Dirac Coupled Channel Analysis of p + 154Sm Inelastic Scattering

심숙이,Shin-Ho Ryu,Min-Soo Kim 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I

The inelastic scattering of an 800-MeV proton from a heavy, deformed nucleus of $^{154}$Sm is analyzed using phenomenological optical potentials in the Dirac coupled channel formalism. Employing the S-V model, we obtain Dirac phenomenological optical potentials using the Woods-Saxon shape. The first order rotational collective model is used to obtain the transition optical potentials for the low-lying excited states of the ground state rotational band (GSRB) of the deformed nucleus. The effect of a multistep process is investigated by including the channel coupling between two adjacent excited states in addition to the couplings between the ground state and excited states. The Dirac coupled channel equations are solved numerically to calculate the differential cross sections by using the sequential iteration method, and the theoretical results are observed to agree reasonably well with the experimental data. The effective Schr\"{o}dinger equivalent central and spin-orbit potentials of the Dirac optical potentials are calculated and compared with those of Schr\"{o}dinger calculations.

p+C12 비탄성 산란의 상대론적 분석

심숙이,김민수,유신호 한국물리학회 2007 새물리 Vol.54 No.2

The inelastic scattering of 800-and 1040-MeV protons from the light, axially-symmetric deformed nucleus of $^{12}$C is analyzed using the phenomenological optical potentials and the relativistic impulse approximation (RIA) optical potentials in the Dirac coupled channel formalism. Employing the S-V model, the Dirac phenomenological optical potentials are obtained using the Woods-Saxon shape and a 3-parameter Fermi shape. The RIA potentials are obtained by folding a modified relativistic Hartree nuclear density with Lorentz invariant NN amplitudes. The first-order rotational collective model is used to describe the low-lying excited states of the ground-state rotational band (GSRB) of the deformed nucleus, and a vibrational model is used for the low-lying 3$^{-}$ state. A reasonable description of both elastic and inelastic observables is obtained, and the strong coupling to the low-lying 2$^{+}$ states is shown to improve the agreement with the large-angle data for 800-MeV p + $^{12}$C elastic scattering. 가벼운 축대칭 변형핵인 $^{12}$C에서의 800MeV와 1040MeV 양성자의 비탄성 산란을 현상론 및 미시적 상대론적 충격 근사법 (Relativistic Impulse Approximation: RIA)에 근거하여 계산한 광학 포텐셜과 디랙 채널 결합 분석법을 이용하여 분석하였다. 스칼라와 벡터 포텐셜을 고려하는 S-V 모델을 적용하여 현상론적 광학 포텐셜을 구하고 보정한 상대론적 Hartree 핵 밀도 분포를 로렌쯔 불변인 핵자-핵자간 산란 진폭과 함께 적분하여 상대론적 충격 근사 광학 포텐셜을 구하였다. 축대칭 변형핵에서의 바닥상태 회전 띠 (Ground State Rotational Band: GSRB)에 속하는 낮은 여기 상태들을 기술하기 위한 전이 광학 포텐셜을 구하는 과정에서 1차 회전 집단 모형을 이용하였고 3$^{-}$상태를 설명하기 위해서는 진동 모형을 이용하였다. 계산 결과 바닥 상태와 낮은 여기 상태들의 가관측량의 실험치를 비교적 잘 설명할 수 있었고 강하게 결합된 낮은 여기상태와의 채널 결합 효과가 800 MeV p + $^{12}$C 탄성산란의 큰각에서 계산치를 하향 편이시켜 실험치와 일치시킨다는 것을 확인하였다.

Relativistic Analysis of Intermediate Energy Proton Inelastic Scatterings from Heavy Deformed Nuclei

심숙이,유신호,김민수 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

A relativistic coupled channel analysis based on the Dirac equation is performed for inelastic scattering of an intermediate energy proton from a heavy, deformed nucleus by using an optical potential model. In order to describe the low-lying excited states of the deformed nucleus, we used a rotational collective model to get the transition optical potentials. The Dirac coupled-channel equations are solved numerically to calculate the differential cross sections by using the sequential iteration method. Employing Dirac phenomenology, we vary the optical potential parameters and deformation parameters to reproduce the experimental observables. The theoretical results are observed to agree reasonably well with the inelastic scattering experimental data of 800 MeV p+176Yb, and the importance of the multistep process for inelastic scatterings at a deformed nucleus is confirmed. The effective Schrodinger-equivalent central and spin-orbit potentials are calculated by reducing the Dirac equation to a Schrodinger-like second-order differential equation and by comparison them with those of a Schrodinger calculation in which the spin-orbit potential is not included, showing the relatively large strength of a real central potential. Surface-peaked phenomena are not observed for eective central potentials when the heavy, deformed nucleus of 176Yb is considered.

