Multiple Coulomb excitation of198Hg and200Hg

Multiple Coulomb excitation measurements on^{198, 200}Hg have been performed with 5MeV/amu²⁰⁸Pb projectiles andB(E2)-values are determined for transitions between states up to spin 8⁺. In¹⁹⁸Hg a reduction of theB(E2)-value for the yrast transition 8⁺→6⁺ by a factor of 3 as compared to the rigid rotor prediction is observed, which supports the earlier proposed idea that the ground state band is crossed between the 6⁺ and 8⁺ state by a weakly interactingvi ₁₃ ^2/2 rotation aligned band. In each of the two nuclei,¹⁹⁸Hg and²⁰⁰Hg, a state with a possibleI ^π=8⁺ assignment is observed, which is tentatively interpreted as the 8⁺ member of the ground state band.     

B(E2)-values of even-a nuclei with 82 neutrons

Coulomb excitation of the first excited 2⁺-state was measured usingα-particles to determine reduced transition probabilities,B(E2; 0 _gs ⁺ →2 ₁ ⁺ ), in nuclei with a closed shell of 82 neutrons. TheB(E2; 0 _gs ⁺ →2 ₁ ⁺ -values are 10.2 single-particle units (spu) for¹³⁸Ba, 13.5 spu for¹⁴⁰Ce, 11.9 spu for¹⁴²Nd and 11.6 spu for¹⁴⁴Sm. The uncertainty ranges from 1.3 % to 2.3 %.     

IsoscalarE2 transition strengths in 10≦A≦48 nuclei

Electric quadrupole transition strengths for the 2 ₁ ⁺ ,T=1→0 ₁ ⁺ ,T=1γ-decay branches are summarized for 10≦A≦42 nuclei. In¹⁰B the corresponding branch has been remeasured by use of the⁹Be(p, γ)¹⁰B resonance reaction atE _p =320 keV; an upper limit of 0.6% is found. The variation of theE2 strengths within each individualT=1 isobaric multiplet reveals the particleor hole-character of the levels involved. The isoscalar 2 ₁ ⁺ →0 ₁ ⁺ transition strengths in 10≦A≦48 nuclei vary between 2 and 20 Weißkopf units showing drastic shell effects. Results for the ratio of neutron and proton matrix elements deduced from analogγ-decay studies and from inelastic pion scattering are compared.     

Reorientation effect measurements and multiple coulomb excitation in102Ru

The quadrupole moment of the first 2⁺ state in¹⁰²Ru and fourB(E2) values have been measured by means of Coulomb excitation. The results are:Q ₂₊=?0.68(8)eb;B(E2, 01/+→21/+)=0.617(5)e ² b ²;B(E2, 01+→22/+)=0.013 (2)e ² b ²;B(E2, 21/+→22/+)= 0.07(1)e ² b ²;B(E2, 2 ₁ ⁺ →4 ₁ ⁺ )=0.30(6)e ² b ². The results are discussed within the frame of the Interacting Boson Approximation.     

E2 transition andQ_{J^ + } systematics of even mass tellurium nucleisystematics of even mass tellurium nuclei

The yrast spectra withJ _max ^π = 6⁺,B(E2) transition probabilities and $Q_{J^ + } $ values are calculated for even-even tellurium isotopes by carrying out Hartree-Fock-Bogoliubov (HFB) anstaz employing a pairing-plus-quadrupole-quadrupole effective interaction operating in a reasonably large valence space outside the¹⁰⁰Sn core. Our calculations reproduce qualitatively the observed parabolic systematics of the low-lying yrast states as a function of mass number for tellurium isotopes. The results onB(E2) transition probabilities predict a dip in the isotopes^114,118,124Te which might be construed to imply different structures for^114,118,124Te as compared to their neighbours. Besides this, our results also reveal that both the HFB technique as well as the quadrupole-quadrupole-plus-pairing model of the two body interaction are fairly reliable in this mass region.     

