ترغب بنشر مسار تعليمي؟ اضغط هنا

Complete set of polarization transfer observables for the ${}^{16}{rm O}(vec{p},vec{n}){}^{16}{rm F}$ reaction at 296 MeV and 0 degrees

111   0   0.0 ( 0 )
 نشر من قبل Tomotsugu Wakasa
 تاريخ النشر 2011
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

We report measurements of the cross section and a complete set of polarization transfer observables for the ${}^{16}{rm O}(vec{p},vec{n}){}^{16}{rm F}$ reaction at a bombarding energy of $T_p$ = 296 MeV and a reaction angle of $theta_{rm lab}$ = $0^{circ}$. The data are compared with distorted-wave impulse approximation calculations employing the large configuration-space shell-model (SM) wave functions. The well-known Gamow-Teller and spin-dipole (SD) states at excitation energies of $E_x$ $lesssim$ 8 MeV have been reasonably reproduced by the calculations except for the spin--parity $J^{pi}$ = $2^-$ state at $E_x$ = 5.86 MeV. The SD resonance at $E_x$ $simeq$ 9.5 MeV appears to have more $J^{pi}$ = $2^-$ strength than $J^{pi}$ = $1^-$ strength, consistent with the calculations. The data show significant strength in the spin-longitudinal polarized cross section $ID_L(0^{circ})$ at $E_x$ $simeq$ 15 MeV, which indicates existence of the $J^{pi}$ = $0^-$ SD resonance as predicted in the SM calculations.

قيم البحث

اقرأ أيضاً

250 - M. Dozono , T. Wakasa , E. Ihara 2007
A complete set of polarization transfer observables has been measured for the $^{12}{rm C}(p,n)$ reaction at $T_p=296 {rm MeV}$ and $theta_{rm lab}=0^{circ}$. The total spin transfer $Sigma(0^{circ})$ and the observable $f_1$ deduced from the measure d polarization transfer observables indicate that the spin--dipole resonance at $E_x simeq 7 {rm MeV}$ has greater $2^-$ strength than $1^-$ strength, which is consistent with recent experimental and theoretical studies. The results also indicate a predominance of the spin-flip and unnatural-parity transition strength in the continuum. The exchange tensor interaction at a large momentum transfer of $Q simeq 3.6 {rm fm}^{-1}$ is discussed.
85 - M. Dozono , T. Wakasa , E. Ihara 2009
Differential cross sections and complete sets of polarization observables are presented for the Gamow-Teller $^{12}{rm C}(vec{p},vec{n})^{12}{rm N}({rm g.s.},1^+)$ reaction at a bombarding energy of 296 MeV with momentum transfers $q$ of 0.1 to $2.2{ rm fm}^{-1}$. The polarization transfer observables are used to deduce the spin-longitudinal cross section, $ID_q$, and spin-transverse cross sections, $ID_p$ and $ID_n$. The data are compared with calculations based on the distorted wave impulse approximation (DWIA) using shell-model wave functions. Significant differences between the experimental and theoretical results are observed for all three spin-dependent $ID_i$ at momentum transfers of $q gtrsim 0.5{rm fm}^{-1}$, suggesting the existence of nuclear correlations beyond the shell model. We also performed DWIA calculations employing random phase approximation (RPA) response functions and found that the observed discrepancy is partly resolved by the pionic and rho-mesonic correlation effects.
232 - T. Wakasa , E. Ihara , M. Dozono 2008
We report measurements of the cross-section and a complete set of polarization transfer coefficients for the ${}^{3}{rm He}(p,n)$ reaction at a bombarding energy $T_p$ = 346 MeV and a reaction angle $theta_{rm lab}$ = $0^{circ}$. The data are compa red with the corresponding free nucleon-nucleon values on the basis of the predominance of quasi-elastic scattering processes. Significant discrepancies have been observed in the polarization transfer $D_{LL}(0^{circ})$, which are presumably the result of the three-proton $T$ = 3/2 resonance. The spin--parity of the resonance is estimated to be $1/2^-$, and the distribution is consistent with previous results obtained for the same reaction at $T_p$ = 48.8 MeV.
283 - M. Dozono , T. Uesaka , N. Fukuda 2020
The parity-transfer $({}^{16}{rm O},{}^{16}{rm F}(0^-,{rm g.s.}))$ reaction is presented as a new probe for investigating isovector $0^-$ states in nuclei. The properties of $0^-$ states provide a stringent test of the threshold density for pion cond ensation in nuclear matter. Utilizing a $0^+ rightarrow 0^-$ transition in the projectile, the parity-transfer reaction transfers an internal parity to a target nucleus, resulting in a unique sensitivity to unnatural-parity states. Consequently, the selectivity for $0^-$ states is higher than in other reactions employed to date. The probe was applied to a study of the $0^-$ states in ${}^{12}{rm B}$ via the ${}^{12}{rm C}({}^{16}{rm O},{}^{16}{rm F}(0^-,{rm g.s.}))$ reaction at $247~{rm MeV/u}$. The excitation energy spectra were deduced by detecting the ${}^{15}{rm O}+p$ pair produced in the decay of the ${}^{16}{rm F}$ ejectile. A known $0^-$ state at $E_x = 9.3~{rm MeV}$ was observed with an unprecedentedly high signal-to-noise ratio. The data also revealed new candidates of $0^-$ states at $E_x=6.6 pm 0.4$ and $14.8 pm 0.3~{rm MeV}$. The results demonstrate the high efficiency of $0^-$ state detection by the parity-transfer reaction.
277 - E. Geis , V. Ziskin , T. Akdogan 2008
We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highl y polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio $G^{n}_{E}/G^{n}_{M}$ was extracted from the beam-target vector asymmetry $A_{ed}^{V}$ at four-momentum transfers $Q^{2}=0.14$, 0.20, 0.29 and 0.42 (GeV/c)$^{2}$.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا