Pion-Rotational Nucleus Scattering and the Interacting Boson Model

A procedure of combining the medium energy scattering theory in the eikonal approximation with the interacting boson model (IBM) is proposed to study the pion-rotational nucleus scattering. The channel coupling effects in the excitation of nuclear collective state with π^- and π⁺ elastic and inelastic scattering are analyzed. The calculated cross sections for the excitation of 2₁⁺ state of ¹⁵²Sm agmree with the experimental data quite well.     

The Three-Pion Decays of the a1(1260)

We investigate the decay of a₁⁺ (1260)→π⁺π⁺π^- with the assumption that the a₁(1260) is dynamically generated from the coupled channel ρπ and KK^* interactions. In addition to the tree level diagrams that proceed via a₁⁺ (1260)→ρ⁰π⁺→π⁺π⁺π^-, we take into account also the final state interactions of ππ→ππ and KK→ππ. We calculate the invariant π⁺π^- mass distribution and also the total decay width of a₁⁺ (1260)→π⁺π⁺π^- as a function of the mass of a₁(1260). The calculated total decay width of a₁(1260) is significantly different from other model calculations and tied to the dynamical nature of the a₁(1260) resonance. The future experimental observations could test of model calculations and would provide vary valuable information on the relevance of the ρπ component in the a₁(1260) wave function.     

B→a0(1450)ρ(ω) Decays in Perturbative QCD Approach

In the two-quark model supposition for the meson a₀(1450), which can be viewed as either the first excited state (scenario I) or the lowest lying state (scenario II), the branching ratios and the direct CP-violating asymmetries for decays B→ a₀(1450)ρ(ω) are studied by employing the perturbative QCD factorization approach. We find the following results: (a) For the decays B^- → a⁰₀(1450)ρ^- and \bar{B}⁰ → a⁺₀(1450)ρ^-, their branching ratios have large
difference between two scenarios. Although their branching ratios are larger than other considered decay modes, their direct CP-violatingasymmetries in both scenarios are small. (b) For the decays B^-→ a^-₀(1450)ρ⁰ and \bar{B}⁰→ a^-₀(1450)ρ⁺, a⁰₀(1450)ρ⁰, a⁰₀(1450)ω, their branching ratios are close to each other between two scenarios, respectively. (c) Comparing with the decays \bar{B}⁰ →π⁰ρ⁰,π⁰π⁰, the decay \bar{B}⁰→ a⁰₀(1450)ρ⁰ receives a
larger branching ratio in each scenario, which is sensitive to the variation of the Cabibbo-Kobayashi-Maskawa angleα.     

On the static quadrupole moments of the 21 states in Te and Te

The reorientation effect in Coulomb excitation was used to measure the static quadrupole moments of the first 2⁺ states in ¹²⁶Te and ¹²⁸Te. The particle-γ coincidence technique using a large NaI(Tl) crystal was employed to measure relative excitation probabilities at backward and forward projectile scattering angles. The Winther-de Boer multiple Coulomb excitation program was used to analyze the data. The influence of the deorientation effect was also determined. For positive interference via the second 2⁺ state the extracted quadrupole moments of the first 2⁺ states are; −0.20±0.09 b and -0.24±0.08 b for ¹²⁶Te and ¹²⁸Te respectively. The quadrupole moments of the first 2⁺ states of^{122,124,126,128,130}Te determined by different techniques are in excellent agreement with one another. The values are compared with recent theoretical calculations.     

THE EXCITATION OF 9.5 MeV LEVEL OF 13C IN QUASI-Δ33 DOORWAY STATE MODEL

We have studied the excitation mechanism of 9.5 MeV Level of ¹³C in ¹³C(π^±,π^1±)¹³C (9.5 MeV) inelastic scattering in the framework of Quasi-X33 Doorway State. Model .Assuming. the transition to 9.5 MeV state is of a pure neutron has received satisfactory agreement with experiment. The results strongly suggest that the spin and parity assignment of state,9.5 MeV of ¹³C should be Jπ=9/2⁺.     

