A. Sulaksono, A.
Departemen Fisika, FMIPA, Universitas Indonesia, Depok 16424

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EFEK VARIASI RADIUS NUKLEON TERHADAP PERSAMAAN KEADAAN BINTANG NEUTRON Suparti, Suparti; Sulaksono, A.; Mart, T.
Jurnal Spektra Vol 15, No 1 (2014): Spektra: Jurnal Fisika dan Aplikasinya
Publisher : Jurnal Spektra

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The isoscalar parameter of SNM and the isovector parameter of PNM from various nucleon sizes as well as the effects of the fitting on medium density and low density prediction regimes of PNM have been investigated. To this end, we have chosen the cut-off parameter β = 0.0005 and β = 0.01, with the nucleon radii of 0, 0.66, 0.76, 0.83, and 0.99 fm. The obtained isoscalar parameters are in a good agreement with the result of the DBHF calculation for all nucleon radii used, except for rN = 0.99 fm, which does not fulfill the SNM EOS prediction based on the result of heavy ion collision. On the other hand, the effect of fitting of the parameters outside the upper and lower bounds leads to a disagreement with the experimental result of Danielwicz et al. It is suspected that this could happen due to the limitation of the parameter range β, as well as the nucleon radius. Keywords: nucleon radius, parameter, equation of state
FENOMENA HALO BERDASARKAN MODEL RELATIVISTIC MEAN FIELD (RMF) Nugraha, A.M.; Diningrum, J.P.; Sumaryada, T.; Sulaksono, A.
Jurnal Spektra Vol 16, No 2 (2015): Spektra: Jurnal Fisika dan Aplikasinya
Publisher : Jurnal Spektra

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AbstrakHalo merupakan salah satu fenomena unik yang terjadi di inti atom, fenomena yang digambarkan adanya tambahan “ekor” dan adanya “ruang kosong” antara core dan ekor pada distribusi neutron. Metode analisa halo yang dikembangkan oleh V. Rotival dkk [Phys. Rev. C79, 054308 (2009)] pada isotop Cr, biasanya diaplikasikan pada model Hartree-Fock-Bogoliubov (HFB). Berbeda dengan Rotrival dkk, kami menggunakan model Relativistic Mean Field (RMF) pada penelitian ini. Berbeda dengan hasil perhitungan dengan model HFB, kami mengamati perilaku yang berbeda pada level  seiring dengan kemunculan halo. Selain itu, pada model RMF prediksi keberadaan halo pada isotop Cr lebih besar dibandingkan dengan prediksi berdasarkan model HFB . Pada penelitian ini kami juga mempelajari efek suku cross coupling meson-, tensor dan suku pertukaran elektromagnetik pada model RMF terhadap kemunculan halo pada isotop Cr. AbstractHalo is one of the unique phenomena that occur in atomic nucleus. In halo nucleus, the neutron density displays an unusually “tail” and “existing empty space” between the core and the tail of the nucleus. New analysis method to investigate halo was developed by V. Rotival, et al. [Phys. Rev. C79, 054308 (2009)]. The method was used to search the halo nuclei in the chain of Cr-isotopes within Hartree-Fock-Bogoliubov (HFB) model. Unlike the Rotival, et al, we use here the Relativistic Mean Field (RMF) model as the framework. We observed that the significant changing of  level behavior is in line with appearancing of halo. Moreover, we have also found that in the case of Cr isotopes, the neutron halo number prediction based RMF model is greater than that of HFB model  In this work we also study the effects of cross coupling meson -, tensor, and electromagnetic exchange terms in RMF model on the appearancing of halo in Cr-isotopes.     Keywords: Halo phenomena, RMF model, Cross coupling meson -, Tensor, Electromagnetic exchange.
EFEK VARIASI RADIUS NUKLEON TERHADAP PERSAMAAN KEADAAN BINTANG NEUTRON Suparti, Suparti; Sulaksono, A.; Mart, T.
Spektra: Jurnal Fisika dan Aplikasinya Vol 15 No 1 (2014): SPEKTRA, Volume 15 Nomor 1, Mei 2014
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstract

AbstrakParameter isoskalar SNM dan parameter isovektor PNM untuk berbagai nilai radius nukleon serta efek fitting pada prediksi daerah medium density dan low density PNM, dengan menggunakan nilai jangkauan parameter β = 0.0005 dan β = 0.01 serta radius nukleon 0, 0.66 fm, 0.76 fm, 0.83 fm, dan 0.99 fm telah berhasil diperoleh. Parameter isoskalar hasil fit menghasilkan nilai yang cocok dengan perhitungan DBHF untuk semua radius nukleon yang digunakan, kecuali untuk radius 0.99 fm yang tidak memenuhi prediksi EOS SNM, menurut hasil eksperimen tumbukan ion berat. Sementara itu, efek fitting untuk parameter-parameter di luar daerah fitting window tidak sesuai dengan jangkauan eksperimen Danielewicz, dkk. Hal ini kemungkinan diakibakan oleh keterbatasan jangkauan parameter (nilai β) dan radius nukleon yang digunakan. AbstrakEffects of the Nucleon Radius Variation on the Equation of State of Neutron Star The isoscalar parameter of SNM and the isovector parameter of PNM from various nucleon sizes as well as the effects of the fitting on medium density and low density prediction regimes of PNM have been investigated. To this end, we have chosen the cut-off parameter β = 0.0005 and β = 0.01, with the nucleon radii of 0, 0.66, 0.76, 0.83, and 0.99 fm. The obtained isoscalar parameters are in a good agreement with the result of the DBHF calculation for all nucleon radii used, except for rN = 0.99 fm, which does not fulfill the SNM EOS prediction based on the result of heavy ion collision. On the other hand, the effect of fitting of the parameters outside the upper and lower bounds leads to a disagreement with the experimental result of Danielwicz et al. It is suspected that this could happen due to the limitation of the parameter range β, as well as the nucleon radius.