اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدTransformations between complex scattering length and binding energy
39
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The use of scattering length of particle-target interaction due to real- valued potential to study the bound states of the particle-target system is well known in nuclear and atomic physics. In view of the current interest in using eta-nucleus scattering length to infer the existence of eta-mesic nucleus, we derive general analytic expressions that relate the binding energy and half-width of an unstable bound state to the complex-valued scattering length due to the same particle-target interaction.
قيم البحث
اقرأ أيضاً
We show that chiral symmetry and gauge invariance enforce relations between the short-distance physics that occurs in a number of electroweak and pionic reactions on light nuclei. Within chiral perturbation theory this is manifested via the appearanc
e of the same axial isovector two-body contact term in pi- d -> n n gamma, p-wave pion production in NN collisions, tritium beta decay, pp fusion, nu d scattering, and the hep reaction. Using a Gamow-Teller matrix element obtained from calculations of pp fusion as input we compute the neutron spectrum obtained in pi- d -> n n gamma. With the short-distance physics in this process controlled from p p -> d e+ nu_e the theoretical uncertainty in the nn scattering length extracted from pi- d -> n n gamma is reduced by a factor larger than three, to <~0.05 fm.
We compute the binding energy of triton with realistic statistical errors stemming from NN scattering data uncertainties and the deuteron and obtain $E_t=-7.638(15) , {rm MeV}$. Setting the numerical precision as $Delta E_t^{rm num} lesssim 1 , {rm k
eV}$ we obtain the statistical error $Delta E_t^{rm stat}= 15(1) , {rm keV}$ which is mainly determined by the channels involving relative S-waves. This figure reflects the uncertainty of the input NN data, more than two orders of magnitude larger than the experimental precision $Delta E_t^{rm exp}= 0.1 , {rm keV}$ and provides a bottleneck in the realistic precision that can be reached. This suggests an important reduction in the numerical precision and hence in the computational effort.
Using the model of hexagonal clusters we express the surface, curvature and Gauss curvature coefficients of the nuclear binding energy in terms of its bulk coefficient. Using the derived values of these coefficients and a single fitting parameter we
are able to reasonably well describe the experimental binding energies of nuclei with more than 100 nucleons. To improve the description of lighter nuclei we introduce the same correction for all the coefficients. In this way we determine the apparent values of the surface, curvature and Gauss curvature coefficients which may be used for infinite nuclear matter equation of state. This simple model allows us to fix the temperature dependence of all these coefficients, if the temperature dependence for the bulk term is known. The found estimates for critical temperature are well consistent both with experimental and with theoretical findings.
$Kbar N$ interactions are investigated {it via} an effective non-linear chiral meson-baryon Lagrangian. The adjustable parameters are determined by a fitting procedure on the $K^-p$ threshold branching ratios and total cross-section data for $p^{lab}
_Kle$ 250 MeV/c. We produce predictions for the $Sigma pi$ mass spectrum, and scattering lenghts $a_{K^-p}$, $a_n(K^-n to K^-n)$, $a_n0(Kbar0 n to Kbar0 n)$, and $a_{ex}(K^-p to Kbar0 n)$. The $Kbar N$ amplitudes thus obtained, as well as those for other two-body channels ($pi N$, $NN$, and $YN$) are used as input to predict the scattering length $A_{K^-d}$, for which we have devised a relativistic version of the three-body Faddeev equations. Results for all two- and three-body coupled channels are reported both in isospin and particle bases. All available $Kbar N$ data are well reproduced and our best results for the $K^-p$ and $K^-d$ scattering lenghts are $a_{K^-p} = (-0.90 + i 0.87) fm$ and $A_{K^-d} = (-1.80 + i 1.55) fm$.
We compute a model-independent correlation between the difference of neutron-neutron and proton-proton scattering lengths |a(nn)-a^C(pp)| and the splitting in binding energies between Helium-3 and tritium nuclei. We use the effective field theory wit
hout explicit pions to show that this correlation relies only on the existence of large scattering lengths in the NN system. Our leading-order calculation, taken together with experimental values for binding energies and a^C(pp), yields a(nn)=-22.9 pm 4.1 fm.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
