Radiative decay of unbound levels in 14N

1985 ◽  
Vol 63 (9) ◽  
pp. 1141-1147 ◽  
Author(s):  
C. Pruneau ◽  
M. B. Chatterjee ◽  
C. Rangacharyulu ◽  
C. St-Pierre
Keyword(s):  
Shell Model ◽  
Radiative Decay ◽  
Branching Ratios ◽  
Gamma Transition ◽  
Model Calculations ◽  
Mixing Ratios ◽  
Decay Properties ◽  
Decay Widths ◽  
Gamma Decay ◽  
Good Agreement

The gamma decay properties of 10.43-, 10.1-, 9.7-, 9.51-, and 8.91-MeV levels are studied by the 13C(p, γ) reaction. The natural widths, gamma decay widths, branching ratios, and multipole mixing ratios are determined. The gamma branching ratios are generally in good agreement with earlier works. However, it is found that the previous (p, γ) measurements overestimated the gamma transition strengths. The results are compared with shell model calculations. Also, a phenomenological description is attempted for a few 14N levels.

RADIATIVE M1-TRANSITIONS OF HEAVY MESONS IN LIGHT-FRONT QUARK MODEL

2008 ◽  
Vol 23 (21) ◽  
pp. 3259-3262
Author(s):  
HO-MEOYNG CHOI
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Quark Model ◽  
Radiative Decay ◽  
Light Front ◽  
Effective Hamiltonian ◽  
Model Calculations ◽  
Heavy Mesons ◽  
Decay Widths ◽  
Good Agreement

We present the magnetic dipole(M1) transitions V → Pγ of various heavy-flavored mesons such as [Formula: see text] and [Formula: see text] using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. Our numerical results for the radiative decay widths are in good agreement with the available experimental data as well as other theoretical model calculations.

A Study of Levels in 25Mg via the 22Ne(α, nγ)25Mg Reaction

1972 ◽  
Vol 50 (13) ◽  
pp. 1539-1553 ◽  
Author(s):  
D. C. Kean ◽  
R. W. Ollerhead
Keyword(s):  
Gamma Rays ◽  
Ground State ◽  
Branching Ratios ◽  
Angular Distributions ◽  
Rotational Model ◽  
Mixing Ratios ◽  
Decay Properties ◽  
Decay Branch ◽  
Band Mixing ◽  
Good Agreement

Levels in the nucleus 25Mg have been studied by measurement of the angular distributions and polarization of gamma rays from the 22Ne(α, nγ)25Mg reaction. Information regarding spins, parities, mixing ratios, and branching ratios has been obtained for the levels between 2.7 and 4.7 MeV excitation. Spin and parity assignments of 5/2+ and 7/2− have been made to the levels at 3.90 and 3.97 MeV. Mixing ratios have been determined or restricted for most of the observed transitions. The decay branch of the 3.40 MeV level to the ground state is found to be considerably stronger than previously reported, bringing the decay properties of this level into good agreement with the predictions of the simple rotational model. The significance of the results within the framework of the rotational model is discussed. There is evidence for considerable band mixing in levels belonging to the second Kπ = 1/2+ and the Kπ = 1/2− bands.

scholarly journals A Search for an Excited Kp=0+ Rotational Band in 24Mg

1976 ◽  
Vol 29 (3) ◽  
pp. 139 ◽  
Author(s):  
D Branford ◽  
LE Carlson ◽  
FCP Huang ◽  
N Gardner ◽  
TR Ophel ◽  
...  
Keyword(s):  
Shell Model ◽  
Quadrupole Moment ◽  
Rotational Band ◽  
Doppler Shift ◽  
Transition Rates ◽  
Model Calculations ◽  
Doppler Shift Attenuation ◽  
Doppler Shift Attenuation Method ◽  
Absolute Transition ◽  
Good Agreement