비선형 증폭 루프에서의 평균 솔리톤의 안정성

심숙이,이성서,김광훈,김기옥 한국광학회 2001 한국광학회지 Vol.12 No.6

A numerical analysis based on the nonlinear Schroedinger equation is presented to analyze the propagation stability of the average soliton in a simple nonlinear amplifying loop mirror. The ratio of amplification period to soliton period and the length fraction of the erbium-doped fiber in the loop are varied to investigate their effects on the soliton stability. It is observed that stable soliton propagation is obtained even when the amplification period is only slightly shorter than the soliton period when the length fraction of the erbium-doped fiber in the loop is small, which is different from the previously published condition for stable average soliton propagation. 간단한 비선형 증폭 루프에서의 평균 솔리톤 전송의 안정성을 비선형 Schroedinger방정식에 기초한 수치해석법을 이용하여 솔리톤 주기에 대한 증폭 주기의 비율과 루프에서의 erbium doped광섬유의 길이 비율을 변화시켜가며 계산하고 그 결과를 분석하였다. 계산 결과 루프에서의 erbium doped광섬유의 길이 비율이 작을 경우 증폭 주기가 솔리톤 주기에 비해 많이 작아야 한다는 기존의 평균 솔리톤 형성 조건이 완화됨을 알 수 있었다.

Soliton Stability in a Nonlinear Amplifying Loop Mirror

심숙이 公州大學校 基礎科學硏究所 1997 自然科學硏究 Vol.6 No.-

비선형 증폭 루프 시스템에서의 솔리톤 전파의 안정성을 루프내의 어뷰움이 첨가된 광섬유의 길이 비율 및 증폭 주기와 솔리톤 주기와의 비율을 변화시키며 비선형 슐레딩거 방정식을 수치적으로 풀어 분석하였다. A numerical analysis based on the nonlinear Schroedinger equation is presented for a nonlinear amplifying loop mirror system. The stability of soliton propagation is investigated by varying the ratio of amplification period to soliton period and the length fraction of erbium doped fiber in the loop.

K￣ - ^(40)Ca의 광학 포텐셜

심숙이,김민수 公州大學校 基礎科學硏究所 2003 自然科學硏究 Vol.10 No.-

간단한 카이랄 이론에 근거하여 핵 안에서의 케이온 광학포텐셜을 유도하고 케이온-핵 산란 현상과 비교하기 위해 Klein-Gordon(KG) 방정식을 풀어 가관측량인 미분산란 단면적을 계산하였다. 800MeV/c 에서의 K￣-^(40)Ca의 산란 현상을 고려하여 실제 실험치와 s 파와 p 파를 고려했을 경우의 이론적 계산 결과를 비교하고 이론치를 현상론적으로 보정한 광학 포텐셜을 이용하였을 경우와 비교, 분석하였다. Kaon optical potential in the nucleus is calculated using a simple chiral model and Klein-Gordon equation is solved using the optical potential in order to calculate the differential cross section and compare the results with experimental values of the nuclear scattering. s and p wave contributions to the optical potential are calculated and compared with thephenomenologically modified optical potentials considering K￣-^(40)Ca scattering at 800MeV/c.

Dirac Coupled Channel Analyses of Proton Inelastic Scattering from the 40Ar Nucleus

심숙이 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.10

Inelastic scatterings of 0.8-GeV protons from 40Ar nuclei are analyzed by using an optical potential model in the Dirac coupled channel formalism. A rotational collective model is used to obtain the transition optical potentials for the low-lying excited states of the rotational band. The optical potential parameters of a Woods-Saxon shape and the deformation parameters of the excited states are searched phenomenologically by using the sequential iteration method to reproduce the experimental differential cross-section data. The effect of a multistep process is investigated by including the channel coupling between two excited states in addition to the couplings between the ground state and the excited states. The calculated deformation parameters of the excited states are compared with those obtained by using the nonrelativistic calculations. The results of the Dirac coupled channel calculations are found to show pretty good agreements with the experimental data for the ground state and the low-lying excited states. The multistep excitation process via channel coupling with the second 2+ state is found to be important for the excitation of the 4+ state for inelastic scatterings from deformed 40Ar nuclei.