The quadrupole moments of some even–even nuclei around the mass of <Emphasis Type="Italic">A</Emphasis> ~ 80: <Superscript>68−80</Superscript>Ge on the neighborhood of <Superscript>76−84</Superscript>Kr and <Superscript>76−84</Superscript>Se isotopes

We have carried out the calculation of the quadrupole moments Q(2₁⁺) and electromagnetic transition rates B(E2) of some levels within the framework of the interacting boson model for even-mass Ge nuclei. The presented predictions of the quadrupole moments and B(E2) ratios for Ge nuclei are compared with the results of some previous experimental and theoretical ones along with those of the neighboring Kr and Se isotopes and then it was seen that they agree well with the previous experimental and theoretical ones.     

Vergleich der Davydov-Theorie mit dem Modell des achsialsymmetrischen Kreisels mit Rotation-Vibrations-Wechselwirkung für deformiertegg-Kerne

For deformed even-mass nuclei the model of the axial-symmetric vibrating top with rotation-vibration-interaction is compared to the Davydov-model without and with aβ-band. TheE2-transition-probabilities are calculated. The coefficientsB _ze andC fromE=A I(I+1) ?B _ze I ²(I+1)²+C I ³(I+1)³ are obtained. For the transition-probabilities from the states of the γ-band to the states of the ground state band as well as forB andC the Davydov-model yields values only about half of those obtained from the RV-theory. A comparision to the present availuable experimental data is made. In the RV-model the agreement is better than in the Davydov-theory.     

E1-M2-E3 mixing of the 1241.7 keV transition in147Yb

The half-life of theI,K ^π=2, 2^? state at 1318 keV in¹⁷⁴Yb has been measured in the¹⁷³Yb(n, γ) reaction to be 0.486±0.015 ns. This half-life determines the absolute transition probabilities of the gamma-ray transitions to the ground state rotational band yielding the following hindrance factors relative to the Weisskopf estimate:F _W(M 2; 2, 2^?→0, 0⁺)=350;F _W(M2; 2, 2^?→2, 0⁺)≧77F _W(M 2;2, 2^?→4, 0⁺)>740;F _W(E 1; 2, 2^?→2, 0⁺)=4.5×10⁶;F _W(E 3; 2, 2^?→2, 0⁺)≈0.1;F _W(E 3; 2, 2^?→4, 0⁺)≈0.4. These data are compared to analogous transitions in neighboring nuclei.     

Gyromagnetic ratio of the 159 keV 3/2+ state of117Sn

TheF-spin formalism is employed to extract scalar boson effective charges from theB(E2, 2 ₁ ⁺ →0_g) systematics in rare-earth nuclei.     

E2 andE3 transition strengths in some rare-earth nuclei

Coulomb excitation byα-particles of vibrational-like states in even-mass rare-earth nuclei is used to determine the reduced transition probabilitiesB(E2; 0 _gs ⁺ →2 _γ ⁺ ),B(E2; 0 _gs ⁺ →2 _β ⁺ ),B(E2; 2 _gs ⁺ →0 _β ⁺ ) andB(E2; 0 _gs ⁺ →3 _oct ^? ) in¹⁵⁰Nd,^{152, 154}Sm,^{154, 158}Gd,¹⁶⁴Dy and¹⁶⁶Er. TheB(Eλ; 0 _gs ⁺ →I=λ)-values range from 2.4 to 6.5 single-particle units for transitions to the 2 _γ ⁺ -states, 0.8 single-particle units for the 2 _β ⁺ -states and from 14.1 to 21.7 single-particle units for the 3^?-states.     

Accurate lifetime measurements for the noble gases by the electron beam alignment technique

Rotational rainbow scattering has been measured in the systems K- and Rb-CO₂ at collision energies 0.17≦E≦0.56 eV and CMS angles 110°≦?≦170°. The ellipsoidal hard shell anisotropy of the normal (repulsive) potentials is evaluated to be (c?a)=0.67Å in K?CO₂, (c?a)=0.63Å in Rb?CO₂, averaged over a slight energy dependence. Below an apparent activation thresholdE _a?0.23 eV, nearly equal in both systems, the scattering largely conforms to that of diatomic molecules, indicating linear, rigid rotor type behaviour as the dominant collisional response of triatomic CO₂. AboveE _a characteristic, eventually drastic distortions set in. They are probably caused by intermediary charge transfer which activates a complex, coupled vibrational, rotational motion inM ⁺-CO ₂ ^? , altering the outcome of the collisions altogether. The simple model of a partially absorptive, hard shell is used to find that some gross features of the distortions are consistent with distinct properties of the acceptingelectronic orbital 6a ₁ in CO ₂ ^? .     