A search is described for an excited Kn = 0+ rotational band based on the 6� 44 MeV level of 24Mg. Mean nuclear lifetimes have been measured by the Doppler shift attenuation method using the 12C('60,a)24Mg reaction and the results are 't'm = 66�29, 28�7 and 13�3 fs for levels at 6'44, 8�65 and 10� 58 MeV respectively. The absolute transition rates found for the y decays from the 6�44 and 8�65 MeV levels are in good agreement with the results of shell model calculations if it is assumed that these levels are the 0+ and 2 + members respectively of the excited Kn = 0+ rotational band. Based on this assumption, a result Qoo = 0�48 �0�08b is obtained for the intraband quadrupole moment. From a study of the 23Na(p, y) reaction, it is established that the J = 4 levels at 12� 63 and 13�05 MeV do not decay by enhanced E2 transitions to the 8� 65 MeV level. This suggests that neither of these levels is the 4 + member of the excited Kn = 0+ rotational band. An assignment of J" = 4+ is made to one member of the doublet at 10�58 MeV.

55 YEARS OF THE SHELL MODEL: A CHALLENGE TO NUCLEAR MANY-BODY THEORY

2005 ◽  
Vol 14 (06) ◽  
pp. 821-844 ◽  
Author(s):  
IGAL TALMI
Keyword(s):  
Shell Model ◽  
Wave Functions ◽  
Many Body ◽  
Apparent Absence ◽  
Model Calculations ◽  
Many Body Theory ◽  
Body Theory ◽  
Nuclear Many Body Theory ◽  
Closed Shells ◽  
Good Agreement

Shell model calculations of nuclear energies and wave functions of nucleons outside closed shells interacting by effective two-body forces yield good agreement with much experimental data. Many attempts have been made to calculate nuclear energies ab initio, by starting from some form of an interaction between free nucleons. Recent results of such calculations claim to obtain reasonable agreement with measured energies. These results, however, are obtained for wave functions which are very complicated. It is difficult to see how such wave functions are consistent with independent nucleon motion, the very essence of the shell model. In some of those calculations, 3-body interactions play a very important role. This is puzzling since nuclear energies are accurately obtained in shell model calculations by using only effective two-body interactions. In this paper, some examples of simple shell model calculations are reviewed. They exhibit good agreement with experiment and the apparent absence of the need for effective 3-body interactions.

Vacuum Structure, Chiral Symmetry Breaking and Radiative Decays of Vector Mesons

1997 ◽  
Vol 06 (01) ◽  
pp. 121-134
Author(s):  
A. R. Panda ◽  
K. C. Roy
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Radiative Decay ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Vector Mesons ◽  
Model Calculations ◽  
Vacuum Structure ◽  
Quark Field ◽  
Decay Widths

The radiative decay widths of vector mesons were considered in a model involving chiral symmetry breaking through a nontrivial vacuum structure where the pion and kaon being treating consistently yield the constituent quark wave functions, approximately the same as that obtained from the gap equations and thus in a way determine the constituent quark field operators. Like its earlier success to some low energy hadronic phenomena, here also the model calculations of radiative decay widths of mesons are in reasonable agreements with other theoretical estimations as well as experimental measurements.

scholarly journals Shell Model Calculations for 18,19,20O Isotopes by Using USDA and USDB Interactions

2018 ◽  
Vol 63 (3) ◽  
pp. 189 ◽  
Author(s):  
A. K. Hasan
Keyword(s):  
Shell Model ◽  
Empirical Data ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Model Space ◽  
Magic Nucleus ◽  
Model Calculations ◽  
O Isotopes ◽  
Good Agreement

The shell model (SM) is used to calculate the energy levels and transition probabilities B(E2) for 18,19,20 O isotopes. Two interactions (USDA and USDB) are used in the SDPN model space. We assume that all possible many-nucleon configurations are defined by the 0d5/2, 1s1/2, and d3/2 states that are higher than in 16 O doubly magic nucleus. The available empirical data are in a good agreement with theoretical energy levels predictions. Spins and parities were affirmed for new levels, and the transition probabilities B(E2; ↓) are predicted.

scholarly journals Understanding d*(2380) in a chiral quark model

2019 ◽  
Vol 199 ◽  
pp. 02017
Author(s):  
F. Huang ◽  
Y. B. Dong ◽  
P. N. Shen ◽  
Z. Y. Zhang
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Chiral Quark Model ◽  
Exotic State ◽  
Decay Properties ◽  
Decay Widths ◽  
Color Components ◽  
Good Agreement ◽  
Made In

We review our recent progresses made in the study of the structure and decay properties of the newly observed d*(2380) within a chiral constituent quark model. It is found that the d*(2380) can be explained as a compact hexaquark-dominated exotic state with a fraction of hidden color components of about 2/3 in its configuration. Based on this scenario the single- and double- pionic partial decay widths are calculated and the corresponding numerical results are in good agreement with the experimental data.

