induced by the administration of selenite at day 14 after birth and in control animals of the same age. Selenite in a concentration of 0.4 mM and more caused an insignificant decrease in 86Rb uptake by the lens in adult rats while in the lens of young rats the uptake decreased significantly already at concentrations lower by two orders. Lenses with cataracts took up significantly less 86Rb than transparent lenses; body weight, the weight of the fresh lens and its dry mass decreased while the water content in the lens was higher as compared with control groups. (author). 2 tabs., 26 refs
Vectorial (transcellular) transport of potassium (86Rb+) by cultured Sertoli cells
Sertoli cells from rats aged 25 days were grown on Millipore filters (pore diameter 0.5 micron) for 7 days and were then used for determination of transport of 86Rb+ through the cells (base to apex); this procedure is referred to as measuring transcellular or vectorial transport. Sertoli cells were also used to measure apical efflux of 86Rb+ by loading the cells with the isotope to steady state and then incubating cells so that the apical surfaces were in contact with medium not containing 86Rb+, from which samples were taken. Basal efflux was measured in the same way except that the opposite surface of the cells was in contact with the medium. Cells grown on filters treated with collagen IV plus fibronectin showed transcellular transport of 86Rb+; t1/2 for equilibration across the cells was 9-12 min. The rate of transport was accelerated by addition of (Bu)2cAMP, forskolin, or FSH to the incubation medium. Half-maximal responses were seen with (Bu)2cAMP at 0.2 mM and with forskolin at 20 microM. Apical efflux (t1/2 9.8 +/- 2.1 min) was not influenced by the presence or absence of K+ in the medium nor by azide or (Bu)2cAMP. Basal efflux showed similar values for t1/2 in the presence of K+ (9.7 +/- 1.9 min) and values of 21.4 +/- 4.2 min in the absence of K+. Vectorial transport of 86Rb+ by these cells may account for the K+ gradient seen in the seminiferous tubule and appears to result from a basolateral potassium pump together with an apical membrane that is permeable to K+
Release of 86Rb from rat submandibular gland slices: relation to sodium pump activity
Slices of rat submandibular gland were preloaded with 86Rb, an isotope that can substitute for K+ in the K+ release process. The efflux of 86Rb was monitored in a superfusion apparatus that efficiently removed the 86Rb as it exited from the tissue slices. Carbachol and the calcium ionophore A23187 activated a calcium-dependent increase in 86Rb efflux. Dibutyryl cGMP had no detectable effect on 86Rb efflux in contrast to its activation of ouabain-sensitive uptake of 86Rb observed in an earlier study. The stimulated release of 86Rb was not dependent on the presence of either sodium or chloride ion. When 86Rb efflux was stimulated by carbachol, the efflux rate returned toward the basal rate after a few minutes of exposure to carbachol in the medium. If ouabain was then introduced into the superfusate, a large increase in efflux was stimulated. In the absence of carbachol, only a small increase in 86Rb efflux was stimulated by ouabain. The effect of ouabain indicates that there was a substantial recycling of 86Rb between the release and uptake processes in the extracellular space of the tissue slice. The significance of this observation is discussed
Loss of receptor-mediated 86Rb efflux from pig aortic endothelial cells in culture.
Ager, A.; Martin, W
1983-01-01
The responsiveness of freshly-isolated and subcultured pig aortic endothelial cells to adenosine triphosphate (ATP), bradykinin and ionophore A23187 was compared by monitoring agonist-induced 86Rb efflux. ATP, bradykinin and ionophore A23187 stimulated 86Rb efflux from freshly-isolated cells. ATP and bradykinin, which act via specific receptors, were less effective at inducing 86Rb efflux from subcultured cells but ionophore A23187 was as effective on subcultured as on freshly-isolated cells....
86Rb Distribution in the Lung of the Rabbit with Pneumothorax
86Rb uptake of some organs and tissues, eg. both lungs, both renal cortices. small intestine, liver and skeletal muscle were studied in the control and the rabbit subjected to pneumothorax. 86Rb in the form of chloride mixed with physiological saline was intravenously injected. The doses were 100 μc for a rabbit. The rabbits were sacrificed at intervals of 10, 20, 40, and 60 seconds after the injection of 86Rb, by the injection of saturated KCI solution. After scarification, the organ and tissue sample were quickly removed. 86Rb uptake in gm of the organs and tissues were measured. On the basis of uptake value, administered doses and body weight, % dose/gm tissues per 200 gm body weight was calculated. Followings were the results: 1. Pneumothorax resulted in a marked elevation in 86Rb uptake value of collapsed lung and returned to normal level lately. 2. Contralateral lung of pneumothorax also showed marked elevation in 86Rb uptake value and recovered to normal level. 3. Initial 86Rb uptake value of liver, small intestine of the rabbit with pneumothorax showed some elevation as compared to control, but that of late stage were similar with control. 4. Local blood flow determination by means of 86Rb uptake were inadequate in the collapsed lung of pneumothorax. 5. It was suggested that the mechanism for the initial elevation of 86Rb uptake value in each organs and tissue were different from each other.
Leiurus quinquestriatus venom inhibits BRL 34915-induced 86Rb+ efflux from the rat portal vein
The effect of the crude venom of the Israeli scorpion Leiurus quinquestriatus hebraeus on the 86Rb+ efflux stimulated by the K+ channel opener BRL 34915 in the rat portal vein was examined. Applied alone, the venom greatly increased the spontaneous mechanical activity of and the concomitant 86Rb+ efflux from the vessel. When the excitability of the vein was suppressed by the dihydropyridine calcium antagonist, PN 200-110, the 86Rb+ efflux stimulated by BRL 34915 could be shown to be inhibited by the venom. From the concentration dependence of this inhibition an IC50 value of 0.17 +/- 0.01 mg/ml was estimated. This venom is thus the most potent blocker of BRL 34915-evoked 86Rb+ efflux reported so far. 17 references, 2 figures
The uptake of 86Rb+ into photoautotrophic mesophyll cells of Papaver somniferum
Uptake of 86Rb+, used as a tracer for potassium, into isolated photoautotrophic mesophyll cells of Papaver somniferum was weakly but consistently stimulated in the light. It showed mono-phasic saturation kinetics with a pH optimum of 7.0, a Vsub(max) of 6.7 μmol mg-1 Chl x h-1 and a Ksub(m) of 2.7 mmol l-1. Different anions as Cl-, NO3- and PO43- had no effects on 86Rb+ uptake. Sodium ions influenced Rb+-uptake very weakly, indicating a high K+ -specificity of the mesophyll cell plasmalemma. Fusicoccin stimulated 86Rb+ -uptake strongly whereas abscisic acid inhibited uptake only following preincubation for two hours. Nitrite, CCCP and Dio-9 inhibited 86Rb+-uptake which gives evidence that this process is dependent on intact pH-gradients within the cells and on ATP-formation. (orig.)
Inhibition of white light of 86Rb+ absorption in the root apex of corn
Measurements of cell lengths made at 0.5 millimeter intervals in median longitudinal sections of the primary roots of corn (Zea mays) were used to construct a growth curve. The region 1.5 to 4.0 millimeters from the apex contained the largest number of elongating cells. Absorption of 86Rb+ was measured using intact, dark-grown corn seedlings. Following uptake and exchange, the terminal 8.0 millimeters of each root was cut into four 2.0 millimeter segments. Maximum 86Rb+ uptake occurred in the region from 0.0 to 4.0 millimeter from the root tip. Washing the intact primary root in fresh 2.0 millimolar CaSO4 for 2 hours prior to uptake augmented the rate of 86Rb+ uptake in all regions. Illumination with white light during washing caused a reduction of 86Rb+ uptake as compared with controls washing in darkness, and the region of greatest light response was the region of elongation. Removal of the coleoptile prior to washing did not prevent the light inhibition of subsequent 86Rb+ uptake. Removal of the root cap prior to washing in light partially reversed the light-induced inhibition of the washing response
Environmental effects on energy metabolism and 86Rb elimination rates of fishes
Relationships between energy metabolism and the turnover rates of number of important chemical and radiological elements (particularly the Group IA alkali metals: K, Rb, and Cs) have been observed in fishes. Using response surface statistics and fractional factorial ANOVA, the author examined the relative influences of temperature, salinity, food intake rate, mass, and their first order interactions on routine energy metabolism and 86Rb elimination rates. Routine metabolic rates were increased primarily by increased temperature and salinity, with a strong body mass effect and a significant effect of food intake. 86Rb elimination rates were increased primarily by increased temperature and salinity. There were no interactive effects between mass and either temperature or salinity for either routine energy metabolism or 86Rb elimination rates. There was a significant interaction effect between temperature and salinity on routine energy metabolism rates, but not on 86Rb elimination. The authors also observed a relationship between routine energy metabolism and 86Rb elimination rates that may possibly be exploited as a means of estimating energy metabolic rates of fishes in the field. The statistical techniques used in this experiment have broad potential applications in assessing the contributions of combinations of environmental variables on contaminant kinetics, as well as in multiple toxicity testing, in that they greatly simplify experimental designs compared with traditional full-factorial methods
Transport of 86Rb+ in corn leaves as influenced by some growth substances
The transport of 86Rb+ supplied to the middle of young corn leaves was scanned by means of a modified chromatogram scanner and it was found that the movement towards the base was larger than to the apex of both intact and excised leaves. Application of 25 ppm of ABA (abscisic acid) or ethrel (2-chloroethane phosphonic acid) did not affect the pattern of transport. However, the growth substances tested, viz, ABA, ethrel, GA3 and IAA generally enhanced the rate of 86Rb+ transport towards the base of the leaf. (orig.)
Leakage of 86Rb+ after ultraviolet irradiation of Escherichia coli K-12
Stationary phase cultures of a DNA repair proficient Escherichia coli K-12 strain showed a release of intracellular material as assessed by three different methods (260 nm absorption; (methyl-3H) thymidine leakage and 86Rb+ leakage) after broad-band near-UV radiation but not after far-UV (254 nm) radiation. As a control response for membrane damage to cells, this leakage of intracellular material was also determined by each method after mild heat (520C) treatment of E. coli K-12. An action spectrum for the release of 86Rb+ from E. coli K-12 after monochromatic irradiation (254 to 405 nm) is also presented. The action spectrum for lethality (F37 values) shows that leakage of 86Rb+ occurs at fluences around those causing inactivation at wavelengths above 305 nm. In contrast, at wavelengths below 305 nm, leakage of 86Rb+ from irradiated cells can be induced but only at fluences significantly greater than was required to cause cell inactivation. These results indicate that near-UV radiation can damage the cell's permeability barrier which may be significant in causing cell death, whereas the effect is not significant in causing cell death by far-UV radiation where DNA is known to be the main cause of lethality. (author)
Effects of the K+ channel blocking agent, glyburide, on the actions of two K+ channel openers, BRL 34915 (cromakalim) and P 1060 (Leo), a potent pinacidil derivative (N-(t-butyl)-N double-prime-cyano-N'-3-pyridyl-guanidine), were ascertained. Tension responses and 86Rb fluxes in rat portal vein strips and single channel electrophysiological recordings in enzymatically dissociated rat portal vein cells were obtained. Glyburide (0.3 microM) increased spontaneous contractile activity and caused concentration-dependent shifts in the relaxation responses to BRL 34915 and P 1060. Increases in 86Rb efflux were obtained only at much higher concentrations of BRL 34915 or P 1060, and these increases were blocked only at higher concentrations of glyburide (5.0 microM). BRL 34915 and P 1060 specifically increase the open-state probability of the Ca+(+)-activated K+ (maxi-K+) channel, and these actions are blocked by glyburide and also by charybdotoxin. Changes in single channel activity and contractile responsiveness occur at similar concentrations of agonists and antagonists. Thus, the membrane channel in rat portal vein affected by glyburide, BRL 34915 and P 1060 appears to be the Ca+(+)-activated maxi-K+ channel (that does not show ATP dependence under the conditions of these experiments). Concentrations of agonists and antagonists effective on maxi-K+ channel activity correspond to those affecting contractile responsiveness and are lower than those eliciting changes in 86Rb flux
This study was carried out to know the uptake pattern of phosphorous and potassium in rice plants using by two radioisotopes, 32P and 86Rb as tracers for two years, 1987 and 1988. Rice plants were grown in the hydroponic culture with Yoshida's solution, and treated with different temperatures, transpiration suppress, shading, and phosphorous and potassium deletions. The uptake amount of 32P and 86Rb were increased with the increasing temperature in root sphere of rice plant, particularly remarkable increase of 86Rb uptake at 35deg C. The uptake of 32P tended to be promoted at the treatment of low air-high water temperature (17-30deg C), while that of 86Rb was not significantly differenced from different temperature treatments. The effect of transpiration on the uptake of 32P and 86Rb was extremely low. This phenomenon may suggest that the absorption be depending on active uptake rather than passive one by transpiration stream. The total carbohydrate contents of rice root were decreased by shading treatment, resulting significant reduction in the uptake of 32P and 86Rb. The uptake of 86Rb was remarkably increased in the treatment of potassium deletion, but that of 32P was not significantly increased in the delection of phosphorous
Burn-up cross sections of 51Cr, 59Fe, 65Zn, 86Rb, 103Ru
Targets of Cr, Fe, Zn, Rb, and Ru were irradiated in the hydraulic tube of the Oak Ridge HFIR reactor at a neutron flux of 2.6 x 1015 n/cm2sec for 1 day and 20 days. The reactor burn-up cross sections (in barns) of the radioactive product nuclides are: 51Cr, 59Fe, 65Zn, 60 +- 30; 86Rb, 103Ru, <20
We investigate here the hypothesis that the high Ca content of sickle cell anemia (SS) red cells may produce a sustained activation of the Ca2+-dependent K+ permeability (Gardos effect) and that the particularly high Ca levels in the dense SS cell fraction rich in irreversibly sickled cells (ISCs) might account for the Na pump inhibition observed in these cells. We measured active and passive 86Rb+ influx (as a marker for K+) in density-fractionated SS cells before and after extraction of their excess Ca by exposure to the Ca ionophore (A23187) and ethylene glycol tetra-acetic acid and with or without adenosine triphosphate depletion or addition of quinine. None of these maneuvers revealed any evidence of a Ca2+-dependent K leak in SS discocytes or dense cells. Na pump inhibition in the dense SS cells was associated with normal activation by external K+ and a low Vmax that persisted after Ca extraction from the cells. These results are consistent with our recent findings that the excess Ca in these cells is compartmentalized in intracellular inside-out vesicles and unavailable as free Ca2+ to the inner membrane surface. Although the steady-state free cytoplasmic Ca2+ in oxygenated SS cells must be below the levels needed to activate the K+ channel, possible brief activation of the channels of some SS cells resulting from transient elevations of cell Ca2+ during deoxygenation-induced sickling cannot be excluded. The dense, ISC-rich SS cell fraction showed a Ca2+-independent increase in the ouabain-resistant, nonsaturable component of 86Rb+ influx that, if uncompensated by Na+ gain, could contribute to the dehydration of these cells
Effects of two K+ channel openers, cromakalim and pinacidil, on mechanical activity and on 86Rb efflux were compared in strips of dog coronary arteries. Cromakalim and pinacidil produced the relaxation in 20.9 mM K(+)-contracted strips with a pD2 of 6.53 and 5.95, respectively. In 65.9 mM K(+)-contracted strips, high concentrations of pinacidil, but not cromakalim, produced relaxation. Ca+(+)-induced contractions in 80 mM K(+)-depolarized strips were also inhibited by pinacidil but not by cromakalim. Glibenclamide, a blocker of ATP-regulated K+ (KATP) channels, competitively antagonized the relaxant responses to cromakalim with a pA2 value of 7.62. However, the antagonism by glibenclamide of the relaxant responses to pinacidil was not a typical competitive type, suggesting the contribution of other effects than the KATP channel opening activity to the relaxant effects of pinacidil. In resting strips preloaded with 86Rb, cromakalim and pinacidil increased the basal 86Rb efflux in a dose-dependent manner. The increase in the 86Rb efflux induced by cromakalim was greater than that by pinacidil. When the effects of cromakalim and pinacidil on the 86Rb efflux were determined in the 20.9 or 65.9 mM K(+)-contracted strips, both drugs increased the 86Rb efflux. Under the same conditions nifedipine, a Ca(+)+ channel blocker, produced the relaxation that is accompanied by the decrease in 86Rb efflux. The increase in the 86Rb efflux induced by cromakalim was much greater than that by pinacidil
Ba2+-inhibitable 86Rb+ fluxes across membranes of vesicles from toad urinary bladder
86Rb+ fluxes have been measured in suspensions of vesicles prepared from the epithelium of toad urinary bladder. A readily measurable barium-sensitive, ouabain-insensitive component has been identified; the concentration of external Ba2+ required for half-maximal inhibition was 0.6 mM. The effects of externally added cations on 86Rb+ influx and efflux have established that this pathway is conductive, with a selectivity for K+, Rb+ and Cs+ over Na+ and Li+. The Rb+ uptake is inversely dependent on external pH, but not significantly affected by internal Ca2+ or external amiloride, quinine, quinidine or lidocaine. It is likely, albeit not yet certain, that the conductive Rb+ pathway is incorporated in basolateral vesicles oriented right-side-out. It is also not yet clear whether this pathway comprises the principle basolateral K+ channel in vivo, and that its properties have been unchanged during the preparative procedures. Subject to these caveats, the data suggest that the inhibition by quinidine of Na+ transport across toad bladder does not arise primarily from membrane depolarization produced by a direct blockage of the basolateral channels. It now seems more likely that the quinidine-induced elevation of intracellular Ca2+ activity directly blocks apical Na+ entry
de-Allie, F. A.; Bolsover, S. R.; Nowicky, A. V.; Strong, P N
1996-01-01
1. The pharmacological characteristics of a putative Ca2+ activated K+ channel (IKCa channel) in rat glioma C6 cells were studied in the presence of the Ca2+ ionophore, ionomycin and various K+ channel blockers, 86Rb+ being used as a radioisotopic tracer for K+. 2. The resting 86Rb+ influx into C6 cells was 318 +/- 20 pmol s-1. The threshold for ionomycin activation of 86Rb+ influx was approx. 100 nM. At ionomycin concentrations above the activation threshold, the initial rate of 86Rb+ influx...
Erythrocyte sodium concentration and 86Rb uptake in weanling Dahl rats
Alterations in Na, K ATPase pump activity as well as erythrocyte (RBC) intracellular sodium concentration (Nai) have been demonstrated in humans and rats with established hypertension. The contribution of hypertension itself to these changes is unclear. Accordingly, we investigated RBC ion transport and plasma ouabain-like factor (OLF) in four- to five-week old normotensive Dahl salt-sensitive (DS) and salt-resistant (DR) rats on low salt diet. Although both strains were normotensive, systolic blood pressure (SBP) of DS (123 ± 2 mm Hg) was higher than that of DR (116 ± 1 mm Hg). No interstrain difference was evident in RBC pump activity measured as ouabain-sensitive 86rubidium (86Rb) uptake (DS = 0.277 ± .030 and DR = 0.271 ± .029 mumol/10(9)RBC/h) even though RBC Nai was greater in DS than DR (14.9 ± 2.0 v 10.7 ± 1.0 mEq/L; P less than 0.05). Plasma OLF was higher in DS than DR (28.9 ± 4.7 v 16.5 ± 2.3 pmol/mL; P less than 0.05), but did not correlate with RBC pump activity in either strain. RBC Nai was directly correlated with pump activity in DS (r = 0.84, P less than 0.01) and demonstrated a trend to correlate in DR (r = 0.71, P = 0.07). RBC Nai was also directly correlated with SBP in DR (r = 0.73, P less than 0.05) and DS (r = 0.70, P = 0.05). We conclude that RBC Nai is genetically determined in Dahl rats and is elevated in normotensive DS who are at risk for hypertension development
Review of metastable states in heavy nuclei
Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.
2016-07-01
The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.
Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86Rb+, at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86Rb+ uptake per plant in the course of a 14-day-period following inoculation; however, it affected its distribution differently in the S- and the R-plants. 86Rb+ uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86Rb+), with the ions more slowly translocated to the shoots in diseased S-plants than in diseased R-plants. Likely factors causing these effects and their relationship to alfalfa resistance to bacterial wilt are discussed. (author)
Effect of ultraviolet radiation on accumulation and leakage of 86Rb+ in guard cells of Vicia faba
The effects of UV-C (254 nm), UV-A (365 nm) and broad-band UV (280–380 nm) on guard cells of Vicia faba L. cv. Long Pod were investigated in the presence of white light (450 μmol m−2 s−1). UV-C (7 μmol m−2 s−1) was found to cause leakage of 86Rb+ from guard cells, while UV-A (0.3 μmol m−2 s−1) stimulated increased uptake in these cells. A relatively small stimulatory effect was observed by broad-band UV (3 μmol m−2 s−1) during the first 30 min of irradiation with an apparent equilibration of influx and efflux thereafter. Leakage of 86Rb+ from guard cells continued despite the removal of UV-C and an increase in the amount of white light from 450 to 1500 μmol m−2 s−1, suggesting that membranes were irreversibly damaged. Irradiation of guard cells with UV-C for 30, 45 and 90 min indicated that these cells began to be affected already by 30 min UV-C irradiation. (author)
The effect of chronic hypobaric hypoxia equivalent to a simulated high altitude of 4000 m was investigated on the Ca2+ and Rb+ uptake in vascular smooth muscle. The decline in systolic blood pressure in SHR due to hypoxia was associated with a significant decrease in 45Ca uptake and ouabain-insensitive 86Rb uptake as well as the tissue Ca2+ and K+ content. It seems likely that the reduction of the higher vascular tone in SHR by chronic hypoxia is due to the alteration of the transmembrane ion fluxes in the vascular smooth muscle cells. However, the meaning and the nature of the active and passive ion fluxes involved in this problem remains to be clarified. (author)
The effect of sodium ions on the light-induced 86Rb release from the isolated crayfish retina
The effect of low external Na+ concentrations on the light-induced K+ release from crayfish photoreceptor cells was tested by labelling intracellular K+ with the isotope 86Rb. The amount of isotope released per light, stimulus is roughly proportional to the external Na+ concentration if the osmolarity is kept constant by replacing Na+ with Tris, choline or sucrose. When sucrose is used to replace the depleted Na+ the light-induced K+ release is a linear function of the external Na+ concentration and is reduced by approx. 95% at an external Na+ concentration of 5 mmol/l. For choline and Tris substitutions the relationships are less clear but at Na+ concentrations + release is smaller in a Tris solution and larger in a choline solution. It is suggested that the light-induced K+ release is due mainly to an activation of voltage sensitive K+ channels. (orig.)
Greenhouse and laboratory studies were conducted on an acid soil in order to evaluate the role of two crop residues i.e. paddy and wheat along with farmyard manure on potassium kinetics and its availability in the potato-garlic sequence using tracer 86Rb. Under rapid equilibrium, application of crop residues of paddy, wheat straw and FYM were able to enhance soil pH and organic carbon content. In addition, their application helped in enhancing soil K availability indices like water soluble, available and non-exchangeable -K. This was further augmented by the Q/I studies using 86Rb where application of organic residues helped in lowering the potassium buffering capacity of the soil. Greenhouse study supplemented the results obtained from laboratory study where application of crop residues/FYM were able to improve the potato yield significantly and maintained higher concentration of K in potato leaf at early growth stages. A significant correlation was obtained between leaf K and haulms-K with that of 86Rb activities in potato leaf at 35 days and 86Rb absorbed in the haulms, respectively. Residues/ FYM and PK application to potato left sufficient residual effect on succeeding garlic crop. In potato-garlic sequence, K recovery was highest with FYM while N and P recoveries were higher with wheat residues. The nutrient recoveries with PK application followed law of diminishing returns. (author)
Turaihi, K.; Khokher, M.A.; Barradas, M.A.; Mikhailidis, D.P.; Dandona, P. (Royal Free Hospital and School of Medicine, London (England))
1989-08-01
Although active transport of potassium into human platelets has been demonstrated previously, there is hitherto no evidence that human platelets have an ouabain-inhibitable Na-K ATPase in their membrane. The present study demonstrates active rubidium (used as an index of potassium influx), {sup 86}Rb(K), influx into platelets, inhibitable by ouabain, and also demonstrates the presence of specific ({sup 3}H)ouabain binding by the human platelet. This {sup 86}Rb(K) influx was stimulated by adrenaline, isoprenaline, and salbutamol, but noradrenaline caused a mild inhibition. Active {sup 86}Rb(K) influx by platelets was inhibited markedly by timolol, mildly by atenolol, but not by phentolamine. Therefore, active {sup 86}Rb(K) influx in human platelets is enhanced by stimulation of beta adrenoceptors of the beta 2 subtype. The platelet may therefore replace the leukocyte in future studies of Na-K ATPase activity. This would be a considerable advantage in view of the ease and rapidity of preparation of platelets.
Andersen, G.Oe.; Enger, M.; Skomedal, T.; Osnes, J.B. [Univ. of Oslo, Dept. of Pharmacology (Norway)
1996-10-01
The aim of the present study was to establish a concentration-response relationship for the {alpha}{sub 1}-adrenoceptor mediated increase of{sup 86}Rb{sup +} efflux, and to characterize the sensitivity of this response to the selective {alpha}{sub 1}-adrenoceptor antagonist prazosin. Isolated rat hearts were perfused retrogradely at constant flow and at 31 deg. Timolol (10{sup -}26 mol/l) was used to block {beta}-adrenoceptors. After a loading period with {sup 86}Rb{sup +} and 55 min. washout, the hearts were exposed to phenylephrine in a concentration range from 3x10{sup -8} mol/l to 10{sup -4} mol/l. Control experiments comparing the effects of {alpha}{sub 1}-adrenoceptor stimulation on {sup 86}Rb{sup +} efflux and {sup 42}K{sup +} efflux were performed. {alpha}{sub 1}-Adrenoceptor stimulation increased the {sup 86}Rb{sup +} efflux with a pD{sub 2}=6.35{+-}0.20 (mean{+-}S.E.M.) The maximal response to phenylephrine was 22.5{+-}2.0% (mean{+-}S.E.M.) of the control values. The concentration-response curve was shifted to higher concentration of agonist in the presence of the {alpha}{sub 1}-adrenoceptor antagonist prazosin (3x10{sup -10} mol/l). The calculated inhibition constant for prazosin was 6.1x10{sup -11} mol/l. {sup 86}Rb{sup +} was found to be a suitable K{sup +} analogue in the study of relative changes in K{sup +} efflux concentration-dependently. A high sensitivity to prazosin confirmed the involvement of the {alpha}{sub 1}-adrenoceptor population. (au) 37 refs.
Neutron reactions with nuclei in isomeric states
The authors give theoretical calculation results for the cross-sections of reactions (n,n'γ) and (n,2n) with high-spin target nuclei in the excited state. It is shown that an increase in the target nucleus excitation energy shifts the cross-section curve to the left along the energy axis, while an increase in the ground state spin considerably reduces the (n,2n) reaction cross-section in the threshold region of the reaction. In the authors' opinion, this change in the excitation functions is due to a sharp rise in the role of gamma competition because of the effect of the spin conservation law on neutron emission. (author)
Transitions between compound states of spherical nuclei
Wigner's statistical matrices are used to study the average reduced g widths and their dispersion for g transitions from a compound state c to another state f, with a lower excitation energy but of arbitrary complexity, for spherical nuclei. It is found that the Porter--Thomas distribution holds for the g widths for all cases of practical interest. In g transitions between compound states c and c' with E/sub g/< or =2 MeV, the most important transitions are M1 transitions involving the major many-quasiparticle components of state c and E1 transitions involving the minor components of state c. It is shown that the strength functions predicted by the various theories for M1 and E1 transitions between compound states with E/sub g/< or =2 MeV are similar. Preference is assigned to the M1-transition version because of experimental results on (n,ga) reactions with thermal and resonance neutrons
Ground State Properties of Neutron Magic Nuclei
Saxena, G
2016-01-01
A systematic study of the ground state properties of the entire chains of even even neutron magic nuclei represented by isotones of traditional neutron magic numbers N = 8, 20, 40, 50, 82 and 126 has been carried out using relativistic mean field (rmf) plus Bardeen Cooper Schrieffer (BCS) approach. Our present investigation includes deformation, binding energy, two proton separation energy, single particle energy, rms radii along with proton and neutron density profiles, etc. Several of these results are compared with the results calculated using non relativistic approach (Skyrme Hartree Fock method) along with available experimental data and indeed they are found with excellent agreement. In addition, the possible locations of the proton and neutron drip lines, the (Z,N) values for the new shell closures, disappearance of traditional shell closures as suggested by the detailed analyzes of results are also discussed in detail.
Density Functional Theory studies of cluster states in nuclei
Ebran, J P; Niksic, T; Vretenar, D
2014-01-01
The framework of nuclear energy density functionals is applied to a study of the formation and evolution of cluster states in nuclei. The relativistic functional DD-ME2 is used in triaxial and reflection-asymmetric relativistic Hartree-Bogoliubov calculations of relatively light $N = Z$ and neutron-rich nuclei. The role of deformation and degeneracy of single-nucleon states in the formation of clusters is analysed, and interesting cluster structures are predicted in excited configurations of Be, C, O, Ne, Mg, Si, S, Ar and Ca $N = Z$ nuclei. Cluster phenomena in neutron-rich nuclei are discussed, and it is shown that in neutron-rich Be and C nuclei cluster states occur as a result of molecular bonding of $\\alpha$-particles by the excess neutrons, and also that proton covalent bonding can occur in $^{10}$C.
Minkov N.
2016-01-01
Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.
Study of fp States in Nuclei with High Neutron Excess
2002-01-01
Previous results obtained at ISOLDE on GT transitions in n-rich Na and Mg nuclei have shown the sharp decrease of excitation energy for fp states when A$>$29. \\\\ \\\\ Independently, shell model calculations have revealed that the onset of a deformation region near N=20 for Ne, Na and Mg nuclei was related to a sudden transition in the ground state properties with the appearance of a major (sd)$^{-2}$(fp)$^2$ component. \\\\ \\\\ We propose to use the new possibilities of producing and detecting n-rich nuclei to study by $\\gamma$ and n spectroscopy the properties of fp states with different cores: around N=20 (Na, Mg and Al) and N=28 (Ar, K and Ca). In particular, the cases of $^3
Coupled cluster calculations of ground and excited states of nuclei
The standard and renormalized coupled cluster methods with singles, doubles, and noniterative triples and their generalizations to excited states, based on the equation of motion coupled cluster approach, are applied to the He4 and O16 nuclei. A comparison of coupled cluster results with the results of the exact diagonalization of the Hamiltonian in the same model space shows that the quantum chemistry inspired coupled cluster approximations provide an excellent description of ground and excited states of nuclei. The bulk of the correlation effects is obtained at the coupled cluster singles and doubles level. Triples, treated noniteratively, provide the virtually exact description
Structure of superdeformed states in Au-Ra nuclei
Energies of superdeformed states in nuclei around 192Hg are calculated using the Strutinsky shell correction method with an average Woods-Saxon potential and a monopole pairing force. The influence of various terms in the model hamiltonian on the excitation energy of the superdeformed minimum is analysed. The systematics of calculated excitation energies of shape-isomeric minima and barrier heights in even-even Hg-Ra nuclei are given together with predictions for one-quasiparticle band-head energies in odd-A Au, Hg, Tl, Pb and Bi nuclei. Possible occurrence of hyperdeformed states in very neutron-deficient Po-Ra isotopes is investigated. It is shown that the presence of these exotic configurations is strongly related to the magnitude of pairing correlations at strongly elongated shapes. Finally, the role played by reflection-asymmetric deformations at superdeformed shapes is discussed. (orig.)
Rotational states in deformed nuclei: An analytic approach
Bentz, W; Enders, J; Richter, A; Wambach, J
2011-01-01
The consequences of the spontaneous breaking of rotational symmetry are investigated in a field theory model for deformed nuclei, based on simple separable interactions. The crucial role of the Ward-Takahashi identities to describe the rotational states is emphasized. We show explicitly how the rotor picture emerges from the isoscalar Goldstone modes, and how the two-rotor model emerges from the isovector scissors modes. As an application of the formalism, we discuss the M1 sum rules in deformed nuclei, and make connection to empirical information.
Deeply bound kaonic states in nuclei
LI Yi-He; WU Shi-Shu
2009-01-01
Using a new phenomenological (K)N interaction which reproduces A(1405) as an I = 0 bound state of (K)N, we have investigated K- -3 He(T = 0) and K- -4 He(T = 1/2) within the framework of the Brueckner-Hartree-Fock(BHF) theory. Our calculations show that the above kaonic nuclear systems are both deeply bound. The binding energy BK- is 124.4 MeV(94.1 MeV) and the width Γ is 11.8 MeV(25.8 MeV) for K- -3 He(T = 0)(K- -4 He(T= 1/2)).
Situation with collective two-phonon states in deformed nuclei
Within the quasiparticle-phonon nuclear model with the operators of phonons depending on the sign of the angular momentum projection, the Pauli principle is taken into account in the two-phonon components of the wave functions. The centroid energies of the collective two-phonon states in even-even deformed nuclei are calculated. It is shown that the inclusion of the Pauli principle leads to their shift by 1-3 MeV towards high energies. The shifts of three-phonon poles due to the Pauli principle are calculated in the three-phonon components of the wave functions. The collective two-phonon states, the centroid energies of which are 3-5 MeV, are expected to be strongly fragmented. The conclusion is confirmed that the collective two-phonon states should not exist in deformed nuclei. The situation in 168Er and in the 228Th isotopes is analysed
Isotopic dependence of isomeric states in heavy nuclei
High-spin K-isomer states, which are usually assumed as two quasiparticle high-spin configurations states, were observed in heavy nuclei 250,256Fm, 252,254No, 266Hs and 270,271Ds. In order to calculate the energies of 2qp isomer states in even-even nuclei, the two-center shell model is used for finding the single-particle levels at the ground state of nucleus. The shape parameterization used in this model effectively includes many even multipolarities. The dependence of the parameters of Is and I2 terms on A and N - Z were modified for the correct description of the ground state spins of odd actinides. The microscopical corrections and quadrupole parameters of deformation calculated with the two-center shell model are close to those obtained with the microscopic-macroscopic approaches of P. Moller et al. and A.Sobiczewski et al. The calculated values of Qa are in reasonable agreement with measured values. The calculated two-quasiparticle energies are in good agreement with the available experimental data. In the even isotope chains of Fm and No the calculated E2qp for high spin K-isomer states are minimal for 250Fm and 252No. In 242,244Fm the K-isomer states with K ≥ 6 are above 1.38 MeV that is larger than the energies of the K-isomer states in 252,254No. In order to observe these states in the neutron-deficient Fm isotopes, one should produce these isotopes with the cross sections similar to those for the nuclei 252,254No. Calculating the potential energy surface near the ground state, one can not exclude the existence of shallow potential minima which can be related to the shape isomers. The possibility of existence of these minima is discussed within the microscopic-macroscopic model. We found the indications for the low-lying shape isomers in 264,266Sg and 268,270Hs The alpha-decay between the isomer states and between the ground states can have similar properties that shields the observation of isomeric states. The population of the isomer states in the
Delta(1232) isobar excitations and the ground state of nuclei
Frick, T; Kaiser, S.; Müther, Herbert; Polls Martí, Artur; Entem, D R; Machleidt, R.
2002-01-01
The influence of $\\Delta$ isobar components on the ground state properties of nuclear systems is investigated for nuclear matter as well as finite nuclei. Many-body wave functions, including isobar configurations, and binding energies are evaluated employing the framework of the coupled-cluster theory. It is demonstrated that the effect of isobar configurations depends in a rather sensitive way on the model used for the baryon-baryon interaction. As examples for realistic baryon-baryon intera...
Unstable states produced in collisions among complex nuclei
A theory about resonant elastic dispersion is formulated and the wave function of unstable states associated with the resonances observed in the differential and total sections is studied. The object of this theory is to extend to the elastic collisions among complex nuclei interesting case, the methods and formalism of the dispersion of particles without structure by an external potential, following an idea originally formulated by H. Feshbach. (author)
Separable interactions and excited states in open-shell nuclei
The relevant matrix elements of the Hamiltonian for a RPA description of collective states in open-shell nuclei are determined. For separable interactions it is found necessary to include the particle-particle and particle-hole interactions simultaneously. The energy-weighted sum rule for the electromagnetic operator (with angular momentum I) is greatly reduced by the use of the pairing interaction with the same angular momentum. (author)
Cluster structure in highly-excited states of light nuclei
The cluster structure in the highly-excited states of light nuclei are investigated using the multi-cluster model. For this purpose, we propose a developed treatment method of the multi-cluster model. The method consists of two parts: One is a systematic construction method of the multi-cluster Pauli-allowed states. Another is a truncation method of the large model space of the multi-cluster system. We show that we can easily solve the equation of the orthogonality condition model (OCM) for complex multi-cluster systems by the use of the method. We apply the multi-cluster models 3α, 4α, 12C + 2α and 16O + 2α to 12C, 16O, 20Ne and 24Mg, respectively. As shown in the Ikeda diagram, these models open a very interesting problem not only of the cluster structure in the highly-excited states of those nuclei but also of the structure change between different cluster structures. We show a typical example of the 16O + 2α model for 24Mg ; 1) many excited states with the 20Ne-α cluster structure are obtained at excitation energies above 10 MeV, 2) the 16O-8Be cluster states are obtained at the energy region higher than 20 MeV, and 3) the very interesting states with the α-16O-α linear-chain-like structure are predicted at about 20 MeV excitation energy. (author)
The ground state of deformed nuclei as a boson condensate
It is shown that the ground state of deformed nuclei can be considered as a condensate of bosons that do not have a well-defined angular momentum. Values for the quadrupole mome-t and the particle number that are very close to the values obtained using the full boson wave function are obtained by retaining only the s- and d-parts of the boson wave function. By comparing with the many-shell (realistic) situation we found the limitations of the single-shell calculations. (orig.)
Ground state properties of superheavy nuclei with Z=117 and Z=119
We review the current studies on the ground-state properties of superheavy nuclei. It is shown that there is shape coexistence for the ground state of many superheavy nuclei from different models and many superheavy nuclei are deformed. This can lead to the existence of isomers in superheavy region and it plays an important role for the stability of superheavy nuclei. Some new results on Z=117 and Z=119 isotopes are presented. The agreement between theoretical results and experimental data clearly demonstrates the validity of theoretical models for the ground-state properties of superheavy nuclei
Unified framework for understanding pair transfer between collective states in atomic nuclei
A new interpretation of two-nucleon pair transfer in collective nuclei is presented. It differs from traditional models and unifies, within a consistent framework, the entire range of monopole pair-transfer phenomenology in collective nuclei. This includes the well-known examples of large cross sections to excited 0+ states in phase transitional nuclei, and small ones in many other nuclei, but also predicts large cross sections elsewhere under particular circumstances. These predictions can be tested experimentally.