광학퍼텐셜을 이용한 ^{40}Ca 에 의한 K^- 산란 연구

심숙이,김민수 한국물리학회 2004 새물리 Vol.48 No.4

Kaon optical potentials in the nucleus are calculated based on a simple chiral model, and they are used in the Klein-Gordon equation to calculate numerically the differential cross - section of $K^-$-$^{40}$Ca scattering at 800 MeV/c. The calculated differential cross sections are compared with the experimental values and analyzed. Also, the calculated optical potentials are compared with the phenomenologically modified optical potentials that can explain the experimental data pretty well.

Dirac Analyses of Proton Inelastic Scatterings from an s-d Shell Nucleus 20Ne

심숙이,김문원 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.3

Proton inelastic scatterings from an s-d shell nucleus 20Ne are analyzed using an optical potentialmodel in the Dirac coupled channel formalism. Lorentz covariant scalar and vector optical potentialsare included in the calculation, and the first-order rotational collective model is used to obtain thetransition potentials for the low-lying excited collective states of the ground state rotational bandof the nucleus. Dirac coupled channel equations are solved phenomenologically to reproduce thedifferential cross section and analyzing power data by varying the optical potential and deformationparameters. The multistep process via coupled channels turns out to be important in describingthe 4+ excited state of the ground state rotational band. The calculated deformation parameters ofthe excited states are compared with those of nonrelativistic calculations based on the Schr¨odingerequations. The Dirac equations are reduced to obtain Schr¨odinger-like second-order differentialequations, and the obtained effective central and spin-orbit optical potentials are analyzed andcompared with those of other s-d shell nuclei.

축대칭 변형핵에서의 중간에너지 양성자 비탄성 산란의 체계적 상대론적 분석

심숙이,김문원 한국물리학회 2010 새물리 Vol.60 No.9

Intermediate-energy proton inelastic scatterings from several axially-symmetric deformed nuclei are analyzed systematically using the optical potential model in the relativistic Dirac coupled chan-nel formalism. By using a sequential iteration method to solve the Dirac coupled channel equations, we obtained the phenomenological optical potentials and compared them to each other to performsystematic Dirac analysis. Also, the Dirac equations were reduced to second-order differential equations to obtain the Schr¨oedinger equivalent effective central and spin-orbit optical potentials, we found that the heavier deformed nuclei had larger central potential strength. First order rotational collective models are used to describe the low-lying excited states of the ground- state rotational band in the deformed nuclei. The lighter deformed nucleus is observed to have the larger deformation parameter for the lowest-lying excited state, the 2+ state, for 800-MeV proton inelastic scatterings. 축대칭 변형핵들에서의 중간에너지 양성자의 비탄성 산란을 광학 포텐셜 모형과 상대론적 디랙 채널 결합 분석법을 이용하여 체계적으로 분석하였다. 디랙 채널 결합 방정식들을 풀어 실험치를 잘 재현하도록 연속 반복(sequential iteration)법을 이용하여 계산한 결과 얻어진 광학 포텐셜 변수들을 비교하고 디랙 방정식을 슈뢰딩거 방정식과 같은 2계 미분방정식으로 활원 시켰을 때 얻어지는 유효 중심 및 스핀-궤도 포텐셜을 계산하여 더 무거운 핵에서 유효 중심포텐셜의 세기가 더 커진다는 것을 관찰하였다. 축대칭 변형핵에서의 바닥상태 회전 띠에 속하는 낮은 들뜬 상태들을 기술하기 위한 전이 광학 포텐셜을 구하는 과정에서 1차 회전 집단 모형을 이용하였고 800MeV 양성자 비탄성산란에서 더 가벼운 변형핵일수록 가장 낮은 들뜬 상태인 2+ 상태에 대한 변형변수들이 점점 커져 바닥상태와 더 강한 결합 상태를 이룬다는 것을 확인하였다.