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Journal articles on the topic 'IsoSPI'

Author: Grafiati

Published: 23 June 2021

Last updated: 7 February 2022

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1

YE, W. "INFLUENCE OF ISOSPIN ON PRESCISSION PARTICLE EMISSION OF LIGHT FISSIONING SYSTEMS." International Journal of Modern Physics E 12, no. 06 (December 2003): 817–26. http://dx.doi.org/10.1142/s0218301303001600.

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The isospin effect on particle emission for fissioning isobaric sources of 110Tc, 110Pd, 110In and for isotopic sources of 110,117,124In is explored in the framework of the Smoluchowski equation. A statistical model including dissipation is employed to study particle emission in asymmetric and symmetric fission of the In nucleus with different isospins. Calculations show that for a fissioning nucleus which has a larger isospin, charged particle multiplicities are no longer sensitive to dissipation strength or the fission time scale. Hence, for those systems with very high isospins, protons and α particles cannot be used as probes of the dissipation in the fission of hot nuclei. This conclusion does not depend on the mass asymmetry of the fission process.

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2

FARIA DA VEIGA, PAULO A., MICHAEL O'CARROLL, and ANTÔNIO FRANCISCO NETO. "ISOSPIN–SPIN INTERCHANGE SYMMETRY AND TWO-BARYON BOUND STATES IN (3+1)-DIMENSIONAL LATTICE QCD WITH TWO-FLAVORS AND STRONG COUPLING." International Journal of Modern Physics A 26, no. 25 (October 10, 2011): 4387–404. http://dx.doi.org/10.1142/s0217751x11054577.

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We determine two-baryon bound states in a 3+1 lattice QCD model with improved Wilson action and two flavors. We work in the strong coupling regime: small hopping parameter κ > 0 and much smaller plaquette coupling β > 0. In this regime, it is known that the low-lying energy–momentum spectrum is comprised of baryons and mesons with asymptotic masses -3 ln κ and -2 ln κ, respectively. We show that the dominant baryon–baryon interaction is an order κ2 space-range-one [Formula: see text]-exchange potential. We also show that this interaction has an important and novel isospin–spin interchange symmetry relating the various possible bound states, and then governing the two-baryon spectral structure. Letting S(I) denote the total spin (total isospin) of the two-baryon bound states, S, I = 0, 1, 2, 3, we find bound states with asymptotic binding energy κ2/4, for I+S = 1, 3, and 4 (here, with I = S = 2); κ2/12, for I+S = 0, 2, 4 and 3 (here, with I = 1, 2). In particular, we show that the two-baryon spectrum contains deuteron (I = 0), diproton (I = 1) and dineutron (I = 1)-like bound states. Using the isospin–spin symmetry, we can circumvent the lack of spin symmetry of the lattice action and show they all have the same asymptotic binding energy, namely κ2/4. Our analysis uses convenient two and four-baryon correlations, their spectral representations and a lattice Bethe–Salpeter equation, which is solved in a ladder approximation. For the isospin, spin part of the interaction, we obtain a permanent representation which describes the interaction of the individual spins and isospins of the quarks of one baryon with those of the other baryon.

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3

ROBSON, B. A. "RELATION BETWEEN STRONG AND WEAK ISOSPIN." International Journal of Modern Physics E 13, no. 05 (October 2004): 999–1018. http://dx.doi.org/10.1142/s0218301304002521.

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The relation between strong isospin I and weak isospin i is discussed. In particular an equation between the third components I3 and i3 is given. This relation indicates that the strong isospin and weak isospin symmetries are both SU (2) subgroups of a new SU (3) symmetry underlying the structure of leptons and quarks.

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4

LI, QINGFENG, and ZHUXIA LI. "THE ISOSPIN DISTRIBUTION OF FRAGMENTS IN REACTIONS 96Ru + 96Ru, 96Ru + 96Zr, 96Zr + 96Ru, and 96Zr + 96Zr AT BEAM ENERGY 400 AMeV." Modern Physics Letters A 17, no. 07 (March 7, 2002): 375–85. http://dx.doi.org/10.1142/s0217732302006618.