Gamma transitions between compound states in spherical nuclei
Average values of the reduced γ widths and their dispersions are investigated, basing on the Wigner statistical matrix method, for γ transitions from a compound state c into a less-energy excited state f of an arbitrary complexity in spherical nuclei. It is shown that in all the cases of practical interest the Porter-Thomas distribution is valid for the γ widths. It is found that in the γ transitions between compound states c and c' with Esub(γ) <= 2 MeV the dominating role is played by the M1 transitions due to the main multiquasiparticle states of c, and by the E1 transitions, due to small components of the state c. In framework of the existent theoretical schemes it is shown that the strength functions of the M1 and E1 transitions between the compound states with Esub(γ) <2 MeV are close. It is deduced thet the variant of the M1 transitions is preferable in view of the experimental results on the (n, γα) reactions induced by thermal and resonance neutrons
Equation of state of hot nuclei before break-up
Following the method developed by the authors, recently, the equation of state of hot nuclei (238U* in concrete) before break-up was investigated numerically. The isotherms are drawn in the plane of the general pressure P versus volume VRT. They are similar to those of Van der Waals gas. The critical temperature of phase transition should correspond to the isotherm with one truning point only. It turns out that the data of mas yield distribution can be reproduced by many pairs of parameters T and VRT (freeze-out temperature and freezeout volume) varying in certain range. For each isotherm (each T), the data are always best reproduced by the value of VRT located at the maximum general pressure within two phases coexistence region
Alternating-parity collective states of yrast and nonyrast bands in lanthanide and actinide nuclei
Nadirbekov, M. S., E-mail: nodirbekov@inp.uz; Yuldasheva, G. A. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan); Denisov, V. Yu. [National Academy of Sciences of Ukraine, Institute for Nuclear Research (Ukraine)
2015-03-15
Excited collective states of even-even nuclei featuring quadrupole and octupole deformations are studied within a nonadiabatic collective model with a Gaussian potential energy. Rotational states of the yrast band and vibrational-rotational states of nonyrast bands are considered in detail. The energies of alternating-parity excited states of the yrast band in the {sup 164}Er, {sup 220}Ra, and {sup 224}Th nuclei; the yrast and first nonyrast bands in the {sup 154}Sm and {sup 160}Gd nuclei; and the yrast, first nonyrast, and second nonyrast bands in the {sup 224}Ra and {sup 240}Pu nuclei are described well on the basis of the proposed model.
Alternating-parity collective states of yrast and nonyrast bands in lanthanide and actinide nuclei
Excited collective states of even-even nuclei featuring quadrupole and octupole deformations are studied within a nonadiabatic collective model with a Gaussian potential energy. Rotational states of the yrast band and vibrational-rotational states of nonyrast bands are considered in detail. The energies of alternating-parity excited states of the yrast band in the 164Er, 220Ra, and 224Th nuclei; the yrast and first nonyrast bands in the 154Sm and 160Gd nuclei; and the yrast, first nonyrast, and second nonyrast bands in the 224Ra and 240Pu nuclei are described well on the basis of the proposed model
Isospin dependence of nucleon correlations in ground-state nuclei
Charity, R.J. [Washington University, Department of Chemistry, St. Louis, Missouri (United States); Dickhoff, W.H. [Washington University, Department of Physics, St. Louis, Missouri (United States); Sobotka, L.G. [Washington University, Department of Chemistry, St. Louis, Missouri (United States); Washington University, Department of Physics, St. Louis, Missouri (United States); Waldecker, S.J. [University of Tennessee, Department of Physics, Chattanooga, Tennessee (United States)
2014-02-15
The dispersive optical model (DOM) as presently implemented can investigate the isospin (nucleon asymmetry) dependence of the Hartree-Fock-like potential relevant for nucleons near the Fermi energy. Data constraints indicate that a Lane-type potential adequately describes its asymmetry dependence. Correlations beyond the mean field can also be described in this framework, but this requires an extension that treats the non-locality of the Hartree-Fock-like potential properly. The DOM has therefore been extended to properly describe ground-state properties of nuclei as a function of nucleon asymmetry in addition to standard ingredients like elastic nucleon scattering data and level structure. Predictions of nucleon correlations at larger nucleon asymmetries can then be made after data at smaller asymmetries constrain the potentials that represent the nucleon self-energy. A simple extrapolation for Sn isotopes generates predictions for increasing correlations of minority protons with increasing neutron number. Such predictions can be investigated by performing experiments with exotic beams. The predicted neutron properties for the double closed-shell {sup 132}Sn nucleus exhibit similar correlations as those in {sup 208}Pb. Future relevance of these studies for understanding the properties of all nucleons, including those with high momentum, and the role of three-body forces in nuclei are briefly discussed. Such an implementation will require a proper treatment of the non-locality of the imaginary part of the potentials and a description of high-momentum nucleons as experimentally constrained by the (e, e' p) reactions performed at Jefferson Lab. (orig.)
F-spin purity of 21+ states in even-even nuclei
A procedure is proposed by which upper limits to the F-spin purity of 21+ states in even-even nuclei can be estimated by an analysis of experimental g-factors. The procedure, applied to 17 nuclei with 46≤Z≤78, shows that Fmax admixture up to 10% are not uncommon. A systematic behavior with Z is also observed
Collective and single particle states in medium mass vibrational nuclei
The particle-core coupling model has been employed to describe the low lying nuclear excitations in the vibrational odd-A nuclei. In the frame of this model the following observables were calculated: excitation energies, spin and parity quantum numbers, electric quadrupole moments, magnetic dipole moments and reduced transition probabilities. Two computer codes were employed. The first one, PCOREC, diagonalized the Hamiltonian providing the eigenvectors and eigenvalues. The second one, PCORECTR, starts from the eigenvector computer by the first program and computes the observables which are compared we results of experiments. A good description of the experimental data has been obtained for the 133 Sb, 123 Sb and 125 Sb nuclei. (authors)
Giant isoscalar monopole states in light even-even nuclei
An attempt is made to set experimental limits on the centroid energy of isoscalar monopole strength in light nuclei, by making use of sum rules and measured EO transition rates. The model-dependence of the non-energy-weighted sum rule is tested in 16O and a reasonable estimate of the centroid energy obtained. Comparison with a simple macroscopic model allows the extraction of the nuclear compressibility. Experimental and theoretical consequences of these results are briefly discussed. (author)
Torres, D A
2016-01-01
The experimental study of magnetic moments for nuclear states near the ground state, $I \\ge 2$, provides a powerful tool to test nuclear structure models. The study of magnetic moments in nuclei far away from the stability line is the next frontier in such studies. Two techniques have been utilized to populated low-spin states in radioactive nuclei: coulomb excitation reactions using radioactive nuclei, and the transfer of $\\alpha$ particles to stable beams to populate low spin states in radioactive nuclei. A presentations of these two techniques, along with the experimental challenges presented for future uses with nuclei far away from the stability line, will be presented.
Study of neutron hole states in N=82 nuclei
This research thesis reports a systematic investigation of neutron holes in the N=82 closed layer by means of the pick-up (p,d) reaction at 24,55 MeV on Ba-138, Ce-140, Nd-142 and Sm-144, leading respectively to N=81 nuclei of Ba-137, Ce-139, Nd-141 and Sm-143. Angular distributions are compared with predictions obtained by computation based on distorted waves and performed with the DWUCK software. Spectroscopic factors are obtained from this comparison. The author first describes the experimental installation, reports the distorted-wave analysis, and finally presents and discusses the obtained results
Candidates for Long Lived High-K Ground States in Superheavy Nuclei
Jachimowicz, P; Skalski, J
2015-01-01
On the basis of systematic calculations for 1364 heavy and superheavy nuclei, including odd-systems, we have found a few candidates for high-K ground states in superheavy nuclei. The macroscopic-microscopic model based on the deformed Woods-Saxon single particle potential which we use offers a reasonable description of SH systems, including known: nuclear masses, $Q_{\\alpha}$-values, fission barriers, ground state deformations, super- and hyper-deformed minima in the heaviest nuclei. %For odd and odd-odd systems, both ways of including pairing correlations, % blocking and the quasi-particle method, have been applied. Exceptionally untypical high-K intruder contents of the g.s. found for some nuclei accompanied by a sizable excitation of the parent configuration in daughter suggest a dramatic hindrance of the $\\alpha$-decay. Multidimensional hyper-cube configuration - constrained calculations of the Potential Energy Surfaces (PES's) for one especially promising candidate, $^{272}$ Mt, shows a $\\backsimeq$ 6 Me...
F-SPIN PURITY OF 2+1 STATES IN EVEN-EVEN NUCLEI
SCHOLTEN, O; CASTEN, RF
1993-01-01
A procedure is proposed by which upper limits to the F-spin purity of 2+1 states in even-even nuclei can be estimated by an analysis of experimental g-factors. The procedure, applied to 17 nuclei with 46 less-than-or-equal-to Z less-than-or-equal-to 78, showed that F
Furusawa, Shun; Yamada, Shoichi [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Sumiyoshi, Kohsuke [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Suzuki, Hideyuki, E-mail: furusawa@heap.phys.waseda.ac.jp [Faculty of Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda, Chiba 278-8510 (Japan)
2013-08-01
We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.
Recent results at ultrahigh spin: Terminating states and beyond in mass 160 rare-earth nuclei
A classic region of band termination at high spin occurs in rare-earth nuclei with around ten valence nucleons above the 146Gd closed core. The results are presented here for such non-collective oblate (γ = 60°) terminating states in odd-Z 155Ho, odd-odd 156Ho, and even-even 156Er, where they are compared with neighboring nuclei. In addition to these particularly favoured states, the occurrence of collective triaxial strongly deformed (TSD) bands, bypassing the terminating states and extending to over 65ℎ, is reviewed
Manifestation of cluster effects in collective octupole and superdeformed states of heavy nuclei.
Shneidman, T. M.; Adamian, G. G.; Antonenko, N. V.; Jolos, R. V.
2016-06-01
The effects of reflection-asymmetric deformation on the properties of the low-lying negative-parity collective states and superdeformed states of heavy nuclei are analyzed basing on dinuclear model. The results of consideration of the alternating parity bands in actinides and the superdeformed bands in 60Zn, Pb and Hg isotopes are discussed.
Constraints on the Skyrme Equations of State from Properties of Doubly Magic Nuclei
Brown, B.Alex
2013-01-01
I use properties of doubly-magic nuclei to constrain nuclear matter and neutron matter equations of state. I conclude that the data determined the value of the neutron equation of state and the symmetry energy near a density of $\\rho_{on}$ = 0.10 nucleons/fm$^{3}$. The slope at that point is constrained by the value of the neutron skin.
High spin states in transitional nuclei in the IBM + broken pair model
For odd-A nuclei the IBFM plus broken pairs describes one and three-fermion states. The model has been applied to the description of high-spin states in the Hg, Sr-Zr and Nd-Sm regions. Calculated spectra and transition probabilities are compared with the experimental data
Regular structure of low-lying states for atomic nuclei under random interactions
In this paper we review regularities of low-lying states for many-body systems, in particular, atomic nuclei, under random interactions. We shall discuss the famous problem of spin zero ground state dominance, positive parity dominance, collective motion, odd-even staggering, average energies, etc., in the presence of random interactions. (author)
Inelastic scattering to collective states in double-magic nuclei
The paper discusses several aspects of inelastic scattering to collective states in the framework of the 'Shell Model RPA Approximation' with special emphasis on the analysis of giant resonance states. (orig./WL)
Study of low-lying states via EC/β+ decay for medium-heavy nuclei
Our previous experimental method and results of (EC+β+) decay for the medium-heavy nuclei 153Er, 157Yb, 209Fr, 128Ce, 130Ce, 128Pr, 130Pm and 140Tb have been briefly summarized. The observed low-lying states in their daughter nuclei and a 1 1/2- isomeric state in 133Pr have been reviewed in a systematic way and compared with different model calculations. Finally, some questions have been put forward for further study and discussion. (author)
It has been shown that IAS, DIAS, CS, and DCS can simultaneously have n-n, n-p, and p-p halo components in their wave functions. Differences in halo structure of the excited and ground states can result in the formation of isomers (halo-isomers). Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei. The structure of the ground and excited states with different isospin quantum number in halo like nuclei is discussed. B(Mλ) and B(Eλ) for γ-transitions in 6,7,8Li, 8,9,10Be, 8,10,11B, 10,11,12,13,14C, 13,14,15,16,17N, 15,16,17,19O, and 17F are analyzed. Special attention is given to nuclei whose ground state does not exhibit halo structure but the excited state may have one
Population and particle decay of isobaric analog states in medium heavy nuclei
The systematic features of proton stripping and neutron pickup reactions to Isobaric Analog States in medium heavy nuclei are presented. The (3He, d) reaction investigated at high incident energy is shown to selectively excite high-spin particle-analog states. Similarly the (3He, α) reaction populates hole-analog states. The recent results related to such highly excited states in a wide range of nuclei (48Ca to 208Pb) are discussed in the framework of the DWBA theory of direct reactions with special emphasis on the treatment of unbound proton states or deeply-bound neutron hole states. The particle decay of Isobaric Analog States are investigated using the (3He, d p tilde) and (3He, α p tilde) sequential processes. The experimental method developed at Orsay (00 detection) for particle-particle angular correlations is presented. The advantage and the limits of such approach are illustrated by typical exemples of particle decays: core-excited states, neutron particle-hole multiplets and the first observation of the proton emission of hole-analog levels. In conclusion new experimental approaches such as asymmetry measurements for analog states observed in transfer reactions or possible population of double analog states in heavy nuclei are discussed. (author)
Open-shell nuclei and excited states from multireference normal-ordered Hamiltonians
Gebrerufael, Eskendr; Calci, Angelo; Roth, Robert
2016-03-01
We discuss the approximate inclusion of three-nucleon (3 N ) interactions into ab initio nuclear structure calculations using a multireference formulation of normal ordering and Wick's theorem. Following the successful application of single-reference normal ordering for the study of ground states of closed-shell nuclei, e.g., in coupled-cluster theory, multireference normal ordering opens a path to open-shell nuclei and excited states. Based on different multideterminantal reference states we benchmark the truncation of the normal-ordered Hamiltonian at the two-body level in no-core shell-model calculations for p -shell nuclei, including 6Li,12C, and 10B. We find that this multireference normal-ordered two-body approximation is able to capture the effects of the 3 N interaction with sufficient accuracy, both for ground-state and excitation energies, at the computational cost of a two-body Hamiltonian. It is robust with respect to the choice of reference states and has a multitude of applications in ab initio nuclear structure calculations of open-shell nuclei and their excitations as well as in nuclear reaction studies.
The ground state of medium-heavy nuclei with non central forces
A. FabrociniINFN and Phys.Dept., Univ.of Pisa, Pisa, Italy
1997-01-01
We study microscopically the ground state properties of 16O and 40Ca nuclei within correlated basis function theory. A truncated version of the realistic Urbana v14 (U14) potential, without momentum dependent terms, is adopted with state dependent correlations having spin, isospin and tensor components. Fermi hypernetted chain integral equations and single operator chain approximation are used to evaluate one- and two-body densities and ground state energy. The results are i...
Model for asymptotic D-state parameters of light nuclei: application to 4 He
A simple method for calculating the asymptotic D state observables for light nuclei is suggested. The method exploits the dominant clusters of the light nuclei. The method is applied to calculate the 4 He asymptotic D to S normalization ratio ρα and the closely related D state parameter Dα2. The study predicts a correlation between Dα2 and Bα, and between ρα and Bα, where Bα is the binding energy of 4 He. The present study yields ρα ∼ -0.14 and Dα2 ∼ -0.12 fm2 consistent with the correct experimental ηD and the binding energies of the deuteron, triton, and the α particle where ηd is the deuteron D state to S state to S state normalization ratio. (author)
Mass formula for T = 0 and T = 1 ground states of N = Z nuclei
An algebraic model is developed to calculate the T = 0 and T = 1 ground-state binding energies for N = Z nuclei. The method is tested in the sd shell and is then extended to the 28-50 shell which is currently the object of many experimental studies. (authors)
Particle-hole description of GDR states in light nuclei with closed shells +- 2 nucleons
The particle-hole model is presented for nuclei with closed core +- 2 nucleons. The model, as applied to 6Li, 14N, 14C and 18O, gives overall agreement with experiment for the low-lying and GDR states
Pairing and high-spin states in proton-rich N =82 nuclei
Andreozzi, F.; Covello, A.; Gargano, A.; Porrino, A. (Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Istituto Nazionale di Fisica Nucleare, Mostra d' Oltremare, Pad. 20, 80125 Napoli (Italy))
1992-04-01
This paper is an extension of a previous study of the pairing effects in the {ital N}=82 isotones. It is concerned with high-spin states in the nuclei from {sup 146}Gd through the recently explored {sup 153}Lu and {sup 154}Hf. The results obtained confirm the importance of proton pairing correlations in the {ital N}=50--82 shell.
State-dependent pairing fields in rotating nuclei
In the present thesis the properties of state-dependent pairing and its influence on the nuclear rotation were studied. For this the HFBC equations were solved by a new developed method in a model with a Nilsson operator for the single-particle part and the surface-delta interaction for the generation of the self-consistently calculated pairing fields. The agreement with the experimental data was improved in all considered cases by regarding the higher multipoles (state-dependent pairing). (orig./HSI)
Low-lying states in near-magic odd-odd nuclei and the effective interaction
Carlsson, B G
2014-01-01
The iterative quasi-particle-random-phase approximation (QRPA) method we previously developed to accurately calculate properties of individual nuclear states is extended so that it can be applied for nuclei with odd numbers of neutrons and protons. The approach is based on the proton-neutron-QRPA (pnQRPA) and uses an iterative non-hermitian Arnoldi diagonalization method where the QRPA matrix does not have to be explicitly calculated and stored. The method is used to calculate excitation energies of proton-neutron multiplets for several nuclei. The influence of a pairing interaction in the $T=0$ channel is studied.
Fermionic molecular dynamics for ground states and collisions of nuclei
The antisymmetric many-body trial state which describes a system of interacting fermions is parametrized in terms of localized wave packets. The equations of motion are derived from the time-dependent quantum variational principle. The resulting Fermionic Molecular Dynamics (FMD) equations include a wide range of semi-quantal to classical physics extending from deformed Hartree-Fock theory to Newtonian molecular dynamics. Conservation laws are discussed in connection with the choice of the trial state. The model is applied to heavy-ion collisions with which its basic features are illustrated. The results show a great variety of phenomena including deeply inelastic collisions, fusion, incomplete fusion, fragmentation, neck emission, promptly emitted nucleons and evaporation. (orig.)
Effects of Beta-Decays of Excited-State Nuclei on the Astrophysical r-Process
Famiano, M A; Kajino, T; Otsuki, K; Terasawa, M; Mathews, G J
2008-01-01
A rudimentary calculation is employed to evaluate the possible effects of beta- decays of excited-state nuclei on the astrophysical r-process. Single-particle levels calculated with the FRDM are adapted to the calculation of beta-decay rates of these excited-state nuclei. Quantum numbers are determined based on proximity to Nilson model levels. The resulting rates are used in an r-process network calculation in which a supernova hot-bubble model is coupled to an extensive network calculation including all nuclei between the valley of stability and the neutron drip line and with masses A<284. Beta-decay rates are included as functional forms of the environmental temperature. While the decay rate model used is simple and phenomenological, it is consistent across all 3700 nuclei involved in the r-process network calculation. This represents an approximate first estimate to gauge the possible effects of excited-state beta-decays on r-process freeze-out abundances.
Studies of K-absorption on light nuclei and the search for bound nuclear kaonic states
The available experimental data on K-absorption on nuclei are rather old and scarce: they are not enough to understand the possible formation of aggregates of nucleons bound together by a kaon, known as 'Bound Kaonic Nuclear States'. The existence of such structures, suggested by a few theoretical models, has not been experimentally ascertained yet. To be observed, their width should be less than their binding energy. A possible decay channel for such states is the non mesonic one, leading to hyperon-nucleon (or light nuclei) final states. Therefore, experimental investigations of possible signatures are mainly based on the analysis of hyperon-nucleon(s) correlations (for instance, of Λp(d,t) pairs) and of invariant mass spectra. Complementary information may also be gathered from missing mass distributions. Recent experiments revived, with much larger statistics, the study of K-A absorption in light nuclei: namely, KEK-E549 studied the K-interactions on 4He, while FINUDA at DAΦNE collected a large statistics on K-6,7Li, K-9Be and K-12C. The experimental results obtained so far by the various experiments studying the K-absorption in nuclei are here summarized.
Potentials for calculating both parity states in p-shell nuclei
A Hamiltonian employing a ''physical'' central two-body potential has been used for simultaneous calculation of both normal and non-normal parity states of p-shell nuclei. Normal parity states have been calculated in a full 0/h bar/ω space and non-normal parity states in a full 1/h bar/ω space with the effects of spurious center-of-mass states completely removed. No explicit core is used in any of the shell model calculations. Results are compared with experimental data and previous shell model calculations for the following nuclei: 4He, /sup 5,6,7,8/Li, 8Be, /sup 13,14/C, and 13N. 34 refs., 9 figs., 3 tabs
Quasiparticle and quasihole states of nuclei around 56Ni
The single-particle spectral function of 56Ni has been computed within the framework of self-consistent Green's functions theory. The Faddeev random phase approximation method and the G matrix technique are used to account for the effects of long- and short-range physics on the spectral distribution. Large-scale calculations have been performed in spaces including up to ten oscillator shells. The chiral N3LO interaction is used together with a monopole correction that accounts for eventual missing three-nucleon forces. The single-particle energies associated with nucleon transfer to valence 1p0f orbits are found to be almost converged with respect to both the size of the model space and the oscillator frequency. The results support that 56Ni is a good doubly magic nucleus. The absolute spectroscopic factors to the valence states on A=55,57 are also obtained. For the transition between the ground states of 57Ni and 56Ni, the calculations nicely agree with heavy-ion knockout experiments.
Final state interaction in semi-inclusive DIS off nuclei
Ciofi degli Atti, C
2003-01-01
The final state interaction in DIS of leptons off a nucleus A, due to the propagation of the struck nucleon debris and its hadronization in the nuclear environment is considered. The effective cross section of such a partonic system with the nucleons of the medium and its time dependence are estimated on the basis of a model which takes into account the production of hadrons due to the breaking of the color string and to gluon radiation. It is shown that the details of the propagation of the partonic system in the nuclear environment can be thoroughly investigated by the semi-inclusive process A(e,e'(A-1))X, in which the scattered lepton is detected in coincidence with the nucleus (A-1) in low energy and momentum states. The rescattering of the struck nucleon debris with the medium damps and distorts the momentum distributions of (A-1) in a way which is very sensitive to the details of effective cross section of the debris. The total cross section of the process on ^4He, ^16O, and ^40Ca, related to the probab...
The influence of s states near threshold on the structure of light nuclei
Hoffman, Calem
2015-10-01
A recent work identified the role of neutron s states, and their proximity to the neutron separation threshold, on the ordering of the 1s1 / 2 and 0d5 / 2 single-particle levels in light nuclei. A simple Woods-Saxon potential was used to reproduce the systematic data available for these two levels with great success by accounting for the s state binding energy. This talk will explore other noticeable trends in light nuclei involving neutron s states and utilizing simple potential models determine the role binding energy plays. The trends and calculations will aim to provide descriptions of data and predictions of yet to be found two-particle two-hole excited states in N = 8 and 10 nuclei ranging from Z = 4-9, as well as the energies of mirror states in neutron deficient Al and Na isotopes. Results will be compared with state-of-the-art calculations. Possible future measurements capable of probing these predictions will be discussed as well. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.
Spectroscopy of high-lying states in actinide nuclei
Ahmad, I.; Back, B.B.; Betts, R.R. [and others
1995-08-01
In the course of studying positron-electron production during the collisions of uranium beams and tantalum targets, a careful measurement of the emitted gamma radiation was made using large Ge detectors. Many new high energy gamma rays were found, associated both with U-like and Ta-like fragments. To determine the origin of these gamma rays, a dedicated set of improved gamma-ray studies were carried out. The studies used four large (> 55%) Ge detectors mounted in the APEX chamber. States in {sup 238}U and {sup 232}Th were Coulomb excited using a {sup 208}Pb beam of 5.8 MeV/u. Heavy ions were detected in the large-area APEX multiwire proportional counters. The extensive beam monitoring of the APEX setup allowed precise normalization and accurate cross-section determinations. The Doppler shifts from upstream and downstream detectors permitted a precise confirmation of the incident beam energy to less than 0.05 MeV/A. A spectrum of gamma rays, corrected assuming emission from {sup 238}U.
He, Yugui; Feng, Jiwen; Huang, Chongyang; Chen, Fang; Liu, Maili; Liu, Chaoyang
2015-01-01
Dynamic nuclear polarization (DNP) has become a very important hyperpolarization method because it can dramatically increase the sensitivity of nuclear magnetic resonance (NMR) of various molecules. Liquid-state DNP based on Overhauser effect is capable of directly enhancing polarizations of all kinds of nuclei in the system. The combination of simultaneous Overhauser multi-nuclei enhancements with the multi-nuclei parallel acquisitions provides a variety of important applications in both MR spectroscopy (MRS) and image (MRI). Here we present two simple illustrative examples for simultaneously enhanced multi-nuclear spectra and images to demonstrate the principle and superiority. We have observed very large simultaneous DNP enhancements for different nuclei, such as 1H and 23Na, 1H and 31P, 19F and 31P, especially for the first time to report sodium ion enhancement in liquid. We have also obtained the simultaneous imaging of 19H and 31P at low field by solution-state DNP for the first time. This method can ob...
Proton Single-Particle States In The Heaviest Actinide Nuclei
The level structure of 249Bk has been investigated by measuring the γ-ray spectra following the α decay of a chemically and isotopically pure 253Es sample. Alpha-gamma coincidence measurement was performed using a Si detector for α particles and a 25% Ge detector for γ rays. A gamma-gamma coincidence measurement was performed with the Gammasphere spectrometer. The Es sample was obtained by extracting the 253Es which grew in a 253Cf source material produced in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Additional information on the 249Bk levels was obtained from the study of γ rays produced in the β- decay of 249Cm. The 249Cm sample was produced by neutron irradiation of 248Cm. Using the results of the present study and the results of previous 248Cm(α,t) and 248Cm(3He,d) reaction spectra, the following single-particle states have been identified in 249Bk: 7/2+[633], 0.0 keV; 3/2-[521], 8.78 keV; 1/2+[400], 377.55 keV: 5/2+[642], 389.17 keV; 1/2-[530], 569.19 keV; 1/2-[521], 643.0 keV; 5/2-[523], 672.8 keV; 9/2+[624], 1075.1 keV. Four vibrational bands were identified at 767.9, 932.2, 1150.7 and 1223.0 keV with tentative assignments of {7/2+[633]x1-}9/2-, {7/2+[633]x0-}7/2-, {7/2+[633]x1-}5/2- and {7/2+[633]x0+}7/2+, respectively
Open-Shell Nuclei and Excited States from Multi-Reference Normal-Ordered Hamiltonians
Gebrerufael, Eskendr; Roth, Robert
2015-01-01
We discuss the approximate inclusion of three-nucleon interactions into ab initio nuclear structure calculations using a multi-reference formulation of normal ordering and Wick's theorem. Following the successful application of single-reference normal ordering for the study of ground states of closed-shell nuclei, e.g., in coupled-cluster theory, multi-reference normal ordering opens a path to open-shell nuclei and excited states. Based on different multi-determinantal reference states we benchmark the truncation of the normal-ordered Hamiltonian at the two-body level in no-core shell-model calculations for p-shell nuclei, including 6-Li, 12-C, and 10-B. We find that this multi-reference normal-ordered two-body approximation is able to capture the effects of the 3N interaction with sufficient accuracy, both, for ground-state and excitation energies, at the computational cost of a two-body Hamiltonian. It is robust with respect to the choice of reference states and has a multitude of applications in ab initio ...
Multiphonon method applied to vibrational (K=O) state study in deformed heavy nuclei
An explicit formulation of the multiphonon method is given where two phonons are introduced as base. Vibrational states can then be studied in the realistic case of pair deformed heavy-nuclei (plutonium, uranium and thorium isotopes). Localization and properties of two-phonon states are particularly examined. Energy spectra are systematically dilated, octupolar vibrations K=O- show more anharmonicity than the K=O+ ones. The two-phonon states are between 1.7 and 2 MeV; they keep a collective nature by their electromagnetic transitions (E1, E2, E3) towards one-phonon states
Skyrme random-phase-approximation description of lowest Kπ=2γ+ states in axially deformed nuclei
Nesterenko, V. O.; Kartavenko, V. G.; Kleinig, W.; Kvasil, J.; Repko, A.; Jolos, R. V.; Reinhard, P.-G.
2016-03-01
The lowest quadrupole γ -vibrational Kπ=2+ states in axially deformed rare-earth (Nd, Sm, Gd, Dy, Er, Yb, Hf, W) and actinide (U) nuclei are systematically investigated within the separable random-phase-approximation (SRPA) based on the Skyrme functional. The energies Eγ and reduced transition probabilities B (E 2 ) of 2γ+ states are calculated with the Skyrme forces SV-bas and SkM*. The energies of two-quasiparticle configurations forming the SRPA basis are corrected by using the pairing blocking effect. This results in a systematic downshift of Eγ by 0.3-0.5 MeV and thus in a better agreement with the experiment, especially in Sm, Gd, Dy, Hf, and W regions. For other isotopic chains, a noticeable overestimation of Eγ and too weak collectivity of 2γ+ states still persist. It is shown that domains of nuclei with low and high 2γ+ collectivity are related to the structure of the lowest two-quasiparticle states and conservation of the Nilsson selection rules. The description of 2γ+ states with SV-bas and SkM* is similar in light rare-earth nuclei but deviates in heavier nuclei. However SV-bas much better reproduces the quadrupole deformation and energy of the isoscalar giant quadrupole resonance. The accuracy of SRPA is justified by comparison with exact RPA. The calculations suggest that a further development of the self-consistent calculation schemes is needed for a systematic satisfactory description of the 2γ+ states.
Structure of excited states in nuclei near doubly magic 100SN
The three neutron-deficient nuclei 94Pd, 98Cd and 104Sn in the vicinity of 100Sn were investigated by means of in-beam γ-ray spectroscopy of excited states. The isomeric decays in 94Pd and 98Cd were studied for the first time with an exclusive experimental setup for delayed γ-ray detection with complete exit channel identification based on information from neutron and charged-particle filter detectors. The structure of excited states of 94Pd showed the first indication of increasing proton-neutron interaction towards the N=Z line in this region of nuclei, that in turn might be related to increased proton-neutron pairing correlations predicted in Tz=0 nuclei. The closest neighbours of 100Sn with two active particles, 98Cd and 102Sn, are now known with their lowest excited states. The measured reduced transition probabilities for the decay of the isomeric 8+ and 6+ states in 98Cd and 102Sn, respectively, allowed to extract an effective quadrupole charge for neutron and proton in this region of nuclei based on the high configurational purity of the states. While the neutron effective charge appeared to be large and in agreement with expectation, the proton effective charge value is very small (eπ≤1). This controversial result, which would indicate that 100Sn is a very good closed shell nucleus with respect to quadrupole excitation, is not understood. An experimental reason for this result, related to existence of a core excited isomer, observed in the experiment by means of its half life but not γ-rays, which may have escaped observation, can not be definitely excluded and is left as possible explanation. (orig.)
Structure of excited states in nuclei near doubly magic {sup 100}SN
Gorska, M.
1998-11-01
The three neutron-deficient nuclei {sup 94}Pd, {sup 98}Cd and {sup 104}Sn in the vicinity of {sup 100}Sn were investigated by means of in-beam {gamma}-ray spectroscopy of excited states. The isomeric decays in {sup 94}Pd and {sup 98}Cd were studied for the first time with an exclusive experimental setup for delayed {gamma}-ray detection with complete exit channel identification based on information from neutron and charged-particle filter detectors. The structure of excited states of {sup 94}Pd showed the first indication of increasing proton-neutron interaction towards the N=Z line in this region of nuclei, that in turn might be related to increased proton-neutron pairing correlations predicted in T{sub z}=0 nuclei. The closest neighbours of {sup 100}Sn with two active particles, {sup 98}Cd and {sup 102}Sn, are now known with their lowest excited states. The measured reduced transition probabilities for the decay of the isomeric 8{sup +} and 6{sup +} states in {sup 98}Cd and {sup 102}Sn, respectively, allowed to extract an effective quadrupole charge for neutron and proton in this region of nuclei based on the high configurational purity of the states. While the neutron effective charge appeared to be large and in agreement with expectation, the proton effective charge value is very small (e{sub {pi}}{<=}1). This controversial result, which would indicate that {sup 100}Sn is a very good closed shell nucleus with respect to quadrupole excitation, is not understood. An experimental reason for this result, related to existence of a core excited isomer, observed in the experiment by means of its half life but not {gamma}-rays, which may have escaped observation, can not be definitely excluded and is left as possible explanation. (orig.)
Scaling of the giant dipole resonance widths in hot rotating nuclei from the ground state values
Banerjee, S R; Pandit, Deepak; Mukhopadhyay, S; Pal, Surajit
2008-01-01
The systematics of the giant dipole resonance (GDR) widths in hot and rotating nuclei are studied in terms of temperature T, angular momentum J and mass A. The ambiguity in describing the experimental data in the temperature range of 1 - 2 MeV in terms of the thermal shape fluctuation model (TSFM) in the liquid drop formalism has been resolved using a modified approach to estimate the average values of T, J and A in the decay of the compound nucleus. The values of the ground state GDR widths have been extracted from the TSFM parametrization in the liquid drop limit for the corrected T, J and A for a given system and compared with the corresponding available systematics of the experimentally measured ground state GDR widths for a range of nuclei from A = 45 to 194. Amazingly, the nature of the theoretically extracted ground state GDR widths matches remarkably well, though 1.5 times smaller, with the experimentally measured ground state GDR widths consistently over a wide range of nuclei.
Macroscopic-microscopic calculations of ground state properties of superheavy nuclei
ZHI Qi-jun; Mao Ying-chen; REN Zhong-zhou
2006-01-01
We systematically calculate the ground state properties of superheavy even-even nuclei with proton number Z=94-118.The calculations are based on the liquid drop macroscopic model and the microscopic model with the modified single-particle oscillator potential. The calculated binding energies and α-decay energies agree well with the experimental data.The reliability of the macroscopic-microscopic(MM)model for superheavy nuclei is confirmed by the good agreement between calculated results and experimental ones. Detailed comparisons between our calculations and M(o)ller's are made.It is found that the calculated results also agree with M(o)ller's results and that the MM model is insensitive to the microscopic single-particle potential. Calculated results are also compared with results from relativistic mean-field (RMF)model and from Skyrme-Hatree-Fock(SHF) model.In addition,half-lives,deformations and shape coexistence are also investigated.The properties of some unknown nuclei are predicted and they will be useful for future experimental researches of superheavy nuclei.
Study of ground and excited state decays in N ≈ Z Ag nuclei
Moschner K.
2015-01-01
Full Text Available A decay spectroscopy experiment was performed within the EURICA campaign at RIKEN in 2012. It aimed at the isomer and particle spectroscopy of excited states and ground states in the mass region below the doubly magic 100Sn. The N = Z nuclei 98In, 96Cd and 94Ag were of particular interest for the present study. Preliminary results on the neutron deficient nuclei 93Ag and 94Ag are presented. In 94Ag a more precise value for the half-life of the ground state’s superallowed Fermi transition was deduced. In addition the energy spectra of the mentioned decay could be reproduced through precise Geant4 simulations of the used active stopper SIMBA. This will enable us to extract Qβ values from the measured data. The decay of 93Ag is discussed based on the observed implantation-decay correlation events.
Systematics of ground state multiplets of atomic nuclei in the delta-interaction approach
Pairing forces between nucleons in an atomic nucleus strongly influence its structure. One of the manifestations of pair interaction is the ground state multiplet (GSM) formation in the spectrum of low-lying excited states of even–even nuclei. The value of GSM splitting is determined by the value of pair interaction of nucleons; for each isotope, it can be estimated on the basis of experimental nuclear masses. The quality of this estimate is characterized by the degree of reproduction of GSM levels in the nucleus. The GSM systematics in even–even nuclei with a pair of identical nucleons in addition to the filled nuclear core is considered on the basis of delta interaction
Systematics of ground state multiplets of atomic nuclei in the delta-interaction approach
Imasheva, L. T.; Ishkhanov, B. S.; Stepanov, M. E.; Tretyakova, T. Yu.
2015-12-01
Pairing forces between nucleons in an atomic nucleus strongly influence its structure. One of the manifestations of pair interaction is the ground state multiplet (GSM) formation in the spectrum of low-lying excited states of even-even nuclei. The value of GSM splitting is determined by the value of pair interaction of nucleons; for each isotope, it can be estimated on the basis of experimental nuclear masses. The quality of this estimate is characterized by the degree of reproduction of GSM levels in the nucleus. The GSM systematics in even-even nuclei with a pair of identical nucleons in addition to the filled nuclear core is considered on the basis of delta interaction.
Systematics of ground state multiplets of atomic nuclei in the delta-interaction approach
Imasheva, L. T.; Ishkhanov, B. S.; Stepanov, M. E., E-mail: stepanov@depni.sinp.msu.ru [Moscow State University, Faculty of Physics (Russian Federation); Tretyakova, T. Yu. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)
2015-12-15
Pairing forces between nucleons in an atomic nucleus strongly influence its structure. One of the manifestations of pair interaction is the ground state multiplet (GSM) formation in the spectrum of low-lying excited states of even–even nuclei. The value of GSM splitting is determined by the value of pair interaction of nucleons; for each isotope, it can be estimated on the basis of experimental nuclear masses. The quality of this estimate is characterized by the degree of reproduction of GSM levels in the nucleus. The GSM systematics in even–even nuclei with a pair of identical nucleons in addition to the filled nuclear core is considered on the basis of delta interaction.
Excited states in the neutron deficient nuclei 138Sm and 139Eu
Excited states in the two N=76 nuclei 138Sm and 139Eu have been identified via 32S induced reactions on different targets using γ-ray spectroscopy methods. Lifetimes have been measured with the Doppler shift recoil distance technique, showing the coexistence of a large nuclear deformation (β-0.24) with excitations of single particle character. The E2 transition strengths in the odd-even nucleus 139Eu and in its core 138Sm are discussed. (orig.)
Properties of the lowest negative parity states in N= 82 magic nuclei
Octupole features in rare earth nuclei observed that, in the region beyond the doubly closed shell structure in 132Sn, the d5/2 and the h11/2 proton orbitals are quite close together and are also near the Fermi surface. In the present paper, the octupole features has been examined in the low lying 3 states in the N=82 isotonic sequence beginning with the doubly closed shell nucleus 132Sn
Effective Field Theory for Halo Nuclei: Shallow p-Wave States
Bertulani, C.A.; Hammer, H. -W.; van Kolck, U.
2002-01-01
Halo nuclei are a promising new arena for studies based on effective field theory (EFT). We develop an EFT for shallow p-wave states and discuss the application to elastic n-alpha scattering. In contrast to the s-wave case, both the scattering length and effective range enter at leading order. We also discuss the prospects of using EFT in the description of other halos, such as the three-body halo nucleus 6He.
Q-phonon approach for low lying dipole two-phonon states in spherical nuclei
The properties of 1- two-phonon states and the characteristics of E1 transition probabilities between low-lying collective states in spherical nuclei were analyzed within the Q-phonon approach to the description of collective states. Several relations between observables were obtained. Microscopic calculations of the E1 01+→11- transition matrix elements were performed on the basis of RPA. A satisfactory description of the experimental data was obtained. The results of the calculations of the electric dipole transition matrix elements are presented
High-Spin States in and Around Doubly-Magic Nuclei
The study of high-spin states in regions of doubly-magic nuclei performed with the use of deep-inelastic heavy ion reactions is reviewed. New and tentative results concerning high-spin states in the 48Ca and yrast structures in 47Ca, 47K, 49Ca and 49Sc isotopes are presented. The status of the high-spin state study in the region of 132Sn and 208Pb is outlined including discussion of recently obtained results in the 208Pb core and the 206Hg two-proton-hole nucleus. (author)
High-spin states in and around doubly-magic nuclei
Broda, R.
