APPLICATION OF THE EIKONAL WAVE FUNCTION TO QUASIFREE SCATTERING

In this paper. we have used the Eikonal wave functionφ_E(r)=(2π)^-3/2 exp(ik.r)X(r)whereexp{-i/hv∫_-∞^zV(x,y,z,')dz'}and V=nk/m to investigate the quasifree scattering ⁶Li (p, pd)α with E_p=156 MeV,590MeV and 670 MeV. In V(x, y, z), the nuclear interaction and the Coulomb inte-raction are included. For the case of 156 MeV, the nuclear potential is taken to be the Woods-Saxon type.The result is shown in fig. 1. This result is compared with those obtained by themethod of partial waves. For the cases of 590MeV and 670MeV, a new method is used to describe thenuclear potential, and the results are showh in fig. 3 and fig. 4, respectively.     

π-NUCLEAR DOUBLE CHARGE EXCHANGE REACTION AND NUCLEAR STRUCTURE

Using Glauber's multiple scattering theory, and using coherent fluctuation nuclearmodel, the double charge exchange (DEC) reaction cross sections for πon ¹⁶O and ¹⁸Ohave been calculated. The calculated values of the ratio of σ(¹⁸O(π⁺,π^-)¹⁸Ne)_g.s. toσ(¹⁶O(π⁺,π^-)¹⁶Ne)_g.s. fit the experimental data quite well. Just as predicted by ourcalculation, the angular distribution of ¹⁸O(π⁺,π^-)¹⁸Ne_g.s. in a recent experiment,exhibits an evident dip around 23°.     

THE U1 GAUGE FIELD IN A SUN GAUGE FIELD AND THE QUANTIZED VALUES OF DUAL CHARGES

Let F be a SU_N gauge field on the space-time manifold M₄, b_λ（x） （λ=0,1, 2, 3） the gauge potentials, the field strengths and Q（x） a Higgs field. All quantities b, f_λμ and Q（x） are SU_N'-valued, i.e. they are represented by N×N anti-hermitian traceless matrices.Let M₄' be the set of x such that Q（x）≠0 and define on M₄', where The following results are obtained:Theorem 1. The 1st set of Maxwell equations F_λμ,v+F_μv,λ+F_vλ,μ=0 are satisfied for arbitrary b_λ if and only if with Here s is an integer, 1≤s≤N-1.Suppose the conditions in theorem 1 are satisfied.Theorem 2. If s is a space-like two-dimensional surface, the value of dual charges contained in s defined by is equal to lq', where l is an integer and Theorem 3. The value of dual charges contained in S is equal to the integral which is independent of the gauge potentials.Theorem 4. The least positive value q' of dual charge can be attained by some Higgs fields.Remarks（a） When N=2, the results obtained are consistent with those of t Hooft, Arafune and Hou etc.（b） For N=3, we give an answer to the question of quantized values of dual charges which was discussed by Marciano and Pagels.（c） The Higgs field ø（x） is a mapping from M'₄ into the AⅢ type symmetric space SU_N/S(U_s X U_N-s) and the integral is an extension of Kronecker index for N=2.     

A Theoretical Study of Super-Excited States of F2

In the framework of quantum defect theory, we study super-excited states of F2 molecules which can dissociate into F^＋ （^3P2,1,0） and F^-（^1 So） ion-pair. Based on our calculation, we present a vibrational resolved assignment of the high precision photofragment yield spectra for F^- from the F2 ion-pair production.     

THE REGGE TRAJECTORY OF MESONS AND THE SU(4) MASS RELATIONS

A relativistic equation of motion of a two particle system under the constraints p_i²-m_i²-U(x²)=0.(i=1,2), where U(x²) is an infinite spherical square well poten-tial, is applied to the SU(4) quark model of mesons. A set of linear mass relations areobtained. Instead of the linear relation between J and M², the Regge trajectory ob-tained is a relation between p_nl² and M², where ζ_nlπ are zeros of the spherical Besselfunctions. The new trajectory seems more satisfactory than the former one.     

SHELL (DEFORMATION) EFFECT IN NUCLEAR CHARGE RADIUS

It is shown that without exception the observed rms charge radius constants of strongly deformed nuclei, rp's, are a little larger than those of the neighbouring spherical nuclei. The local variations among the charge radii of the sequence of isotopes, the in complete neutron shells [1p_3/2(N~3—6), 1d_5/2(N~9—14), 1f_7/2(N~20—28), 1g_9/2(N~40—50), 1h_11/2(N~70—82)], display some peculiar behaviors (eg. rms cnarge radii decrease with increasing A) which are sharply conflicting with the traditional A^1/3 law. Taking the deformation effect into account, these strange variations can be accounted for with the Z^1/3-law.     