Analysis of the scattering of 46 MeV protons from Be and C

An analysis is made of the measurements of the elastic and inelastic scattering of 46 MeV protons by ³Be and ¹²C. The optical and collective models are used. There is considerable ambiguity in the optical parameters, and it was not found possible to obtain good fits to cross sections and polarizations simultaneously. Large quadrupole deformations were found for both ¹²C (β₂ ≈ 0.6) and ⁹Be(β₂ ≈ 1). The inelastic scattering from ¹²C agrees best with deformation of both real and imaginary parts of the optical potential, while ⁹Be shows a preference for real coupling. The 14.1 MeV level in ¹²C is interpreted as the 4⁺ rotational state, while the angular distribution for the 7.6 MeV 0⁺ level is well described by double quadrupole excitation via the lowest 2⁺. Interpretations are suggested for other inelastic transitions, including the excitation of spin and isospin oscillations.     

What About the Contribution from Reggeons in Hard Process of Strong Interactions?

We discuss in this paper the possible contributions from IR_ρ (ρ-reggeon associated with ρ meson) in DIS process on protons. Using results from phenomenological analysis of high energy π-N charge-exchange scattering process, we get the expression of effective propagator of IR_ρ and the coupling constant β_ρ between IR_ρ and light quarks. As a simple and concrete example, we use them to evaluate the contributions of ρ to F₂(χ, Q²) from charge-exchange photoproduction quark-pair process, γ^* + p → n + q_u + q_d(→ n + X), in HERA kinematical regions. For comparison, we also evaluate contributions both from pomeron and partons in the same process. The ratio of contributions in F₂(χ, Q²) from IR_ρ versus IP is larger than 1%, therefore, the former may be tested experimentaly.     

STUDIES OF P-MESCN DECAY BY THE TRANSITION POTENTIAL Vq-qqq OF A QUARK-ANTIQUARK PAIR CREATIOR MODEL

Decay rate of p-meson into two n-mesons was calculated by using the transition potential of a quark-antiguark pair creation model.The theoretical result is in good agreement with the experimental data .Also, the difference of decay widths for processes ρ^±π^±π⁰ and ρ⁰π⁺π^- was discussed.     

Effects of a Family Non-universal Z' Boson in \bar{B}_d→μ+μ- and B- →π-μ+μ-,ρ-μ+μ- Decays

Motivated by the recently updated experimental measurement on \bar{B}_d→μ⁺μ^- and B^-→π^-μ⁺μ^- decays by CDF and Belle collaborations, we revisit these
decays, as well as B^-→ρ^-μ⁺μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z' boson. Under the constraint from {\cal B}(B^-→π^-μ⁺μ^-), we find the ranges of the Z' couplings S^LR_μμ< -5.2×10^-2 or D^LR_μμ < -8.1× 10^-2 are excluded. Within the allowed Z' parameters spaces, comparing with the SM predictions, we find that {\cal B}(\bar{B}_d→ μ⁺μ^-, {\cal B}(B^-→ π^-μ⁺μ^-), and {\cal B}(B^-→ρ^-μ⁺μ^-) could be enhanced by a factor about
226%, 245%, and 254%, respectively, byZ' contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^- →ρ^-μ⁺μ^- decay at low dimuon mass always exists.     

Inelastic electron scattering from He

The spectra of electrons scattered inelastically from ⁴He have been measured at incident energies from 150 MeV to 400 MeV for scattering angles from 38° to 90°. Through the use of a liquid ⁴He target, a high momentum resolution (≈0.25%) was obtained, and the 20 MeV 0⁺ state of the -particle was observed for the first time in electron scattering. The excitation energy and the total width of this state were determined and are in good agreement with the results from other experimental methods. It was found that the total disintegration cross section appears be smaller than 2(σ_p+σ_n) by more than an order of magnitude at the lowest q²(≈ 0.33 fm⁻²). In earlier work the assumption of a total cross section of 2(σ_p+σ_n) was found to be quite accurate for higher q². As a new result, the partial radiative width for the 0⁺ state is determined to be Γ_rad = 1.1±0.3 meV.     