2001-01-01
The study of high-spin states in regions of doubly-magic nuclei performed with the use of deep-inelastic heavy ion reactions is reviewed. New and tentative results concerning high-spin states in the 48Ca and yrast structures in 47Ca, 47K, 49Ca and 49Sc isotopes are presented. The status of the high-spin state study in the region of 132Sn and 208Pb is outlined, including discussion of recently obtained results in the 208Pb core and the 206Hg two-proton-hole nucleus.
Collective nature of $0^{+}$-states in deformed rare-earth nuclei
Garistov, V P
2000-01-01
The description of the energiy spectra of $0^{+}$ states for rare-earth nuclei has been done involving the degree of the collectivity of corresponding $0^{+}$-state as a systematics parameter. Holshtein-Primakoff representation leads to very good agreement with experiment. Within the framework of this approach the parameter of the collectivity is mainly determined by pairs of particles constructed on single ''effective'' level. The results may be helpful both for nuclear structure experimentalists and theorists in their investigations of low-lying states structure and transition probabilities.
Present status of alpha-particle condensate states in self-conjugate 4n nuclei
Low density states near the 3α and 4α breakup threshold in 12C and 16O, respectively, are discussed in terms of the α-particle condensation. Calculations are performed in OCM (Orthogonality Condition Model) and THSR (Tohsaki-Horiuchi-Schuck-Roepke) approaches. The 02+ state in 12C and the 06+ state in 16C are shown to have dilute density structures and give strong enhancement of the occupation of the S-state c.o.m. orbital of the α-particles. The 06+ state in 16C has a large component of α + 12C(02+) configuration, which is another reliable evidence of the state to be of 4α condensate nature. The possibility of the existence of α-particle condensed states in heavier nα nuclei is also discussed. (author)
Halo Structure of Isobaric Analogue States in A= 21 and 17 Mirror Nuclei
周书华; 周静
2002-01-01
The root-mean-square (rms) radii of the last nucleons in the 2s1/2 states of 21 Ne, 21 Na, 17 O and 17 F are found to be 4.4±0.5, 5.2±0.6, 4.3±0.5 and 5.0±0. 6 fm, respectively, from transfer reaction data. The results show that the 2s1/2 states of 21 Na and 17F are proton halo states, while the analogous states in their mirror nuclei 21 Ne and 17O can be considered as neutron skin states. Comparisons among the rms radii of these states lead us to expect that a neutron halo nucleus has a proton halo mirror partner, and the Coulomb barrier is a determinant factor limiting the extension of the rms radius of the loosely bound proton.
Halo Structure of the Isobaric Analog States in Some Mirror Nuclei
2001-01-01
Using ANC method the rms radius of the last nucleon in the 2s1/2 isobaric analog states of 21Ne/2lNa and 17O / 17F is extracted from transfer reaction data. The results are summarized in Tab. 1. The 2s1/2 single proton states in 21Na and 17O have the rms radii almost twice as large as that for their core nuclei (2.88 fin for 20Ne and 2.71 fm for 16O) and are proton halo states, while their isobaric analog states in 2INe and I7O can be considered as neutron skin states, because the neutrons in these states have one third of the probability staying out of the nuclear interaction range. The obvious difference in the rms radii between a mirror pair indicates the binding energy difference between the
High-spin states in the transitional odd-odd nuclei 150Eu and 152Tb
The (7Li, 5n) and (11B, 5n) reactions have been used to study the high-spin states in the two odd-odd nuclei 150Eu and 152Tb. Three decoupled bands have been evidenced in each nucleus belonging to the same configurations [f 7/2]sub(n) [h 11/2]sub(p), [h 9/2]sub(n) [h 11/2 ]sub(p) and [i 13/2]sub(n) [h 11/2]sub(p). The latter one is well developped and improves our knowledge of this system between the spherical and deformed region. The analysis of the collective moment of inertia and transition ratios strongly suggests an increase of the deformation when the rotational frequency increases in these two transitional nuclei 150Eu and 152Tb
High-spin states in boson models with applications to actinide nuclei
Kuyucak, S
1995-01-01
We use the 1/N expansion formalism in a systematic study of high-spin states in the sd and sdg boson models with emphasis on spin dependence of moment of inertia and E2 transitions. The results are applied to the high-spin states in the actinide nuclei ^{232}Th, ^{234-238}U, where the need for g bosons is especially acute but until now, no realistic calculation existed. We find that the d-boson energy plays a crucial role in description of the high-spin data.
Izosimov, I. N., E-mail: izosimov@jinr.ru [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)
2015-10-15
It has been shown that IAS, DIAS, CS, and DCS can simultaneously have n-n, n-p, and p-p halo components in their wave functions. Differences in halo structure of the excited and ground states can result in the formation of isomers (halo-isomers). Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei. The structure of the ground and excited states with different isospin quantum number in halo like nuclei is discussed. B(Mλ) and B(Eλ) for γ-transitions in {sup 6,7,8}Li, {sup 8,9,10}Be, {sup 8,10,11}B, {sup 10,11,12,13,14}C, {sup 13,14,15,16,17}N, {sup 15,16,17,19}O, and {sup 17}F are analyzed. Special attention is given to nuclei whose ground state does not exhibit halo structure but the excited state may have one.
Influence of spin components of the effective nuclear forces on the structure of electric type eicited states is investigated. Both the central and spin components of the effective NN-forces are selected in a separable form with the same radial dependence. As is shown, there are no considerable changes in characteristics of the lowest excited states in spherical nuclei as well as in the integral properties of electric resonances (like the region of the localization, the total excitation probability, etc.). Changes in the structure and transition densities for a number of collective states in 208Pb with energies Esub(x)>10 MeV are noted. At an excitation energy Esub(x) approximately 20 MeV the collective states, which are formed by single-particle spin-flip transitions, appear. These states have a small reduced probability B(Elambda; 0+ → lambdasup(π)) but they are strongly excited in the inelastic electron stattering at backward angles
The equation of state of nuclear matter, and nuclei in laboratories and in neutron-star crusts
We examine a relationship between the phenomenological equation of state (EOS) of nuclear matter near normal nuclear density and neutron-rich nuclei in laboratories and in neutron-star crusts. In this study, we use about 200 EOS's, which are systematically constructed in such a way as to provide a reasonable fit to empirical masses and radii of stable nuclei by simplified Thomas-Fermi calculations. As for neutron-rich nuclei in laboratories, matter radii and masses are shown to be functions of the symmetry energy density derivative coefficient L. We also find that the boundary density between the core and crust of neutron stars is a decreasing function of L. We expect that future systematic measurements of the matter radii and masses of neutron-rich nuclei could help deduce the L value, which in turn could give useful information about nuclei in neutron-star crusts. (author)
Gound State Properties of Nuclei in 295118 α-Decay Chain
The properties of nuclei belonging to the α-decay chain of superheavy element 295118 have been studied in the framework of axially deformed relativistic mean field (RMF) theory with the parameter set of NL-Z2 in the blocked BCS approximation. Some ground state properties such as binding energies, deformations, and α-decay energies Qα have been obtained and agree well with those from finite-range droplet model (FRDM). The single-particle spectra of nuclei in 295118 α-decay chain show that the shell gaps present obviously nucleon number dependence. The root-mean-square (rms) radii of proton, neutron and matter distributions change slowly from 283112 to 295118 but dramatically from 279110 to 283112, which may be due to the subshell closure at Z = 110 in 279110. The α-decay half-lives in 295118 decay chain are evaluated by employing the cluster model and the generalized liquid drop model (GLDM), and the overall agreement is found when they are compared with the known experimental data. The α-decay lifetimes obtained from the cluster model are slightly larger than those of GLDM ones. Finally, we predict the α-decay half-lives of Z = 118, 116, 114, 112 isotopes using the cluster model and GLDM, which also indicate these two models can corroborate each other in studies on superheavy nuclei. The results from GLDM are always lower than those obtained from the cluster model. (nuclear physics)
Structure of high spin states of 76Kr and 78Kr nuclei
U R Jakhar; H L Yadav; A Ansari
2005-12-01
Following a fully self-consistent cranked Hartree-Fock-Bogoliubov (CHFB) approach with a pairing+quadrupole+hexadecapole model interaction Hamiltonian the structure of the yrast states of 76,78Kr nuclei is studied up to angular momentum = 24. Evolution of the shape with spin, and rotation alignment of proton as well as neutron 0g9/2 orbitals is investigated along with the inter- and intra-nucleus variations of the factors as a function of . We find that the shape of 78Kr remains prolate all through up to = 24, whereas 76Kr becomes triaxial beyond = 12.
Alpha cluster states in light nuclei populated through the (6Li,d) reaction
Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (xα) and(xα+ν) nuclei through the (6Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (xα) and (xα+ν) thresholds. Measurements of the 12,13C(6Li,d) 16,17O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4α) breakup threshold in 16O, three narrow alpha resonances, not previously measured, were detected, revealing important α + 12C(G.S.) components. One of these resonances corresponds to the known 0+ state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4α condensate state, with a very dilute density and a large component of α + 12C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the α + 12C(G.S.) component in the wave function. (author)
Core polarization and 3/2 states of some f-p shell nuclei
The energies, wavefunctions, spectroscopic factors and M1 transition strengths have been calculated for the 3/2- states excited via single proton transfer to 2p3/2 orbit of the target nuclei 50Ti, 52Cr, 54Fe and 56Fe. The calculations have been done by using the Kuo and Brown interaction in the entire four shell space as well as the shrunk Kuo and Brown interaction calculated in (1f7/2-2p3/2) space. The salient feature of the calculation is that whereas the systematics of single particle strength distribution are well reproduced, the energy splitting between the calculated T> centroid and the centroid of T> states is always much smaller than that observed experimentally. It has been found, however, that the modified KB interaction widens the energy gap between the T> centroid and the centroid of T> states without appreciably affecting the final wave-functions. (author)
Study of the giant dipole resonance built on highly excited states in Sn and Dy nuclei
A study is presented of the giant dipole resonance built on highly excited states. The aim is to get more detailed information on the properties of the GDR and to use it as a tool for the investigation of nuclear structure at high excitation energy. The high energy γ-rays seen from the decay of excited state GDRs in heavy ion fusion reactions reflect the average properties of the states populated by the γ-emission. The measurements at different initial excitation energies of 114Sn provide information on the nuclear level density near the particle separation energy at an average angular momentum of 10ℎ. The study of shape changes at very high spin in 152-156Dy nuclei is presented. A theoretical model developed to describe fusion-evaporation reactions is presented. 149 refs.; 63 figs.; 13 tabs
Interplay of collective and single-particle states in neutron deficient transitional nuclei
This thesis reports several in-beam γ-ray spectroscopic studies of rotational states in neutron deficient nuclei in the transitional A = 120 and A = 170 mass regions following heavy-ion reactions. The experiments were performed using high-resolution multidetector arrays at Daresbury Laboratory, England and the Tandem Accelerator Laboratory, Niels Bohr Institute, Denmark. The Daresbury Recoil Separator and a 4π charged particle Si-detector system in conjunction with 11 neutron detectors were used in order to identify some of the very neutron deficient and previously unknown residual nuclei that were produced in the reactions. The experimental results are compared to theoretical mean field calculations which minimize the total energy of the nucleus as a function of rotational frequency and deformation, for various configurations. Within the limitations of these so called Total Routhian Surface (TRS) calculations it is possible to draw conclusions of the underlying microscopic mechanisms behind the experimentally observed properties of rotational band structures. The emphasis is put on studies of the shape polarizing properties of different single-particle orbits, especially on the role of deformed intruder states. (39 refs.) (au)
Coulomb excitation is a very precise tool to measure excitation probabilities and provide insight on the collectivity of nuclear excitations and in particular on nuclear shapes. In the last few years radioactive ion beam facilities such as HRIBF opened unique opportunities to explore the structure of nuclei in the regions near the doubly magic nuclei 78Ni (Z=28 and N=50) and 132Sn (Z=50 and N=82). For this purpose we have developed specialized methods and instrumentation to measure various observables. There is also the opportunity to perform precision experiments with stable beams using exactly the same state-of-the-art instrumentation and techniques as with their radioactive ion beam counterpart. I describe some of the recent efforts at HRIBF to do more precise measurements using particle-gamma techniques.
Fermionic structure of collective states of light nuclei and the Dyson boson mapping
Full text: The main objective of studying microscopic nature of collective states is to derive the parameters of the model of interacting bosons based on nucleon degrees of freedom. To achieve this the paper represents [1, 2], first of all, cutoff of huge Hilbert shell space to so-called SD - pair subspace, constructed from the S-and D-nucleon pairs. For this purpose, we used the Dyson-type boson mapping of fermion operators of the studied system. We prove the validity of cutting off huge fermionic space, since it is considered in the model of interacting bosons that low-energy states of nuclei are determined by the properties of nucleons located in such cut off SD - pair space. So we can divide the Dyson boson Hamiltonian into the collective and non-collective parts. This Hamiltonian includes another term reflecting the relationship between collective and non-collective freedom degrees of the system. Diagonalization of such Hamiltonian and comparison of the obtained numerical values with the numerical results of exact shell-model calculations for the same nuclei in the sd- and pf - shell region shows that our method gives a good approximation to description of nuclei properties. It is shown that the role of coupling effect between collective and non-collective freedom degrees in the formation of spectrum and B(E2) values is essential. It should be noted that after mapping of the shell space as the ideal boson one, only three - s, d, g - the bosons corresponding to collective Tamm-Dancoff-skiy phonon modes with l=0, 2, 4, respectively, are left as collective bosons. The boson Hamiltonian is diagonalized in this model pair space. The method effectively reproduces not only excitation energies, but also the values of B(E2) and quadrupole moments obtained during exact shell-model calculations. The theory is applied to light nuclei 40,42Ca, 44Ti. The numerical results represent the experimental data quite satisfactorily. (author) Reference: 1. K. Takada, et al
The evaporation residue in the fission state of Barium nuclei within relativistic mean-field theory
Bhuyan, M; Gupta, Raj K
2013-01-01
The evaporation residue of Barium isotopes are investigated in a microscopic study using relativistic mean field theory. The investigation includes the isotopes of Barium from the valley of stability to exotic proton-rich region. The ground as well as neck configurations for these nuclei are generated from their total nucleonic density distributions of the corresponding state. We have estimated the constituents (number of nucleons) in the elongated neck region of the fission state. We found the $\\alpha$-particle as the constituent of neck of Ba-isotopes, referred to as the evaporated residue in heavy-ion reaction studies. A strong correlation between the neutron and proton is observed throughout the isotopic chain.
Contribution of excited states to stellar weak-interaction rates in odd-A nuclei
Sarriguren, P.
2016-05-01
Weak-interaction rates, including β decay and electron capture, are studied in several odd-A nuclei in the p f -shell region at various densities and temperatures of astrophysical interest. Special attention is paid to the relative contribution to these rates of thermally populated excited states in the decaying nucleus. The nuclear structure involved in the weak processes is studied within a quasiparticle random-phase approximation with residual interactions in both particle-hole and particle-particle channels on top of a deformed Skyrme Hartree-Fock mean field with pairing correlations. In the range of densities and temperatures considered, it is found that the total rates do not differ much from the rates of the ground state fully populated. In any case, the changes are not larger than the uncertainties due to the nuclear-model dependence of the rates.
Population of Metastable States in Stable Hafnium and Ytterbium Nuclei via Beam Break-up
The ''Chessboard'' section of the DIAMANT charged-particle array has been coupled with the AFRODITE γ-ray spectrometer at the iThemba Laboratory for Accelerator Based Sciences. Charged-particle-γ-ray coincidence data were recorded during the bombardment of a 176Yb target with a 13C beam at an energy of 90 MeV. The purpose of the investigation was to study the population of metastable states in hafium nuclei via incomplete fusion reactions in which the beam breaks up due to its α-cluster character. Of note was the observation of the band based on the Kπ = 16+, T1/2 = 31 year isomer in 178Hf to its 19+ member. Also, decays from the high-K isomeric states in 174Yb and 176Yb. which were populated via 3αxn channels, indicative of complete break-up of the 13C beam
Contribution of excited states to stellar weak-interaction rates in odd-A nuclei
Sarriguren, Pedro
2016-01-01
Weak-interaction rates, including beta-decay and electron capture, are studied in several odd-A nuclei in the pf-shell region at various densities and temperatures of astrophysical interest. Special attention is paid to the relative contribution to these rates of thermally populated excited states in the decaying nucleus. The nuclear structure involved in the weak processes is studied within a quasiparticle random-phase approximation with residual interactions in both particle-hole and particle-particle channels on top of a deformed Skyrme Hartree-Fock mean field with pairing correlations. In the range of densities and temperatures considered, it is found that the total rates do not differ much from the rates of the ground state fully populated. In any case, the changes are not larger than the uncertainties due to the nuclear model dependence of the rates.
Correlation of β-band with ground state band in medium mass nuclei
The low energy levels of even Z even N nuclei in medium mass region A = 150-200 away from closed shells develop collective characteristics. The lowest levels can be grouped into three K-bands. The lowest one based on the ground state forms the ground state rotational band. The rotational band, based on the axially symmetric vibration of the nuclear core with K= 02 is called the beta vibrational band. The one based on the axially asymmetric vibration of the nuclear core with K=2 projection on the symmetry axis is called the K=2, γ-vibrational band. There is interest in the nature of the K= 02 band. This is called the geometric view of the Bohr Mottelson unified collective model
Halo structure of isobaric analogue states in A = 21 and 17 mirror nuclei
Zhou Shu Hua
2002-01-01
The root-mean-square (rms) radii of the last nucleons in the 2s sub 1 sub / sub 2 states of sup 2 sup 1 Ne, sup 2 sup 1 Na, sup 1 sup 7 O and sup 1 sup 7 F are found to be 4.4 +- 0.5, 5.2 +- 0.6, 4.3 +- 0.5 and 5.0 +- 0.6 fm, respectively, from transfer reaction data. The results show that the 2s sub 1 sub / sub 2 states of sup 2 sup 1 Na and sup 1 sup 7 F are proton halo states, while the analogous states in their mirror nuclei sup 2 sup 1 Ne and sup 1 sup 7 O can be considered as neutron skin states. Comparisons among the rms radii of these states lead authors to expect that a neutron halo nucleus has a proton halo mirror partner, and the Coulomb barrier is a determinant factor limiting the extension of the rms radius of the loosely bound proton
The proton-neutron degree of freedom in collective states of medium heavy nuclei
In this thesis the collective excitation forms of heavy nuclei are studied in the framework of the interacting boson model (IBM) which was developed by A. Arima and F. Iachello (1984). A description equivalent to the description of the dynamics of the surface is obtained in the IBM by the IBM-1 which not discriminates between protons and neutrons. The introduction of the proton-neutron degree of freedom occurs in the IBM-2 by the introduction of proton and neutron bosons. It is an essential aim of the present thesis to explain the apparent contradiction between the dominance of the proton-neutron interaction (IBM-2) and the phenomenological description power of the IBM-1 respectively to draw consequences from this. An essential mean for this is the introduction of the F spin which allows there application of the SU(2) group to the study of the Hamiltonian on its properties in connection with the proton-neutron exchange symmetry. The M1-transitions were used in order to study the purity of the F spin. In this connection the collective states of the nuclei 128Xe and 168Er could be consistently described in the energies, the B(E2) and the M1-transitions. (orig./HSI)
Alpha cluster states in light nuclei populated through the (6Li,d) reaction
Borello-Lewin, Thereza; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy). Istituto Nazionale di Fisica Nucleare. Lab. Nazionali del Sud; Ukita, Gilberto Mitsuo [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Fac. de Psicologia
2011-07-01
Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (x{alpha}) and(x{alpha}+{nu}) nuclei through the ({sup 6}Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (x{alpha}) and (x{alpha}+{nu}) thresholds. Measurements of the {sup 12},{sup 13}C({sup 6}Li,d) {sup 16},{sup 17}O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4{alpha}) breakup threshold in {sup 16}O, three narrow alpha resonances, not previously measured, were detected, revealing important {alpha} + {sup 12}C(G.S.) components. One of these resonances corresponds to the known 0{sup +} state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4{alpha} condensate state, with a very dilute density and a large component of {alpha} + {sup 12}C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the {alpha} + {sup 12}C(G.S.) component in the wave function. (author)
Investigation of the structure of the intermediate-energy excited states of the deformed nuclei
This paper reports that at present, the comprehensive experimental information is available on the properties of low-lying states of atomic nuclei which allows one to describe on a microscopic level the basic regularities of their simplest excitations. The use of the neutron spectroscopy methods formed the experimental basis for studying complex highly excited states lying with a high density in the nucleon binding energy region. They are mainly described in the framework of the statistical approach. At the same time, the study of the transitional region of intermediate excitation (3 MeV approx-lt E approx-lt Bn) has not long ago been undertaken. These states are very complicated in structure and their density is so high that the traditional experimental methods of studying and microscopic describing nuclear states developed for the low-energy regions turned out to be ineffective and inapplicable. The statistical methods also cannot describe to the full the properties of intermediate states since, as experiment shows, different structural effects arise systematically in this energy region
For the test of nuclear models the study of the properties of nuclear states of high angular momentum is especially important, because such states can often be given very simple theoretical descriptions. High spin states are easily populated by use of reactions initiated by alpha particles or heavy ions. In this thesis a number of low-medium mass nuclei have been studied, with emphasis on high spin states. (Auth.)
Particle-number conserving treatment for the ground state bands in even-even transfermium nuclei
The ground state bands observed in even-even transfermium nuclei 250Fm and 252,254No are investigated by the cranked shell model with the particle-number conserving treatment for the monopole and quadrupole pairing correlations. The experimental variations of the kinematic moment of inertia with rotational frequency are reproduced very well in our calculation. Our results show backbendings of ℑ(1) at ħω ≈ 0.275 and 0.300 MeV in 252No and 254No, respectively. The detailed information about the contribution to alignment from each cranked single particle level exhibits that the backbending is mainly due to the rapidly aligned angular momentum of proton 1j15/2 [770]1/2 pairs and neutron 2h11/2 [761]3/2, 1j15/2 [734]9/2 pairs the band crossing. (author)
Study of particle unbound states in 25Mg and 25Al nuclei by the reaction 24Mg(d,pn)
Stripping reactions to unbound states in 25Mg and 25Al nuclei were investigated by measuring proton-neutron angular correlation. An analysis of triple differential cross sections has been given. New high excited unbound states in the energy range from 8.1 to 11.6 MeV for 25Mg and from 4.6 to 8.3 MeV for 25Al nuclei were observed. Angular distributions of double differential cross sections were found for most of the levels. (author)
Deep-hole and high-lying particle states in heavy nuclei
Our present knowledge on single-particle strength functions from one nucleon transfer reactions is reviewed. Results on deeply-bound neutron hole states in the Sn and Pb region are discussed with emphasis on the investigation of a very large excitation energy range. The first measurements on the γ-decay of deeply-bound hole states in the Sn isotopes are reported. High energy neutron and proton stripping reactions are used to study the particle response function. These reactions are particularly well suited to the study of high-spin outer subshells. For the proton states, the behaviour of the 1h11/2 and 1i13/2 strength distributions, as a function of deformation in the Sm region, is discussed. Strong transitions to high-lying neutron states are observed in the 112,116,118,120,122,124Sn and 208Pb nuclei. The empirical systematics for both proton and neutron particle strength distributions are compared to the predictions from the quasi particle-phonon and the single-particle vibration coupling nuclear models. (orig.)
High-Resolution NMR of Quadrupolar Nuclei in the Solid State
Gann, Sheryl Lee
1995-11-30
This dissertation describes recent developments in solid state nuclear magnetic resonance (NMR), for the most part involving the use of dynamic-angle spinning (DAS) NMR to study quadrupolar nuclei. Chapter 1 introduces some of the basic concepts and theory that will be referred to in later chapters, such as the density operator, product operators, rotations, coherence transfer pathways, phase cycling, and the various nuclear spin interactions, including the quadrupolar interaction. Chapter 2 describes the theory behind motional averaging experiments, including DAS, which is a technique where a sample is spun sequentially about two axis oriented at different angles with respect to the external magnetic field such that the chemical shift and quadrupolar anisotropy are averaged to zero. Work done on various rubidium-87 salts is presented as a demonstration of DAS. Chapter 3 explains how to remove sidebands from DAS and magic-angle spinning (MAS) experiments, which result from the time-dependence of the Hamiltonian under sample spinning conditions, using rotor-synchronized {pi}-pulses. Data from these experiments, known as DAH-180 and MAH-180, respectively, are presented for both rubidium and lead salts. In addition, the applicability of this technique to double rotation (DOR) experiments is discussed. Chapter 4 concerns the addition of cross-polarization to DAS (CPDAS). The theory behind spin locking and cross polarizing quadrupolar nuclei is explained and a method of avoiding the resulting problems by performing cross polarization at 0{sup o} (parallel) with respect to the magnetic field is presented. Experimental results are shown for a sodium-23 compound, sodium pyruvate, and for oxygen-17 labeled L-akmine. In Chapter 5, a method for broadening the Hartmann-Hahn matching condition under MAS, called variable effective field cross-polarization (VEFCI?), is presented, along with experimental work on adamantane and polycarbonate.
We present a new approach for the measurement of resonance excitation functions of neutron-rich nuclei using Doppler shift information. Preliminary data from the first application of the method is presented in the spectroscopy studies of 7He isobaric analog states in 7Li. (orig.)
Rong-Yao, Yang; Si-Na, Wei; Dong-Rui, Zhang
2016-01-01
The sensitive correlations between the low-density halo structure and the high-density properties of the nuclear equation of state (EOS) are constructed in light kaonic nuclei with the relativistic mean-field theory. More specifically, the $1p_{1/2}$ halo spreads out linearly with increasing the pressure and sound velocity square at supra-normal densities and quadratically with decreasing the incompressibility at saturation density. These results suggest that the novel halo in light kaonic nuclei can serve as a sensitive indicator of the nuclear EOS of symmetric matter at supra-normal densities.
Sharma, Natasha
2016-01-01
The excellent particle identification capabilities of the ALICE detector, using the time projection chamber and the time-of-flight detector, allow the detection of light nuclei and anti-nuclei. Furthermore, the high tracking resolution provided by the inner tracking system enables the separation of primary nuclei from those coming from the decay of heavier systems. This allows for the reconstruction of decays such as the hypertriton mesonic weak decay ($^3_{\\Lambda}$H$\\rightarrow ^3$He + $\\pi^-$), the decay of a hypothetical bound state of a $\\Lambda$n into a deuteron and pion or the H-dibaryon decaying into a $\\Lambda$, a proton and a $\\pi^{-}$. An overview of the production of stable nuclei and anti-nuclei in proton-proton, proton-lead and, in particular, lead-lead collisions is presented. Hypernuclei production rates in Pb--Pb are also shown, together with the upper limits estimated on the production of hypothetical exotica candidates. The results are compared with predictions for the production in thermal...
Fujita, Y; Fujita, H; Adachi, T; Berg, GPA; Caurier, E; Fujimura, H; Hara, K; Hatanaka, K; Janas, Z; Kamiya, J; Kawabata, T; Langanke, K; Martinez-Pinedo, G; Noro, T; Roeckl, E; Shimbara, Y; Shinada, T; van der Werf, SY; Yoshifuku, M; Yosoi, M; Zegers, RGT
2002-01-01
Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states of T = 1, T-z = +/-1 nuclei to the common excited states of the T-z = 0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow
Collective excited states in even–even nuclei with quadrupole and octupole deformations
Deformed even–even nuclei with quadrupole and octupole deformations are investigated on the basis of a nonadiabatical collective model. It is shown that the model satisfactorily describes energy levels of the yrast and first nonyrast bands with alternating parity in the rare-earth nuclei 150Nd, 152,154Sm, 154Gd, 156Dy, 162,164Er and the actinides 232,234,236,238U. In the nuclei 156,158Gd, 224Ra, 228Th and 240Pu the energy levels of second nonyrast bands are also described. The structure of the considered alternating-parity bands is examined in terms of odd–even staggering diagrams. (author)
Study of superdeformed state of nuclei in $Z=70-80$ drip-line region
Mahapatro, S; Kumar, Bharat; Patra, S K
2015-01-01
We study binding energy, root- mean square radius, quadrapole deformation parameter, two-neutron separation energy and single particle energy levels for various isotopes of Ytterbium (Yb), Hafnium(Hf), Tungsten(W), Osmium(Os), Platinum(Pt) and Mercury(Hg) in $Z = 70 - 80$ drip-line region starting from $N =80$ to $N=170$ within the formalism of relativistic mean field (RMF) theory. We compared our results with Finite Range Droplet Model(FRDM) and experimental data and found that the calculated results are in good agreement. The nuclei $^{168}$Yb,$^{172}$Hf, $^{176}$W, $^{184}$Os, $^{188}$Pt, $^{196}$Hg are found to be most stable isotope in the respective series in the neutron-deficient region. We also observe that there is a shape transition at about $A=190$ in $Z=70-80$ region. The shape changes from oblate to highly prolate shape in their intrinsic ground state. We have also studied probable decay mechanisms of these elements.
Evolution of ground state nuclear shapes in tungsten nuclei in terms of interacting boson model
Khalaf, A. M.; El-Shal, A. O.; Taha, M. M.; El-Sayed, M. A.
2016-03-01
The tungsten nuclei 180-190W are investigated within the framework of the interacting boson model using an intrinsic coherent state formalism. The Hamiltonian operator contains only multipole operators of the subalgebra associated with the dynamical symmetries SU(3) and O(6). The study includes the behavior of potential energy surfaces (BES's) and critical points in the space of the model parameters to declare the geometric character of the tungsten isotopic chain. Some selected energy levels and reduced E2 transition probabilities B(E2) for each nucleus are calculated to adjust the model parameters by using a computer code PH INT and simulated computer fitting programme to fit the experimental data with the IBM calculation by minimizing the root mean square deviations. The 180-190W isotopes lies in shape transition SU(3)-O(6) region of the IBM such that the lighter isotopes comes very clare to the SU(3) limit, while the behavior ones tend to be near the γ-unstable O(6) limit.
Rotating nuclei: from ground state to the extremes of spin and deformation
Afanasjev, A V
2015-01-01
The rotating nuclei represent one of most interesting subjects for theoretical and experimental studies. They open a new dimension of nuclear landscape, namely, spin direction. Contrary to the majority of nuclear systems, their properties sensitively depend on time-odd mean fields and currents in density functional theories. Moreover, they show a considerable interplay of collective and single-particle degrees of freedom. In this chapter, I discuss the basic features of the description of rotating nuclei in one-dimensional cranking approximation of covariant density functional theory. The successes of this approach to the description of rotating nuclei at low spin in pairing regime and at high spin in unpaired regime in wide range of deformations (from normal to hyperdeformation) are illustrated. I also discuss the recent progress and open questions in our understanding of the role of proton-neutron pairing in rotating nuclei at $N\\approx Z$, the physics of band termination and other phenomena in rotating nuc...
On the direct nucleon decay of high-spin subbarrier single-particle states in near-magic nuclei
Chekomazov, G. A.; Urin, M. H.
1996-01-01
The description of the direct nucleon decay of high-spin subbarrier one-particle states in near-magic nuclei is attempted using a simple optical model and the simplest version of the coupled-channel approach. The branching ratios for the direct decay of the several single-neutron states in $^{209}Pb$ and $^{91}Zr$ to the ground state and to the low-lying collective states of $^{208}Pb$ and $^{90}Zr$, respectively, are evaluated. Results are compared with recent experimental data.
Superdeformation was first proposed some twenty years ago to explain the fission isomers observed in some actinide nuclei. It was later realized that superdeformed shapes can occur at high angular momentum in lighter nuclei. The interest in the mechanisms responsible for these exotic shapes has increased enormously with the discovery of a superdeformed band of nineteen discrete lines in 152Dy (8). At about the same time, evidence for highly deformed nuclei (axis ratio 3:2) was also reported near 132Ce(9). Striking properties emerged from the first experiments, such as the essentially constant energy spacing between transitions (picket-fence spectra), the unexpectedly strong population of superdeformed bands at high spins, and the apparent lack of a link between the superdeformed states and the yrast levels. These findings were reviewed by Nolan and Twin. The present article follows upon their work and discusses the wealth of information that has since become available. This includes the discovery of a new island of superdeformation near A = 190, the detailed spectroscopy of ground and excited bands in the superdeformed well near A = 150 and A = 190, the surprising occurrence of superdeformed bands with identical transition energies in nuclei differing by one or two mass units, and the improved understanding of mechanisms responsible for the feeding into and the decay out of the superdeformed states
Buendia, E; Sarsa, A
2004-01-01
Variational wave functions based on a Margenau-Brink cluster model with short range and state dependent correlations, and angular momentum projection are obtained for some nuclei with $12 \\leq A \\leq 16$. The calculations have been carried out starting from the nucleon-nucleon interaction by using the Variational Monte Carlo method. The configuration used consists of three alpha clusters located at the apexes of an equilateral triangle, and an additional cluster, not necessarily of alpha type, forming a tetrahedron. This cluster is located at the top of its height. Short-range and state dependent correlations are included by means of a central Jastrow factor and a linear operatorial correlation factor respectively. Angular momentum projection is performed by using the Peierls-Yoccoz operators. Optimal structures are obtained for all the nuclei studied. Some aspects of our methodology have been tested by comparing with previous calculations carried out without short range correlations. The binding energy, the ...
Alpha-decays to members of ground-state rotational band of heavy even-even nuclei
We apply a simple barrier penetration approach to calculate α-decay branching ratios to members of ground-state rotational band of heavy even-even nuclei. The influence of α-decay energy, the angular momentum of α-particle, and the excitation probability of the daughter nucleus is taken into account in our calculations. The theoretical branching ratios of α-transitions are found to agree with the available experimental data well. (author)
Projected Shell Model Study of Yrast States of Neutron-Deficient Odd-Mass Pr Nuclei
Ibanes, A. [Instituto de Fisica, Mexico; Ortiz, Mark E [ORNL; Velazquez, V. [Universidad Nacional Autonoma de Mexico (UNAM); Galindo-Uribarri, Alfredo {nmn} [ORNL; Hess, P. O. [Universidad Nacional Autonoma de Mexico (UNAM); Sun, Y. [Shanghai Jiao Tong University, Shanghai
2011-01-01
A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A = 130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the 125,127,129,131,133Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J (2), kinetic moment of inertia J (1), the crossing of rotational bands, and backbending effects.
Projected shell model study of yrast states of neutron-deficient odd-mass Pr nuclei
A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A=130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the 125,127,129,131,133Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J(2), kinetic moment of inertia J(1), the crossing of rotational bands, and backbending effects.
Contribution to the study of collective states of heavy nuclei by means of coulomb excitation
The following nuclei were excited by protons of 5 MeV maximum energy: 182W - 184W - 186W - 186Os - 188Os - 189Os - 190Os - 192Os - 194Pt - 196Pt - 198Pt - 198Hg - 200Hg - 202Hg - 204Hg - 206Pb. The reduced probabilities of the various transitions were deduced from the coulomb excitation cross-section measurements. For some even-even nuclei two 2 + levels were excited. The properties of the excited levels are interpreted in terms of the collective model. (author)
A method is proposed for simultaneously determining the interval of the most probable values of the density of levels excited in the radiative capture of slow neutrons and the sum of radiative E1 and M1 strength functions in the excitation-energy interval extending nearly up to the neutron binding energy. Experimental data on the intensities of two-step photon cascades between the compound state and a given low-lying level of the nucleus being studied are analyzed together with the total radiative widths of neutron resonances. Such an analysis can be performed for nuclei having an arbitrary level density, including deformed ones. The resulting data demonstrate that there are significant deviations from the predictions of commonly accepted level-density models--for example, the Fermi gas model--and specify the range of nuclei and the regions of their excitation energies where a further experimental investigation can furnish new important information about the properties of nuclear matter
Cascade. gamma. -decay of compound state of the nuclei /sup 163/Dy, /sup 167/Er and /sup 179/Hf
Boneva, S.T.; Khitrov, V.A.; Popov, Yu.P.; Sukhovoj, A.M.; Vasilieva, E.V.; Yazvitsky, Yu.S.
1988-06-01
An attempt has been made to reveal the general characteristics of two-quanta cascades, populating the low-lying states of an excitation energy < or approx.1 MeV. The difference observed between the experimental cascade intensities and statistical model calculations has been analysed. Qualitative explanation of the measured two-quanta cascade intensities was achieved in the framework of a quasi-particle phonon model description of highly excited states. A considerable enhancement was revealed of the radiative strength function of the E2-transitions in the studied nuclei.
Cascade γ-decay of compound state of the nuclei 163Dy, 167Er and 179Hf
An attempt has been made to reveal the general characteristics of two-quanta cascades, populating the low-lying states of an excitation energy < or approx.1 MeV. The difference observed between the experimental cascade intensities and statistical model calculations has been analysed. Qualitative explanation of the measured two-quanta cascade intensities was achieved in the framework of a quasi-particle phonon model description of highly excited states. A considerable enhancement was revealed of the radiative strength function of the E2-transitions in the studied nuclei. (orig.)
Grzywacz, R. [Warsaw Univ. (Poland)]|[Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Anne, R.; Auger, G.; Corre, J.M. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Borcea, C. [Institute of Atomic Physics, Bucharest (Romania); Doerfler, T. [Goettingen Univ. (Germany); Fomichov, A. [Joint Inst. for Nuclear Research, Dubna (Russian Federation); Grevy, S.; Guillemaud-Mueller, D. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Huyse, M. [Louvain Univ. (Belgium). Inst. for Nuclear- and Radiationphysics; and others
1996-09-01
Correlation between detected ions and following gamma decay of the {mu}s isomeric state provides for unambiguous identification of the nuclei implanted at the final focus of projectile fragment separators. (K.A.). 5 refs.
Improvement of sensitivity and resolution of solid state NMR for quadrupolar nuclei
In NMR measurements of quadrupolar nuclei, the spectral analysis has troublesome because of large line width of NMR peak that is caused by second-order quadrupolar interaction. As a result of application of MQMAS to structural analyses of coal and clay minerals, the substantial increase of spectral resolution archived has enabled us to elucidate their fine chemical structures. On the other hand, we have addressed establishment of STMAS method, because sensitivity of MQMAS is too low to perform the analysis of trace amounts of elements. A new developed NMR probe with feature of very precise adjustment of magic angle, which is critical in STMAS, has attained sensitivity enhancement of up to approximately 5 times compared to MQMAS. Since sensitivity and resolution of these methods are furthermore improved by the combination with high magnetic field strength, their application are promised for low-sensitive nuclei and low-level elements, which have been regarded as quite difficult to measure. (author)
Microscopic structure of high-spin vibrational states in superdeformed A=190 nuclei
Nakatsukasa, Takashi [Chalk River Labs., Ontario (Canada); Matsuyanagi, Kenichi [Kyoto Univ. (Japan); Mizutori, Shoujirou [Oak Ridge National Lab., TN (United States)] [and others
1996-12-31
Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed (SD) bands in even-even A=190 nuclei. The K = 2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. The Coriolis coupling at finite frequency produces different effects depending on the neutron and proton number of nucleus. The calculations also indicate that some collective excitations may produce moments of inertia almost identical to those of the yrast SD band. An interpretation of the observed excited bands invoking the octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in even-even SD A=190 nuclei.