THE COLLECTIVE MOTION OF THE BAG AND THE NUCLEON STRUCTURE FUNCTIONS

Using the hypothesis of the bag-quarks' wave-function with the property of transla-tion invariance, and introducing a Lorentz-invariant effective Lagrangian, we have cal-culated the nucleon deep -inelastic structure functions In our calculation the4-momentum conservation is satisfied automatically, while the resultant structurefunctions are positive-definite and vanish when x>1. Furthermore, using the assumptionof the asymptotic freedom, we obtain explicitly the Bjorken scaling, the approximateexpession F₁ (x～1)∝(1--x)⁴, and by the way, a new counting rule Computercalculation gives the F₂(x) curve which seems to be consistent with the data in therange of 0.4<x<1.     

Radial excitation states of η and η' in the chiral quark model

A chiral quark model is applied to calculate the spectra of pseudoscalar mesons η and η'. By analyzing the obtained spectra, we find that the mesons η'(2¹S₀), η(4¹S₀), η'(3¹S₀) and η'(4¹S₀) are the possible candidates of η(1760), X(1835), X(2120) and X(2370). The strong decay widths of these pseudoscalars to all the possible two-body decay channels are calculated within the framework of the ³P₀ model. Although the total width of η'(2¹S₀) is compatible with the BES Collaboration's experimental value for η(1760), the partial decay width to ωω is too small, which is not consistent with the BES result. If X(1835) is interpreted as η(4¹S₀), the total decay width is compatible with the experimental data, and the main decay modes will be mπ a₀(980) and m π a₀(1450), which needs to be checked experimentally. The assignment of X(2120) and X(2370) to η'(3¹S₀) and η'(4¹S₀) is disfavored in the present calculation because of the incompatibility of the decay widths.     

TESTING GLUON DISTRIBUTION FUNCTION OF HADRONS IN LARGE PT PROCESS WITH DIRECT PHOTON EMISSION

In this paper we disscuse disscuse the physicsical aspect of cross-section differences Δ_AB^cγ=dσ(AB→cγX)-dσ(AB→cγX) and give the simple rules to select the elementary subprocesses which contribute to cross-section differences.
We bind a way to test the gluon distribution functions of hadrons through the measurement of cross-section difference or combination of cross-section differences in the large P_T process with direct photon emission. Moreover we obtain simple relations between each combination of cross-sections and the corresponding gluon distribution functions of proton, neutron, pion and daon:
G_p⁸(x)/(Δ_pp^hγ－Δ_pp^hγ)=G_n⁸(x)/(Δ_pp^hγ)=G_π⁸(x)/(Δ_π+p^hγ+Δ_π－p^hγ=G_K⁸(x)/(Δ_K+p^hγ+Δ_K－p^hγ)which are expected to be test in experiment.     

THE BEHAVIOURS OF F2ep(X,Q2)-F2en(X,Q2) AND THE SCALE-BREAKING PARAMETER

The scale-breaking parameter F₂^ep(x, Q²) of non-singlet component F₂^ep-F₂^en and some other quantities in the electro-production process are discussed by usinb the analytic expression for the distribution function of valence quarks in ha.drons up to leading log approximation given by a, previous paper^[1]. Comparisons with data are also given.

     

THE DIFFICULTY OF THE DECAY τ→πντ AND SPIN 3/2 HEAVY LEPTON

We discuss the suppression of the decay of heavy lepton τ into πv_τ,by assuming that τ and/or v_τ carry spin 3/2. For the case of spin 3/2 T and spin 1/2 v_τ, using the weak current ψ_μ^(τ)(a+b_^γ5)Ψ^(v_τ)we find that the πv_τ decay channel relative to the v_τv_ll^-channel is suppressed 12/5 times, while other decay channels are not changed appreciably. △R=σ（e⁺e^-→τ⁺τ^-）/σ（e⁺e^-→μ⁺μ^-） is also discussed.     

A METHOD FOR FINDING POTENTIALS CORRESPONDING TO POLYNOMIAL-FACTOR EIGENFUNCTIONS IN QUANTUM MECHANICS

A method for finding potentials corresponding to polynomial-factor eigenfunc-tions is given for the Schr（?）dinger equation as an example.It is shown that theeigen-solutions for harmonic and Columb's potentials in quantum mechanics are the twoexamples which can be given by this method and some other examples are discovered.This method and some results of this paper may be useful for hadron structure mo-del theory.One of the examples is the equation in Ref.（4）which is derived fromBethe-Salpeter equation for the case that the straton is tightly bounded in certain po-tential well.When this method is applied to that equation for three dimensionalcentral symmetric potential V（r）=V₀—2（N+（1/2））β^-1（√V₆r²）+（V₆r⁶）, some resultsare obtained as shown in Fig. 2 in which λ′ must be considered as a linear function of m².The so called“quasic Regge trajectory”behavior is manifested.     

ON THE “DIRECT CHANNEL DIAGRAM” OF THE PRODUCTION OF THE （π+ π-）s S-STATE ATOMS

In this paper we work out the relativistic covariant B-S wave function for the（π⁺ π^-）_s atoms.Some properties of the“direct channel diagram”of the produc-tion the （π⁺ π^-）_s atoms are discussed by calculating the cross-section of the process π⁺ +n→p+（π⁺ π^-）_s with the help of the relativistic covariant wave function and assuming the lowest termin the perturbation expansion series of the quantized composite field theory——the“direct channel diagram”is dominant.Besides this calcuation perhaps presentsa rough estimate for the interesting process μ⁺ +n→（μ⁺ π^-）+p.     