Penetration effects in111Cd

Penetration effects in the conversion process of the 7/2⁺→5/2⁺, 171 keV and 5/2⁺→1/2⁺, 245 keV transitions in¹¹¹Cd have been investigated. The decay of¹¹¹In has been studied to deduce the relative intensity of theK-conversion lines I_K(171)/I_K(245) and the ratioI _K(245)/I _L+M... (245). The values obtained for the penetration parameters of the two transitions are 0≦λ(171)≦2.3 and ?0.4≦λ ₁(245)≦1.9.     

CP violation with beautiful baryons

CP violation can be studied in modes of charmed or bottom baryons when a decay process is compared with its charge-conjugated partner. It can show up as a rate asymmetry and in a study of other decay parameters. Neither tagging nor time-dependences are required to observeCP violation with modes of baryons, in contrast to the conventionalB ⁰ modes. Numerous modes of bottom baryons have the potential to show largeCP-violating effects within the Standard Model. Those effects can be substantial for modes with aD ⁰, which is seen in a final state that can also be fed from a \(\bar D^0 \) . For instance, a comparison of theΛ _b→Λ _CP ⁰ with the \(\bar \Lambda _b \to \bar \Lambda D_{CP}^0 \) process can show sizeableCP violation. HereD _CP ^o denotesCP eigenstates ofD ⁰, which occur at a few percent. Six related processes, such asΛ _b→ΛD ⁰, \(\Lambda _b \to \Lambda \bar D^0 \) ,Λ _b→Λ _CP ⁰ , and their charge-conjugated counterparts, can extract ?, which is the most problematic angle of the unitarity triangle and which is conventionally probed with theB _s→ρ⁰ K _S asymmetry. HereD ⁰ andD ^?0 are identified by their charged kaon or lepton. We predictB(Λ _b→ΛD ⁰)～10^?5, thusB(Λ _b→Λ _CP ⁰ )～10^?7. Under favourable circumstances,CP violation can occur at the few tens of percent level. Thus 10²–10³ Λ _b→Λ _CP ⁰ decays start probing ?. Tables list many additional modes with typical branching ratios at the 10^?5–10^?6 level, with large detection efficiencies (in contrast to theD _CP ⁰ ), and with potentially largeCP-violating effects, such as Ξ _b ⁰ →ΛΨ, Λ?, ΛK^*0; Ξ _b ^? →ΛK^(*)?, Ξ^?K_s, Ξ^?K^*0, Ω _b ^? →Ξ^?φ, Ξ^?ρ⁰, ΛK^(*)?, ΩK_s, Ω^?K^*0.     

Microscopic description of collective states near the yrast line of nuclei with stable octupole deformation

Collective states near the yrast line in nuclei with stable octupole deformation are discussed in the framework of the random phase approximation (RPA) based on the cranking model. These vibrational states are characterized by the quantum number of generalized signature (eigenvalue of the operator S_x = PR_x^?1(π)). In the zero-octupole deformation limit the RPA equations of motion are reduced to the well-known ones characterized by both values of parity and signature, respectively. The connection of the translational and rotational symmetry of the model hamiltonian with the spurious solutions of the RPA equation of motion is discussed. Expressions for the reduced probabilities B(E1), B(E2) and B(E3) are obtained. These expressions confirm the conclusions of phenomenological models for the strong E1 and E3 intraband transitions in nuclei with stable octupole deformation.     

Projected Shell Model Description of Positive Parity Band of <Superscript>130</Superscript>Pr Nucleus

Theoretical investigation of positive parity yrast band of odd-odd ¹³⁰Pr nucleus is performed by applying the projected shell model. The present study is undertaken to investigate and verify the very recently observed side band in ¹³⁰Pr theoretically in terms of quasi-particle (qp) configuration. From the analysis of band diagram, the yrast as well as side band are found to arise from two-qp configuration πh _11/2???νh _11/2. The present calculations are viewed to have qualitatively reproduced the known experimental data for yrast states, transition energies, and B(M1) / B(E2) ratios of this nucleus. The recently observed positive parity side band is also reproduced by the present calculations. The energy states of the side band are predicted up to spin 25⁺, which is far above the known experimental spin of 18⁺ and this could serve as a motivational factor for future experiments. In addition, the reduced transition probability B(E2) for interband transitions has also been calculated for the first time in projected shell model, which would serve as an encouragement for other research groups in the future.     