Nesterenko, V O; Kleinig, W; Jolos, R V; Kvasil, J; Reinhard, P -G
2015-01-01
The lowest quadrupole $\\gamma$-vibrational $K^{\\pi}=2^+$ states in axially deformed rare-earth (Nd, Sm, Gd, Dy, Er, Yb, Hf, W) and actinide (U) nuclei are systematically investigated within the fully self-consistent separable random-phase-approximation (SRPA) based on the Skyrme functional. The energies $E_{\\gamma}$ and reduced transition probabilities $B(E2)$ of $2^+_{\\gamma}$-states are calculated with the Skyrme forces SV-mas10 and SkM$^*$. We demonstrate that the blocking effect in pairing plays an important role. It leads to a systematic downshift of $E_{\\gamma}$ by 0.3-0.5 MeV and thus to a significant improvement of agreement with the experiment, especially in Sm, Gd, Dy, Hf, and W regions. For other isotopic chains, a noticeable overestimation of $E_{\\gamma}$ and too weak collectivity of $2^+_{\\gamma}$-states still persist. It is shown that domains of nuclei with a low and high $2^+_{\\gamma}$-collectivity are related with the structure of the lowest 2-quasiparticle states and maintenance of the Nilsso...
The reduced transition probabilities for excited states of rare-earths and actinide even-even nuclei
The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models
Nuclear structure studies in the A approx. 150 region by γ-ray spectroscopy following heavy ion induced reactions are summarized. Yrast states of N = 82 nuclei close to the proton drip line have been identified as rather pure (πh/sub 11/2)/sup n/ excitations of seniority 2 and 3. The high-spin level structure of 154Dy has been determined through the 124Sn(34S,4nγ) reaction. Both the structure and the level lifetimes indicate a transition at I approx. 32 from collective to few-particle character, with possible shape changes from prolate-to-triaxial-to-oblate
Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus 208Pb
Kocheva D.
2016-01-01
Full Text Available In this work we present the results from two experiments dedicated to search for quadrupolecollective isovector valence-shell excitation, the states with so-called mixed proton-neutron symmetry (MSS, in nuclei around the doubly magic nucleus 208Pb. 212Po was studied in an α-transfer reaction. 204Hg was studied in an inverse kinematics Coulomb excitation reaction on a carbon target. Both experiments provide indications for existence of one-phonon MSSs. Those are the first experimentally identified MSSs in the mass A ≈ 208 region.
Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus
Kocheva D.; Stegmann R.; Rainovski G.; Jolie J.; Pietralla N.; Stahl C.; Petkov P.; Blazhev A.; Hennig A; Bauer C.; Braunroth Th.; Carpenter M.P.; Cortes L.; Dewald A.; Djongolov M.
2015-01-01
In this work we present the results from two experiments dedicated to search for quadrupole-collective isovector valence-shell excitation, the states with so-called mixed proton-neutron symmetry (MSS), in nuclei around the doubly magic nucleus $^{208}$Pb. $^{212}$Po was studied in an α-transfer reaction. $^{204}$Hg was studied in an inverse kinematics Coulomb excitation reaction on a carbon target. Both experiments provide indications for existence of one-phonon MSSs. Those are the first expe...
The reduced transition probabilities for excited states of rare-earths and actinide even-even nuclei
Ghumman, S. S. [Department of Physics, Sant Longowal Institute of Engineering and Technology (Deemed University), Longowal, Sangrur-148106, Punjab, India s-ghumman@yahoo.com (India)
2015-08-28
The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models.
Regan, P. H.
2015-11-01
Precision measurements of electromagnetic transition rates provide accurate inputs into nuclear data evaluations and are also used to test and validate predictions of state of the art nuclear structure models. Measurements of transition rates can be used to ascertain or rule out multipolarity assignments for the measured EM decay, thereby providing spin- and parity-difference information for states between which the EM transition takes place. This conference paper reports on a measurements of electromagnetic transition rates between excited nuclear states using coincidence `fast-timing' gamma-ray spectroscopy with cerium-doped, lanthanum-tribromide (LaBr3(Ce)) detectors. Examples of recent precision measurements using a combined LaBr3-HpGe array based at the tandem accelerator, Bucharest, Romania include studies around the N=20 and N=82 shell closures using stable-beam induced fusion-evaporation reactions; and the evolution of nuclear deformation around in neutron-rich Hf, W and Os nuclei using 7Li-induced light-ion transfer reactions. This paper also presents the ongoing development of a new multidetector LaBr3(Ce) array for future studies of exotic nuclei produced at the upcoming Facility for Anti-Proton and Ion Research (FAIR) as part of the NUSTAR-DESPEC project, and reports on the pre-NUSTAR implementations of detectors from this array to study electromagnetic transition rates in neutron-rich fission fragments at ILL-Grenoble, France and RIBF at RIKEN, Japan.
Isospin Symmetry of Odd-Odd Mirror Nuclei: Identification of Excited States in N=Z-2 48Mn
Excited states have been observed in the N=Z-2 odd-odd nucleus 48Mn for the first time. Through comparison with the structure of 48V, a first high-spin study of an odd-odd mirror pair has been achieved. Differences between the T=1 analogue states in this pair have been interpreted in terms of Coulomb effects, with the aid of shell-model calculations in the full pf valence space. Unlike other mirror pairs, the energy differences have been interpreted almost entirely as due to a monopole effect associated with smooth changes in radius (or deformation) as a function of angular momentum. In addition, the large energy shift between analogue negative-parity states is interpreted in terms of the electromagnetic spin-orbit interaction in nuclei
We present the first systematic calculations based on the angular momentum projection of cranked Slater determinants. We propose the Iy→I scheme, by which one projects the angular momentum I from the one-dimensional cranked state constrained to the average spin projection of y>=I. Calculations performed for the rotational band in 46Ti show that the AMP Iy→I scheme offers a natural mechanism for correcting the cranking moment of inertia at low spins and shifting the terminating state up by ∼2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A∼44 nuclei and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously
Zdunczuk, H; Dobaczewski, J; Kosmulski, M
2007-01-01
We present the first systematic calculations based on the angular-momentum projection of cranked Slater determinants. We propose the Iy --> I scheme, by which one projects the angular momentum I from the 1D cranked state constrained to the average spin projection of =I. Calculations performed for the rotational band in 46Ti show that the AMP Iy --> I scheme offers a natural mechanism for correcting the cranking moment of inertia at low-spins and shifting the terminating state up by ~2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A~44 nuclei, and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously.
A test experiment for the study of excited states in Z≅56, N≅80 nuclei via deep inelastic reactions
To check the feasibility of deep inelastic heavy-ion reactions in populating the high-spin states in Z ≅56, N ≅ 80 nuclei, a test experiment has been carried out by using the reaction of 410 MeV 82Se + na'tBa. γ-γ coincidence measurements have been performed using in-beam γ spectroscopy techniques. Population cross-section of excited states in both target-like fragments and projectile-like fragments have been estimated. New γ transitions were identified in several target-like fragments. A new level scheme including five new levels has been established for 136Ba. The preliminary results show that deep inelastic heavy-ion reactions are very promising for populating the excited states in the Z ≅ 56, N ≅ 80 region
Patra, S K; Centelles, M; Viñas, X
2001-01-01
Binding energies, quadrupole deformation parameters, spins and parities of the neutron-deficient odd $Z=N+1$ nuclei in the $A\\sim 80$ region are calculated in the relativistic mean field approximation. The ground-state and low-lying configurations of the recently observed $^{77}$Y, $^{79}$Zr and $^{83}$Mo nuclei are analyzed. The calculated results are compared with other theoretical predictions.
Probing single-particle and collective states in atomic nuclei with Coulomb excitation
DiJulio, Douglas
A series of experiments and developments, related to stable and radioactive isotopes, have been carried out. These studies have focused on measuring the low-lying excitations of spherical and deformed nuclei using electromagnetic (Coulomb) excitation and also on developments in detector technology for upcoming radioactive ion beams facilities. The low-lying excitations in the nuclei 107,109Sn and 107In have been investigated using low-energy Coulomb excitation at the REX-ISOLDE facility at CERN. The measured reduced transition probabilities were compared to predictions of nuclear structure models. In addition, a relativistic Coulomb excitation experiment was carried out using the FRS at GSI with the nucleus 104Sn. These radioactive ion beam experiments provide important constraints for large-scale-shell-model calculations in the region of the doubly magic nucleus 100Sn. A stable Coulomb excitation experiment was also carried out in order to explore the properties of low-lying structures in the nucleus 170Er...
The spontaneous fission half-lives for heavy and superheavy nuclei between U and Hs isotopes are calculated in framework of the generalized liquid drop model by applying a new method of numerically solving Schrödinger equation compared with the semi-empirical WKB approximation. The calculated half-lives are in very good agreement with the experimental data, indicating the reliability of the new approach. The second part of this work is to estimate the fission half-lives of 238Np⁎ at excited state of 7.3 MeV and 239U⁎ at excited states of 7.081, 8.078, 8.387 and 8.989 MeV with the numerical method. The estimated results compared with the experimental values and with the results by WKB approximation show the numerical method is applicable to both the spontaneous fission and excited fission
Ring, P; Lalazissis, G A
1997-01-01
A Fortran program for the calculation of the ground state properties of axially deformed even-even nuclei in the relativistic framework is presented. In this relativistic mean field (RMF) approach a set of coupled differential equations namely the Dirac equation with potential terms for the nucleons and the Glein-Gordon type equations with sources for the meson and the electromagnetic fields are to be solved self-consistently. The well tested basis expansion method is used for this purpose. Accordingly a set of harmonic oscillator basis generated by an axially deformed potential are used in the expansion. The solution gives the nucleon spinors, the fields and level occupancies, which are used in the calculation of the ground state properties.
Excited collective states of nuclei within Bohr Hamiltonian with Tietz-Hua potential
Chabab, M; Hamzavi, M; Lahbas, A; Oulne, M
2016-01-01
In this paper, we present new analytical solutions of the Bohr Hamiltonian problem that we derived with the Tietz-Hua potential, here used for describing the {\\beta}-part of the nuclear collective potential plus harmonic oscillator one for the {\\gamma}-part. Also, we proceed to a systematic comparison of the numerical results obtained with this kind of {\\beta}-potential with others which are widely used in such a framework as well as with the experiment. The calculations are carried out for energy spectra and electromagnetic transition probabilities for {\\gamma}-unstable and axially symmetric deformed nuclei. In the same frame, we show the effect of the shape flatness of the {\\beta}-potential beyond its minimum on transition rates calculations.
The results of our measurements on the yrare states up to spin 20(ℎ/2π) in 152,154,155Gd, using (α,xn) reactions and the AFRODITE γ-ray spectrometer, are presented. We find that in 155Gd the decay scheme is divided into levels feeding the [505]11/2- band, that is extruded by the prolate deformation from the h11/2 orbital, and levels feeding the i13/2[651]3/2+ intruder orbital and the h9/2[521]3/2- orbital. The decay scheme of 154Gd is very complex. We find no evidence for the existence of β-vibrational levels below 1.5 MeV. We discover that the level scheme can be best understood as a set of collective states built on the ground state configuration |01+> plus a 'congruent' set of collective states based on the |02+> state at 681 keV. The data suggest that this second vacuum has reduced pairing. Our data do not support IBA and phonon interpretations of these transitional nuclei
Sharpey-Schafer, J. F.; Mullins, S. M.; Bark, R. A.; Gueorguieva, E.; Kau, J.; Komati, F.; Lawrie, J. J.; Maine, P.; Minkova, A.; Murray, S. H. T.; Ncapayi, N. J.; Vymers, P.
2008-05-01
The results of our measurements on the yrare states up to spin 20ℏ in 152,154,155Gd, using (α,xn) reactions and the AFRODITE γ-ray spectrometer, are presented. We find that in 155Gd the decay scheme is divided into levels feeding the [505]11/2- band, that is extruded by the prolate deformation from the h11/2 orbital, and levels feeding the i13/2[651]3/2+ intruder orbital and the h9/2[521]3/2- orbital. The decay scheme of 154Gd is very complex. We find no evidence for the existence of β-vibrational levels below 1.5 MeV. We discover that the level scheme can be best understood as a set of collective states built on the ground state configuration |01+> plus a ``congruent'' set of collective states based on the |02+> state at 681 keV. The data suggest that this second vacuum has reduced pairing. Our data do not support IBA and phonon interpretations of these transitional nuclei.
Dogonowski, Anne-Marie; Siebner, Hartwig R; Sørensen, Per Soelberg;
2013-01-01
matched controls underwent a 20-minute resting-state fMRI session at 3 Tesla. Independent component analysis was applied to the fMRI data to identify disease-related changes in motor resting-state connectivity. RESULTS: Patients with MS showed a spatial expansion of motor resting-state connectivity in...
It has been shown previously that, below a critical angular momentum, yrast bands of non-magic nuclei are well described by the two-parameter variable moment of inertia model. Some striking exceptions to this rule are found in nuclei which have the same mass number as doubly magic nuclei but possess either one (or two) proton pairs beyond a magic number and one (or two) neutron hole pairs, or vice versa. Yrast bands in these 'pseudomagic' nuclei resemble those in magic nuclei. (author)
This thesis is devoted to the study of very neutron deficient nuclei in the lead region of the nuclear chart and more precisely to the investigation of the single particle states and collective properties of the 187,189Bi isotopes by gamma-ray spectroscopy. These nuclei were produced via fusion-evaporation reaction induced by a krypton beam on a silver target. In this mass region, the cross section for producing these nuclei are very low, of the order of a few micro-barns, making experimental studies very difficult. The identification of the nuclei was done using the very powerful RDT (Recoil Decay Tagging) technique, based on the selection of the isotopes through their characteristic alpha-particle decays. The experiments were performed at the university of Jyvdskyla (Finland) with the facility combining the gamma-ray spectrometer JUROSPHERE and the magnetic gas-filled separator RITU. Isomeric states were observed in both nuclei and their life-times measured. The systematics of individual proton states in odd-mass bismuth isotopes have been reproduced with a shell model up to 20 neutrons away from the valley of stability. Furthermore, rotational bands, a signature of collective nuclear motion, have been established for the first time in these nuclei. The interpretation of these results led to the conclusion that 187,189Bi have a prolate shape at low excitation energy, unlike the heavier bismuth isotopes which have been interpreted to have oblate deformation, implying a shape transition in this mass region. Hartree-Fock-Bogolyubov calculations are consistent with the experimental indication of shape coexistence, as seen in the neighbouring even-even lead nuclei. (author)
Description of the interplay between different nuclear shapes is an interesting but challenging problem. The original projected shell model (PSM) is applicable to nuclei with fixed shapes. We extend the PSM by superimposing (angular-momentum- and particle-number-) projected product wave functions in the spirit of the generate coordinate method. With this development, the Gd isotopes across the N = 90 region are studied, and the results indicate spectroscopic features of shape phase transition with varying neutron number. In order to illustrate the shape distribution in microscopic wave functions, we introduce a deformation representation and show that the collectively excited Kπ= 0+ states in the Gd isotopes have characters of shape vibration. (authors)
Nuclear halo and its scaling laws in the excited states of nuclei near the β-stability line
The excited states of some odd A nuclei near the stability line have been systematically investigated from light to intermediate mass with the spherical relativistic mean field (RMF) model. The ratio between the valence nucleon root-mean-square (RMS) radius and the core rms radius, the separation energy and the density distribution have been deduced as signatures for halo or skin structure. We have presented the scaling laws of the ratio of valence particle rms radii and square-potential radii versus the scaled separation energies. The probability for a valence particle being out of the binding potential has also been extracted. We proposed a relaxed necessary condition for nuclear halo occurrence. (author)
Jin, Guanghao; Yoon, Jin-Hee; Cha, Dongwoo
2008-03-01
We examine the effects of the additional term of the type {\\sim} e^{- \\lambda^{\\prime} N_pN_n} on the recently proposed empirical formula for the lowest excitation energy of the 2+ states in even-even nuclei. This study is motivated by the fact that this term carries the favorable dependence of the valence nucleon numbers dictated by the NpNn scheme. We show explicitly that there is not any improvement in reproducing Ex(2+1) by including the extra NpNn term. However, our study also reveals that the excitation energies Ex(2+1), when calculated by the NpNn term alone (with the mass number A dependent term), are quite comparable to those calculated by the original empirical formula.
The All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer has continuously monitored a number of active galactic nuclei (AGNs) with similar sampling rates for 14 years, from 1996 January to 2009 December. Utilizing the archival ASM data of 27 AGNs, we calculate the normalized excess variances of the 300-day binned X-ray light curves on the longest timescale (between 300 days and 14 years) explored so far. The observed variance appears to be independent of AGN black-hole mass and bolometric luminosity. According to the scaling relation of black-hole mass (and bolometric luminosity) from galactic black hole X-ray binaries (GBHs) to AGNs, the break timescales that correspond to the break frequencies detected in the power spectral density (PSD) of our AGNs are larger than the binsize (300 days) of the ASM light curves. As a result, the singly broken power-law (soft-state) PSD predicts the variance to be independent of mass and luminosity. Nevertheless, the doubly broken power-law (hard-state) PSD predicts, with the widely accepted ratio of the two break frequencies, that the variance increases with increasing mass and decreases with increasing luminosity. Therefore, the independence of the observed variance on mass and luminosity suggests that AGNs should have soft-state PSDs. Taking into account the scaling of the break timescale with mass and luminosity synchronously, the observed variances are also more consistent with the soft-state than the hard-state PSD predictions. With the averaged variance of AGNs and the soft-state PSD assumption, we obtain a universal PSD amplitude of 0.030 ± 0.022. By analogy with the GBH PSDs in the high/soft state, the longest timescale variability supports the standpoint that AGNs are scaled-up GBHs in the high accretion state, as already implied by the direct PSD analysis.
Effect of phonon interaction on the ground state of even-even spherical nuclei
The equations for calculating the energy and the structure of the excited states with the wave function containing one- and two-phonon components are obtained. The phonon correlations in the ground state of the nucleus due to the interaction of the phonon modes excitation are taken into account. The numerical estimations of the phonon correlations influence on the energy of the lowest excited states are given
Mean field description of the ground state of many boson systems relevant to nuclei
In the present paper we give the explicit expressions for the ground state of a many boson system in different mean field approximations, such as Hartree-Bose, Bogoliubov, the particle-hole random phase approximation (RPA), and its coupling with the particle-particle (RPA). The ground states obtained satisfy the requirement that the annihilation operators of the ''elementary excitations'' annihilates them. In all cases the ground state wave functions can be understood as a condensate of pairs of bosons
Skyrme RPA description of γ-vibrational states in rare-earth nuclei
Nesterenko V.O.
2016-01-01
Full Text Available The lowest γ-vibrational states with Kπ = 2+γ in well-deformed Dy, Er and Yb isotopes are investigated within the self-consistent separable quasiparticle random-phase-approximation (QRPA approach based on the Skyrme functional. The energies Eγ and reduced transition probabilities B(E2γ of the states are calculated with the Skyrme force SV-mas10. We demonstrate the strong effect of the pairing blocking on the energies of γ-vibrational states. It is also shown that collectivity of γ-vibrational states is strictly determined by keeping the Nilsson selection rules in the corresponding lowest 2qp configurations.
Skyrme RPA description of γ-vibrational states in rare-earth nuclei
Nesterenko V.O.; Kartavenko V.G.; Kleinig W.; Kvasil J.; Repko A.; Jolos R.V.; Reinhard P.-G.
2016-01-01
The lowest γ-vibrational states with Kπ = 2+γ in well-deformed Dy, Er and Yb isotopes are investigated within the self-consistent separable quasiparticle random-phase-approximation (QRPA) approach based on the Skyrme functional. The energies Eγ and reduced transition probabilities B(E2)γ of the states are calculated with the Skyrme force SV-mas10. We demonstrate the strong effect of the pairing blocking on the energies of γ-vibrational states. It is also shown that collectivity of γ-vibration...
Miyazawa, Hideyuki; Tanaka, Hajime
2007-07-01
It is a fundamental physical problem how a state is selected in a nonequilibrium steady state where the energy is continuously dissipated. This problem is common to phase transitions in liquids under shear flow and those in solids under deformation or electric current. In particular, soft matter often exhibits a strong nonlinear response to an external field, since its structural susceptibility to the external field is extremely large due to its softness and flexibility. Here we study the nucleation and growth process of the lamellar phase from the sponge phase under shear flow in a bilayer-forming surfactant system. We found an interesting shape selection of lamellar nuclei under shear flow between multilamellar vesicles (onions) and cylinders (leeks). These two types of behavior are separated sharply at a critical shear rate: a slight change of the shear rate is enough to switch one behavior to the other. We also found that, under a sufficiently strong shear flow, nucleated onions decrease their size with time, and eventually transform into leeks. This suggests that leeks may be the stable morphology under steady shear flow. However, the stability is limited only to the lamellar-sponge coexistence region. When a system enters into the lamellar phase region by further cooling, leeks lose their stability and break up into rather monodisperse onions, presumably via Rayleigh-like instability of a fluid tube. On the basis of these results, we draw a dynamic state diagram of smectic membrane organization under shear flow.
Yoshinaga, N.; Arima, A.; Zhao, Y. M.
2006-01-01
In this report we study the origin of spin-zero ground-state dominance for even-even nuclei in the presence of random two-body interactions. We evaluate the ground-state energy in terms of the energy centroid and the width of the random Hamiltonian. For both fermions and bosons in a single orbital, we obtain excellent agreement between the spin-I ground state probabilities predicted by using our formula and those obtained by diagonalizing the random Hamiltonian.
Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force
Nomura, K; Robledo, L M
2015-01-01
Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean field calculations with the Gogny energy density functional. The link between both frameworks is the ($\\beta_2\\beta_3$) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive and negative parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited $0^{+}$ states and its connection with double octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and o...
Study of some excited states in 21Ne-21Na, 18O-18F and 15N-15O nuclei
The study of 21Ne-21Na, 18O-18F and 15N-15O nuclei was performed through proton capture and transfer reactions and allows to determine the spins and parities of some excited states, give the gamma deexcitation schemes of these levels, compute the neutron and proton reduced width γ2sub(n) and γ2sub(p). The levels studied are: in 21Na 4.1520Ne(p,p), (p,p'), (p,p'γ) and (pγ) reactions) and in 21Ne: E(exc)=4.73, 5.69 and 5.78 MeV (20Ne (p,p) reaction); in 18O: E(exc)17O(d,p) reaction); in 15O: 8.92 MeV doublet and 8.98 MeV level (angular correlation 14N(p,γγ) and in 15N: 9.0514N(d,p) reaction). A comparison with theoretical results is discussed and analog states are pointed out
The topics presented at the 1989 Joliot-Curie Lectures are reported. Two main subjects were retained: a simplified description of the N-body motion of particles in the quasi-particle configuration; study of the dynamics of nuclear components which are not described by nucleons in their ground state. The following themes were presented: quasiparticles and the Green functions, relativistic aspects of the quasiparticle concept, the dimensions of nucleons in the nuclei and the EMC effect, quarks and gluons in the nuclei, the delta in the nuclei, the strangeness, quasiparticles far from the Fermi sea, diffusion of electrons, stellar evolution and nucleosynthesis
A MAG spectrometer is designed to analyze kinematics of hadron-nuclear interactions with identification of nucleus final state. Spectrometer consists of a wide-aperture magnetic spectrometer with proportional chambers, scintillation counters, hodoscopes and a Ge(Li)-detector base γ-spectrometer. Paper describes an electronic system for acquisition and processing of spectrometric information. MAG spectrometer ensures ∼ 1.2 mm coordinate resolution and 3 mrad angular resolution. Its average efficiency within 0-5 deg angle range is equal to 85%. Energy resolution of γ-spectrometer is equal to 8 and 16 keV at 0.5 and 2.0 MeV photon energy, respectively. Error of 1 GeV energy particle pulse damnation constitutes 2.2%. Resolution of two-particle state efficient mass is equal to 14 MeV/s2
Octupole correlations in positive-parity states of rare-earth and actinide nuclei
Spieker M.
2015-01-01
Full Text Available In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite Jπ = 0+ states in 240Pu. spdf interacting boson model (IBM calculations suggest that the previously proposed double-octupole phonon nature of the Jπ = 0+2 state is not in conflict with its strong (p, t population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positiveand negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (Jπ = 10+ leading to the change in yrast structure observed in 146Nd.
In-beam studies of high-spin states of actinide nuclei
High-spin states in the actinides have been studied using Coulomb- excitation, inelastic excitation reactions, and one-neutron transfer reactions. Experimental data are presented for states in 232U, 233U, 234U, 235U, 238Pu and 239Pu from a variety of reactions. Energy levels, moments-of-inertia, aligned angular momentum, Routhians, gamma-ray intensities, and cross-sections are presented for most cases. Additional spectroscopic information (magnetic moments, M1/E2 mixing ratios, and g-factors) is presented for 233U. One- and two-neutron transfer reaction mechanisms and the possibility of band crossings (backbending) are discussed. A discussion of odd-A band fitting and Cranking calculations is presented to aid in the interpretation of rotational energy levels and alignment. In addition, several theoretical calculations of rotational populations for inelastic excitation and neutron transfer are compared to the data. Intratheory comparisons between the Sudden Approximation, Semi-Classical, and Alder-Winther-DeBoer methods are made. In connection with the theory development, the possible signature for the nuclear SQUID effect is discussed. 98 refs., 61 figs., 21 tabs
Final-state interaction in semi-inclusive DIS off nuclei
Ciofi degli Atti, C
2003-01-01
The Final-State Interaction (FSI) in Deep-Inelastic Scattering (DIS) of leptons off a nucleus A, due to the propagation of the struck nucleon debris and its hadronization in the nuclear environment is considered. The effective cross-section of such a partonic system with the nucleons of the medium and its time dependence are estimated, for different values of the Bjorken scaling variable, on the basis of a model which takes into account both the production of hadrons due to the breaking of the color string, which is formed after a quark is knocked out off a bound nucleon, as well as the production of hadrons originating from gluon radiation. It is shown that the interaction, the evolution and the hadronization of the partonic system in the nuclear environment can be thoroughly investigated by a new type of semi-inclusive process, denoted A(e,e'(A-1))X, in which the scattered lepton is detected in coincidence with a heavy nuclear fragment, namely a nucleus (A-1) in low energy and momentum states. As a matter o...
In-beam studies of high-spin states of actinide nuclei
Stoyer, M.A. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div. California Univ., Berkeley, CA (USA). Dept. of Chemistry)
1990-11-15
High-spin states in the actinides have been studied using Coulomb- excitation, inelastic excitation reactions, and one-neutron transfer reactions. Experimental data are presented for states in {sup 232}U, {sup 233}U, {sup 234}U, {sup 235}U, {sup 238}Pu and {sup 239}Pu from a variety of reactions. Energy levels, moments-of-inertia, aligned angular momentum, Routhians, gamma-ray intensities, and cross-sections are presented for most cases. Additional spectroscopic information (magnetic moments, M{sub 1}/E{sub 2} mixing ratios, and g-factors) is presented for {sup 233}U. One- and two-neutron transfer reaction mechanisms and the possibility of band crossings (backbending) are discussed. A discussion of odd-A band fitting and Cranking calculations is presented to aid in the interpretation of rotational energy levels and alignment. In addition, several theoretical calculations of rotational populations for inelastic excitation and neutron transfer are compared to the data. Intratheory comparisons between the Sudden Approximation, Semi-Classical, and Alder-Winther-DeBoer methods are made. In connection with the theory development, the possible signature for the nuclear SQUID effect is discussed. 98 refs., 61 figs., 21 tabs.
Ground-state shape phase transitions in nuclei: Thermodynamic analogy and finite-N effects
We study quantum phase transitions between spherical, prolate, and oblate nuclear ground-state shapes using the interacting sd-boson model (sd-IBM) and demonstrate the analogy between the IBM results (also results of any axially symmetric quadrupole collective model) and predictions of the Landau theory of phase transitions in classical thermodynamics. A detailed comparison of the two frameworks is performed exploiting the concept of 'specific heat', introduced in four alternative ways in the quantum case. All these definitions (two of them based on spectroscopic features of the ground state, the others on a randomized version of the model) lead to similar peaked forms of the 'specific heat' at the point of the quantum phase transition. We analyze the effect of an increasing boson number on these curves and observe convergence to the singular phase-transitional behavior in the classical limit. Other observable signatures of the IBM structural phase transitions are also discussed with the aim to facilitate the location of a particular nucleus in the parameter space (extended Casten triangle) near the transitions
Hyperon-nucleon bound states and electroproduction of strangeness on light nuclei.
Dohrmann, F.; Abbott, D.; Ahmidouch, A.; Ambrozewicz, P.; Armstrong, C. S.; Arrington, J.; Bailey, K.; Cummings, W. J.; Gao, H.; Garrow, K.; Geesaman, D. F.; Hafidi, K.; Hansen, J. O.; Jackson, H. E.; Mueller, B.; O' Neill, T. G.; Potterveld, D.; Reimer, P. E.; Reinhold, J.; Zeidman, B.
2002-06-25
The A(e,e{prime}K{sup +})Y X reaction has been investigated in Hall C at Jefferson Lab. Data were taken for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at a beam energy of 3.245 GeV for {sup 1}H, {sup 2}H, {sup 3}He and {sup 4}He, C and Al targets. The missing mass spectra are fitted with Monte Carlo simulations including {Lambda}, {Sigma}{sup 0}, {Sigma}{sup -} hyperon production. Models for quasifree production are compared to the data, excess yields close to threshold are attributed to FSI. Evidence for {Lambda}-hypernuclear bound states is seen for {sup 3,4}He targets.
Study of the superdeformed states of the gadolinium nuclei: neutron excitations in 147Gd nucleus
This work is devoted to nuclear structure studies of superdeformed states in the second potential well. Under focus are the gadolinium isotopes and in particular the 147Gd nucleus. High spin states in 147Gd have been populating by 122Sn (30Si,5n)147Gd fusion-evaporation reaction with a silicon beam of 158 MeV delivered by the VIVITRON accelerator of the Institut de Recherches Subatomiques. The nucleus γ de-excitations have been measured using the EUROGAM II γ-ray multidetector. On the basis of multiple coincidences, four new superdeformed (SD) rotational bands have been assigned to 147Gd nucleus. Nuclear structures corresponding to these bands have been investigated by shell model calculations using a harmonic oscillator potential with cranking, in the Nilsson Strutinsky formalism. Comparison of dynamical moments of inertia of band (1) and (5) in 147Gd with 148Gd(2) and 146Gd(1) SD bands has fixed the role of the [651 1/2]α = -1/2 orbital crossing frequency. Theoretical calculations reproduce quite well the 148Gd(2), 127Gd(1,5) and G146Gd(1) dynamical moments of inertia. Using the particle hole excitation nature of 149,148,147,146Gd bands, effective spin alignment of [651 1/2]α= ±1/2, [770 1/2]α = -1/2 and [441 1/2]α = +1/2 orbitals have been deduced from the experiment in agreement with the theoretical values. Of particular interest, the spin alignment measured for the [441 1/2]α +1/2 orbital, with a value close to zero, is in contradiction with the value predicted by the Pseudo SU(3) model, formalism often used to explain the identical band phenomenon. (author)
The influence of the mechanisms of nuclear reactions on the population of 195mHg and 197mHg(7/2−), 198mTl and 196mTl(7+), and 196mAu and 198mAu(12−) isomeric nuclear states obtained in reactions induced by beams of 3He, 6Li, and 6He weakly bound nuclei is studied. The behavior of excitation functions and high values of isomeric ratios (δm/δg) for products of nuclear reactions proceeding through a compound nucleus and involving neutron evaporation are explained within statistical models. Reactions in which the emission of charged particles occurs have various isomeric ratios depending on the reaction type. The isomeric ratio is lower in direct transfer reactions involving charged-particle emission than in reactions where the evaporation of charged particles occurs. Reactions accompanied by neutron transfer usually have a lower isomeric ratio, which behaves differently for different direct-reaction types (stripping versus pickup reactions)
Solid state NMR study of quadrupolar nuclei at high magnetic fields
Padro, D
2002-01-01
Solid state sup 4 sup 7 sup , sup 4 sup 9 Ti NMR spectra have been obtained for a large number of titanium oxides at a field of 14.1 T. At this field a usable signal has been obtained in almost all Ti sup 4 sup + compounds investigated allowing reliable measurement of shifts and electric field gradients (EFG) up to 24 MHz. For samples where the efg was less than 5 MHz Magic Angle Spinning at 17 kHz gave extra resolution. The effects of chemical shift anisotropy (DELTA sub c sub s > 150 ppm) were detected and were measured in various cases. In order to investigate the potential of titanium NMR as a structural probe a number of compounds containing titanium in different coordination have been studied. The EFG at TiO sub 4 , TiO sub 5 and TiO sub 6 sites was found to correlate well with the shear strain independent of the structure. The chemical shift in perovskite and related structures varies by approx 160. Results for sup 4 sup 7 sup , sup 4 sup 9 Ti NMR in model compounds where titanium is in 4-fold and 5-fo...
The nuclei far from the β-stability valley which are referred to as exotic nuclei have attracted considerable interest in recent years. Undoubtedly the study of the exotic nuclei is destined to be one of the frontier fields in nuclear structure physics. The recent experiments with radioactive beams have opened up this new era in nuclear spectroscopy. The lighter exotic nuclei are observed to show quite interesting features. For example, a halo structure has been attributed to 11Li in order to explain the observed large matter radius. Also, it is seen that 31--33Na show deformed characteristics rather than the spherical shape expected from the shell closure at N = 20. This points towards a need for a new investigation of the shell structure as one moves away from the β - stability valley. With the aforementioned interesting features observed for the lighter nuclei, clearly one question of great interest is whether similar effects can be seen in heavy nuclei. New calculations using the relativistic mean field approach have been performed for a range of nuclei over a wide range of isotopes up to those with a large excess of neutrons. In the present talk, some interesting new results obtained from these calculations win be discussed
Measurement of lifetimes of high spin states in the N = 106 nuclei {sup 183}Ir and {sup 182}Os
Ahmad, I.; Blumenthal, D.; Carpenter, M.P. [and others
1995-08-01
Lifetimes of high spin states in the isotones {sup 183}Ir and {sup 182}Os were measured using the Notre Dame plunger device in conjunction with the Argonne Notre Dame {gamma}-ray facility. The aim of these measurements was to determine the deformation-driving properties of the h{sub 9/2} proton intruder orbital by comparing the values of the intrinsic quadrupole moments in the ground state bands in the odd-mass Ir nucleus and the even-even Os core. Levels in these nuclei were populated by the {sup 150}Nd ({sup 37}Cl,4n) and {sup 150}Nd ({sup 36}S,4n) reactions using a {sup 37}Cl beam of 169 MeV and 164-Mev {sup 36}S beam. The {sup 150}Nd target was 0.9-g/cm{sup 2} thick and was prepared by evaporating enriched {sup 150}Nd onto a stretched 1.5-mg/cm{sup 2} gold foil. The target was covered with a layer of a 60-{mu}g/cm{sup 2} Au to prevent its oxidation. Gamma-ray spectra were accumulated for approximately 4 hours for each target-stopper distance. Data were collected for 20 target-stopper distances ranging from 16 {mu}m to 10.4 mm. Preliminary analysis indicates that it will be possible to extract the lifetimes of the levels in the yrast bands up to and including part of the backbending region with sufficient accuracy. Detailed analysis of the data is in progress.
Full text: It is interesting to obtain values of asymptotical normalization coefficients (ANC) of overlapping functions for a few first levels of bound state of nuclei 14N and 20Ne for calculation of astrophysical S-factors of radiative proton capture 13C(p,γ )14N and 19F(p,γ )20Ne. For this purpose the differential cross sections of the reaction 19F(3He,d20Ne at projectile beam of 3He with energy of 22.3 MeV measured at angels of forward hemisphere and cross sections of reaction 13C(3He,d)14N at region of main stripping peak have been analyzed. The experimental values are taken from our earlier work [1]. At that work the role of coupling channels and contribution of peripheral processes into the amplitude of the reaction were analyzed. In present work in frame of modified DWBA [2, 3] empirical values of ANC of proton binding have been obtained. In frame of EPN [4, 5] method the values of asymptotical coefficients b of bound state function for bindings 14N->13C+p and 20Ne->19F+ p for a few first levels have been calculated. With the values of ANC and b the empirical values of spectroscopic factors have been calculated. The theoretical values of ANC corresponding shell model were calculated with the theoretical values of spectroscopic factors known from literature. Some comparative analysis is made. An opportunity of using the data for estimation of contribution of direct processes into cross section of radiative proton capture is discussed. The work is supported by grant Uzbek Acad. Sci. No 5-04
Microscopic model for three-cluster configuration of light nuclei has been formulated in the frameworks of resonating group method in its algebraic version. The model has been applied for the ground states of 6He and 8He in configuration of α-particle plus two n-clusters and α-particle plus two 2n-clusters. The results have been obtained emphasize the importance of three-cluster moving mode for adequate description of nuclear properties, especially neutron halo
Collective states of the odd-mass nuclei within the framework of the Interacting Vector Boson Model
Ganev, H. G.
2007-01-01
A supersymmetric extension of the dynamical symmetry group $Sp^{B}(12,R)$ of the Interacting Vector Boson Model (IVBM), to the orthosymplectic group $OSp(2\\Omega/12,R)$ is developed in order to incorporate fermion degrees of freedom into the nuclear dynamics and to encompass the treatment of odd mass nuclei. The bosonic sector of the supergroup is used to describe the complex collective spectra of the neighboring even-even nuclei and is considered as a core structure of the odd nucleus. The f...
Gysel, M.; Laborde, M.; Bukowiecki, N.; Juranyi, Z.; Hammer, E.; Zieger, P.; Baltensperger, U.; Weingartner, E.
2012-12-01
Black carbon (BC) emitted from combustion sources is the major absorbing component of atmospheric aerosols. The Earth's climate can be influenced by BC particles in several ways, e.g. through absorption of solar radiation or through decreasing the surface albedo of glaciers due to deposited BC particles. Cloud droplets only form on cloud condensation nuclei (CCN). The CCN activation behaviour of BC particles is important for their atmospheric life cycle as wet removal is an important sink. Several laboratory and field studies have shown that BC is less hygroscopic and less CCN active than inorganic or water-soluble organic aerosol components. The goal of this study was to investigate the CCN activation behaviour of BC-containing particles in dependence of their mixing state and compared to non-BC containing particles. In situ measurements of the cloud droplet activation behaviour of aerosol particles were done in winter 2010 at the high-alpine research station Jungfraujoch (3580 m asl), Switzerland. Two different inlets were employed during cloud episodes to selectively collect the interstitial aerosol (all particles that did not form cloud droplets) as well as the total aerosol (interstitial aerosol plus cloud droplet residuals). Both types of aerosol samples were characterized using a Single Particle Soot Photometer (SP2), providing quantitative measurement of BC mass in individual particles as well as information on the mixing state of BC, and further aerosol measurement techniques. Outdoor measurements of microphysical cloud properties were also available. Comparison of the aerosol samples from the interstitial and total inlets makes it possible to determine the properties of the CCN active aerosol as opposed to the interstitial aerosol. The analysis of several cloud events revealed that coated BC particles are more readily activated to CCN compared to uncoated BC particles with equal BC mass. This can actually be expected even for non-hygroscopic coatings due
Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru
2008-04-01
Studies at the RIKEN RI beam factory / T. Motobayashi -- Dilute nuclear states / M. Freer -- Studies of exotic systems using transfer reactions at GANIL / D. Beaumel et al. -- First results from the Magnex large-acceptance spectrometer / A. Cunsolo et al. -- The ICHOR project and spin-isospin physics with unstable beams / H. Sakai -- Structure and low-lying states of the [symbol]He exotic nucleus via direct reactions on proton / V. Lapoux et al. -- Shell gap below [symbol]Sn based on the excited states in [symbol]Cd and [symbol]In / M. Górska -- Heavy neutron-rich nuclei produced in the fragmentation of a [symbol]Pb beam / Zs. Podolyák et al. -- Breakup and incomplete fusion in reactions of weakly-bound nuclei / D.J. Hinde et al. -- Excited states of [symbol]B and [symbol]He and their cluster aspect / Y. Kanada-En'yo et al. -- Nuclear reactions with weakly-bound systems: the treatment of the continuum / C. H. Dasso, A. Vitturi -- Dynamic evolution of three-body decaying resonances / A. S. Jensen et al. -- Prerainbow oscillations in [symbol]He scattering from the Hoyle state of [symbol]C and alpha particle condensation / S. Ohkubo, Y. Hirabayashi -- Angular dispersion behavior in heavy ion elastic scattering / Q. Wang et al. -- Microscopic optical potential in relativistic approach / Z.Yu. Ma et al. -- Exotic nuclei studied in direct reactions at low momentum transfer - recent results and future perspectives at fair / P. Egelhof -- Isotopic temperatures and symmetry energy in spectator fragmentation / M. De Napoli et al. -- Multi-channel algebraic scattering theory and the structure of exotic compound nuclei / K. Amos et al. -- Results for the first feasibility study for the EXL project at the experimental storage ring at GSI / N. Kalantar-Nayestanaki et al. -- Coulomb excitation of ISOLDE neutron-rich beams along the Z = 28 chain / P. Van Duppen -- The gamma decay of the pygmy resonance far from stability and the GDR at finite temperature / G. Benzoni et al
Doma, S B
2002-01-01
Phenomenological nucleon-nucleon interaction consisting of central, tensor, spin-orbit and quadratic spin-orbit terms, with Gaussian radial dependence, are constructed by varying their parameters in order to obtain the best fit between the calculated and the experimental values of the binding energy, the root mean-square radius, the D-state probability, the magnetic dipole moment and the electric quadrupole moment of deuteron. The ground-state nuclear wave function of deuteron is expanded in terms of the translation-invariant shell model basis functions corresponding to the number of quanta of excitation 0 <= N <=10. Moreover, the binding energy, the root mean-square radius and the magnetic dipole moment of the nuclei sup 3 H, sup 4 He, sup 5 He and sup 6 Li are also calculated by using the new interactions. The wave functions of these nuclei are expanded in terms of the basis functions of the translation-invariant shell model with N = 10 for the first tow nuclei, N = 7 for sup 5 he and N = 6 for sup 6 ...