Electromagnetic properties of nonstrange Baryons in a nonrelativistic quark model

2017 ◽  
Vol 26 (07) ◽  
pp. 1750049 ◽  
Author(s):  
Zahra Ghalenovi ◽  
Masoumeh Moazzen
Keyword(s):  
Quark Model ◽  
Radiative Decay ◽  
Magnetic Moments ◽  
Theoretical Models ◽  
Branching Ratios ◽  
Electromagnetic Properties ◽  
Nonrelativistic Quark Model ◽  
Decay Widths ◽  
Helicity Amplitudes ◽  
Hyperspherical Approach

Masses and magnetic moments of [Formula: see text] and [Formula: see text] resonances are calculated employing the hyperspherical approach. We extend our scheme to obtain the helicity amplitudes and transition magnetic moments of the [Formula: see text] process. We also compute the radiative decay widths and branching ratios of [Formula: see text] baryons. A comparison of our results with the predictions obtained in recent theoretical models is also presented.

Reinvestigation of two-phonon γ-vibrational band in neutron-rich 114Pd

2016 ◽  
Vol 25 (09) ◽  
pp. 1650064 ◽  
Author(s):  
Y. Huang ◽  
S. J. Zhu ◽  
J. H. Hamilton ◽  
A. V. Ramayya ◽  
E. H. Wang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Spontaneous Fission ◽  
Level Structure ◽  
Vibrational Band ◽  
Projected Shell Model ◽  
Previous Suggestion ◽  
Model Calculations ◽  
Good Agreement

The level structure in neutron-rich [Formula: see text]Pd nucleus has been reinvestigated by measuring prompt [Formula: see text] rays emitted in the spontaneous fission of [Formula: see text]Cf. A two-phonon [Formula: see text]-vibrational band built on the 1639.3[Formula: see text]keV level is observed, which confirms the previous suggestion from a [Formula: see text]-decay experiment. Systematical comparison supports the assignment for a two-phonon [Formula: see text]-vibrational band in [Formula: see text]Pd. Triaxial projected shell model calculations for the multi-phonon [Formula: see text] bands of [Formula: see text]Pd are in good agreement with the experimental data.

Resonances in the 15N(α,γ)19F Reaction Between Eα = 1.68 and 2.72 MeV

1972 ◽  
Vol 50 (20) ◽  
pp. 2428-2443 ◽  
Author(s):  
D. W. O. Rogers ◽  
R. P. Beukens ◽  
W. T. Diamond
Keyword(s):  
Shell Model ◽  
Weak Coupling ◽  
Coupling Model ◽  
Branching Ratios ◽  
Negative Parity ◽  
Angular Distributions ◽  
Model Calculations ◽  
Spin Parity ◽  
The Third

Using the 15N(α,γ)19F reaction, the properties of 6 levels between 5.3 and 6.2 MeV in 19F have been studied. In conjunction with previously reported restrictions on spins for these levels, measurements of branching ratios, radiative widths, and angular distributions have been used to make the following spin–parity assignments; 5618 keV, 3/2−; 5938 keV, 1/2+; 6070 keV, 7/2+; 6088 keV, 3/2−; 6160 keV, 7/2−. The properties of these levels and that at 5336 keV have been compared in detail to the various shell model calculations done for 19F. The properties of the third Jπ = 7/2+ level at 6.07 MeV can be used to clear up some of the confusion caused by the first two Jπ = 7/2+ levels in 19F and the properties of the Jπ = 3/2− levels confirm the fact that the weak coupling model does not explain the negative parity states outside the K = 1/2− band.

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