Application of low energy theorems to the new particles

Discussion Compton scattering on the new states we establish the following: The spin J^P = 2⁺ state, an orbital excitation of ψ, must exist, and its coupling to the ψ(3084) is related to the coupling ψX(2800). A spin higher than 2 (probably 3) with negative charge conjugation must exist, and its couplings can be related to the ψ2⁺γ and ψ′2⁺γ couplings. This state might have a substantial radiative width to the 2⁺. These results depend on a saturation assumption of the sum rules, which has always worked well. Its failure will also be of interest.     

K+ Inelastic Scattering From 2+, 3- State of 12C at 800 MeV/c

The differential cross sections of the inelastic scattering 6f K⁺ at 800 MeV/c on 2⁺, 3^- excited states of ¹²C are calculated by means of the eikonal approximation and the collective coordinate. It seems that the 2⁺ state of ¹²C is quadrupole rotational state, the 3^- state of ¹²C is octupole vibrational state. The results are in agreement with experimental data.     

Proton–neutron structure of the N=52 nucleus Zr

Following the successful identification of mixed-symmetric one- and two-phonon states in the N=52 nuclei ⁹⁴Mo and ⁹⁶Ru, we have performed a photon scattering experiment on the N=52 isotone ⁹²Zr. Experimental data and shell model calculations show that both, single particle and collective degrees of freedom are present in the low-lying levels of ⁹²Zr. The second excited quadrupole state shows the signatures of the one-phonon mixed-symmetric 2⁺ state, while calculations and data indicate an almost pure neutron configuration for the 2⁺₁ state, in contradiction with the F-spin symmetric limit. Furthermore, two strong dipole excitations, which are candidates for the two-phonon quadrupole–octupole coupled E1 excitation and for the mixed-symmetric 1⁺ two-phonon state, were observed.     

Nuclear excitation effects on heavy-ion scattering

The detailed coupled-channel analysis, including a ground state rotational coupling up to the 4⁺ state, for ¹⁶O scattering from ¹⁵²Sm at the incident-ion energy of 72 MeV is performed. It is found that nuclear excitation plays an important role in the reproduction of details of the observed experimental data, and that the extracted nuclear deformation lengths from this analysis agree with those from light-ion experiments.     

Spectroscopy of C

The ¹⁴C(t, p)¹⁶C reaction locates five new states in ¹⁶C, at excitation energies of 3120 ± 15, 3983 ± 10, 4136 ± 10 and 6109 ± 15 keV, in addition to the g.s. and 1.76 MeV states. The 3.02 and 3.98 MeV states appear to be the second 0⁺ and 2⁺ 2p-2h states, respectively. The 4.14 MeV state has J^π = 4⁺ and the 6.11 MeV state has J^π = 2⁺, 3⁻, or 4⁺.     

The Role of a1(1260) in π-p→a1-(1260)p and π-p→π-ρ0p Reactions Near Threshold

We report on a theoretical study of the π^-p→a₁^-(1260) p and π^-p→π^-ρ⁰p reactions near threshold within an effective Lagrangian approach. The production process is described by t-channel ρ⁰ meson exchange. For the π^-p→π^-ρ⁰p reaction, the final π^-ρ⁰ results from the decay of the a₁(1260) resonance, which is assumed as a dynamically generated state from the K^*K and ρπ coupled channel interactions. We calculate the total cross section of the π^-p→a₁^-(1260)p reaction. It is shown that, with the coupling constant of the a₁(1260) to ρπ channel obtained from the chiral unitary theory and a cut off parameter Λρ~1.5 GeV in the form factors, the experimental measurement can be reproduced. Furthermore, the total and differential cross sections of π^-p→a₁^-(1260)p→π^-ρ⁰p reaction are evaluated, and it is expected that our model calculations can be tested by future experiments. These reactions are important for the study of the a₁(1260) resonance and would provide further constraints on the properties of the a₁(1260) state.