The power law suggests that the spin is varied with non integer spin more appropriately than other energy expressions. The PL gives the better fit of the energy because the RMSD is very smaller in comparison to SRF for Nd nuclei
Brown, B.Alex; Schwenk, A.
2014-01-01
We use properties of doubly-magic nuclei and ab-initio calculations of low-density neutron matter to constrain Skyrme equations of state for neutron-rich conditions. All of these properties are consistent with a Skyrme functional form and a neutron-matter equation of state that depends on three parameters. With a reasonable range for the neutron-matter effective mass, the values of the two other Skyrme parameters are well constrained. This leads to predictions for other quantities. The neutro...
Mareš, Jiří; Friedman, E.; Gal, A.
-, č. 56 (2006), s. 95-98. ISSN 0323-0465 R&D Projects: GA AV ČR IAA1048305 Institutional research plan: CEZ:AV0Z10480505 Keywords : key words * kaonic nuclei * Kbar-nucleus interactions Subject RIV: BE - Theoretical Physics Impact factor: 0.647, year: 2006
Energy sharing in the decay of the compound nuclei 44Ti and 90Ru excited in high spin states
A detailed study of the decay of 44Ti and 90Ru compound nuclei, via two particle channels involving at least one alpha particle has been performed for the p,α and 2 α channels. This was possible using the combination of the two powerful experimental apparatuses DIAMANT and EUROGAM II. A peculiar behaviour of the energy sharing between the two light particles was found for both systems as a function of the excitation energy in the residual nuclei. Notably, the proton energies are almost independent of the residual nucleus excitation energies Ef while the alpha particle energies decrease when the Ef rises. This experimental results obtained for the first time in exclusive measurements were confirmed also in simulations. It was shown that the implied particles in the compound nucleus decay do not play the same role in the energy sharing. In the case of 90Ru a strong correlation between the residual nucleus excitation energy and its angular momentum was observed
Kelkar, N G; Moskal, P
2015-01-01
The possibility for the existence of unstable bound states of the S11 nucleon resonance N$^*$(1535) and nuclei is investigated. These quasibound states are speculated to be closely related to the existence of the quasibound states of the eta mesons and nuclei. Within a simple model for the N N$^*$ interaction involving a pion and eta meson exchange, N$^*$-nucleus potentials for N*-$^3$He and N*-$^{24}$Mg are evaluated and found to be of a Woods-Saxon like form which supports two to three bound states. In case of N*-$^3$He, one state bound by only a few keV and another by 4 MeV is found. The results are however quite sensitive to the N N$^*$ $\\pi$ and N N$^*$ $\\eta$ vertex parameters. A rough estimate of the width of these states, based on the mean free path of the exchanged mesons in the nuclei leads to very broad states with $\\Gamma \\sim$ 80 and 110 MeV for N*-$^3$He and N*-$^{24}$Mg respectively.
Błaszczak, Z; Marinova, K; LASER 2006
2007-01-01
7th International Workshop on Application of Lasers in Atomic Nuclei Research, LASER 2004, held in Poznan, Poland, May 29-June 01, 2006 Researchers and PhD students interested in recent results in the nuclear structure investigation by laser spectroscopy, the progress of the experimental technique and the future developments in the field will find this volume indispensable. Reprinted from Hyperfine Interactions (HYPE) Volume ???
Doma, S B
2016-01-01
The method of group theory is applied to investigate the ground and the excited states of the triton and helium nuclei by using the translation invariant shell model with basis functions corresponding to even number of quanta of excitations in the range 0 less than or equal to N less than or equal to 20. Accordingly, the ground and first excited state wave functions and energies, the S, P and D state probabilities, the root mean square radius and the magnetic dipole moment of triton have been investigated. Also, the energies and wave functions of the ground and the even parity excited states and the root mean square radius of helium have been investigated. Two residual two body interactions together with two three nucleon interactions have been used in the calculations. Moreover, the convergence of calculations has been examined by extrapolating the results with N less than or equals to 20 step by step to reach N equals to 30 for the two nuclei.
Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states of T=1, Tz=±1 nuclei to the common excited states of the Tz=0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow-Teller (GT) transitions obtained from a (p,n)-type charge-exchange reaction on a target nucleus with Tz=1 with those from the β-decay of the Tz=-1 nucleus. The A=58 system is the heaviest for which such a comparison is possible. As a part of the symmetry study, we measured the GT transitions from 58Ni (Tz=1) to 58Cu (Tz=0) by using the zero-degree (3He,t) reaction at 150 MeV/nucleon. With the achieved resolution of 50 keV, many hitherto unresolved GT states have been identified. The GT transition strengths were obtained for states up to 8 MeV excitation, i.e., near to the Q window limitation (QEC=9.37 MeV) of the β-decay from 58Zn (Tz=- 1) to 58Cu. The strength distribution is compared with that from shell-model calculations. (orig.)
D I Salmov; T Babacan; A Kücükbursa; S Ünlü; İ Maraṣ
2006-06-01
Within the framework of quasiparticle random phase approximation (QRPA), Pyatov–Salamov method [23] for the self-consistent determination of the isovector effective interaction strength parameter, restoring a broken isotopic symmetry for the nuclear part of the Hamiltonian, is used. The isospin admixtures in the ground state of the parent nucleus, and the isospin structure of the isobar analog resonance (IAR) state were investigated with the inclusion of the pairing correlations between nucleons for the medium and heavy mass regions: 80 < < 90, 102 < < 124, and 204 < < 214. It was determined that the influence of the pairing interaction between nucleons on the isospin admixtures in the ground state and the isospin structure of the IAR state is more pronounced for the light isotopes ( ≈ ) of the investigated nuclei.
4 nuclei of Nickel-48 have been produced in the GANIL accelerator. This nucleus is made up of 28 protons and 20 neutrons, it has at least 10 neutrons less than natural nickel but it is doubly magic: both protons and neutrons are distributed on full shells. It appears as if being doubly magic could compensate for the instability due to the shortage of neutrons. (A.C.)
Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1998-07-22
For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.
Theoretical analysis of an Uqp(u2) model for ground-state bands in even-even nuclei
The validity of an Uqp(u2) model for the nuclear rotational spectrum is systematically analysed by investigating the Mallmann plots and fitting the experimental data for the even-even rare-earth and actinide nuclei. The results show that the theoretical values obtained from the Uqp(u2) model are in a good accordance with the experimental findings. Thus the Uqp(u2) model has some advantages over the SUq(2) model as far as energy levels are concerned. Further more, a relationship between the parameters of deformations and the nuclear softness is also established
Experimental and theoretical aspects of the multiple-quantum magic-angle spinning experiment (MQMAS) are discussed in this review. The significance of this experiment, introduced by Frydman and Harwood, is in its ability to provide high-resolution NMR spectra of half-integer quadrupolar nuclei (I /geq 3/2). This technique has proved to be useful in various systems ranging from inorganic materials to biological samples. This review addresses the development of various pulse schemes aimed at improving the signal-to-noise ratio and anisotropic lineshapes. Representative spectra are shown to underscore the importance and applications of the MQMAS experiment. Refs. 97 (author)
Agbemava, S E; Ring, P
2016-01-01
A systematic investigation of octupole deformed nuclei is presented for even-even systems with $Z\\leq 106$ located between the two-proton and two-neutron drip lines. For this study we use five most up-to-date covariant energy density functionals of different types, with a non-linear meson coupling, with density dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole deformed nuclei. In addition, a detailed comparison with the predictions of non-relativistic models is performed. A new region of octupole deformation, centered around $Z\\sim 98, N\\sim 196$ is predicted for the first time. In terms of its size in the $(Z,N)$ plane and the impact of octupole deformation on binding e...
Brown, B Alex
2013-01-01
We use properties of doubly-magic nuclei and ab-initio calculations of low-density neutron matter to constrain Skyrme equations of state for neutron-rich conditions. All of these properties are consistent with a Skyrme functional form and a neutron-matter equation of state that depends on three parameters. With a reasonable range for the neutron-matter effective mass, the values of the two other Skyrme parameters are well constrained. This leads to predictions for other quantities. The neutron skins for $^{208}$Pb and $^{48}$Ca are predicted to be 0.182(10) fm and 0.173(5) fm, respectively. Other results including the dipole polarizability are discussed.
O'Dell, Luke A; Ratcliffe, Christopher I
2011-02-10
A combination of density functional and optimal control theory has been used to generate amplitude- and phase-modulated excitation pulses tailored specifically for the (33)S nuclei in taurine, based on one of several reported crystal structures. The pulses resulted in significant signal enhancement (stemming from population transfer from the satellite transitions) without the need for any experimental optimization. This allowed an accurate determination of the (33)S NMR interaction parameters at natural abundance and at a moderate magnetic field strength (11.7 T). The (33)S NMR parameters, along with those measured from (14)N using frequency-swept pulses, were then used to assess the accuracy of various proposed crystal structures. PMID:21174418
Yasuda, N.; Sekiguchi, M. [National Inst. of Radiological Sciences, Chiba (Japan); Nakamura, S.; Kitamura, T. [Yokohama National University, Yokohama, Kanagawa (Japan); Tawara, H. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Doke, T. [National Space Development Agency of Japan (NASDA), Tsukuba, Ibaraki (Japan)
2001-10-01
The HNX (Heavy Nuclear eXplorer) project has been tentatively accepted as one of the NASA's Small Explorer (SMEX) Program. Purpose of this project is the measurement of abundances for heavy nuclei in galactic cosmic rays (GCRs). This information will contribute to get a great knowledge for the origin of GCR. HNX has two large and high sensitive detectors, ENTICE (Energetic Trans-Ion Composition Experiment) and ECCO (Extremely Heavy Cosmic-ray Composition Observer). ECCO experimental module consists the large BP-1 glass detectors (total area; 23 m{sup 2}), will collect the GCRs ({approx}2,000 events for Pt-group and {approx}100 events for actinide) with its high charge resolution (<0.35 e) in space at least 3 years. We report the outline of HNX project and the new techniques for the measurement of large glass detectors. (author)
Chandran, C Vinod; Hempel, Günter; Bräuniger, Thomas
2011-09-01
In solid-state NMR studies of minerals and ion conductors, quadrupolar nuclei like (7)Li, (23)Na or (133)Cs are frequently situated in close proximity to fluorine, so that application of (19)F decoupling is beneficial for spectral resolution. Here, we compare the decoupling efficiency of various multi-pulse decoupling sequences by acquiring (19)F-decoupled (23)Na-NMR spectra of cryolite (Na(3)AlF(6)). Whereas the MAS spectrum is only marginally affected by application of (19)F decoupling, the 3Q-filtered (23)Na signal is very sensitive to it, as the de-phasing caused by the dipolar interaction between sodium and fluorine is three-fold magnified. Experimentally, we find that at moderate MAS speeds, the decoupling efficiencies of the frequency-swept decoupling schemes SW(f)-TPPM and SW(f)-SPINAL are significantly better than the conventional TPPM and SPINAL sequences. The frequency-swept sequences are therefore the methods of choice for efficient decoupling of quadrupolar nuclei with half-integer spin from fluorine. PMID:21856132
Agbemava, S E; Ray, D; Ring, P
2014-01-01
Covariant density functional theory (CDFT) is a modern theoretical tool for the description of nuclear structure phenomena. The current investigation aims at the global assessment of the accuracy of the description of the ground state properties of even-even nuclei. We also estimate {\\it theoretical uncertainties} defined here as the spreads of predictions within four covariant energy density functionals (CEDF) in known regions of the nuclear chart and their propagation towards the neutron drip line. Large-scale axial relativistic Hartree-Bogoliubov (RHB) calculations are performed for all $Z\\leq 104$ even-even nuclei between the two-proton and two-neutron drip lines with four modern covariant energy density functionals such as NL3*, DD-ME2, DD-ME$\\delta$ and DD-PC1. The physical observables of interest include the binding energies, two-particle separation energies, charge quadrupole deformations, isovector deformations, charge radii, neutron skin thicknesses and the positions of the two-proton and two-neutro...
Collisions between complex atomic nuclei
The use of heavy ion accelerators in the study of nuclear structure and states is reviewed. The reactions discussed are the quasielastic reactions in which small amounts of energy and few particles are exchanged between the colliding nuclei. The development of heavy ion accelerators is also discussed, as well as detection equipment. Exotic phenomena, principally the possible existence of superheavy nuclei, are also treated. (JIW)
Vector analyzing powers A(theta) and differential cross sections σ(theta) have been measured, with the use of a polarized proton beam of 22.0 MeV and a magnetic spectrograph, for (p,t) reactions leading to the first-excited 2+ (21+) states of the following eighteen nuclei of N = 50 - 82: sup(92,94,96)Mo, sup(98,100,102)Ru, sup(102,104,106,108)Pd, sup(110,112,114)Cd, 116Sn, sup(120,126,128)Te, and 136Ba. In addition A(theta) and σ(theta) for sup(104,110)Pd(p,t) sup(102,108) Pd(0sub(g)+,21+) transitions have been measured at Esub(p) = 52.2 MeV. The experimental results are analyzed in terms of the first- and second-order DWBA including both inelastic two-step processes and sequential transfer (p,d)(d,t) two-step processes. Inter-ference effect between the direct and the two-step processes is found to play an essential role in the (p,t) reactions. A sum-rule method for calculating the (p,d)(d,t) spectroscopic amplitudes has been developed so as to take into account the ground-state correlation in odd-A nuclei. The nuclear-structure wave functions are constructed under the boson expansion method and the quasiparticle random phase approximation (qp RPA) method by using the monopole-pairing, quadrupole-pairing, and QQ forces. The characteristic features of the experimental A(theta) and σ(theta) are better explained in terms of the boson expansion method than in terms of the qp RPA. Dependence of the (p,t) analyzing powers on the static electric quadrupole moment of the 21+ state is found to be strong because of the reorientation (anharmonic) effect in the 21+ yiedls 21+ transfer process. (J.P.N.)
Octupole shapes in heavy nuclei
Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets
We have investigated systematically kaonic nuclei which are ppnK-, pppK-, pppnK-, 6BeK-, 9BK- and 11CK-. Since I = 0 K-barN interaction, which is very attractive, plays an essential role in kaonic nuclei, we should treat it adequately. For this purpose, we have improved the framework of antisymmetrized molecular dynamics (AMD): 1) we can treat pK-/nK-bar0 mixing and 2) perform not only angular-momentum projection but also isospin projection. As a result of our calculation with a new framework of AMD, all kaonic nuclei we calculated are deeply bound by about 100 MeV as a discrete state. They have various structures with highly dense state. We have also investigated double kaonic nuclei, ppnK-K- and ppnK-K-. They are more shrunk than single kaonic nuclei, but the binding energy per single kaon (E(K-bar)) is about 100 MeV, which is equal to that in the case of single kaonic nuclei. (author)
Discoveries of many different types of nuclear shape coexistence are being found at both low and high excitation energies throughout the periodic table, as documented in recent reviews. Many new types of shape coexistence have been observed at low excitation energies, for examples bands on more than four different overlapping and coexisting shapes are observed in 185Au, and competing triaxial and prolate shapes in 71Se and 176Pt. Discrete states in super-deformed bands with deformations β 2 ∼ 0.4-0.6, coexisting with other shapes, have been seen to high spin up to 60ℎ in 152Dy, 132Ce and 135Nd. Super-deformed nuclei with N and Z both around 38 and around Z = 38, N ≥ 60. These data led to the discovery of new shell gaps and magic numbers of 38 for N and Z and 60 for N but now for deformed shapes. Marked differences in structure are observed at spins of 6 to 20 in nuclei in this region, which differ by only two protons; for example, 68Ge and 70Se. The differences are thought to be related to the competing shell gaps in these nuclei
Theoretical models for exotic nuclei
Sagawa, Hiroyuki [RIKEN Nishina Center, Saitama (Japan); University of Aizu, Center for Mathematics and Physics, Fukushima (Japan); Hagino, Kouichi [Tohoku University, Department of Physics, Sendai (Japan); Tohoku University, Research Center for Electron Photon Science, Sendai (Japan); National Astronomical Observatory of Japan, Tokyo (Japan)
2015-08-15
We review various theoretical models which have been used to study the properties of the ground state and excited states of nuclei close to and beyond the neutron and proton drip lines. The validity and limitations of these models are discussed with applications to recent experimental findings such as di-neutron correlations in Borromian nuclei, the soft dipole excitations, direct two-neutron and two-proton decays, and odd-even staggerings of reaction cross sections. The role of isoscalar spin-triplet pairing interaction is also pointed out in the low-lying energy spectra as well as the spin- and isospin-dependent decay rates for N = Z and N = Z + 2 nuclei with mass A < 60. A characteristic feature of the Coulomb energy displacement of the Borromian nucleus {sup 11}Li is discussed in connection to the energies of isobaric analogue states (IAS) of T = 5/2 multiples in the A = 11 systems. (orig.)
Review on theoretical researches of superheavy nuclei
We review the recent progress of theoretical researches on heavy nuclei and superheavy nuclei. At first we analyze the experimental data of long lifetime heavy nuclei and discuss their stability. Then the calculated binding energies and alpha-decay energies of heavy and superheavy nuclei from different models are compared and discussed. This includes the results from the local binding energy formula of heavy nuclei with Z ≥ 90 and N ≥ 130, those from the relativistic mean-field model, and from other models. For the local binding energy formula, it can reproduce experimental binding energies of known heavy and superheavy nuclei well. The relativistic mean-field model and non-relativistic mean-field model show that there is shape coexistence in superheavy nuclei. For some superheavy nuclei, superdeformed prolate shape can be their ground states and there are isomers in lowly excited states due to shape coexistence. The properties of some unknown superheavy nuclei are predicted. Some new views on the stability and on half-lives of heavy and superheavy nuclei are presented. Possible new phenomenon in superheavy region is analyzed and discussed. (author)
Wu, Xian-Ye
2015-01-01
We present a comprehensive study of low-lying states in even-even Ne, Mg, Si, S, Ar isotopes with the multireference density functional theory (MR-DFT) based on a relativistic point-coupling energy density functional (EDF). Beyond mean-field (BMF) effects are taken into account by configuration mixing of both particle-number and angular-momentum projected axially deformed states with generator coordinate method (GCM). Global performance of the MR-DFT for the properties of both ground state and of the first $2^+, 4^+$ states is examined, in comparison with previous studies based on nonrelativistic EDFs and available data. Our results indicate that an EDF parameterized at the BMF level is demanded to achieve a quantitative description.
The authors have observed the cross section and analyzing-power distributions of 2p-1h configurations from targets of oxygen, calcium, and strontium. Each target isotope was chosen to have the highest filled neutron orbital correspond to an empty proton orbital. Respectively, the observed states are based on the configurations (1d/sub 5/2/)3, (1f/sub 7/2/)3, and (1g/sub 9/2/)3 having spins as large as 13/2+, 19/2-, and 25/2+. From the authors' strontium measurements, they have identified previously unknown 25/2+ and 21/2+ states in 89Zr. Relative cross sections for these two transitions are well reproduced by simple model calculations. The analyzing power distributions for the stretched-state transitions seem to show a yet unexplained mass-independent signature. This past fall the authors carried out measurements on samarium and lead isotopes hoping to identify high-spin states based on (1h/sub 11/2/)3 and (li/sub 13/2/)3 2p-1h configurations. On-line spectra indicate some reaction cross section at the predicted excitation, though experimental energy resolution may prevent identification of particular states. Off-line data analysis is currently under way at IUCF
Ground and excited states of doubly open-shell nuclei from ab initio valence-space Hamiltonians
Stroberg, S R; Holt, J D; Bogner, S K; Schwenk, A
2015-01-01
We present ab initio predictions for ground and excited states of doubly open-shell fluorine and neon isotopes based on chiral two- and three-nucleon interactions. We use the in-medium similarity renormalization group, in both flow-equation and Magnus formulations, to derive mass-dependent sd valence-space Hamiltonians. The experimental ground-state energies are reproduced through neutron number N=14, beyond which a new targeted normal-ordering procedure improves agreement with data and large-scale multi-reference calculations. For spectroscopy, we focus on neutron-rich 23-26F and 24-26Ne isotopes near N=14,16 magic numbers. In all cases we find an agreement with experiment competitive with established phenomenology. Moreover, yrast states are well described in 20Ne and 24Mg, providing an ab initio description of deformation in the medium-mass region.
PPCO: polarizational-polarizational correlation from oriented nuclei
A Polarizational-Polarizational Correlation from Oriented Nuclei (PPCO) measuring method is described. The method allows one to determine spin and parity of the excited states of nuclei as well as multipole gamma transitions
An introduction to mesic nuclei
Wilkin, Colin
2016-01-01
There is much speculation and a modest amount of evidence that certain mesons might form quasi-bound states with nuclei to produce really exotic states of matter. For this to be a practical possibility, the interaction between the meson and nucleons at low energies must be strong and attractive and the production rates "healthy". The conditions for this are surveyed for the light mesons. How this might lead to quasi-bound states is then discussed in a few typical cases.
Chirality has recently been proposed as a novel feature of rotating nuclei [1]. Because the chiral symmetry is dichotomic, its spontaneous breaking by the axial angular momentum vector leads to doublets of closely lying rotational bands of the same parity. To investigate nuclear chirality, next to establish the existence of almost degenerate rotational bands, it is necessary to measure also other observables and compare them to the model predictions. The crucial test for the suggested nuclei as candidates to express chirality is based on precise lifetime measurements. Two lifetime experiments and theoretical approaches for the description of the experimental results will be presented. Lifetimes of exited states in 134Pr were measured [2,3] by means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The branching ratios and the electric or magnetic character of the transitions were also investigated [3]. The experiments were performed at IReS, Strasbourg, using the EUROBALL IV spectrometer, in conjunction with the inner bismuth germanate ball and the Cologne coincidence plunger apparatus. Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F, 4n)134Pr. The possible chiral interpretation of twin bands was investigated in the two-quasiparticle triaxial rotor [1] and interacting boson-fermion-fermion models [4]. Both theoretical approaches can describe the level-scheme of 134Pr. The analysis of the wave functions has shown that the possibility for the angular momenta of the proton, neutron, and core to find themselves in the favorable, almost orthogonal geometry, is present but is far from being dominant [3,5]. The structure is characterized by large β and γ fluctuations. The existence of doublets of bands in 134Pr can be attributed to weak chirality dominated by shape fluctuations. In a second experiment branching ratios and lifetimes in 136Pm were measured by means of the recoil distance Doppler-shift and
Coupled-Cluster Theory for Nuclei
The quantum-many body problem spans numerous scientific disciplines ranging from condensed matter to quantum dots, to high-temperature superconductors, and to nuclei. In these proceedings, we discuss the development of coupled-cluster techniques and their application to nuclei. We concentrate specifically on calculations pertaining to the ground- and excited-state properties of 4He and 16O
The deexcitation of the 8.6 μs isomer of 3999Y has been studied using γ-ray spectroscopy techniques at LOHENGRIN and JOSEF. The resultant level scheme is analyzed within the framework of the particle-rotor coupling model. The ground-state band, to spin 19/2+, is found to have band properties consistent with a π[422 5/2] Nilsson assignment. The 8.6 μs isomer and a side band with a band-head half-life of 1.4 ns are found to have Jsup(π) values of 17+/2 and 11+/2, respectively. Their properties are consistent with a [π[422 5/2]ν[411 3/2]ν[404 9/2
Venhart, M; Boston, A J; Cocolios, T E; Harkness-Brennan, L J; Herzberg, R -D; Joss, D T; Judson, D S; Kliman, J; Matousek, V; Motycak, S; Page, R D; Patel, A; Petrik, K; Sedlak, M; Veselsky, M
2016-01-01
A new technique of elucidating $\\beta$-decay schemes of isotopes with large density of states at low excitation energies has been developed, in which a Broad Energy Germanium (BEGe) detector is used in conjunction with coaxial hyper-pure germanium detectors. The power of this technique has been demonstrated on the example of 183Hg decay. Mass-separated samples of 183Hg were produced by a deposition of the low-energy radioactive-ion beam delivered by the ISOLDE facility at CERN. The excellent energy resolution of the BEGe detector allowed $\\gamma$ rays energies to be determined with a precision of a few tens of electronvolts, which was sufficient for the analysis of the Rydberg-Ritz combinations in the level scheme. The timestamped structure of the data was used for unambiguous separation of $\\gamma$ rays arising from the decay of 183Hg from those due to the daughter decays.
Wloch, Marta [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Gour, Jeffrey R [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Piecuch, Piotr [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Dean, David J [Physics Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Center of Mathematics for Applications, University of Oslo, N-0316 Oslo (Norway); Hjorth-Jensen, Morten [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Center of Mathematics for Applications, University of Oslo, N-0316 Oslo (Norway); Department of Physics, University of Oslo, N-0316 Oslo (Norway); Papenbrock, Thomas [Physics Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)
2005-08-01
We discuss large-scale ab initio calculations of ground and excited states of {sup 16}O and preliminary calculations for {sup 15}O and {sup 17}O using coupled-cluster methods and algorithms developed in quantum chemistry. By using realistic two-body interactions and the renormalized form of the Hamiltonian obtained with a no-core G-matrix approach, we are able to obtain the virtually converged results for {sup 16}O and promising results for {sup 15}O and {sup 17}O at the level of two-body interactions. The calculated properties other than binding and excitation energies include charge radius and charge form factor. The relatively low costs of coupled-cluster calculations, which are characterized by the low-order polynomial scaling with the system size, enable us to probe large model spaces with up to seven or eight major oscillator shells, for which nontruncated shell-model calculations for nuclei with A = 15-17 active particles are presently not possible.
Sun, Xiao-Dong; Li, Xiao-Hua
2016-01-01
In this work, we systematically investigate the favored $\\alpha$-decay half-lives and $\\alpha$ preformation probabilities of both odd-$A$ and doubly-odd nuclei related to ground and isomeric states around the doubly magic cores at $Z=82$, $N=82$ and at $Z=82$, $N=126$, respectively, within a two-potential approach from the view of the valence nucleon (or hole). The results show that the $\\alpha$ preformation probability is linear related to $N_\\text{p}N_\\text{n}$ or $N_\\text{p}N_\\text{n}I$, where $N_\\text{p}$, $N_\\text{n}$, and $I$ are the number of valence protons (or holes), the number of valence neutrons (or holes), and the isospin of the parent nucleus, respectively. Fitting the $\\alpha$ preformation probabilities data extracted from the differences between experimental data and calculated half-lives without a shell correction, we give two analytic formulas of the $\\alpha$ preformation probabilities and the values of corresponding parameters. Using those formulas and the parameters, we calculate the $\\alp...
Yarmukhamedov, R
2016-01-01
Asymptotic expressions for the radial and full wave functions of a three{body bound halo nuclear system with two charged particles in relative coordinates are obtained in explicit form, when the relative distance between two particles tends to infinity. The obtained asymptotic forms are applied to the analysis of the asymptotic behavior of the three-body (pn?) wave functions for the halo ($E^*=3.562$ MeV, $J^{\\pi}=0^+$, $T=1$) state of $^6$Li derived by D. Baye within the Lagrange-mesh method for two forms of the $\\alpha N$ -potential. The agreement between the calculated wave function and the asymptotic formula is excellent for distances up to 30 fm. Information about the values of the three-body asymptotic normalization functions is extracted. It is shown that the extracted values of the three-body asymptotic normalization function are sensitive to the form of the $\\alpha N$ -potential. The mirror symmetry is revealed for the three-body asymptotic normalization functions derived for the isobaric ($^6$He, $^...
Neutron scattering on deformed nuclei
Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9Be, C, 181Ta, 232Th, 238U and 239Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP
In this talk I discuss properties of hot stellar matter at sub-nuclear densities which is formed in supernova explosions. I emphasize that thermodynamic conditions in this case are rather similar to those created in the laboratory by intermediate-energy heavy-ion collisions. Theoretical methods developed for the interpretation of multi-fragment final states in such reactions can be used also for description of the stellar matter. I present main steps of the statistical approach to the equation of state and nuclear composition, dealing with an ensemble of nuclear species instead of one “average” nucleus. Finally some results of this approach are presented. The emphasis is put on possible formation of heavy and superheavy nuclei. (author)
This paper covers the following aspects of isobar excitations in nuclei: Nuclear spin response; Electromagnetic probes; Pion-nuclear reactions; Baryon charge exchange reactions; Charge exchange reactions on nuclei; and Exclusive spectra
Decay of heavy and superheavy nuclei
K P Santhosh
2014-04-01
We present here, an overview and progress of the theoretical works on the isomeric state decay, decay fine structure of even–even, even–odd, odd–even and odd–odd nuclei, a study on the feasibility of observing decay chains from the isotopes of the superheavy nuclei = 115 in the range 271 ≤ ≤ 294 and the isotopes of = 117 in the range 270 ≤ ≤ 301, within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The computed half-lives of the favoured and unfavoured decay of nuclei in the range 67 ≤ ≤ 91 from both the ground state and isomeric state, are in good agreement with the experimental data and the standard deviation of half-life is found to be 0.44. From the fine structure studies done on various ranges of nuclei, it is evident that, for nearly all the transitions, the theoretical values show good match with the experimental values. This reveals that CPPMDN is successful in explaining the fine structure of even–even, even–odd, odd–even and odd–odd nuclei. Our studies on the decay of the superheavy nuclei 271−294115 and 270−301117 predict 4 chains consistently from 284,285,286115 nuclei and 5 chains and 3 chains consistently from 288−291117 and 292117, respectively. We thus hope that these studies on 284−286115 and 288−292117 will be a guide to future experiments.
Collective excitations in nuclei
Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)
1998-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.
Collective excitations in nuclei
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors)
Basing on a phenomenological approach accounting for the shell structure, pair correlations and coherent excitations of vibrational type, the energy dependence is discussed of the coefficient of vibrational level density increase for spherical nuclei with A approximately equal to 60. The relationship found is satisfactorily describing the level density for a number of nuclei, the neutron spectra and excitation functions of the 56Fe(n, 2n)55Fe reaction
Jurányi, Z.; Tritscher, T.; Gysel, M.; Laborde, M.; Gomes, L.; Roberts, G.; Baltensperger, U.; Weingartner, E.
2013-07-01
Ambient aerosols are a complex mixture of particles with different physical and chemical properties and consequently distinct hygroscopic behaviour. The hygroscopicity of a particle determines its water uptake at subsaturated relative humidity (RH) and its ability to form a cloud droplet at supersaturated RH. These processes influence Earth's climate and the atmospheric lifetime of the particles. Cloud condensation nuclei (CCN) number size distributions (i.e. CCN number concentrations as a function of dry particle diameter) were measured close to Paris during the MEGAPOLI campaign in January-February 2010, covering 10 different supersaturations (SS = 0.1-1.0%). The time-resolved hygroscopic mixing state with respect to CCN activation was also derived from these measurements. Simultaneously, a hygroscopicity tandem differential mobility analyser (HTDMA) was used to measure the hygroscopic growth factor (ratio of wet to dry mobility diameter) distributions at RH = 90%. The aerosol was highly externally mixed and its mixing state showed significant temporal variability. The average particle hygroscopicity was relatively low at subsaturation (RH = 90%; mean hygroscopicity parameter κ = 0.12-0.27) and increased with increasing dry diameter in the range 35-265 nm. The mean κ value, derived from the CCN measurements at supersaturation, ranged from 0.08 to 0.24 at SS = 1.0-0.1%. Two types of mixing-state resolved hygroscopicity closure studies were performed, comparing the water uptake ability measured below and above saturation. In the first type the CCN counter was connected in series with the HTDMA and and closure was achieved over the whole range of probed dry diameters, growth factors and supersaturations using the κ-parametrization for the water activity and assuming surface tension of pure water in the Köhler theory. In the second closure type we compared hygroscopicity distributions derived from parallel monodisperse CCN measurements and HTDMA measurements
Z. Jurányi
2013-01-01
Full Text Available Ambient aerosols are a complex mixture of particles with different physical and chemical properties and consequently distinct hygroscopic behaviour. The hygroscopicity of a particle determines its water uptake at subsaturated relative humidity (RH and its ability to form a cloud droplet at supersaturated RH. These processes influence the Earth's climate and the atmospheric lifetime of the particles.
Cloud condensation nuclei (CCN number size distributions (i.e. CCN number concentrations as a function of dry particle diameter were measured close to Paris during the MEGAPOLI campaign in January–February 2010 covering 10 different supersaturations (SS = 0.1–1.0%. The time-resolved hygroscopic mixing state with respect to CCN activation was also derived from these measurements. Simultaneously, a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA was used to measure the hygroscopic growth factor (ratio of wet to dry mobility diameter distributions at RH = 90%. The aerosol was highly externally mixed and its mixing state showed significant temporal variability. The average particle hygroscopicity was relatively low at subsaturation, RH = 90% (mean hygroscopicity parameter κ = 0.12–0.27 and increased with increasing dry diameter in the range 35–265 nm. The mean κ value, derived from the CCN measurements at supersaturation, ranged from 0.08 to 0.24 at SS = 1.0–0.%.
Two types of mixing state resolved hygroscopicity closure studies were performed comparing the water uptake ability measured below and above saturation. In the first type the CCN counter was coupled with the HTDMA and closure was achieved over the whole range of probed dry diameters, growth factors and supersaturations using the κ-parameterisation for the water activity and assuming surface tension of pure water in the Köhler theory. In the second closure type we compared hygroscopicity distributions derived from parallel monodisperse CCN measurements
Understanding Nuclei in the upper sd - shell
Sarkar, M Saha; Ray, Sudatta; Kshetri, Ritesh; Sarkar, S
2013-01-01
Nuclei in the upper-$sd$ shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A$\\simeq$ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.
Topics covered include: precision measurements of nuclear ground-state quadrupole moments in the mass region A = 150 to A = 193; monopole and quadrupole charge parameters of deformed nuclei; quadrupole and hexadecapole moments of U and Pu nuclei; systematics of nuclear charge radii (isotope and isotone shifts) in the A = 100 to A = 140 mass region; and pionic-atom measurements
Relativistic symmetry breaking in light kaonic nuclei
Yang, Rong-Yao; Jiang, Wei-Zhou; Xiang, Qian-Fei; Zhang, Dong-Rui; Wei, Si-Na
2014-01-01
As the experimental data from kaonic atoms and $K^{-}N$ scatterings imply that the $K^{-}$-nucleon interaction is strongly attractive at saturation density, there is a possibility to form $K^{-}$-nuclear bound states or kaonic nuclei. In this work, we investigate the ground-state properties of the light kaonic nuclei with the relativistic mean field theory. It is found that the strong attraction between $K^{-}$ and nucleons reshapes the scalar and vector meson fields, leading to the remarkabl...
Electron scattering off nuclei
Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author)
Multiple phonon excitation in nuclei
The studies of multiphonon excitations in nuclei are reviewed both from the theoretical and experimental points of view. The presence of giant resonances in nuclei is described in the framework of macroscopic and microscopic models and the relative merits of different probes to excite such states are illustrated. The existence of giant resonances built on excited states is stressed. An exhaustive description of the theoretical estimates of the properties of the multiphonon states is presented. The theory predicts that such multiple collective excitations should closely follow a harmonic pattern. Recent experimental results on the double giant dipole resonance using the (π+π-) double charge exchange reaction are shown. The status of the search for isoscalar multiphonon excitations by means of the strong nuclear potential produced by heavy ions is presented. Conclusions are drawn and new prospects are discussed. (authors) 293 refs., 67 figs., 8 tabs
Moessbauer effects on oriented nuclei
Standard nuclear orientation methods (not sensitive to the polarization) do not give information on the sign of the magnetic moment. Mossbauer effect separates right-hand and left-hand circularly polarized components, thus its detection on oriented nuclei (T approximately 10 mK) gives the sign of the magnetic moment of oriented state. In this thesis we applied this method to study the 3/2- ground states of 191Pt and 193Os, which are in the prolate-oblate transition region, where assignement of experimental levels to theoretical states is often umbiguous. We show that for those nuclei the sign of the magnetic moment is the signature of the configuration, and its determination establishes the correspondance between experimental and theoretical levels
This document gathers the slides and their commentaries that have been presented at the conference 'physics and fundamental questions' by P. Chomaz. The author reviews the different quantum aspects of nuclei: tunnel effect, symmetries, magic numbers, wave functions, size, shapes and deformations. The author shows that nuclei are quantum objects of great complexity, their structures are not yet well understood and the study of exotic nuclei will continue bringing valuable information
Phonon operators for deformed nuclei
The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator
Phonon operators in deformed nuclei
For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator
Cluster structure of nuclei based on AMD
The technique of cooling the energy of the system being examined by using molecular dynamics is utilized for multi-dimensional variation calculation in the fields of physical properties and chemistry. By simulating the cooling of a finite nucleon system, the ground state of atomic nuclei can be studied. By antisymmetrized molecular dynamics, as for the ordinary nuclei with proton number Z=2n and neutron number N=2n, the cluster structure is examined. Further, the nuclei with excess neutrons, to which attention has been paid recently, are examined, and the feature of the systems with different Z and N are noticed. As to AMD method, the wave function, the ground state and the extension of the wave function are explained. AMD was applied to the even-even nuclei of A=4n. The results of density distribution are shown. It is known that most of 4n nuclei are constituted with the basic unit of alpha cluster. In the atomic nuclei with 4 nucleons in a closed shell, they have the developed cluster structure. The various internal deformation corresponding to the number of nucleons was observed. In the nuclei with excess neutrons Z< N, because the shell structures of protons and neutrons are different, the overall structure is determined by respective effects. The dependence of nuclear structure on the number of neutrons is reported. (K.I.)