An interpretation of the energy-momentum tensor of the dirac field with anomalous magnetic moment

The ground state radiative widths of the 1.56 MeV (3/2⁺) and the 1.35 MeV (5/2^?) levels in¹⁹F were determined by inelastic electron scattering. The measured cross sections have been analysed using DWBA calculations. The resultsΓ _y ⁰ (5/2^?→1/2^?,E3)=(8.1±1.7)·10^?10eV andΓ _y ⁰ (3/2⁺→1/2⁺,E2=(1.76±0.15)·10^?4eV are in agreement with, but more accurate than, former measurements.     

Estimating of CP-violation in <Emphasis Type="Italic">B</Emphasis><Superscript>0</Superscript>→ψ(2<Emphasis Type="Italic">S</Emphasis>)π<Superscript>0</Superscript> decay

I present estimates of CP-violating asymmetries in the non-leptonic charmonium two-body B⁰→ψ(2S)π⁰ decay and the same decays of B⁺→ψ(2S)π⁺ and B⁺→ψ(2S)K⁺ These estimates are based on QCD and improved QCD factorization approach making use of next-to-leading order (NLO) contributions. The CP-violating asymmetry for B⁰→ψ(2S)π⁰ decay is not available, according to the same calculations, it is expected if it can be measured in the future its value will be S_ψ(2S)π0(B⁰ → ψ(2S)π⁰)= 0.662 ± 0.197 and C_ψ(2S)π0(B⁰ → ψ(2S)π⁰)= 0.024 ± 0.007.     

A coupled-channel treatment of Cabibbo-angle favoured (D,D s + )→VP decays

We have performed a two-channel calculation of Cabibbo-angle favoured decays,D _s ⁺ →VP. We find a satisfactory fit toS _s ⁺ →φπ ⁺,ρ ⁰ π ⁺ andK ⁺ \(\bar K^{ * 0} \) data from ARGUS and E-691. We have also studied Cabbibo-angle favouredD→VP decays in a coupled channel formalism. We coupleD→K ^*π,K _? and \(\bar K^0 \phi \) channels inI=1/2 state, andK ^*π andK _? channels inI=3/2 state. We leave the two channels, \(\bar K^0 \omega \) and \(\bar K^{ * 0} \eta \) out of our unitarization scheme. Particular attention is paid to the role of the weak annihilation term in these decays.     

The study of the ground state rotational bands in U 233 and U 235 by the inelastic scattering of deuterons

The ground state rotational bands in the odd isotopes of uranium U 233 and U 235, were studied by the inelastic scattering of 13.1 MeV deuterons. Seven members of these bands were seen in both nuclei. By fitting the experimental energies of the levels to the relation E(I)= =AI(I+1)+B[I(I+1)]², the parametersA andB were determined. Their values and the upper limits of the quadrupole reduced transition probabilities determined from the cross sections were: U 233:A=(5.93±0.10)keV,B=(?0.002±0.001)keV,B(E2,5/2→7/2)= =(6.51±0.66)×10^?48 e² cm⁴,B(E2,5/2→9/2)=(2.80±0.37) X 10^?48 e² cm⁴. U 235:A=(5.36±0.04)keV,B=(?0.0017±0.0004) keV,B(E2,7/2→9/2)=(8.05±0.71) × × 10^?48 e² cm⁴,B(E2,7/2→11/2)=(2.17±0.39) X 10^?48 e² cm⁴.     

Testing QCD: Direct photons ine + e − collisions

We discuss QCD predictions for the production of direct photons ine ⁺ e ^? collisions,e ⁺ e ^?→ γ^*→γ+ hadrons (C=+). A simple derivation of the QCD results for the structure functions is presented. These turn out to be exactly predicted by the theory, in contrast to hadron production where only the change withQ ² is predictable. We also take up the phenomenology of this process. A dramatic rise of the γ/π⁰ ratio withz=E _γ/E _B (E _π/E _B ) and withQ ² is predicted.