PION-18O INELASTIC SCATTERING

In the framework of the eikonal form of DWIA and using the transition densitymethod, the differential cross sections for ¹³O (π,π') .¹⁸O^* (2⁺, 1.98 MeV) inelasticscattering at T_π=230 MeV are calculated. The ratios of the integrated cross sectionsfor π^- vs. π⁺ bombardments, are analyzed and the effects of changing the neutron radiusto the differential cross sections are studied as well. Our results fit the data quite well.     

Observation of a pp mass threshold enhancement in ψ′→π+π－J/ψ(J/ψ→γpp) decay

The decay channel ψ′→π⁺π^－J/ψ(J/ψ→γpp) is studied using a sample of 1.06×10⁸ ψ′ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the pp invariant mass spectrum. The enhancement can be fitted with an S-wave Breit-Wigner resonance function with a resulting peak mass of M=1861⁺⁶_－13 (stat)⁺⁷_－26 (syst) MeV/c² and a narrow width that is Γ<38 MeV/c² at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with well established mesons.

     

THE STUDY OF SOME NON-SOLATED RESONANCES FOR THE 23Na （p,α）20Ne REACTION

The excitation functions of the ²³Na（p,α₀）²⁰Ne_g·s.and the ²³Na（p,α₁）²⁰Ne_lst reae-tion have been measured from E_p=1 to 2.5 MeV at θ_L=30°,150° and 30°,respectively.Around the resonance at 2.171 MeV,the excitation functions of the（p,α₀）reactionhave been measured at 12 angles,then,some angular distributions have been obtained from these excitation functions.In addition,the angular distribution of the（p,α₀）reaction for the resonance at 2.171 MeV has also been measured directly at energy ofthe resonance peak of the excitation function at 150°.For the resonance at 2.117MeV,the angular distribution have been measured at two energies,one at the energyof the resonance peak of the excitation function at 150°,another at the energy of thehalf maximum point of the resonance peak on the higher energy side.Around the re-sonance at 2.075 MeV,the excitation functions have been measured at 16 angles,andthe angular distribution has been obtained from three excitation functions.The an-gular distributions of the three resonances are not symmetric about 90°,and the posi-tions of the resonance peaks of these resonances varies with the angle of measurement.By means of the compound nucleus theory,discussions have been made for these non-solated resonances.     

STUDY OF THE MECHANISM OF 12C（d,d）12C AND 12C（d,p）13C* REACTIONS

A formalism for studying the interference between the direct reaction and the compound resonance processes is presented by the S-matrix theory; The mechanism of ¹²C（d, d） ¹²C, ¹²C（d, p₁） ¹³C* and ¹²C（d, p₂） ¹³C* reactions in the energy range E_d=1.63 MeV to 2.05 MeV is analysed.Te results show that: the interference between these two processes exists; and the quantitative relation between them is given. While the parameters of direct reactions and compound resonance processes, particularly for four resonance states with E_d=1.726, 1.767, 1.792 and 1.86 MeV are determined.     

CONFINEMENT PROPERTIES OF THE PURE GAUGE FIELDS ON COSET SPACE OF AN ABELIAN CHIRAL GROUP

In this paper the lattice current-current propagator is calculated and the influence of coset pure gauge fields of an Abelian chiral group G=U₁×U⁵ on confinement properties of a quark system is discussed by virtue of the Wilson's criterion of lattice gauge theory. When subgroup H is U₁, the coset pure gauge fields only contribute a perimeter law factor to the current-current propagator which has no influence on confinement properties of the system. When subgroup H is U⁵, the coset pure gauge fields also have no influence on confinement properties of the system.     

One Loop PGBs Effects on tt Production in High Energy e+e- Annihilation

The Technicolor(TC)O(αm_t²/m_w²)corrections to top pair production in high energy e⁺e^－ annihilation are calculated in the one generation TC model.The analytic expressions are given for the form factor, the renormalized matrix element and its square.Numerical examples are presented for the corrections to the total cross-section ,the forward-backward asymmetry A_FB and the left-right asymmetry A_LR.We found that the corrections can reach －12.3%, －3.3% and －11.7% to the observables,A_FB and A_LR respectively for the favorable parameter values.The level of these corrections might be achieved at the next-generation linear collider(NLC).It might open a window for testing TC theory.     

Measurement of J/ψ→ηcγ at KEDR

We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e⁺e^－ collider. We measure the branching fraction of radiative decay J/ψ→η_cγ, η_c width and mass. Our preliminary results are: M(η_c)=2979.4±1.5±1.9 MeV/c², Γ(η_c) = 27.8±5.1±3.3 MeV, B(J/ψ→η_cγ)=(2.34±0.15±0.40)%.