Direct Reactions with Exotic Nuclei
We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances
Direct Reactions with Exotic Nuclei
Baur, G
2005-01-01
We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances.
Superheavy nuclei and fission barriers
Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui
In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.
Geometric symmetries in light nuclei
Bijker, Roelof
2016-01-01
The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Permutation group in light nuclei
From general features of the multiplet scheme, a framework is provided for the application of permutation groups to the structure of light nuclei. It is shown that the description of nuclear states in terms of cluster configurations offers possibilities of finding the best orbital states for a given partition f. The significance of the orbital partition for orbital states is explained in terms of selection rules. Specific methods and results obtained in shell configurations, cluster configurations, and nuclear reactions are discussed. (2 figures, 4 tables, 42 references) (U.S.)
Properties of superheavy nuclei with Z = 124
Mehta, M S; Kumar, Bharat; Patra, S K
2015-01-01
We employ Relativistic Mean Field (RMF) model with NL3 parametrization to investigate the ground state properties of superheavy nucleus, Z = 124. The nuclei selected (from among complete isotopic series) for detailed investigation show that the nucleon density at the center is very low and therefore, these nuclei can be treated as semi-bubble nuclei. The considerable shell gap appears at neutron numbers N = 172, 184 and 198 showing the magicity corresponding to these numbers. The results are compared with the macro-microscopic Finite Range Droplet Model (FRDM) wherever possible.
Relativistic symmetry breaking in light kaonic nuclei
Yang, Rong-Yao; Xiang, Qian-Fei; Zhang, Dong-Rui; Wei, Si-Na
2014-01-01
As the experimental data from kaonic atoms and $K^{-}N$ scatterings imply that the $K^{-}$-nucleon interaction is strongly attractive at saturation density, there is a possibility to form $K^{-}$-nuclear bound states or kaonic nuclei. In this work, we investigate the ground-state properties of the light kaonic nuclei with the relativistic mean field theory. It is found that the strong attraction between $K^{-}$ and nucleons reshapes the scalar and vector meson fields, leading to the remarkable enhancement of the nuclear density in the interior of light kaonic nuclei and the manifest shift of the single-nucleon energy spectra and magic numbers therein. As a consequence, the pseudospin symmetry is shown to be violated together with enlarged spin-orbit splittings in these kaonic nuclei.
Collective excitations in nuclei
Chomaz, Ph
1997-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.
Collective excitations in nuclei
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author)
If some β- emitters are particularly interesting to study in light, medium, and heavy nuclei, another (and also) difficult problem is to know systematically the properties of these neutron rich nuclei far from the stability line. A review of some of their characteristics is presented. How far is it possible to be objective in the interpretation of data is questioned and implications are discussed
The purpose of 1991 Joliot-Curie Summer School is to review the most advances in the understanding of the nuclei physics after the considerable progress in gamma spectroscopy. It covers the following topics: Highly and super-deformed nuclei, nuclear structures, mean-field approach and beyond, fission isomers, nuclear excitations with long lifetime and metal clusters
Probing intruder structures in lead nuclei
In-beam γ-ray spectroscopy measurements provide important information on coexisting normal and intruder configurations in lead nuclei. However, in these experiments the yrast states are preferentially populated so that in many cases nothing is known about non-yrast states that are essential for obtaining a fuller understanding. Complementary experiments designed to study fine structure in the α decays of polonium nuclei have led to the discovery of low-spin non-yrast states in the daughter lead nuclei, while higher-spin states can be identified through the γ decays of isomeric states. The α-decay studies have the additional benefit of allowing information on configuration mixing in the polonium parents to be deduced from the measured hindrance factors. (orig.)
Probing intruder structures in lead nuclei
Page, R.D. [Dept. of Physics, Oliver Lodge Lab., Univ. of Liverpool, Liverpool (United Kingdom); Ackerman, D.; Andreyev, A.N.; Cagarda, P.; Eskola, K.; Gerl, J.; Greenlees, P.T.; Hessberger, F.P.; Heyde, K.; Hofmann, S.; Huyse, M.; Jones, P.; Joss, D.T.; Julin, R.; Juutinen, S.; Kankaanpaeae, H.; Keenan, A.; Kettunen, H.; Kleinboehl, A.; Kuusiniemi, P.; Lavrentiev, A.; Leino, M.; Matos, M.; Melarangi, A.; Moore, C.J.P.; Muikku, M.; Muenzenberg, G.; Nieminen, P.; O' Leary, C.D.; Rahkila, P.; Reshitko, S.; Schaffner, H.; Schlegel, C.; Scholey, C.; Taylor, M.J.; Uusitalo, J.; Van de Vel, K.; Van Duppen, P.; Weissman, L.; Wheldon, C.; Wyss, R.
2003-07-01
In-beam {gamma}-ray spectroscopy measurements provide important information on coexisting normal and intruder configurations in lead nuclei. However, in these experiments the yrast states are preferentially populated so that in many cases nothing is known about non-yrast states that are essential for obtaining a fuller understanding. Complementary experiments designed to study fine structure in the {alpha} decays of polonium nuclei have led to the discovery of low-spin non-yrast states in the daughter lead nuclei, while higher-spin states can be identified through the {gamma} decays of isomeric states. The {alpha}-decay studies have the additional benefit of allowing information on configuration mixing in the polonium parents to be deduced from the measured hindrance factors. (orig.)
Structure of collective modes in transitional and deformed nuclei
Caprio, M. A.
2005-01-01
The collective structure of atomic nuclei intermediate between spherical and quadrupole deformed structure presents challenges to theoretical understanding. However, models have recently been proposed in terms of potentials which are soft with respect to the quadrupole deformation variable beta. To test these models, information is needed on low-spin states of transitional nuclei. The present work involves measurement of electromagnetic decay properties of low-spin states for nuclei in the A=...
Under the axial symmetry assumption ,the relativistic mean field (RMF) theory has been applied to all even-even nuclei from 8O until 50Sn up to the drip lines. The agreement of the results for the binding energies with the experimental data is within 3 MeV.The comparison of the RMF results and predictions using macroscopic-macroscopic calculation shows large discrepancies for far from the stability line.From the distribution of the deformation on the N-Z plane, it is found that the disappearance of the magi city when neutron numbers are magic as 20,28 and 50. But the magi city remains intact for the proton magic number. The RMF theory predicts a very thick neutron skin for neutron rich nuclei as well as thick proton skin for proton rich nuclei. With triaxial symmetry assumption, the RMF has been also applied to some sulfur isotopes.A smooth transition has been found from the prolate shape at 42-46S to the triaxial shape at 48-52S and then to the oblate shape at 54S and finally to the spherical shape at 56S
Symmetry and Phase Transitions in Nuclei
Phase transitions in nuclei have received considerable attention in recent years, especially after the discovery that, contrary to expectations, systems at the critical point of a phase transition display a simple structure. In this talk, quantum phase transitions (QPT), i.e. phase transitions that occur as a function of a coupling constant that appears in the quantum Hamiltonian, H, describing the system, will be reviewed and experimental evidence for their occurrence in nuclei will be presented. The phase transitions discussed in the talk will be shape phase transitions. Different shapes have different symmetries, classified by the dynamic symmetries of the Interacting Boson Model, U(5), SU(3) and SO(6). Very recently, the concept of Quantum Phase Transitions has been extended to Excited State Quantum Phase Transitions (ESQPT). This extension will be discussed and some evidence for incipient ESQPT in nuclei will be presented. Systems at the critical point of a phase transition are called 'critical systems'. Approximate analytic formulas for energy spectra and other properties of 'critical nuclei', in particular for nuclei at the critical point of the second order U(5)-SO(6) transition, called E(5), and along the line of first order U(5)-SU(3) transitions, called X(5), will be presented. Experimental evidence for 'critical nuclei' will be also shown. Finally, the microscopic derivation of shape phase transitions in nuclei within the framework of density functional methods will be briefly discussed.(author)
Mass-23 nuclei in astrophysics
Fraser, P. R.; Amos, K.; Canton, L.; Karataglidis, S.; Svenne, J. P.; van der Kniff, D.
2015-09-01
The formation of mass-23 nuclei by radiative capture is of great interest in astrophysics. A topical problem associated with these isobars is the so-called 22Na puzzle of ONe white dwarf novae, where the abundance of 22Na observed is not as is predicted by current stellar models, indicating there is more to learn about how the distribution of elements in the universe occurred. Another concerns unexplained variations in elements abundance on the surface of aging red giant stars. One method for theoretically studying nuclear scattering is the Multi-Channel Algebraic Scattering (MCAS) formalism. Studies to date have used a simple collective-rotor prescription to model the target states which couple to projectile nucleons. While, in general, the target states considered all belong to the ground state rotor band, for some systems it is necessary to include coupling to states outside of this band. Herein we discuss an extension of MCAS to allow coupling of different strengths between such states and the ground state band. This consideration is essential when studying the scattering of neutrons from 22Ne, a necessary step in studying the mass-23 nuclei mentioned above.
From Nucleons To Nuclei To Fusion Reactions
Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W
2012-02-15
Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.
Brueckner-AMD study of light nuclei
In many states of light nuclei, the cluster structure is observed in addition to the shell structure. To understand the mechanism of clustering, we apply the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD) based on realistic nuclear interactions. The Bethe-Goldstone equation in the Brueckner theory is solved for every nucleon pair described by wave packets of AMD, and the G-matrix is calculated with single-particle orbits in AMD self-consistently. We show applicability of this method not only to self-conjugate nuclei but also to N ≠ Z nuclei with A ≤ 12. It is confirmed that these results present reasonable description of cluster structures and energy-level schemes in comparison with the experimental ones in light nuclei. For 8Be having a typical α + α cluster structure, the structure dependence of the G-matrix is investigated and the role of tensor force is shown to be important in understanding the clustering mechanism.
The density functional determining the Coulomb energy of nuclei is calculated to the first order in e2. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CCE is shown to come from the surface region of nuclei. The CCE effect on the calculated proton drip line is examined, and the maximum charge Z of nuclei near this line is found to decrease by 2 or 3 units. The effect of Coulomb interaction on the effective proton mass is analyzed
Shaginyan, V R
2001-01-01
The density functional determining the Coulomb energy of nuclei is calculated to the first order in $e^2$. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CCE is shown to come from the surface region of nuclei. The CCE effect on the calculated proton drip line is examined, and the maximum charge $Z$ of nuclei near this line is found to decrease by 2 or 3 units. The effect of Coulomb interaction on the effective proton mass is analyzed.
Shaginyan, V. R.
2002-01-01
The density functional determining the Coulomb energy of nuclei is calculated to the first order in $e^2$. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CC...
A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs
Electroweak interactions in nuclei
Henley, E. M.
1984-06-01
Nuclear and subnuclear degrees of freedom and lepton nucleus scattering were discussed. Electroweak interactions in nuclei were examined. Topics discussed include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms.
Quantum Monte Carlo calculations of light nuclei
Quantum Monte Carlo calculations using realistic two- and three-nucleon interactions are presented for nuclei with up to eight nucleons. We have computed the ground and a few excited states of all such nuclei with Greens function Monte Carlo (GFMC) and all of the experimentally known excited states using variational Monte Carlo (VMC). The GFMC calculations show that for a given Hamiltonian, the VMC calculations of excitation spectra are reliable, but the VMC ground-state energies are significantly above the exact values. We find that the Hamiltonian we are using (which was developed based on 3H, 4He, and nuclear matter calculations) underpredicts the binding energy of p-shell nuclei. However our results for excitation spectra are very good and one can see both shell-model and collective spectra resulting from fundamental many-nucleon calculations. Possible improvements in the three-nucleon potential are also be discussed
Static quadrupole moments in 120Te nuclei
In recent years the region in the vicinity of tin isotopes has been intensively investigated both from experimental and theoretical perspectives. In tellurium nuclei with two protons outside the major shell, the partial level schemes are dominated by the 1g7/2 orbit leading to 6+ isomers in the vicinity of N=82 shell closure. At low spin, the Te nuclei are considered to be one of the best examples of quadrupole vibrators. For any nuclei to be vibrational namely three criteria must be satisfied : (i) the R4/2 ratio is equal to 2, (ii) a nearly degenerate two-phonon triplet of 0+, 2+ and 4+ states (iii) collective electric quadrupole transitions between states differing by one phonon and strong hindrance of E2 transition between states differing by more than one phonon
Symmetry energy, unstable nuclei and neutron star crusts
Iida, Kei [Kochi University, Department of Natural Science, Kochi (Japan); RIKEN Nishina Center, Saitama (Japan); Oyamatsu, Kazuhiro [RIKEN Nishina Center, Saitama (Japan); Aichi Shukutoku University, Department of Human Informatics, Aichi (Japan)
2014-02-15
The phenomenological approach to inhomogeneous nuclear matter is useful to describe fundamental properties of atomic nuclei and neutron star crusts in terms of the equation of state of uniform nuclear matter. We review a series of researches that we have developed by following this approach. We start with more than 200 equations of state that are consistent with empirical masses and charge radii of stable nuclei and then apply them to describe matter radii and masses of unstable nuclei, proton elastic scattering and total reaction cross sections off unstable nuclei, and nuclei in neutron star crusts including nuclear pasta. We finally discuss the possibility of constraining the density dependence of the symmetry energy from experiments on unstable nuclei and even observations of quasi-periodic oscillations in giant flares of soft gamma-ray repeaters. (orig.)
Production of light nuclei in the thermal and coalescence models
Mrowczynski, Stanislaw
2016-01-01
The thermal model properly describes the yield of light nuclei in relativistic heavy-ion collisions even so the loosely bound sizable nuclei cannot exist in the dense and hot hadron gas. Within the coalescence model, light nuclei are formed at the latest stage of nuclear collisions due to final state interactions. After discussing the models, we derive simple analytic formulas showing that the thermal and coalescence model predictions are quantitatively close to each other.
AMD study of cluster structures in light nuclei
We review the AMD study of cluster structures in stable and unstable light nuclei. We place emphasis on the characteristic features of the AMD approach, which include variation after parity projection, three-dimensional cranking and variation after angular momentum projection, superposition of Slater determinants for the study of excited states, and unified treatment of structure and reaction calculations. We discuss the novel features of clustering in neutron-rich nuclei in comparison with clustering in stable nuclei. (author)
Superdeformation in the bismuth nuclei
High angular-momentum states in 196,197Bi were populated in the reaction 183W (19F,xn) at a beam energy of 108 MeV, and γ rays were detected with the Gammasphere array. Two weakly populated rotational bands, with energy spacings characteristic of superdeformation have been found. Both cascades can be assigned unambiguously to the Bi nuclei; however, their isotopic assignment to 197Bi is tentative. The properties of the bands and their possible structures are discussed. Our results represent the first identification of superdeformed bands in a nucleus of the A∼190 mass region with Z>82
Single Pion production from Nuclei
We have studied charged current one pion production induced by νμ(ν-barμ) from some nuclei. The calculations have been done for the incoherent pion production processes from these nuclear targets in the Δ dominance model and take into account the effect of Pauli blocking, Fermi motion and renormalization of Δ properties in the nuclear medium. The effect of final state interactions of pions has also been taken into account. The numerical results have been compared with the recent results from the MiniBooNE experiment for the charged current 1π production, and also with some of the older experiments in Freon and Freon-Propane from CERN
Level density parameter for nuclei with few nucleons above magic number nuclei Z = 82
Since nuclei with extreme neutron richness formed in collisions, or otherwise, or obtained as fission fragments, may be in an excited state, they require a thermodynamical approach in which both the spin degree of freedom and temperature effects have been incorporated. This is similar to the earlier works where these effects have been incorporated to reproduce microscopic fluctuations in high spin nuclei. This spin degree of freedom inherently involves deformation and structural or shape changes
Investigation of copper nuclei
An extensive study has been performed on copper isotopes in the mass region A=63-66. The results of a precise measurement are presented on the properties of levels of 64Cu and 66Cu. They were obtained by bombarding the 63Cu and 65Cu nuclei with neutrons. The gamma spectra collected after capture of thermal, 2-keV, 24-keV neutrons have been analysed and combined to give a rather extensive set of precise level energies and gamma transition strengths. From the angular distribution of the gamma rays it is possible to obtain information concerning the angular momentum J of several low-lying states. The level schemes derived from such measurements have been used as a test for calculations in the framework of the shell model. The spectral distributions of eigenstates in 64Cu for different configuration spaces are presented and discussed. In this study the relative importance of configurations with n holes in the 1f7/2 shell with n up to 16, are investigated. It is found that the results strongly depend on the values of the single-particle energies. The results of the spectral-distribution method were utilized for shell-model calculations. From the information obtained from the spectral analysis it was decided to adopt a configuration space which includes up to one hole in the 1f7/2 shell and up to two particles in the 1g9/2 shell. Further, restrictions on seniority and on the coupling of the two particles in the 1g9/2 orbit have been applied and their effects have been studied. It is found that the calculated excitation energies reproduce the measured values in a satisfactory way, but that some of the electromagnetic properties are less well in agreement with experimental data. (Auth.)
Ab Initio Path to Heavy Nuclei
Binder, Sven; Calci, Angelo; Roth, Robert
2014-01-01
We present the first ab initio calculations of nuclear ground states up into the domain of heavy nuclei, spanning the range from 16-O to 132-Sn based on two- plus three-nucleon interactions derived within chiral effective field theory. We employ the similarity renormalization group for preparing the Hamiltonian and use coupled-cluster theory to solve the many-body problem for nuclei with closed sub-shells. Through an analysis of theoretical uncertainties resulting from various truncations in this framework, we identify and eliminate the technical hurdles that previously inhibited the step beyond medium-mass nuclei, allowing for reliable validations of nuclear Hamiltonians in the heavy regime. Following this path we show that chiral Hamiltonians qualitatively reproduce the systematics of nuclear ground-state energies up to the neutron-rich Sn isotopes.
Shape coexistence and triaxiality in nuclei near 80Zr
Zheng, S J; Shen, S F; Liu, H L; Wyss, R
2013-01-01
Total-Routhian-Surface calculations have been performed to investigate the shape evolutions of $A\\sim80$ nuclei, $^{80-84}$Zr, $^{76-80}$Sr and $^{84,86}$Mo. Shape coexistences of spherical, prolate and oblate deformations have been found in these nuclei. Particularly for the nuclei, $^{80}$Sr and $^{82}$Zr, the energy differences between two shape-coexisting states are less than 220 keV. At high spins, the $g_{9/2}$ shell plays an important role for shape evolutions. It has been found that the alignment of the $g_{9/2}$ quasi-particles drives nuclei to be triaxial.
Unique features of transuranic odd-odd nuclei
Odd-odd nuclei in the transuranic region have significantly longer half-lives than their odd-mass core nuclei. Further, the occurrence of long-lived isomers is a quite common feature in these nuclei. Interestingly in almost all the known isomer pairs, the ambiguity in the relative energy placement of the two isomers does not enable to know which of the two isomers is the real ground state. This is due to the fact that due to large difference in isomer spins, the two do not connect through an isomeric transition (IT). In this report these properties are illustrated by discussing the Z=99 Einsteinium sequence of nuclei
Relativistic mean field study of clustering in nuclei
Clustering phenomenon in exotic, light, heavy and superheavy nuclei is studied within the relativistic mean field (RMF) approach. Numerical calculations are done by using the axially deformed harmonic oscillator basis. The calculated nucleon density distributions and deformation parameters are analyzed to look for the cluster configurations. In case of light nuclei, the calculations explain many of the well established cluster structures in both the ground and intrinsic excited states. In the heavy and superheavy nuclei, interesting results are obtained and the results indicate new possibilities of exotic clusters at the centre of superheavy nuclei. (author)
The present collection of letters from JINR, Dubna, contains seven separate records on kinematic separation and mass analysis of heavy recoiling nuclei, dynamical effects prior to heavy ion fusion, VACTIV-DELPHI graphical dialog based program for the analysis of gamma-ray spectra, irradiation of nuclear emulsions in relativistic beams of 6He and3H nuclei, optical and structural investigations of PLZT x/65/35 (x = 4, 8 %) ferroelectric ceramics irradiated by a high-current pulsed electron beam, the oscillating charge and first evidence for neutrinoless double beta decay
The present collection of letters from JINR, Dubna, contains seven separate records on physics from extra dimensions, new physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos, the (μ-, e+) conversion in nuclei mediated by light Majorana neutrinos, exotic muon-to-positron conversion in nuclei: partial transition sum evaluation by using shell model, solar neutrino problem accounting for self consistent magnetohydrodynamics solution for solar magnetic fields, first neutrino observations from the Sudbury neutrino observatory and status report on BOREXINO and results of the muon-background measurements at CERN
Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra
Delayed-particle spectroscopy on very exotic nuclei at Ganil
This paper describes recent developments concerning the spectroscopy of the preponderate decay mode of these nuclei far off stability: their high β decay energy 0β opens up the window for decay into particle-unstable states of the daughter nucleus leading to β delayed proton or neutron emission in the case of very neutron-deficient or neutron-rich nuclei, respectively
Microscopic properties of superdeformed nuclei
Karlsson, Lennart B
1999-04-01
Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments
Nuclear Shell Structure and Beta Decay I. Odd A Nuclei II. Even A Nuclei
Mayer, M.G.; Moszkowski, S.A.; Nordheim, L.W.
1951-05-01
In Part I a systematics is given of all transitions for odd A nuclei for which sufficiently reliable data are available. The allowed or forbidden characters of the transitions are correlated with the positions of the initial and final odd nucleon groups in the nuclear shell scheme. The nuclear shells show definite characteristics with respect to parity of the ground states. The latter is the same as the one obtained from known spins and magnetic moments in a one-particle interpretation. In Part II a systematics of the beta transitions of even-A nuclei is given. An interpretation of the character of the transitions in terms of nuclear shell structure is achieved on the hypothesis that the odd nucleon groups have the same structure as in odd-A nuclei, together with a simple coupling rule between the neutron and proton groups in odd-odd nuclei.
Two-phase model of rotating nuclei
Using the generator-coordinate method a model is formulated in which the nucleus is treated as a triaxial rotator with coupled normal and superconductive phases. Averaging the model hamiltonian over coherent states the effects of different orientations of the mass quadrupoloid with respect to the angular momentum are studied in the case of 156166Er nuclei. (Auth.)
Two-phase model of rotating nuclei
Using the generator-coordinate method the model is formulated in which the nucleus is treated as a triaxial rotator with coupled normal and superconductive phases. Averaging the model Hamiltonian over coherent states the effects of different orientations of the mass quadrupoloid with respect to the angular momentum are studied in the case of 156Er and 166Er nuclei. (author)
Alpha-particle condensation in nuclei
A round up of the present status of the conjecture that nα nuclei form an α-particle condensate in excited states close to the nα threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed. (authors)
Alpha-particle condensation in nuclei
A round-up of the present status of the conjecture that nα nuclei form an α-particle condensate in excited states close to the nα threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed. (author)
Physics of the continuum of borromean nuclei
Vaagen, J.S.; Rogde, T. [Dept. of Physics, Univ. of Bergen (Norway); Danilin, B.V. [RRC The Kurchatov Inst., Kurchatov, Moscow (Russian Federation); Ershov, S.N. [JINR, Dubna, Moscow (Russian Federation); Thompson, I.J. [Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom); Zhukov, M.V. [Chalmers Univ. of Technology and Goeteborg Univ., Goeteborg (Sweden); RNBT Collaboration
1998-06-01
The continuum states of two-neutron halo nuclei are calculated in the method of hyperspherical harmonics. Using DWIA theory appropriate for dilute halo matter we have probed the structure of the low-lying {sup 6}He continuum via calculations of charge-exchange and inelastic scattering. (orig.)
Four-body correlations in nuclei
Sambataro, M
2015-01-01
Low-energy spectra of 4$n$ nuclei are described with high accuracy in terms of four-body correlated structures ("quartets"). The states of all $N\\geq Z$ nuclei belonging to the $A=24$ isobaric chain are represented as a superposition of two-quartet states, with quartets being characterized by isospin $T$ and angular momentum $J$. These quartets are assumed to be those describing the lowest states in $^{20}$Ne ($T_z$=0), $^{20}$F ($T_z$=1) and $^{20}$O ($T_z$=2). We find that the spectrum of the self-conjugate nucleus $^{24}$Mg can be well reproduced in terms of $T$=0 quartets only and that, among these, the $J$=0 quartet plays by far the leading role in the structure of the ground state. The same conclusion is drawn in the case of the three-quartet $N=Z$ nucleus $^{28}$Si. As an application of the quartet formalism to nuclei not confined to the $sd$ shell, we provide a description of the low-lying spectrum of the proton-rich $^{92}$Pd. The results achieved indicate that, in 4$n$ nuclei, four-body degrees of f...
Hoyer, Paul
1995-01-01
I review hard photon initiated processes on nuclei. The space-time development of the DIS reaction as viewed in the target rest frame qualitatively describes the nuclear shadowing of quark and gluon distributions, although it may be difficult to understand the very weak $Q^2$ dependence of the low $x$ data. The current jet hadron energy distribution at large $\
Electroweak interactions in nuclei
Topics include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms. 52 references
Nuclei with tetrahedral symmetry
We discuss a point-group-theory based method of searching for new regions of nuclear stability. We illustrate the related strategy with realistic calculations employing the tetrahedral and the octahedral point groups. In particular, several nuclei in the rare earth region appear as excellent candidates to study the new mechanism. (author)
Octupole collectivity in nuclei
Butler, P. A.
2016-07-01
The experimental and theoretical evidence for octupole collectivity in nuclei is reviewed. Recent theoretical advances, covering a wide spectrum from mean-field theory to algebraic and cluster approaches, are discussed. The status of experimental data on the behaviour of energy levels and electric dipole and electric octupole transition moments is reviewed. Finally, an outlook is given on future prospects for this field.
Triaxiality in superheavy nuclei
In this work, triaxial degree of freedom is explicitly utilized in calculating alpha decay lifetimes. The synthesis of superheavy nuclei with Z = 114-116 and 118 were detected by their decaying alpha chains with terminating spontaneous fission events. The lifetime of alpha decay chains measured are to be compared with the values evaluated theoretically
Fissibility of compound nuclei
Iwata, Yoritaka
2012-01-01
Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and fission events are expected to appear. In this paper, a microscopic method of calculating the fissibility of compound nuclei is presented.
Huerstel, A
2002-11-01
This thesis is devoted to the study of very neutron deficient nuclei in the lead region of the nuclear chart and more precisely to the investigation of the single particle states and collective properties of the {sup 187,189}Bi isotopes by gamma-ray spectroscopy. These nuclei were produced via fusion-evaporation reaction induced by a krypton beam on a silver target. In this mass region, the cross section for producing these nuclei are very low, of the order of a few micro-barns, making experimental studies very difficult. The identification of the nuclei was done using the very powerful RDT (Recoil Decay Tagging) technique, based on the selection of the isotopes through their characteristic alpha-particle decays. The experiments were performed at the university of Jyvdskyla (Finland) with the facility combining the gamma-ray spectrometer JUROSPHERE and the magnetic gas-filled separator RITU. Isomeric states were observed in both nuclei and their life-times measured. The systematics of individual proton states in odd-mass bismuth isotopes have been reproduced with a shell model up to 20 neutrons away from the valley of stability. Furthermore, rotational bands, a signature of collective nuclear motion, have been established for the first time in these nuclei. The interpretation of these results led to the conclusion that {sup 187,189}Bi have a prolate shape at low excitation energy, unlike the heavier bismuth isotopes which have been interpreted to have oblate deformation, implying a shape transition in this mass region. Hartree-Fock-Bogolyubov calculations are consistent with the experimental indication of shape coexistence, as seen in the neighbouring even-even lead nuclei. (author)
Angular velocity: a new dimension in nuclei
Diamond, R.M.; Stephens, F.S.
1984-08-09
Nuclei can be studied from their ground states (approx.O(h/2..pi..)) up to angular momenta of order 100 (h/2..pi..), where they are literally pulled apart by centrifugal effects. This range of angular momenta can be viewed as resulting from cranking the nucleus around a rotation axis, where the critical variable is the cranking velocity. The calculated response of nuclei to such an imposed angular velocity corresponds well with recent observations, and includes a rich and varied interplay of collective and single-particle phenomena.
Governor model for asymmetric deformed nuclei
The governor model is extended to include the asymmetric shape of nuclei which allows a simultaneous analysis of the data for both the ground state and the γ-vibrational bands in deformed even-even nuclei. The rotationally invariant core is assumed to be a spheroid with an axis of symmetry parallel to the axis of rotation. The calculations are carried out under the assumption of no stretching. The static γ-deformation results are compared with the VMI(ARM) and Krutov values, and the calculated energies are in good agreement with the experimental data
Dissipation and the population of compound nuclei
The importance of nuclear dissipative efforts on the formation of compound nuclei is studied with the γ-ray decay of the giant dipole resonance (GDR) built on highly excited states. The compound nuclei 164Yb, 160Er, and 110Sn were produced with very mass-asymmetric and with more mass-symmetric target/projectile combinations. The large deviation from statistical model prediction observed in the γ-ray spectra from the more symmetrically formed 160Er and 164Yb can be qualitatively explained within the particle exchange model
Medium energy hadron scattering from nuclei
The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154Sm and 154Gd. 27 refs., 5 figs., 1 tab
Probing nuclei by stripping them
The towing mode appears in nucleus collisions in which forward moving particles with specific angular correlations are emitted. In fact some particles are extracted from the target and towed along for a short while by the projectile during the collision. This process was discovered at the GANIL accelerator in the nineties. These collisions are peripheral. A simulation has shown that the energy and angle features of the particles emitted depends on their initial quantum state inside the target nucleus just before their emission which means that towing mode can be used as a tool to study quantum states in nuclei and their correlations. Experimental results concerning the following reactions: 11Be + 48Ti and 6He + Pb are presented. (A.C.)
Analysis of E1-transitions (ΔK=1) of the 5/2-(512)↔7/2+(633)type, which are observed in odd-neutron nuclei of rare earth elements 165Dy, 167,169Er, 169,171,173Yb, 173,175Hf, 173,175W is carried out in this paper. Comparison of the experimental values of probabilities of this type E1-transitions shows considerable fluctuations of their values. The values of experimental and theoretical (at different approximations) probabilities given for E1-transitions of the type investigated are presented in tables. Analysis carried out for probabilities of E1-transitions of the type investigated showed that, besides including pairing interaction, which plays in this case an important role, consequently calculation in the framework of the non-adiabatic rotational model taking into account state Coriolis mixing is necessary
Triaxiality in 146,148Sm nuclei
Recently, attempts have been made to use the dynamic pairing plus quadrupole model to evaluate B(E2) values, B(E2) branching ratios, and low-lying energy levels for 146,148Sm nuclei, which are in poor agreement with experiment. Application of the boson expansion technique on 148Sm shows too much splitting and an incorrect order for the quintet states, while other properties have not been discussed. In the present work, 146,148Sm nuclei have been described using an asymmetric rotor model framework. The nonaxiality parameter γ has been evaluated using the energy ration E2+'/E6+. Remarkable success has been achieved in explaining the correct ordering of known low-lying energy levels, B(E2) values, and B(E2) branching ratios, which indicate that the so-called spherical nuclei may be treated as triaxial. (author). 8 refs., 9 tabs., 1 fig
Acceleration of heavy nuclei in solar flares
The overabundance of heavy nuclei in solar cosmic rays of energy approximately less than 5 MeV/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with keV electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions. (U.S.)
New approaches to studies of exotic nuclei
New generations of 4π gamma-ray detectors, recoil mass spectrometers (RMS), and radioactive beam accelerators will open up many new areas of research, including present inaccessible in-beam and radioactive decay studies of exotic nuclei still farther off stability. The new generation RMS and radioactive beam developments at the Holifield Heavy Ion Research Facility are presented. Current research and further prospects to probe the N -- Z line up to 100Sn are described. Superdeformation in A -- 70 to 190 nuclei is described in terms of its underlying physics of reinforcing proton and neutron shell gaps which lead to new superdeformed, doubly-magic nuclei. Recent results provide new insights into the coexistence of multiple nuclear shapes near the ground states
Gyromagnetic ratios of the states with spins between 7/2- and 21/2- (inclusive) in the 1/2-[521] ground-state band of 171Yb were measured by the transient-field technique following Coulomb excitation. Multipolarity mixing ratios were determined from measured particle-γ-ray angular correlations and total branching ratios were determined from intensity balances in a γ-γ coincidence measurement. The electromagnetic properties of the low-lying natural parity states in 171Yb are compared with particle-rotor calculations and can be well described in the limit of a pure K=1/2 band. A comparison of measured g-factors in the ground-state rotational bands of 155Gd, 169Tm and 171Yb with particle-rotor model calculations suggests that the renormalization of the rotational g-factor in the low-K, single-quasiparticle bands of odd rare-earth nuclei, compared with their even neighbours, is predominantly due to Coriolis interactions
A new spin-oriented nuclei facility: POLAREX
Etilé A.
2014-03-01
Full Text Available Using the On-Line Nuclear Orientation method, POLAREX (POLARization of EXotic nuclei is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows to measure nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at Accélérateur Linéaire auprés du Tandem d’Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program.
A new spin-oriented nuclei facility: POLAREX
Using the On-Line Nuclear Orientation method, POLAREX (Polarization of Exotic nuclei) is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows the measurement of nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at the linear accelerator in Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program. The first experiment will be the nuclear magnetic moment measurement of 125Sb as final commissioning
Spectroscopic Studies of Exotic Nuclei at ISOLDE
2002-01-01
Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...
Pairing correlations in exotic nuclei
Sagawa, H
2012-01-01
The BCS and HFB theories which can accommodate the pairing correlations in the ground states of atomic nuclei are presented. As an application of the pairing theories, we investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a 3-body model, respectively. We show that the odd-even staggering in the reaction cross sections of $^{30,31,32}$Ne and $^{14,15,16}$C are successfully reproduced, and thus the staggering can be attributed to the unique role of pairing correlations in nuclei far from the stability line. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for $s$- and p-waves using the HFB wave functions. We also propose effective density-dependent pairing interactions which reproduce both the neutron-neutron ($nn$) scattering length at zero density and the neutron pairing gap in uniform matter. Then, we apply these interactions to study pairing gaps in ...
The analysis of elastic and inelastic scattering of α-particles with energy ∼ 50 MeV by nuclei with mass numbers A = 54-124 and 3He-particles by nucleus 64Ni is given in the framework of the optical model by means of coupled channel method and distorted waves. The parameter of multipole deformations for lower states are determined. The parameters for quadrupole and octupole deformations of the potential for nucleus 112Sn are extracted, the values of hexadecupole deformation β4 of the potential for nuclei 94Zr, 120,124Sn are found. Information on the ratio of deformation parameters for the neutron and proton components and lower collective states (21+, 31-) by nuclei with A = 90-124 is extracted. 79 refs.; 4 figs.; 3 tabs
Octupole correlations in U and Pu nuclei
We study the even-even U and Pu nuclei in the framework of the spdf interacting boson model. Analysis of the systematics of positive and negative parity bands, together with the E1, E2, and E3 transitions, suggests that the properties of low-lying states can be understood without the introduction of stable octupole deformation. Double octupole phonon characteristics are also identified in certain low-lying 0+ excited states in U and Pu
Disintegration of comet nuclei
The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies. (physics of our days)
Nuclei in the Cosmos is the foremost bi-annual conference of nuclear physicists, astrophysicists, cosmochemists, and others to survey the recent achievements in Nuclear Astrophysics. As an interdisciplinary meeting it promotes mutual understanding and collaboration over fields fundamental to solve a range of open questions, from the origin of the elements to stellar evolution. Inherent part of the conference is a school devoted to students and young scientists where prominent scientists introduce the field of nuclear astrophysics to the participants. Conference Topics: Cosmology and big bang nucleosynthesis; Element production, stellar evolution and stellar explosions; Evidences of nucleosynthesis in stars and in presolar grains; Experiments in nuclear astrophysics; Nuclei far from stability; Nuclear theory in astrophysics; New facilities. [TRA
Effenberger, M.; Mosel, U.
1997-01-01
We calculate the total photoabsorption cross section and cross sections for inclusive pion and eta photoproduction in nuclei in the energy range from 300 MeV to 1 GeV within the framework of a semi-classical BUU transport model. Besides medium modifications like Fermi motion and Pauli blocking we focus on the collision broadening of the involved resonances. The resonance contributions to the elementary cross section are fixed by fits to partial wave amplitudes of pion photoproduction. The cro...
Ayala, A. L.; Ducati, M. B. Gay; Levin, E. M.
1996-01-01
In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and ...
Low energy Q-phonon excitations in nuclei
One-, two-, and multi-Q-phonon excitations in heavy nuclei are discussed. We describe the Q-phonon scheme for low-lying, isoscalar, positive parity states in γ-soft nuclei and compare the predictions of the Q-phonon scheme to new data on the nucleus 132Ce. We report on the experimental proof for the quadrupole-octupole coupled two-phonon nature of the lowest-lying 1- state in the semi-magic N=82 nuclei 142Nd and 144Sm. Finally, low-lying proton-neutron asymmetric mixed-symmetry states are discussed in terms of the Q-phonon scheme. We report on recent lifetime measurements of the mixed-symmetry one-Q-phonon excitation, the 2ms+ state, in the nuclei 125,128Xe, 136Ba, and 144Nd. (c) 1999 American Institute of Physics
Low energy Q-phonon excitations in nuclei
One-, two-, and multi-Q-phonon excitations in heavy nuclei are discussed. We describe the Q-phonon scheme for low-lying, isoscalar, positive parity states in γ-soft nuclei and compare the predictions of the Q-phonon scheme to new data on the nucleus 132Ce. We report on the experimental proof for the quadrupole-octupole coupled two-phonon nature of the lowest-lying 1- state in the semi-magic N=82 nuclei 142Nd and 144Sm. Finally, low-lying proton-neutron asymmetric mixed-symmetry states are discussed in terms of the Q-phonon scheme. We report on recent lifetime measurements of the mixed-symmetry one-Q-phonon excitation, the 2ms+ state, in the nuclei 125,128Xe, 136Ba, and 144Nd
Bruge, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1967-01-01
This report gives the results from a systematic study by 44 MeV {alpha} particle scattering on the collective states of closed shell nuclei with 28 neutrons, 28 and 50 protons especially in the energy region corresponding to the two phonon vibrational triplet. The nuclei studied are: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn and {sup 124}Sn. The theoretical analysis has been made with the Austern and Blair model using a phase shift analysis of the elastic scattering. Deformation lengths {delta}{sub I} = {beta}{sub I}R and transition probabilities obtained are compared with several experimental and theoretical data. (author) [French] Ce rapport donne les resultats d'une etude systematique par diffusion de particules {alpha} de 44 MeV des etats collectifs des noyaux au voisinage des couches fermees a 28 neutrons et 28 et 50 protons, specialement dans la region correspondant au triplet vibrationnel a deux phonons. Les noyaux etudies sont: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn et {sup 124}Sn. L'analyse theorique a ete faite a l'aide du modele de Austern et Blair utilisant une analyse en dephasages de la diffusion elastique. Les longueurs de deformation {delta}I = {beta}{sub I}R obtenues pour chaque niveau sont comparees a plusieurs donnees experimentales et theoriques. (auteur)
Relativistic Brueckner-Hartree-Fock theory for finite nuclei
Shen, Shihang; Liang, Haozhao; Meng, Jie; Ring, Peter; Zhang, Shuangquan
2016-01-01
Starting with a bare nucleon-nucleon interaction, for the first time the full relativistic Brueckner-Hartree-Fock equations are solved for finite nuclei in a Dirac-Woods-Saxon basis. No free parameters are introduced to calculate the ground-state properties of finite nuclei. The nucleus $^{16}$O is investigated as an example. The resulting ground-state properties, such as binding energy and charge radius, are considerably improved as compared with the non-relativistic Brueckner-Hartree-Fock results and much closer to the experimental data. This opens the door for \\emph{ab initio} covariant investigations of heavy nuclei.
Particle-unstable nuclei in the Hartree-Fock theory
Kruppa, A T; Flocard, Hubert; Liotta, R J
1997-01-01
Ground state energies and decay widths of particle unstable nuclei are calculated within the Hartree-Fock approximation by performing a complex scaling of the many-body Hamiltonian. Through this transformation, the wave functions of the resonant states become square integrable. The method is implemented with Skyrme effective interactions. Several Skyrme parametrizations are tested on four unstable nuclei: 10He, 12O, 26O and 28O.
A study of strange-, charmed, and beauty nuclei
An analyses is made of the bound states of nuclei in the strange-, charm-, and beauty sector using a spin-dependent Gaussian two-body interaction in the microscopic formalism. Coulomb corrections are also included for the charmed nuclei. Our simple model is in reasonable agreement with other existing theoretical and experimental results and it predicts many new bound states. (author). 21 refs, 2 figs, 10 tabs
Description of deformed nuclei in the sdg boson model
S. C. Li; Kuyucak, S.
1996-01-01
We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical $1/N$ expansion techniques. The focus is on description of high-spin states which have recently become computationally accessible through the use of computer algebra in the $1/N$ expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei.
Description of deformed nuclei in the sdg boson model
Li, S C
1996-01-01
We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical 1/N expansion techniques. The focus is on description of high-spin states which have recently become computationally accessible through the use of computer algebra in the 1/N expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei.
Quasifree kaon photoproduction on nuclei
Frank Lee; T. MART; Cornelius Bennhold; Lester Wright
2001-12-01
Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.
Quadrupole moments of odd-odd near-magic nuclei
Achakovskiy O.
2012-12-01
Full Text Available Ground state quadrupole moments of odd-odd near-double-magic nuclei are calculated in the approximation of non-interacting odd neutron and odd proton. Under such a simple approximation the problem is reduced to the calculations of quadrupole moments of corresponding odd-even nuclei. These calculations are performed within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. with the known DF3-a parameters. A reasonable agreement with the available experimental data is obtained for odd-odd nuclei and odd near-magic nuclei investigated. The self-consistent approach under consideration allowed us to predict the unknown quadrupole moments of odd-even and odd-odd nuclei near the double-magic 56,78Ni, 100,132Sn nuclides.
Schild, Rudolph E.; Leiter, Darryl J.; Robertson, Stanley L.
2008-03-01
We show how direct microlensing-reverberation analysis performed on two well-known quasars (Q2237, the Einstein Cross, and Q0957, the Twin) can be used to observe the inner structure of two quasars which are in significantly different spectral states. These observations allow us to measure the detailed internal structure of Q2237 in a radio-quiet high-soft state, and compare it to Q0957 in a radio-loud low-hard state. When taken together we find that the observed differences in the spectral states of these two quasars can be understood as being due to the location of the inner radii of their accretion disks relative to the co-rotation radii of the magnetospheric eternally collapsing objects (MECO) in the centers of these quasars. The radiating structures observed in these quasars are associated with standard accretion disks and outer outflow structures, where the latter are the major source of UV-optical continuum radiation. While the observed inner accretion disk structure of the radio-quiet quasar Q2237 is consistent with either a MECO or a black hole, the observed inner structure of the radio-loud quasar Q0957 can only be explained by the action of the intrinsic magnetic propeller of a MECO with its accretion disk. Hence a simple and unified answer to the long-standing question: "Why are some quasars radio loud?" is found if the central objects of quasars are MECO, with radio-loud and radio-quiet spectral states similar to the case of galactic black hole candidates.
Sturmian method for light exotic nuclei
This research concentrates on halo like systems: Abnormally large light nuclei at the neutron dripline which exhibit a clear separation between a ''normal'' core nucleus and a loosely bound low-density veil of neutrons. This phenomenon offers very interesting possibilities for studies of neutron matter under extreme conditions in a low-density background. This work is focused on few-body theory for light halo-like nuclei: Borromean systems, i.e. while the three-body-like system is bound (but very loosely) none of the binary subsystems are bound. Three representatives were closely investigated: 6He. 11Li and 14Be. The aim of this work was to gain an insight how important are for light exotic nuclei different aspects of three-body description. The investigation was performed by applying for light halo systems a few-body model originally developed for ordinary heavy well-bound nuclei. Special features of the Borromean systems, most important of which are enormous size and weak binding, suggested the need for modifications of the method to allow more subtle treatment. Theoretical considerations and numerical tests provided evidences for importance to accurately include certain effects into the description scheme. Our calculations are based on Bisturmian three-body method. The two-particle (three body) bound state is expanded on a set of Sturm-Liouville basis functions. These basis functions are derived from a well-depth-prescription method where single-particle wave functions are used which are eigenstates in a Saxon-Woods potential with one-nucleon separation energy ε each. The basis set is in principle infinite, but discrete, and corresponds to the intuitive picture of increasingly deeper wells, all able to support bound motion with energy ε. The three-body bound state is found by diagonalising with the neutron-core and neutron-neutron potentials simultaneously. Pauli blocking is taken into account by projecting out those basis states coinciding with occupied
From the requirement of the time periodicity of a (quasi) stable state, frequencies of the normal modes, which compose the state, are commensurable (integer ratios) with each other, and the excitation energies Ex are written as a sum of inverse integers. We propose an expression: Ex = GΣ1/n, where n = integers and G = 34.5 MeV. Recurrence time is defined as LCM(nj) x τo, where τ0 = 2πℎ/G = 1.20 x 10-22s. LCM vs. Ex are illustrated for all possible nj of 2 and 3 normal modes. In 16O +n resonances, integer ratios are found between the recurrence frequencies of 17O and the de Broglie wave frequencies of incident neutron, meaning time coherency between them. A simple branch pattern is found in 16O +n resonance levels. (author)
Beckmann, Volker
2012-01-01
This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d
Blandford, RD; Woltjer, L
1990-01-01
Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory
The present collection of letters from JINR, Dubna, contains eight separate records on the interaction of high energy Λ6He hypernuclear beams with atomic nuclei, the position-sensitive detector of a high spatial resolution on the basis of a multiwire gas electron multiplier, pseudorapidity hadron density at the LHC energy, high precision laser control of the ATLAS tile-calorimeter module mass production at JINR, a new approach to ECG's features recognition involving neural network, subcriticity of a uranium target enriched in 235U, beam space charge effects in high-current cyclotron injector CI-5, a homogeneous static gravitational field and the principle of equivalence
The present collection of letters from JINR, Dubna, contains six separate records on the DELPHI experiment at LEP, the Fermi-surface dynamics of rotating nuclei, production of large samples of the silica dioxide aerogel in the 37-litre autoclave and test of its optical properties, preliminary radiation resource results on scintillating fibers, a new algorithm for the direct transformation method of time to digital with the high time resolution and development and design of analogue read-out electronics for HADES drift chamber system
Effenberger, M.; Hombach, A; Teis, S.; Mosel, U.
1996-01-01
We calculate the total photoabsorption cross section on nuclei in the energy range from 300 MeV to 1 GeV within the framework of a semi-classical phase space model. Besides medium modifications like Fermi motion and Pauli blocking we focus on the collision broadening of the involved resonances. The resonance contributions to the elementary cross section are fixed by fits to partial wave amplitudes of pion photoproduction. The cross sections for $N \\, R \\to N \\, N$, needed for the calculation ...
Few-Body Models of Light Nuclei
Ershov, S. N.; Vaagen, J. S.; Zhukov, M. V.
2015-06-01
Experiments confirm a variety of cluster structures in many light nuclei. The observation of nuclear halos at drip-lines has accentuated the question of the degrees of freedom for bound and low-lying continuum states. In these cases the many-body dynamics of nuclear structure may be well approximated by few-body cluster models that often suggest conceptually simple approaches explaining successfully many features of light nuclei. Thus few-body cluster models have been successfully used for description of the nuclear structure of weakly bound halo nuclei and their emergent cluster degrees of freedom. They have attractive features supplying in a most transparent way the asymptotic behavior and continuum properties of weakly bound systems. Such models assume a separation in internal cluster (core) degrees of freedom and the relative motion of few-body constituents. Such separation is only an approximation, and low-lying states appear where the core cannot be considered as inert system and additional degrees of freedom connected to excited core states have to be taken into account. For fixed total angular momentum a coupling to excited core states having different spins involves additional partial waves into the consideration. This allows to account for some emergent (collective) core degrees of freedom and gives a more realistic description of nuclear properties. It is an analogue to increasing the number of shells within the framework of shell-model approaches. Some examples from recent nuclear structure exploration within few-body halo cluster models are presented.
Ho, L C; Sargent, W L W; Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W.
1996-01-01
We describe a new sample of Seyfert nuclei discovered during the course of an optical spectroscopic survey of nearby galaxies. The majority of the objects, many recognized for the first time, have luminosities much lower than those of classical Seyferts and populate the faint end of the AGN luminosity function. A significant fraction of the nuclei emit broad H-alpha emission qualitatively similar to the broad lines seen in classical Seyfert 1 nuclei and QSOs.
Electron scattering for exotic nuclei
Toshimi Suda
2014-11-01
A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.
The extended local-scale transformation method (LSTM) in combination with the natural orbital representation is applied to investigate the nuclear ground state local density and momentum distributions. The 'breathing' monopole excitation mode is considered within this approach and the adiabatic limit of the time-dependent Hartree-Fock theory (ATDHF). Numeric calculations for the nucleus 16O with the effective Skyrme forces have been carried out. The occupation numbers are determined, taking into account the experimantal charge density distribution data. 2 figs., 1 tab., 13 refs
Photoproduction of Mesons off Light Nuclei - The Search for η-Mesic Nuclei
Photoproduction of η mesons off light nuclei (d, 3He, 7Li) has been measured at the tagged photon beam of the Mainz MAMI accelerator with the combined Crystal Ball/TAPS detection system. Special attention was given to the threshold behavior of the reactions in view of possible indications for the formation of (quasi-) bound η-nucleus states, so-called η-mesic nuclei. A very strong threshold enhancement of coherent η photoproduction off 3He was found and coherent η photoproduction off 7Li was observed for the first time. Preliminary results will be discussed. (authors)
The dynamics of the nuclei-nuclei interactions at very high energies
The lectures on the dynamics of nuclei-nuclei interactions at very high energies, presented in the Summer School on Nuclear Physics and Particle Physics (1988), are shown. The equation of state of the hadronic matter is analyzed, by means of simple models, and some orders of magnitude can be asserted. The main characteristics of the high energy hadronic interactions are recalled. The basis of the dynamics of the relativistic fluids are given. Applications of this dynamics in the description of the space-time evolution of a plasma, generated by heavy ions collision, are carried out
Quasiparticle-phonon interaction in non-magic nuclei
A general microscopic approach to describe properties of excited states in non-magic nuclei is formulated. It is based on the consistent use of the Green function method in Fermi systems with Cooper pairing. The main attention is paid to even-even nuclei, but for odd nuclei with pairing some important relations are obtained too. The quasiparticle-phonon interaction which is introduced acts also in the particle-particle channel and gives a quasiparticle-phonon contribution to pairing. When applied to the theory of giant multipole resonances, the approach includes all known sources of resonance width, i.e. QRPA configurations (which correspond to Landau damping in magic nuclei), the single-particle continuum (escape width) and more complex configurations (spreading width). The use of the Green function method makes it possible to include consistently the ground-state correlations induced by the more complex configurations. In the approximation of the collective phonon creation amplitude squared, which is considered in detail here, these are the ground-state correlations caused by two-quasiparticle-phonon configurations; effects of these correlations have been found earlier to be noticeable for magic nuclei. Such a unified approach will give a reasonable description of the giant resonances' integral characteristics including their widths and of some more delicate properties like fine structure and decay characteristics. Physical arguments and earlier results of a similar approach for magic nuclei allow to use the known parameters of the Landau-Migdal non-separable interaction for all non-magic nuclei (except the light ones). This means that the theory developed is suitable for realistic predictions of the properties of unknown nuclei including unstable ones. The inclusion of the single-particle continuum allows to consider also nuclei with separation energy near zero. (orig.)
QCD Effects in Particle Production on Nuclei
Hoyer, Paul
1993-01-01
I discuss some questions related to hard scattering processes in nuclei and corrections to the leading twist approximation. The QCD factorization theorem requires that high energy partons do not lose energy while traversing the nucleus. I explain the physical reason for this. The theorem also states that spectator partons, not involved in the hard collision, have no influence on the inclusive cross section. Important spectator effects are, however, seen in the data for certain reactions and i...
Mean Field Studies of Exotic Nuclei}
Chinn, C. R.; Umar, A. S.; Vallières, M.; Strayer, M. R.
1994-01-01
{Full three dimensional static and dynamic mean field calculations using collocation basis splines with a Skyrme type Hamiltonian are described. This program is developed to address the difficult theoretical challenges offered by exotic nuclei. Ground state and deformation properties are calculated using static Hartree-Fock, Hartree-Fock+BCS and constrained Hartree-Fock models. Collective properties, such as reaction rates and resonances, are described using a new alternate method for evaluat...
Nuclear magnetic resonance of thermally oriented nuclei
The more recent developments in the spectroscopy of Nuclear Magnetic Resonance on Oriented Nuclei (NMRON) are reviewed; both theoretical and experimental advances are summarised with applications to On-Line and Off-Line determination of magnetic dipole and electric quadrupole hyperfine parameters. Some emphasis is provided on solid state considerations with indications of where likely enhancements in technique will lead in conventional hyperfine studies. (orig.)
On Closed Shells in Nuclei. II
Mayer, M. G.
1949-04-01
Discussion on the use of spins and magnetic moments of the even-odd nuclei by Feenberg and Nordheim to determine the angular momentum of the eigenfunction of the odd particle; discussion of prevalence of isomerism in certain regions of the isotope chart; tabulated data on levels of square well potential, spectroscopic levels, spin term, number of states, shells and known spins and orbital assignments.
Fayans functional for deformed nuclei. Uranium region
Tolokonnikov, S V; Kortelainen, M; Lutostansky, Yu S; Saperstein, E E
2015-01-01
Fayans energy density functional (EDF) FaNDF^0 has been applied to the nuclei around uranium region. Ground state characteristics of the Th, U and Pu isotopic chains, up to the two-neutron drip line, are found and compared with predictions from several Skyrme EDFs. The two-neutron drip line is found for FaNDF^0, SLy4 and SkM^* EDFs for a set of elements with even proton number, from Pb up to Fm.
Structure of residual interaction in spherical nuclei
Kamchatnov, A. M.; Nosov, V. G.
2003-01-01
The effect of residual interaction between nucleons (quasiparticles) on shell oscillations of the masses of spherical nuclei is considered. The singularity of the ground state energy of the system in the vicinity of nucleon magic numbers is analyzed for various types of the dependence of residual interaction on orbital momentum of the quasiparticle. It is shown that only the perturbation band width of the Fermi distribution due to residual interaction which is proportional to the square of th...
Light nuclei production in heavy ion collisions
K.H. Khan; Suleymanov, M. K.; Wazir, Z.; Khan, E. U.; Haseeb, Mahnaz Q.; Ajaz, M.
2009-01-01
Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.
Fourth nuclear theory workshop 'clusters in nuclei'
This document gathers the slides of 3 lectures: 1) the R-matrix method, 2) from realistic NN-interactions to cluster structures in nuclei - in this part the unitary correlation operator method (UCOM) is applied to 3 domains: the fermionic molecular dynamics, the Hartree-Fock approximation, and the no-core shell model -, and 3) the shell model point of view on cluster states
Electromagnetic properties of nuclei at high spins
A photon emitted by an excited state is likely to carry away, at most, 1 or 2 h-bar of angular momentum. Therefore, a profusion of photons is needed to deexcite the rapidly rotating states of nuclei formed by heavy-ion reactions. The study of electromagnetic properties has become the primary source of information on nuclear structure at high spins and, also, at the warm temperatures present in the initial stage of the electromagnetic cascade process. The purpose of this paper is a review of the E1, M1, and E2 properties of such highly excited states. 42 refs., 5 figs
We study nuclear potential-energy surfaces, ground-state masses and shapes calculated by use of a Yukawa-plus-exponential macroscopic model and a folded-Yukawa single-particle potential for 4023 nuclei ranging from 16O to 279112. We discuss extensively the transition from spherical to deformed shapes and study the relation between shape changes and the mass corresponding to the ground-state minimum. The calculated values for the ground-state mass and shape show good agreement with experimental data throughout the periodic system, but some discrepancies remain that deserve further study. We also discuss the effect of deformation on Gamow-Teller #betta#-strength functions
A systematic study of low energy nuclear structure at normal deformation has been carried out using the Generator Coordinate Method mapped onto a 5-Dimensional Collective quadrupole Hamiltonian (5DCH) by using the Gaussian Overlap Approximation (GCM-GOA). The collective space is spanned by Hartree Fock Bogoliubov (HFB) states under axial and triaxial quadrupole constraints deduced with the D1S Gogny force. In addition, our 5DCH includes the Thouless-Valatin dynamical corrections to its rotational kinetic terms. The work is described in detail elsewhere together with the corresponding comparisons with experimental data when it is available. Many properties show a satisfactory agreement with experiment, but there is an almost systematic overestimation of vibrational band head energies, which is the subject of the present paper. We show here the performance of the theory on related observables, and propose improvements of the theory to address the problem of the vibrational band heads. An important reason for the deficient is the treatment of vibrational inertial parameters. In particular, the theory needs to include the dynamical Thouless-Valatin corrections to the vibrational terms in the 5DCH. In present work, on the aim of a simple formula grounded by known symmetry rules within the 5DCH, these dynamical TV corrections are roughly estimated, allowing us to handle their possible effects in term of spectroscopic properties, to present a guess of the next model improvment, and to isolate some areas in the chart where states Inπ = 0+2, 2+2 or 2+3 seem to have important components out of the scope of a pure collective quadrupole approach.
A schematic microscopic method is developed to calculate the M1 transition probabilities between the mixed-symmetry and the fully symmetric states in γ-soft nuclei. The method is based on the random-phase approximation-interacting boson model (RPA-IBM) boson mapping of the most collective isoscalar boson. All other boson modes with higher excitation energies, including the mixed-symmetry boson, are described in the framework of RPA. As an example the M1 transition probabilities are calculated for the 124-134Xe isotopes and compared with the experimental data. The results agree well with the data for the ratio B(M1;1ms+→22+)/B(M1;1ms+→01+). However, the calculated ratio B(M1;2ms+→21+)/B(M1;1ms+→01+) shows a significantly weaker dependence on the mass number than the experimental data.
Analysis of Orientation Relations Between Deformed Grains and Recrystallization Nuclei
West, Stine S.; Winther, Grethe; Juul Jensen, Dorte
Nucleation in 30 pct rolled high-purity aluminum samples was investigated by the electron backscattering pattern method before and after annealing. A total of 29 nuclei including two twins were observed, and approximately one third of these nuclei had orientations not detected in the deformed state....... Possible orientation relations between these nuclei and the deformed state were by 20 to 55 deg rotation around axes. These axes were compared with the active slip systems, and the crystallographic features of the deformation-induced dislocation boundaries. Good agreement was found between the rotation...... axes and the normal to slip planes with which dislocation boundaries align. The exact nucleation mechanism has not been established, but the observed orientation relations allow for prediction of which grains are likely to form rotated nuclei, although these may not all do so....
2007-01-01
The evolution of the unknown ground-state ${\\beta}$-decay properties of the neutron-rich $^{84-89}$Ge, $^{90-93}$Se and $^{102-104}$Sr isotopes near the r-process path is of high interest for the study of the abundance peaks around the N=50 and N=82 neutron shells. At ISOLDE, beams of certain elements with sufficient isotopic purity are produced as molecular sidebands rather than atomic beams. This applies e.g, to germanium, separated as GeS$^{+}$, selenium separated as SeCO$^{+}$ and strontium separated as SrF$^{+}$. However, in case of neutron-rich isotopes produced in actinide targets, new "isobaric" background of atomic ions appears on the mass of the molecular sideband. For this particular case, the ECR charge breeder, positioned in the experimental hall after ISOLDE first mass separation, can be advantageously used as a purification device, by breaking the molecules and removing the molecular contaminants. This proposal indicates our interest in the study of basic nuclear structure properties of neutron...
Pions in nuclei, from virtual-pion exchange to real-pion transfer
Tracing the work of Miyazawa on nuclear magnetic moments, we discuss possible experimental ways to see whether a real pion exists in nuclei or not. While virtual pions are known to play an important role in nuclei, as clarified experimentally from anomalous orbital g factors of nucleons in nuclei, nearly nothing is known for the behavior of real pions in nuclei. We have shown that deeply bound hybrid states of π- are expected to exist in heavy nuclei, which can be populated by ''pion transfer'' reactions. (author)
Shell structure evolution in nuclei: new paradigm
Shell structure evolution in nuclei situated at the extremes of neutron and proton excess are investigated using in-beam gamma spectroscopy techniques with radioactive beams at GANIL. A selection of results obtained very recently is presented: i) The reduced transition probabilities B(E2;01+ → 2+) of the neutron-rich 74Zn and 70Ni nuclei have been measured using Coulomb excitation at intermediate energy. An unexpected large proton core polarization has been found in 70Ni and interpreted as being due to the monopole interaction between the neutron g9/2 and protons f7/2 and f5/2 spin-orbit partner orbitals. ii) Two proton knock-out reactions has been performed in order to study the most neutron-rich nuclei at the N=28 shell closure. Gamma rays spectra and momentum distribution have been obtained for 42Si and neighboring nuclei. Evidences has been found for a deformed structure for 42Si and for the disappearance of the spherical N=28 shell effect. iii) The in-beam gamma spectroscopy of 36Ca performed using neutron knock-out reactions revealed that N=16 is as large sub-shell closure as large as Z=16 in 36S. The uniquely large excitation energy difference of the first 2+ state in these mirror nuclei turns out to be a consequence of the relatively pure neutron (in 36Ca) or proton (in 36S) 1p(d3/2)-1h(s1/2) nature. (author)
The present collection of letters from JINR, Dubna, contains ten separate records on the properties of the N=82 even-even nuclei, an investigation of the charge collection for strongly irradiated silicon strip detectors of the CMS ECAL preshower, the rate capability of the CSC cathode readout electronics, the timing resolution of cathode strip chambers of the CMS ME1/1 muon station and bunch crossing identification, strengthening and damping of synchrotron oscillations, photoradiation hardness of organic scintillators, as well as on a method of anode wire incident angle calculation of the first muon station (ME1/1) of the Compact Muon Solenoid set-up (CMS), heavy ion studies with CMS HF calorimeter, an investigation of the possibility of developing iodine-containing treatment and prophylactic pharmaceuticals based on blue-green algae Spirulina platensis using neutron activation analysis, a comparison between schemes for heavy ion injection into Nuclotron booster
The present collection of letters from JINR, Dubna, contains nine separate records on the transport of the evanescent electron beam in the vacuum section with plasma disks, determination of ΔΓs from analysis of untagged decays Bs0→J/ψφ by using the method of angular moments, investigation of light nucleus clustering in relativistic multifragmentation processes, secondary fragments of relativistic 22Ne at 4.1 A · GeV/c nuclei in nuclear emulsion, extrapolation of experimental data of accelerated radiation aging to the operation condition of dipole magnet electrical insulation at low dose rates, automatic quality control system of the installed straws into TRT wheels, a new method of fast simulation for a hadron calorimeter response, empirical evidence for relation between threshold effects and neutron strength function as well as on what information can be derived when no events are registered
The present collection of letters from JINR, Dubna, contains seven separate records on the integral representation for structure functions and target mass effects, multiscale properties of DNA primary structure including cross-scale correlations, dissipative evolution of the elementary act, the fine structure of the MT=1 Gamow-Teller resonance in 147gTb→147Gd β+/EC decay, the behaviour of the TVO temperature sensors in the magnetic fields, a fast method for searching for tracks in multilayer drift chambers of HADES spectrometer, a novel approach to particle track etching including surfactant enhanced control of pore morphology, azimuthal correlations of secondary particles in 32S induced interactions with Ag(Br) nuclei at 4.5 GeV/ c/ nucleon
The present collection of letters from JINR, Dubna, contains ten separate records on Wien filter using in exploring on low-energy radioactive nuclei, memory effects in dissipative nucleus-nucleus collision, topological charge and topological susceptibility in connection with translation and gauge invariance, solutions of the multitime Dirac equation, the maximum entropy technique. System's statistical description, the charged conductor inside dielectric. Solution of boundary condition by means of auxiliary charges and the method of linear algebraic equations, optical constants of the TGS single crystal irradiated by power pulsed electron beam, interatomic pair potential and n-e amplitude from slow neutron scattering by noble gases, the two-coordinate multiwire proportional chamber of the high spatial resolution and neutron drip line in the region of O-Mg isotopes
What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction. (author)
The applications of skyrmions to the derivation of the nucleon-nucleon force are now over a dozen years old, and this occasion is used to assess the degree of success of the endeavor. A very brief review is given of the use of skyrmions for determining single-baryon properties. Then their use for two-nucleon systems is described, with attention to the use of the product ansatz, the full structure of the lagrangian, baryon resonance admixtures, dilatons, and exact solutions for the B=2 system in order to find the sources of attraction in the central potential. We briefly address possible insights into the behavior of the nucleon in nuclei achieved from the skyrmion approach. (author)
Ayala, A P; Levin, E M
1996-01-01
In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus - nucleus cascade.
Beck, Christian
Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics: - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...
Introduction to the study of collisions between heavy nuclei
Bayman, B.F.
1980-01-01
Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)
Quadrupole moments of odd-odd near-magic nuclei
Achakovskiy O.; Voitenkov D.; Kamerdzhiev S.; Tolokonnikov S.
2012-01-01
Ground state quadrupole moments of odd-odd near double magic nuclei are calculated in the approximation of no interaction between odd particles. Under such a simple approximation, the problem is reduced to the calculations of quadrupole moments of corresponding odd-even nuclei. These calculations are performed within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. with the known DF3-a parameters. A reasonable agreement with the availa...
Introduction to the study of collisions between heavy nuclei
Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables
Holt Roy J.
2016-01-01
Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Holt, Roy J.
2016-03-01
Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
3rd International conference on nuclei far from stability, Cargese, Corsica, 19-26 May 1976
These conference proceedings contain 103 contributions which are grouped under the following headings: Experimental methods and techniques; Perspectives in research on exotic nuclei; Nuclear masses - experiment and theory; Nuclear spins, moments, and radii; Light nuclei; Delayed particle emission and statistical aspects; Excited states of neutron-deficient nuclei; Excited states of fission products and other neutron-rich isotopes; Heavy elements and astrophysical aspects. Also included are the Scientific programme and a List of participants. (AJ)
Antiproton Induced Fission and Fragmentation of Nuclei
2002-01-01
The annihilation of slow antiprotons with nuclei results in a large highly localized energy deposition primarily on the nuclear surface. \\\\ \\\\ The study of antiproton induced fission and fragmentation processes is expected to yield new information on special nuclear matter states, unexplored fission modes, multifragmentation of nuclei, and intranuclear cascades.\\\\ \\\\ In order to investigate the antiproton-nucleus interaction and the processes following the antiproton annihilation at the nucleus, we propose the following experiments: \\item A)~Measurement of several fragments from fission and from multifragmentation in coincidence with particle spectra, especially neutrons and kaons. \\item B)~Precise spectra of $\\pi$, K, n, p, d and t with time-of-flight techniques. \\item C)~Installation of the Berlin 4$\\pi$ neutron detector with a 4$\\pi$ Si detector placed inside for fragments and charged particles. This yields neutron multiplicity distributions and consequently distributions of thermal excitation energies and...
Nuclear structure investigations on spherical nuclei
This report discusses the following topics: electron scattering studies on spherical nuclei; electron scattering from collective states in deformed nuclei; proton and pion scattering studies; 12C(e,e'p) and 16O(e,e'p); 12C(e,e'α) and 16O(e,e'α); studies at high q at Bates; measurements with rvec e at Bates; 12C(γ,p); future directions in giant resonance studies; proton knockout from 16O; quasielastic studies at Bates; triple coincidence studies of nuclear correlations; contributions to (e,e'2p) at KIKHEF; contributions to instrumentation at CEBAF; instrumentation development at UNH; the Bates large acceptance spectrometer toroid; shell model and core polarization calculations; and the relativistic nuclear model
Effective Field Theory for Lattice Nuclei
Barnea, N.; Contessi, L.; Gazit, D.; Pederiva, F.; van Kolck, U.
2015-02-01
We show how nuclear effective field theory (EFT) and ab initio nuclear-structure methods can turn input from lattice quantum chromodynamics (LQCD) into predictions for the properties of nuclei. We argue that pionless EFT is the appropriate theory to describe the light nuclei obtained in LQCD simulations carried out at pion masses heavier than the physical pion mass. We solve the EFT using the effective-interaction hyperspherical harmonics and auxiliary-field diffusion Monte Carlo methods. Fitting the three leading-order EFT parameters to the deuteron, dineutron, and triton LQCD energies at mπ≈800 MeV , we reproduce the corresponding alpha-particle binding and predict the binding energies of mass-5 and mass-6 ground states.
Effective Field Theory for Lattice Nuclei
Barnea, N; Gazit, D; Pederiva, F; van Kolck, U
2013-01-01
We show how nuclear effective field theory (EFT) and ab initio nuclear-structure methods can turn input from lattice quantum chromodynamics (LQCD) into predictions for the properties of nuclei. We argue that pionless EFT is the appropriate theory to describe the light nuclei obtained in recent LQCD simulations carried out at pion masses much heavier than the physical pion mass. We solve the EFT using the effective-interaction hyperspherical harmonics and auxiliary-field diffusion Monte Carlo methods. Fitting the three leading-order EFT parameters to the deuteron, dineutron and triton LQCD energies at $m_{\\pi}\\approx 800$ MeV, we reproduce the corresponding alpha-particle binding and predict the binding energies of mass-5 and 6 ground states.
Isospin Mixing In N $\\approx$ Z Nuclei
Srnka, D; Versyck, S; Zakoucky, D
2002-01-01
Isospin mixing in N $\\approx$ Z nuclei region of the nuclear chart is an important phenomenon in nuclear physics which has recently gained theoretical and experimental interest. It also forms an important nuclear physics correction in the precise determination of the $ft$-values of superallowed 0$^+ \\rightarrow 0^+ \\beta$- transitions. The latter are used in precision tests of the weak interaction from nuclear $\\beta$- decay. We propose to experimentally measure isospin mixing into nuclear ground states in the N $\\approx$ Z region by determining the isospin forbidden Fermi-component in the Gamow-Teller dominated $J^{\\pi} \\rightarrow J^{\\pi} \\beta$- transitions through the observation of anisotropic positron emission from oriented nuclei. First measurements were carried out with $^{71}$As and are being analyzed now.
Light unstable nuclei in the continuum
It is discussed that the complex scaling method is one of the most available frameworks to solve many body resonances. As the recent developments of the complex scaling method, we present several ways to analyse the properties of resonant states; the matrix elements associated with resonant states, the extended completeness relation and partial widths of resonances. We also show the discussions on the binding mechanism and excited resonant structure of the Borromean systems 4He+n+n and 9Li+n+n. It is shown that the pairing correlation between valence neutrons and among core neutrons plays an important role in neutron-rich nuclei. (author)
Light unstable nuclei in the continuum
Kato, Kiyoshi [Hokkaido Univ., Division of Physics, Hokkaido (Japan)
2000-01-01
It is discussed that the complex scaling method is one of the most available frameworks to solve many body resonances. As the recent developments of the complex scaling method, we present several ways to analyse the properties of resonant states; the matrix elements associated with resonant states, the extended completeness relation and partial widths of resonances. We also show the discussions on the binding mechanism and excited resonant structure of the Borromean systems {sup 4}He+n+n and {sup 9}Li+n+n. It is shown that the pairing correlation between valence neutrons and among core neutrons plays an important role in neutron-rich nuclei. (author)
Interaction of eta mesons with nuclei
Kelkar, N. G.; Khemchandani, K. P.; Upadhyay, N. J.; Jain, B. K.
2013-06-01
Back in the mid-1980s, a new branch of investigation related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta-meson producing reactions. The vast literature of experimental as well as theoretical works that studied various aspects of eta-producing reactions such as the π+n → ηp, pd → 3Heη, p 6Li → 7Be η and γ 3He → η X, to name a few, had but one objective in mind: to understand the eta-nucleon (ηN) and hence the η-nucleus interaction which could explain the production data and confirm the existence of some η-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the ηN and hence the η-nucleus interaction. Therefore, this review is an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations. The ηN scattering length (which represents the strength of the η-nucleon interaction) using different theoretical models and analyzing the data on η production in pion, photon and proton induced reactions was found to be spread out in a wide range, namely, 0.18 ⩽ ℜe aηN ⩽ 1.03 fm and 0.16 ⩽ ℑm aηN ⩽ 0.49 fm. Theoretical searches of heavy η-mesic nuclei based on η-nucleus optical potentials and lighter ones based on Faddeev type few-body approaches predict the existence of several quasibound and resonant states. Although some hints of η-mesic states such as ^3_{\\eta} He and ^{25}_{\\eta} Mg do exist from previous experiments, the promise of clearer signals for the existence of η-mesic nuclei lies in the experiments to be performed at the J-PARC, MAMI and COSY facilities in the near future. This review is aimed at giving an overall
Borromean halo, Tango halo, and halo isomers in atomic nuclei
Izosimov Igor
2016-01-01
Full Text Available Structure of the ground and excited states in halo-like nuclei is discussed. Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei.Structure of the halo may be different for the different levels and resonances in atomic nuclei. Isobar analog, double isobar analog, configuration, and double configuration states can simultaneously have n-n, n-p, and p-p halo components in their wave functions. When the halo structure of the excited state differs from that of the ground state, or the ground state has non-halo structure, the γ-transition from the excited state to the ground state can be essentially hindered, i.e. the formation of a specific type of isomers (halo isomers becomes possible. B(Mγ and B(Eγ values for γ-transitions in 6,7,8Li, 8,9,10Be, 8,10,11B, 10,11,12,13,14C, 13,14,15,16,17N, 15,16,17,19O, and 17F are analyzed. Special attention is given to nuclei which ground state does not exhibit halo structure but the excited state (halo isomer may have one.
Monopole transitions in hot nuclei
Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs
Spectroscopy of heavy fissionable nuclei
S K Tandel
2015-09-01
Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.
The present collection of letters from JINR, Dubna, contains ten separate records on the role of the Coulomb distortion in form-factor calculations for 12C with alpha-clusterization and nucleon-nucleon correlations, optimization of a set-up for the investigation of the light-nuclei spin structure at the internal target of the Nuclotron, precessing deuteron polarization, connection of the parameter estimation quality of maximum likelihood and generalized moments, determination of the total energy QEC for 156Ho(T1/2∼56 min)β+/EC decay using the total absorption γ-ray spectrometer, selection of signal events in the DUBTO experiment, a search for the dineutron in the interaction of neutrons with deuterons, tracking performance of the HERA-B outer tracker PC chambers, construction and manufacture of large size straw-chambers of the COMPASS spectrometer tracking system, as well as on the charge form factor and the nucleon momentum distribution of 24He and their centre-of-mass correction
Mishustin, I N; Buervenich, T J; Stöcker, H; Greiner, W
2005-01-01
We study the possibility of producing a new kind of nuclear systems which in addition to ordinary nucleons contain a few antibaryons (antiproton, antilambda, etc.). The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from He to Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by factor 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that due to significant reduction of the reaction Q-values, the in-medium annihilation rates should be strongly suppressed leading to relativel...
In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab
Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)
1996-10-01
In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.
From nuclear matter to finite nuclei. Pt. 2
We discuss various relativistic models describing ground-state properties of spherical nuclei, are discussed. Relativistic mean-field and Hartree-Fock theories, which serve as a startingpoint for subsequent models, are reviewed. Using a density-dependent parametrization of the Dirac-Brueckner G-matrix in nuclear matter, we achieve an effective Dirac-Brueckner-Hartree-Fock model for finite nuclei. Finite nuclei results obtained with this model are compared with the less advanced Density-Dependent Mean-Field model, which simulates Dirac-Brueckner calculations for nuclear matter as well. It is shown that the effective Dirac-Brueckner-Hartree-Fock approach most successfully reproduces experimental data concerning spherical nuclei. (orig.)
Magnetic moments of odd-odd spherical nuclei
Achakovskiy, O I; Saperstein, E E; Tolokonnikov, S V
2013-01-01
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground and excited states are calculated within the self-consistent TFFS based on the EDF method by Fayans {\\it et al}. We limit ourselves to nuclei with a neutron and a proton particle (hole) added to the magic or semimagic core. A simple model of no interaction between the odd nucleons is used. In most the cases we analyzed, a good agreement with the experimental data is obtained. Several cases are considered where this simple model does not work and it is necessary to go beyond. The unknown values of magnetic moments of many unstable odd and odd-odd nuclei are predicted including sixty values for excited odd-odd nuclei.
Photoproduction of Pseudoscalar Mesons off Nuclei at Forward Angles
Gevorkyan, S; Gan, L; Larin, I; Khandaker, M
2009-01-01
With the advent of new photon tagging facilities and novel experimental technologies it has become possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths from these measurements at forward angles is done by the Primakoff method, which requires theoretical treatment of all processes participating in these reactions at the same percent level. In this work we review the theoretical approach to meson photoproduction amplitudes in the electromagnetic and strong fields of nuclei at forward direction. The most updated description of these processes are presented based on the Glauber theory of multiple scattering. In particular, the effects of final state interactions, corrections for light nuclei, and photon shadowing in nuclei are discussed.
Deformed $sd$-shell nuclei from first principles
Jansen, G R; Hagen, G; Navrátil, P
2015-01-01
We extend the ab initio coupled-cluster effective interaction (CCEI) method to deformed open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei $^{20}$Ne and $^{24}$Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory for deformed nuclei, thereby demonstrating that collective phenomena in $sd$-shell nuclei emerge from complex ab initio calculations.
Effect of properties of superheavy nuclei on their production and decay
Adamian, G. G.; Antonenko, N. V.; Bezbakh, A. N.; Jolos, R. V.
2016-05-01
Properties and stability of superheavy nuclei resulting from hot fusion are discussed. It is shown that the microscopic-macroscopic approach allows obtaining the closed proton shell at Z ≥ 120. Isotopic trends of K-isomeric states in superheavy nuclei are predicted. Evaporation residue cross sections in hot fusion reactions are calculated using the predicted properties of superheavy nuclei. Interruption of α decay chains by spontaneous fission is analyzed. Alpha decay chains through isomeric states are considered. Internal level densities in superheavy nuclei are microscopically calculated.
Symmetry Remnants in the Face of Competing Interactions in Nuclei
Leviatan, A
2015-01-01
Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.
Symmetry remnants in the face of competing interactions in nuclei
Leviatan, A., E-mail: ami@phys.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Macek, M., E-mail: michal.macek@yale.edu [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States)
2015-10-15
Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.
Physics with loosely bound nuclei
Chhanda Samanta
2001-08-01
The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to ﬁnd a consistent picture for the unstable nuclei starting from their stable counterparts. Some signiﬁcant differences in the structure and reaction mechanisms are found.
PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa
History of cluster structure in nuclei
This contribution focuses on the history of clustering in nuclei. Elementary alpha models treat light 4-n nuclei as systems of alpha-particles obeying Bose Einstein statistics. These models neglect the internal structure of the alphas and effects of the Pauli principle between the nucleons in the alpha clusters are taken into account by introducing a short range repulsion between the clusters. The orthogonality condition model and excluded state model treat the alphas as elementary particles, but include effects of the Pauli principle in a more microscopic way. Wheeler's resonating group method is a fully microscopic theory for calculating properties of cluster systems. It makes simplifying assumptions about the internal structure of the clusters but takes the Pauli principle explicitly. Hartree-Fock theory can be used for a microscopic theory of nuclear structure but it is not suitable for light nuclei because there is no well defined mean field. Margenau's microscopic cluster model avoids this problem by using trial wave functions which are antisymmetrized products of parametrized single particle wave functions
Fusion excitation functions involving transitional nuclei
Rehm, K.E.; Jiang, C.L.; Esbensen, H. [and others
1995-08-01
Measurements of fusion excitation functions involving transitional nuclei {sup 78}Kr and {sup 100}Mo showed a different behavior at low energies, if compared to measurements with {sup 86}Kr and {sup 92}Mo. This points to a possible influence of nuclear structure on the fusion process. One way to characterize the structure of vibrational nuclei is via their restoring force parameters C{sub 2} which can be calculated from the energy of the lowest 2{sup +} state and the corresponding B(E2) value. A survey of the even-even nuclei between A = 28-150 shows strong variations in C{sub 2} values spanning two orders of magnitude. The lowest values for C{sub 2} are observed for {sup 78}Kr, {sup 104}Ru and {sup 124}Xe followed by {sup 74,76}Ge, {sup 74,76}Se, {sup 100}Mo and {sup 110}Pd. In order to learn more about the influence of {open_quotes}softness{close_quotes} on the sub-barrier fusion enhancement, we measured cross sections for evaporation residue production for the systems {sup 78}Kr + {sup 104}Ru and {sup 78}Kr + {sup 76}Ge with the gas-filled magnet technique. For both systems, fusion excitation functions involving the closed neutron shell nucleus {sup 86}Kr were measured previously. The data are presently being analyzed.
Adiabatic fission barriers in superheavy nuclei
Jachimowicz, P; Skalski, J
2016-01-01
Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy we calculated static fission barriers $B_{f}$ for 1305 heavy and superheavy nuclei $98\\leq Z \\leq 126$, including even - even, odd - even, even - odd and odd - odd systems. For odd and odd-odd nuclei, adiabatic potential energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from the 10-th below to the 10-th above the Fermi level. The parameters of the model that have been fixed previously by a fit to masses of even-even heavy nuclei were kept unchanged. A search for saddle points has been performed by the "Imaginary Water Flow" method on a basic five-dimensional deformation grid, including triaxiality. Two auxiliary grids were used for checking the effects of the mass asymmetry and hexadecapole non-axiallity. The ground states were found by energy minimization over configurations and deformations...
Spectrin-like proteins in plant nuclei
Ruijter, de N.C.A.; Ketelaar, T.; Blumenthal, S.S.D.; Emons, A.M.C.; Schel, J.H.N.
2000-01-01
We analysed the presence and localization of spectrin-like proteins in nuclei of various plant tissues, using several anti-erythrocyte spectrin antibodies on isolated pea nuclei and nuclei in cells. Western blots of extracted purified pea nuclei show a cross-reactive pair of bands at 220–240 kDa, ty
Cluster formation, breaking, and excitation in light nuclei
In this paper, we discuss cluster phenomena in light nuclei based on calculations using the antisymmetrized molecular dynamics (AMD) method. Cluster structures in C, B, and Be were studied systematically, and their cluster formation and excitation are discussed. Cluster gas states and their band members are suggested for the excited states of 12C and 11B. The ground state cluster correlation and excited cluster gas state are discussed from the point of view of symmetry breaking and restoration. (authors)
{Delta}I = 2 energy staggering in normal deformed dysprosium nuclei
Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others
1996-12-31
Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.
A quasi-particle model for computational nuclei
A model Hamiltonian is derived which provides a computationally efficient means of representing nuclei. The Hamiltonian includes both coulomb and isospin dependent terms, and incorporates antisymmetrization effects through a momentum dependent potential. Unlike many other classical or semiclassical models, the nuclei of this simulation have a well-defined ground state with a a non-vanishing 2>. It is shown that the binding energies per nucleon and r.m.s. radii of these ground states are close to the measured values over a wide mass range
Modification of meson properties in the vicinty of nuclei
Filip Peter
2014-01-01
Full Text Available We suggest that modification of meson properties (lifetimes and branching ratios can occur due to the interaction of constituent quark magnetic moments with strong magnetic fields present in the close vicinity of nuclei. A superposition of (J =0 and (J =1, mz =0 particle-antiparticle quantum states (as observed for ortho-Positronium may occur also in the case of quarkonium states J/Ψ, ηc ϒ, ηb in heavy ion collisions. We speculate on possible modification of η(548 meson properties (related to C parity and CP violation in strong magnetic fields which are present in the vicinity of nuclei.
Alteration of alpha 1 Na+,K(+)-ATPase 86Rb+ influx by a single amino acid substitution
The sodium- and potassium-dependent adenosine triphosphatase (Na+,K(+)-ATPase) maintains the transmembrane Na+ gradient to which is coupled all active cellular transport systems. The R and S alleles of the gene encoding the Na+,K(+)-ATPase alpha 1 subunit isoform were identified in Dahl salt-resistant (DR) and Dahl salt-sensitive (DS) rats, respectively. Characterization of the S allele-specific Na+,K(+)-ATPase alpha 1 complementary DNA identified a leucine substitution of glutamine at position 276. This mutation alters the hydropathy profile of a region in proximity to T3(Na), the trypsin-sensitive site that is only detected in the presence of Na+. This mutation causes a decrease in the rubidium-86 influx of S allele-specific sodium pumps, thus marking a domain in the Na+,K(+)-ATPase alpha subunit important for K+ transport, and supporting the hypothesis of a putative role of these pumps in hypertension
Mareš, Jiří; Cieplý, Aleš; Friedman, E.; Gal, A.; Gazda, D.
Vol. 234. Dordrecht: Springer, 2015, s. 49-56. ISSN 0304-3843. [5th International Conference on Exotic Atoms and Related Topics (EXA). Vienna (AT), 15.09.2014-19.09.2014] R&D Projects: GA ČR(CZ) GAP203/12/2126 Institutional support: RVO:61389005 Keywords : K- nuclear states * eta nuclear states * Meson-baryon interactions Subject RIV: BE - Theoretical Physics
Double-beta decay in deformed nuclei
A brief review of theoretical results for the double-beta decay and the double-electron capture in heavy deformed nuclei is presented. The ββ half life of 160Gd is evaluated using an extended version of the pseudo SU(3) model. While the 2ν mode is forbidden when the most probable occupations are considered, states with different occupation numbers can be mixed through the pairing interaction. The amount of this mixing is calculated using perturbation theory. The possibility of observing the ββ decay in 160Gd is discussed for both the 2ν and 0ν modes. (author)
Isovector excitations of N ≠ Z nuclei
We show that the method based on the tensor coupling of an appropriate family of isovector excitation operators to the parent isospin multiplet can be used, to advantage, for the correct treatment of the isospin degree of freedom in non isoscalar nuclei. This method is applicable to any isovector excitation operator and for parent states which need not to be of the closed subshells type. As an illustration we apply it to the study of the Gamow-Teller transition strength in 90Zr. (author)
Inclusive inelastic electron scattering from nuclei
Fomin, Nadia
2007-01-01
Inclusive electron scattering from nuclei at large x and $Q^2$ is the result of a reaction mechanism that includes both quasi--elastic scattering from nucleons and deep inelastic scattering from the quark constituents of the nucleons. Data in this regime can be used to study a wide variety of topics, including the extraction of nuclear momentum distributions, the influence of final state interactions and the approach to $y$-scaling, the strength of nucleon-nucleon correlations, and the approach to $x$- scaling, to name a few. Selected results from the recent experiment E02-019 at the Thomas Jefferson National Accelerator Facility will be shown and their relevance discussed.
Probing Chiral Interactions in Light Nuclei
Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P
2004-01-08
Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.
Signature Inversion in Odd-odd Nuclei
LIU Min-liang; ZHANG Yu-hu; ZHOU Xiao-hong; GUO Ying-xiang; LEI Xiang-guo; GUO Wen-tao
2009-01-01
Signature inversion in odd-odd nuclei is investigated by using a proton and a neutron coupling to the coherent state of the core.Two parameters are employed in the Hamiltonian to set the energy scales of rotation,neutron-proton coupling and their competition.Typical level staggering is extracted from the calculated level energies.The calculation can approximately reproduce experimental signature inversion.Signature inversion is attributed to the rotational motion and neutronproton residual interaction having reversed signature splitting rules.It is found signature inversion can appear at axially symmetric shape and high-K band.
Selected topics on Hadrons in Nuclei
Oset, E; Hernandez, E; Ramos, A; Magas, V K; Yamagata-Sekihara, J; Hirenzaki, S; Gamermann, D; Molina, R; Tolos, L; Roca, L
2011-01-01
In this talk we report on selected topics on hadrons in nuclei. The first topic is the renormalization of the width of the $\\Lambda(1520)$ in a nuclear medium. This is followed by a short update of the situation of the $\\omega$ in the medium. The investigation of the properties of $\\bar{K}$ in the nuclear medium from the study of the $(K_{flight},p)$ reaction is also addressed, as well as properties of X,Y,Z charmed and hidden charm resonances in a nuclear medium. Finally we address the novel issue of multimeson states.
Photoproduction of pions in 12C nuclei
A preliminary analysis was carried out of relativistic effects in coherent and incoherent pion production for the reaction 12C(γ, π0)12C by considering all the diagrams that contribute to the scattering amplitude. For the coherent pion the contribution to the scattering cross section mainly comes from the direct and exchange diagrams of γN → Δ → Nπ0, where N is a nucleon. The results were compared with the nonrelativistic calculations done in 12C nuclei assuming the nuclear effects and the final state interactions to be the same
From heavy nuclei to super-heavy nuclei
The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)
The major part of this work is about the realization and complete analysis of an experiment for studying isomeric states in 138,139,140Nd nuclei. This was performed at Jyvaeskylae laboratory (Finland) using a fusion-evaporation reaction with 48Ca beam on a thin 96Zr target. Experimental setup consisted in the target position gamma ray detector Jurogam II which was coupled with the RITU recoil separator and the GREAT focal plane detector array. This particularly well adapted setup permit to manage γ spectroscopy of the interest nuclei around isomeric states. Indeed, we used prompt-delayed matrices to separate rays that come onto isomeric states and these who decay from them. Then, the correlations between the two components permit to establish feeding transitions of isomeric states. Thanks to this experiment, a new isomeric state was also highlighted in 139Nd with spin 23/2+, which was predicted and interpreted in Cranked-Nilsson-Strutinsky calculation. Finally, very clean time spectra allow to determine precisely life-time of four states in four nuclei. This Ph.d. is also made of a part of the analysis of the first experimental search for fingerprints of tetrahedral symmetry in 156Gd using high fold gamma ray spectroscopy. Thanks to a large number of triple coincidence events, we managed a detailed spectroscopy of this nucleus. Particularly, we found out 13 new transitions in positive parity bands. As a complement of this work, we have done GEANT4 simulations about the detection limits of low intensity transitions by Agata multidetector. Indeed, tetrahedral symmetry predicts vanishing of E2 transitions at lower spin states and simulations permit to determine observation limit of these transitions with different version of Agata. (author)
Charming Mesons with Baryons and Nuclei
Tolos, Laura
2013-11-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future FAIR facility.
Charming mesons with baryons and nuclei
Tolos, Laura
2013-01-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future F...
Cavitation inception from bubble nuclei.
Mørch, K A
2015-10-01
The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes. PMID:26442138
Skyrme RPA for spherical and axially symmetric nuclei
Repko, Anton; Nesterenko, V O; Reinhard, P -G
2015-01-01
Random Phase Approximation (RPA) is the basic method for calculation of excited states of nuclei over the Hartree-Fock ground state, suitable also for energy density functionals (EDF or DFT). We developed a convenient formalism for expressing densities and currents in a form of reduced matrix elements, which allows fast calculation of spectra for spherical nuclei. All terms of Skyrme functional were taken into account, so it is possible to calculate electric, magnetic and vortical/toroidal/compression transitions and strength functions of any multipolarity. Time-odd (spin) terms in Skyrme functional become important for magnetic M1 and isovector toroidal E1 transitions. It was also found that transition currents in pygmy region (low-lying part of E1 resonance) exhibit isoscalar toroidal flow, so the previously assumed picture of neutron-skin vibration is not the only mechanism present in pygmy transitions. RPA calculations with heavy axially-symmetric nuclei now become feasible on ordinary PC. Detailed formul...
Isobar doorway approach to pion scattering on open shell nuclei
Delta-hole approach developed for the pion scattering on closed shell nuclei is extended to be applied to the case of open shell nuclei. The doorway space is spanned by the states of the form vertical strokeΨ(A-1) x ψ(Δ)> which correspond to vertical strokeΔ x h> states in the usual delta-hole approach for closed shell nuclei. In this approach, the effects of the couplings between elastic and inelastic channels are incorporated in a natural way. As a first application of this approach, some numerical calculations have been done for the elastic and inelastic pion scattering on 12C and the elastic scattering on 14N and 14C. The effects of the nuclear structure and the coupling between elastic and inelastic channels are discussed. (orig.)
Clusters in neutron-rich light nuclei
Jelavić Malenica D.
2016-01-01
Full Text Available Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states, but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.
Clusters and Halos in light Nuclei
The Fermionic Molecular Dynamics (FMD) approach [1] is used to study light nuclei in the p-and sd-shell. FMD uses Gaussian wave packets as single-particle states. The flexibility of the wave packet basis allows to consistently describe states with shell structure as well as states featuring clusters and halos. The many-body basis states are Slater determinants projected on parity, angular momentum and total linear momentum. The Hamiltonian is diagonalized in a set of many-body basis states obtained in a variation after projection procedure. I will present results for the spectrum of 12C with a special emphasis on the excited states above the 3α-threshold including the Hoyle state. It is found to be dominated by dilute a-cluster configurations, a picture that is confirmed by comparison with inelastic electron scattering data [2]. Recently we studied the structure of the Neon isotopes 17-22Ne and compared with experimentally measure charge radii [3]. In case of 17Ne and 18Ne the low-lying states can be described as 160 and 160 cores plus two protons in either s2 or d2 configurations. The s2 admixture of about 40% explains the large charge radius of 17Ne. In 18Ne the s2 admixture is only about 15%. Very large charge radii are again observed for 19,20Ne. This is explained by the admixture of 3He and 4He cluster configurations in the ground states.(author)
Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion
Artemenkov, D A; Zarubin, P I
2016-01-01
A role of the unstable nuclei ${}^{6}$Be, ${}^{8}$Be and ${}^{9}$B in the dissociation of relativistic nuclei ${}^{7,9}$Be, ${}^{10}$B and ${}^{10,11}$C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration ${}^{6}$Be + $\\mit{n}$ to the ${}^{7}$Be nucleus structure is 8 $\\pm$ 1% which is near the value for the configuration ${}^{6}$Li + $\\mit{p}$. Distributions over the opening angle of $\\alpha$-particle pairs indicate to a simultaneous presence of virtual ${}^{8}$Be$_{g.s.}$ and ${}^{8}$Be$_{2^+}$ states in the ground states of the ${}^{9}$Be and ${}^{10}$C nuclei. The core ${}^{9}$B is manifested in the {${}^{10}$C} nucleus with a probability of 30 $\\pm$ 4%. Selection of the ${}^{10}$C "white" stars accompanied by ${}^{8}$Be$_{g.s.}$ (${}^{9}$B) leads to appearance in the excitation energy distribution of 2$\\alpha$2$\\mit{p}$ "quartets" of the distinct peak with a maximum at 4.1 $\\pm$ 0.3 MeV. ${}^{8}$Be$_{g.s.}$ decays are p...
Photodissociation of neutron deficient nuclei
Sonnabend, K.; Babilon, M.; Hasper, J.; Mueller, S.; Zarza, M.; Zilges, A. [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)
2006-03-15
The knowledge of the cross sections for photodissociation reactions like e.g. ({gamma}, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained. (orig.)
Photodissociation of neutron deficient nuclei
Sonnabend, K.; Babilon, M.; Hasper, J.; Müller, S.; Zarza, M.; Zilges, A.
2006-03-01
The knowledge of the cross sections for photodissociation reactions like e.g. (γ, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained.
Cavitation inception from bubble nuclei
Mørch, Knud Aage
2015-01-01
experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The...... cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model...... and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes....
Fission barrier in even-even superheavy nuclei
In this work, the ground state properties of even-even superheavy nuclei (Z=112-120) are studied. The work has given emphasis on the role of deformation on the structure of superheavy nuclei. The problem of superdeformed ground state, their deformation energy curves and the potential energy surface of these nuclei is addressed. Both the nonrelativistic Skyrme-Hartree-Fock SHF and the deformed Relativistic Mean Field RMF models have been used in a constrained calculation. The systematic investigations of fission barriers in even-even superheavy nuclei with charge number Z=112-120 within relativistic mean field theory including the triaxial shapes and octupole shapes with axial symmetry. The improved version of NL3 parameter set (NL3), standard NL3, SkI4 and SLy4 parameter sets are used for the calculations. The pairing correlations are treated using the BCS approximation using the seniority pairing forces adjusted to empirical values of the gap parameters. The investigations for potential energy surface (PES), and the deformation energy curves for several isotopes with charge number Z=112, 114, 116, 118 and 120 nuclei obtained with the NL3 parameterization of the RMF Lagrangian is presented. The results will be for the case of axial solution with reflection symmetry, triaxial solutions with reflection symmetry, and octupole deformation solutions with axial symmetry
曹李刚; 马中玉
2003-01-01
A fully consistent relativistic random-phase approximation is applied to study the systematic behaviour of the isovector giant dipole resonance of nuclei along the β-stability line in order to test the effective Lagrangians recently developed. The centroid energies of response functions of the isovector giant dipole resonance for stable nuclei are compared with the corresponding experimental data and the good agreement is obtained. It is found that the effective Lagrangian with an appropriate nuclear symmetry energy, which can well describe the ground state properties of nuclei, could also reproduce the isovector giant dipole resonance of nuclei along the β-stability line.
Algebraic benchmark for prolate-oblate coexistence in nuclei
Leviatan, A
2016-01-01
We present a symmetry-based approach for prolate-oblate and spherical-prolate-oblate shape coexistence, in the framework of the interacting boson model of nuclei. The proposed Hamiltonian conserves the SU(3) and $\\overline{\\rm SU(3)}$ symmetry for the prolate and oblate ground bands and the U(5) symmetry for selected spherical states. Analytic expressions for quadrupole moments and $E2$ rates involving these states are derived and isomeric states are identified by means of selection rules.
Light Nuclei of Even Mass Number in the Skyrme Model
Battye, Richard A.; Manton, Nicholas S.; Sutcliffe, Paul M.; Wood, Stephen W.
2009-01-01
We consider the semiclassical rigid-body quantization of Skyrmion solutions of mass numbers B = 4, 6, 8, 10 and 12. We determine the allowed quantum states for each Skyrmion, and find that they often match the observed states of nuclei. The spin and isospin inertia tensors of these Skyrmions are accurately calculated for the first time, and are used to determine the excitation energies of the quantum states. We calculate the energy level splittings, using a suitably chosen parameter set for e...
Spontaneous fission of superheavy nuclei
R A Gherghescu; D N Poenaru
2015-09-01
The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.
International Symposium on Exotic Nuclei
Sobolev, Yu G; EXON-2014
2015-01-01
The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).
Coulomb displacement energies in nuclei
In the present work the positions of the isobaric analog resonances (IAR) are calculated using the HF-TDA theory with a complete proton particle-neutron hole basis. The important feature of this approach is the fact that the HF potential and the particle-hole interaction used in the TDA are derived from the same two-body interactions. In this theroy all the higher order effects are taken into account in one consistent framework. The calculations are performed for several N > Z, closed shell nuclei. For these nuclei good agreement between the experimental and theoretical excitation energies of the IAR is obtained. (orig.)
Accardi, Alberto
2016-01-01
I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.
Nuclei, hadrons, and elementary particles
This book is a short introduction to the physics of the nuclei, hadrons, and elementary particles for students of physics. Important facts and model imaginations on the structure, the decay, and the scattering of nuclei, the 'zoology' of the hadrons and basic facts of hadronic scattering processes, a short introduction to quantum electrodynamics and quantum chromodynamics and the most important processes of lepton and parton physics, as well as the current-current approach of weak interactions and the Glashow-Weinberg-Salam theory are presented. (orig.) With 153 figs., 10 tabs
Structure of exotic nuclei and superheavy elements in meson field theory
In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)
Structure of exotic nuclei and superheavy elements in meson field theory
Linn, Khin Nyan
2008-07-15
In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)
Spectroscopy of N approximately 82 nuclei near the proton drip line
The yrast spectroscopy of Z>64 nuclei close to the proton drip line is discussed. This is a region of shell model nuclei in which high-spin excitations are accessible with heavy ion beams, and the occurrence of many isomers will facilitate future spectroscopic study of these nuclei to much higher spins that were observed in these investigations. The study of πhsub(11/2)sup(n) excitations in n=82 nuclei above 146Gd provided particularly interesting results, since in certain respects their properties match shell model predictions better than those of jsup(n) states near traditional doubly magic nuclei. First results for N=81 nuclei above Z=64 were also reported, but much work remains to be done in the Z>64, N<82 quadrant
The present collection of letters from JINR, Dubna, contains eight separate records on status of 116Cd double β decay study with 116CdWO4 scintillators, new limits on 2β processes in 40Ca and 46Ca by using low radioactive CaF2(Eu) crystal scintillators, the single state dominance in 2νββ-decay transitions to excited 0+ and 2+ final states, present status of the MONOLITH project, technique of neutrino-induced muon detection on the Earth surface, high-sensitive spectrometer of fast neutrons and the results of fast neutron background flux measurements at the gallium-germanium solar neutrino experiment (SAGE), new experimental limits on the electron stability and excitation of nuclear levels in 23Na, 127I and 129Xe induced by the electron decay on the atomic shell and element-loaded organic scintillators for neutron and neutrino physics
Description of Superdeformed Bands of the Nuclei in A ～ 60 Mass Region
刘玉鑫; 孟祥明
2003-01-01
Using the supersymmetry scheme including many-body interactions, we investigate the superdeformed (SD) bands of the nuclei in A ～ 60 mass region systematically. Quantitatively good results of the γ-ray energy spectra and the dynamical moments of inertia are obtained. It shows that the supersymmetry approach is powerful to describe the generic rotational property of SD states of light nuclei.
Stripping reactions of neutron rich 11Be and 19C nuclei
In recent times, the stripping reactions measuring the longitudinal momentum distribution and absorption cross section have been used as a prolific tool to investigate the ground state properties of neutron rich nuclei. The nuclei 11Be and 19C, being paradigm for single neutron halo, have attracted a significant interest, both theoretically as well as experimentally
Polarimetry of 16Ngs produced in μ--capture on 16O nuclei
A polarimetry technique based on stack targets and β-γ-coincidences has been applied to the 16N nuclei produced in the ground state capture of negative muons on 16O nuclei. The performance of the polarimeter and the first measurements of β-asymmetry due to the longitudinal nuclear polarization are discussed. (author)
Status and Perspectives of the Search for Eta-Mesic Nuclei
Moskal, Pawel; Krzemien, Wojciech
2016-01-01
In this report the search for eta-mesic nuclei is reviewed. The brief description of the experimental studies is presented with a focus on the possible production of the eta-nucleus bound states for light nuclei like 4He and 3He.
A new superfluid phase in atomic nuclei
The influence of pairing and the dynamical α-type correlations on the structure of nuclear states is studied within the enlarged superfluid model (ESM). A comparison between ESM and different modern nuclear structure models such as: the quasiparticle-phonon nuclear model, interaction boson model, Hartree-Fock-Bogoliubov, temperature dependent Hartree-Fock-Bogoliubov and Migdal's finite Fermi system model, is done for particular cases. New gap equations are obtained. The phase structure is enriched by a new superfluid phase - the so-called α-like superfluid phase-dominated by α-type correlations. New first and second order phase transitions are predicted. A first order phase transition between the α-like superfluid phase and the pairing superfluid phase seems to be observed in Sm region. New types of isomers, the so-called ''superfluid isomers'', with their bands of elementary excitations are predicted. One of them is observed in 152Sm. These isomers correspond to a second (local) minimum of the correlation energy versus pairing deformations, analogous to the fission or superdeformed (shape) isomers, which correspond to the second (local) minimum of the potential energy along the elongation degree of shape deformation. The superfluidities of neutron and proton systems in heavy nuclei region may be generated by one another. This fact leads to the explanation of the origin of the odd-even staggering of the charge radii of chains of isotopes of different nuclei. The fact that the magnitude of the α-decay reduced widths (γ2) of the neutron-defficient Pb isotopes is almost equal to the γ2 of the actinide α-decaying nuclei is due to the above mentioned induction of the neutron superfluidity into the proton system also. Such exotic data ESM can explain especially in the region of single magic nuclei. Within ESM we could find a natural microscopic description of the scissors mode that dominates the structure of the Kπ=1+ magnetic states. (author). 89 refs, 27 figs
Collective properties of octupole-deformed atomic nuclei
Collective properties of even-even nuclei in the radium region are studied theoretically. Energy of the lowest collective states and reduced probabilities B(E2) and B(E3) of electromagnetic transitions between these states are mainly analysed. The excited states are treated as large-amplitude quadrupole and octupole vibrations coupled with each other. A large anharmonicity of the spectrum and a large value B(E3) of the transition from the first octupole excited state to the ground state are obtained, for octupole-deformed nuclei. A strong dependence of the results on the shape of the potential energy of a nucleus, treated as a function of its deformation, is stressed. (author)
Green's Function Monte Carlo calculations of light nuclei
Recently, Green's Function Monte Carlo methods have been developed which enable one to perform exact calculations for the ground states of three and four body nuclei. These methods allow the alpha particle to be used as a testing ground for a variety of two- and three-nucleon interaction models, both in terms of their ground state energies and a variety of other ground state expectation values. We present a brief review of GFMC methods as applied to light nuclei, including recent improvements of the algorithm and a discussion of the prospects for the inclusion of momentum-dependent terms. We then discuss results for the ground state energy, one- and two-body density distributions, D-state probability, coulomb sum rule, and momentum distributions. The GFMC results are compared to experimental results and to variational Monte Carlo calculations. 27 refs., 5 figs., 1 tab
Investigation of exotic nuclei with absolute transition probabilities
Transition probabilities are crucial for the understanding of nuclear structure. Deep inelastic reactions, knockout reactions and projectile Coulomb excitation with fast radioactive beams are suited to populate excited states in exotic nuclei. Examples are presented which demonstrate that recoil Doppler shift lifetime measurements can be applied successfully in combination with such reactions to measure level lifetimes.
Auxiliary-field quantum Monte Carlo methods in nuclei
Alhassid, Y
2016-01-01
Auxiliary-field quantum Monte Carlo methods enable the calculation of thermal and ground state properties of correlated quantum many-body systems in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization methods. We review recent developments and applications of these methods in nuclei using the framework of the configuration-interaction shell model.
Towards a microscopic description of α-condensates in nuclei
A theory to describe α-condensates in nuclei is presented. The corresponding quasiparticles consist of fermions as well as bosons. The fermions are combinations of one-particle and three-hole states, while the bosons are combinations of pair-particles and pair-holes. A relation between the fermionic and bosonic gap parameters is predicted and confirmed by experimental data. (authors)
The possibility of connecting apparently different descriptions of quarks in nuclei has already been shown. The authors pursue the consequences of this 'duality' for flavour-singlet distributions. An interesting possibility is that nuclear pions may have unusual quark-gluon substructure. Indeed, pions in general could be relatively 'rich' in glue. (author)
Magnetic shift of magic nuclei
The shell effect of nuclei in strong magnetic fields associated with magnetars' is considered within the shell model. It is demonstrated that the magnetic field gives rise to a change of the phase in shell-oscillations of nuclear masses. The nuclear magic numbers of the iron region are shifted significantly towards smaller mass numbers. (author)
Fission dynamics of hot nuclei
Santanu Pal; Jhilam Sadhukhan
2014-04-01
Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.
Low energy + scattering on = nuclei
Swapan Das; Arun K Jain
2003-11-01
The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.
Nuclear astrophysics of light nuclei
Fynbo, Hans Otto Uldall
2013-01-01
A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...
The application of the Skyrme model to nuclear physics is discussed. A new approach is presented in which nuclei are identified with static soliton solutions in the appropriate topological sector. When this approach is applied to the deuteron, it yields automatically the correct spin, isospin, and parity quantum numbers. 4 refs
Generalized parton distributions of nuclei
Guzey, V.
2009-01-01
We review recent theoretical results on generalized parton distributions (GPDs) of nuclei, emphasizing the following three roles of nuclear GPDs: (i) complementarity to free proton GPDs, (ii) the enhancement of traditional nuclear effects such as nuclear binding, EMC effect, nuclear shadowing, and (iii) an access to novel nuclear effects such as medium modifications of bound nucleons.
Octupole correlation effects in nuclei
Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions
Fission Dynamics of Compound Nuclei
Iwata, Yoritaka; Heinz, Sophia
2012-01-01
Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and quasi-fission events are expected to appear. In this paper, possible fission dynamics of compound nuclei is presented.
Percolation and multifragmentation of nuclei
A method to build the 'cold' nuclei as percolation clusters is suggested. Within the framework of definite assumptions of the character of nucleon-nucleon couplings breaking resulting from the nuclear reactions as description of the multifragmentation process in the hadron-nucleus and nucleus-nucleus reactions at high energies is obtained. 19 refs.; 6 figs
Chiral Electroweak Currents in Nuclei
Riska, D O
2016-01-01
The development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown's role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.
Static multipole deformations in nuclei
The physics of static multipole deformations in nuclei is reviewed. Nuclear static moments result from the delicate balance between the vibronic Jahn-Teller interaction (particle-vibration coupling) and the residual interaction (pairing force). Examples of various permanent nuclear deformations are discussed
Coherent Photoproduction from Nuclei
Frankfurt, L L; Zhalov, M B
2003-01-01
We argue that study of the cross section of coherent photo(electro) production of vector mesons off nuclear targets provides an effective method to probe the leading twist hard QCD regimes of color transparency and perturbative color opacity as well as the onset of black body limit (BBL) in the soft and hard QCD interactions. In the case of intermediate energies we use the Generalized Vector Dominance Model to take into account coherence effects for two distinctive limits - the soft interactions for production of $\\rho$ and $\\rho'$-mesons and the color transparency regime for production of charmonium states. We demonstrate that GVDM describes very well $\\rho$-meson coherent photoproduction at $6 \\leq E_{\\gamma} \\leq 10$ GeV and predict an oscillating energy dependence for the coherent charmonium production. In the limit of small $x$ we find that hard QCD leads to onset of the perturbative color opacity even for production of very small onium states, like $\\Upsilon$. The advantages of the process of coherent d...
Nuclei at extreme conditions. A relativistic study
Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)
2014-11-14
The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.
The superdeformation phenomenon in atomic nuclei
Meyer, M.; Vivien, J. P.
After the discovery of discrete rotational bands corresponding to superdeformed nuclei with spin around 60h, the study of the structure of these nuclei over the last five years has witnessed a significant expansion in physical understanding with the emergence of new phenomena and in a technical development with the construction of sophisticated apparatus to examine these nuclei. On the eve of the approaching operation of news detectors such as EUROGAM resulting from a French-British collaboration,or the American GAMMASPHERE, this article discusses the present state of knowledge on superdeformation and exposes the theoretical basis as well as recent experimental results in the field. Avec la découverte de bandes de rotations discrètes correspondant à des noyaux superdéformés ayant des moments angulaires avoisinant 60h, l'étude de la structure de ces noyaux connait depuis les cinq dernières années un essor important tant sur le plan de la physique avec l'apparition de phénomènes nouveaux que sur le plan de la technique avec le développement d'appareillages sophistiqués pour scruter ces noyaux. A la veille de l'entrée en fonction de nouveaux détecteurs comme EUROGAM issu d'une collaboration Franco-Britannique ou GAMMASPHERE résultant des efforts des laboratoires Americains, cet article fait le point des connaissances actuelles sur la superdéformation et relate les acquis théoriques ainsi que les resultats expérimentaux accumulés récemment dans ce domaine.
Liquid layer model for non-magic nuclei
A liquid layer model (LLM) is developed for studying the low-energy oscillations of non-magic spherical nuclei. It is assumed that at low excitations only nucleons off the double-magic core take part in the collective motion. These nuclear states are modellized by the motion of a layer of homogeneously charged, incompressible, isotropic liquid around a solid, inert core. Inertia, stiffness and energies of the lowest quadrupole, octupole and hexadecapole excitations are calculated. A fairly good agreement between the calculated and experimental values are obtained in the validity regions of LLM, that is for near magic nuclei. (author) 29 refs.; 5 figs
General Relativistic Mean Field Theory for rotating nuclei
Madokoro, Hideki [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki
1998-03-01
The {sigma}-{omega} model Lagrangian is generalized to an accelerated frame by using the technique of general relativity which is known as tetrad formalism. We apply this model to the description of rotating nuclei within the mean field approximation, which we call General Relativistic Mean Field Theory (GRMFT) for rotating nuclei. The resulting equations of motion coincide with those of Munich group whose formulation was not based on the general relativistic transformation property of the spinor fields. Some numerical results are shown for the yrast states of the Mg isotopes and the superdeformed rotational bands in the A {approx} 60 mass region. (author)
Stability of bubble nuclei through Shell-Effects
Dietrich, Klaus; Pomorski, Krzysztof
1997-01-01
We investigate the shell structure of bubble nuclei in simple phenomenological shell models and study their binding energy as a function of the radii and of the number of neutron and protons using Strutinsky's method. Shell effects come about, on the one hand, by the high degeneracy of levels with large angular momentum and, on the other, by the big energy gaps between states with a different number of radial nodes. Shell energies down to -40 MeV are shown to occur for certain magic nuclei. E...
Magnetic moments of odd-odd spherical nuclei
Achakovskiy, O. I.; Kamerdzhiev, S. P.; Saperstein, E. E.; Tolokonnikov, S. V.
2013-01-01
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground and excited states are calculated within the self-consistent TFFS based on the EDF method by Fayans {\\it et al}. We limit ourselves to nuclei with a neutron and a proton particle (hole) added to the magic or semimagic core. A simple model of no interaction between the odd nucleons is used. In most the cases we analyzed, a good agreement with the experimental data is obtained. Several cases are considered where this s...
Modes of decay in neutron-rich nuclei
Kumar, B; Singh, S K; Lahiri, C; Patra, S K
2016-01-01
We calculate the ground, first intrinsic excited states and density distribution for neutron-rich thorium and uranium isotopes, within the framework of relativistic mean field(RMF) approach using axially deformed basis. The total nucleon densities are calculated, from which the cluster-structures inside the parent nuclei are determined. The possible modes of decay, like {\\alpha}-decay and \\b{eta} -decay are analyzed. We find the neutron-rich isotopes are stable against {\\alpha}-decay, however they are very much unstable against \\b{eta} -decay. The life time of these nuclei predicted to be tens of second against \\b{eta} -decay.
Spin-isospin collective modes Δ in nuclei
The charge-exchange reactions display the response of nuclei to a spin-isospin excitation. This response is concentrated in two excitation energy domains: - At low excitation energy, several particle-hole states contribute, the Gamow-Teller resonance and higher multipolarity spin-flip resonances. - Around 300 MeV, a nucleon from the target is excited into a Δ 1232 resonance. The strength in the Δ sector has the same order of magnitude as in the nuclear sector. The peak corresponding to Δ excitation in nuclei is energy shifted from the peak of the free Δ created in the reaction on hydrogen
Relativistic mean field study of clustering in light nuclei
The clustering phenomenon in light, stable and exotic nuclei is studied within the relativistic mean field (RMF) approach. Numerical calculations are done by using the axially deformed harmonic oscillator basis. The calculated nucleon density distributions and deformation parameters are analyzed to look for the cluster configurations. The calculations explain many of the well-established cluster structures in both the ground and intrinsic excited states. Comparisons of our results with other model calculations and the available experimental information suggest that the RMF theory is well suited for studying clustering in light nuclei. A few discrepancies and their possible sources are also discussed
Spin-isospin excitation modes of the nuclei
The theoretical study of spin-isospin excitation modes of the nuclei is presented in the form of lectures. After recalls on formalism of the isospin and the isovectorial excitation, recent experimental results, rapid review on elementary theory of beta-decay, quark model allowing to calculate matrix elements of Gamow-Teller operator between nucleon states or Δ resonances are presented. The giant resonances of nuclei and their formalism, the study of the charge exchanges modes, the energy of analog isobaric resonances, the attenuation of β Gamow-Teller transitions and the missing force in (p,n) reactions are studied
Thermodynamics of pairing transition in hot nuclei
Liu, Lang; Zhao, Peng-Wei
2014-01-01
The pairing correlations in hot nuclei $^{162}$Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The heat capacities $C_V$ are evaluated in the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. A S-shaped heat capacity curve, which agrees qualitatively with the experimental data, has been obtained and analyzed in details. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.
Halo exotic nuclei and Schroedingers's cat
A 'doorway' description of Ε1 transitions in the Coulomb excitation of 'halo'exotic nuclei is formulated. The 'doorway'is defined as that (normalizable, non-stationary) state which can be reached from the ground state through the action of the relevant transition operator. In this picture, the Coulomb excitation process naturally appears in the form of a non Breit-Wigner resonance production process, while the so called 'soft'and 'hard' dipole modes can be related to the non standard spectral distribution of the doorway in its host physical system. Coherence and decoherence effects involving the different spectral components in fast Coulomb excitation processes and photon inelastic scattering are briefly discussed. (author)
Momentum distribution of N$^*$ in nuclei
Kelkar, N G
2016-01-01
Due to its dominance in the low energy eta-nucleon interaction, the S11 N$^*$(1535) resonance enters as an important ingredient in the analyses of experiments aimed at finding evidence for the existence of eta-mesic nuclei. The static properties of the resonance get modified inside the nucleus and its momentum distribution is used in deciding these properties as well as the kinematics in the analyses. Here we show that given the possibility for the existence of an N$^*$-$^3$He quasibound state, the relative momentum distribution of an N$^*$ and $^3$He inside such a $^4$He is narrower than that of neutron-$^3$He in $^4$He. Results for the N$^*$-$^{24}$Mg system are also presented. The present exploratory work could be useful in motivating searches of exotic N$^*$-nucleus quasibound states as well as in performing analyses of eta meson production data.
Four-body correlations in heavy nuclei
The origin of four-body correlations in heavy nuclei is studied. It is found that the physical picture for this phenomenon can be different in heavy and light nuclei. An application to the /sup 208/Pb region is made
The present collection of letters from JINR, Dubna, contains eight separate letters on analysis of experimental data on relativistic nuclear collisions in the Lobachevski space, relativistic contribution of the final-state interaction to deuteron photodisintegration, on the charge asymmetry of the like-sign lepton pairs induced by B - B bar - production asymmetry, limits on the νe → νe neutrino oscillation parameters from an experiment at the IHEP-JINR neutrino detector, excitation of high spin isomers in photonuclear reactions, study of product formation in proton-nuclear reactions on the 129I target induced by 660-MeV protons, application of jet pumps in the cryogenic system of the Nuclotron - superconducting accelerator of relativistic particles and study of the silicon drift detector performance with inclined tracks