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The isospin distribution of particles and fragments in collisions 96Ru + 96Ru, 96Ru + 96Zr, 96Zr + 96Ru and 96Zr + 96Zr at beam energy 400 AMeV is studied with isospin-dependent QMD model. We find that the rapidity distribution of differential neutron–proton counting in neutron rich nucleus–nucleus collisions at intermediate energies is sensitive to the isospin-dependent part of nuclear potential. The study of the N/Z ratio of nucleons, light charged particles (LCP) and intermediate mass fragments (IMF) shows that the isospin-dependent part of nuclear potential drives IMF to be more isospin symmetric and emitted nucleons to be more neutron rich. From the study of the time evolution of the isospin distribution in emitted nucleons, LCP and IMF we find that neutrons diffuse much faster than protons at the beginning and the final isospin distribution is a result of dynamical balance of symmetry potential and Coulomb force under the charge conservation.

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5

Jain, Ashok Kumar, and Swati Garg. "Isospin Conservation in Neutron Rich Systems of Heavy Nuclei." EPJ Web of Conferences 178 (2018): 05007. http://dx.doi.org/10.1051/epjconf/201817805007.

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It is generally believed that isospin would diminish in its importance as we go towards heavy mass region due to isospin mixing caused by the growing Coulomb forces. However, it was realized quite early that isospin could become an important and useful quantum number for all nuclei including heavy nuclei due to neutron richness of the systems [1]. Lane and Soper [2] also showed in a theoretical calculation that isospin indeed remains quite good in heavy mass neutron rich systems. In this paper, we present isospin based calculations [3, 4] for the fission fragment distributions obtained from heavy-ion fusion fission reactions. We discuss in detail the procedure adopted to assign the isospin values and the role of neutron multiplicity data in obtaining the total fission fragment distributions. We show that the observed fragment distributions can be reproduced rather reasonably well by the calculations based on the idea of conservation of isospin. This is a direct experimental evidence of the validity of isospin in heavy nuclei, which arises largely due to the neutron-rich nature of heavy nuclei and their fragments. This result may eventually become useful for the theories of nuclear fission and also in other practical applications.

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6

RAFALSKI, M., W. SATUŁA, and J. DOBACZEWSKI. "ISOSPIN MIXING OF ISOSPIN-PROJECTED SLATER DETERMINANTS: FORMALISM AND PRELIMINARY APPLICATIONS." International Journal of Modern Physics E 18, no. 04 (April 2009): 958–64. http://dx.doi.org/10.1142/s0218301309013105.

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We report on the development of a new theoretical tool that allows for isospin projection of Slater determinants and we present its first applications. In particular, we determine the isospin mixing in ground states of N = Z nuclei and discuss its dependence on the size of the harmonic-oscillator basis used in the calculations. We also discuss the unphysical contribution to the isospin mixing caused by the spurious isospin-symmetry breaking inherent to the mean-field approach. We show that these contributions may be as large as 30% of the value of the isospin-mixing parameter.

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7

Li, Bao-An, Che Ming Ko, and Wolfgang Bauer. "Isospin Physics in Heavy-Ion Collisions at Intermediate Energies." International Journal of Modern Physics E 07, no. 02 (April 1998): 147–229. http://dx.doi.org/10.1142/s0218301398000087.

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In nuclear collisions induced by stable or radioactive neutron-rich nuclei a transient state of nuclear matter with an appreciable isospin asymmetry as well as thermal and compressional excitation can be created. This offers the possibility to study the properties of nuclear matter in the region between symmetric nuclear matter and pure neutron matter. In this review, we discuss recent theoretical studies of the equation of state of isospin-asymmetric nuclear matter and its relations to the properties of neutron stars and radioactive nuclei. Chemical and mechanical instabilities as well as the liquid-gas phase transition in asymmetric nuclear matter are investigated. The in-medium nucleon-nucleon cross sections at different isospin states are reviewed as they affect significantly the dynamics of heavy ion collisions induced by radioactive beams. We then discuss an isospin-dependent transport model, which includes different mean-field potentials and cross sections for the proton and neutron, and its application to these reactions. Furthermore, we review the comparisons between theoretical predictions and available experimental data. In particular, we discuss the study of nuclear stopping in terms of isospin equilibration, the dependence of nuclear collective flow and balance energy on the isospin-dependent nuclear equation of state and cross sections, the isospin dependence of total nuclear reaction cross sections, and the role of isospin in preequilibrium nucleon emissions and subthreshold pion production.

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8

Garg, Swati, and Ashok Kumar Jain. "Does Compound Nucleus remember its Isospin- An Evidence from the Fission Widths." EPJ Web of Conferences 178 (2018): 05008. http://dx.doi.org/10.1051/epjconf/201817805008.

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We present an evidence of isospin effects in nuclear fission by comparing the fission widths for reactions involving different isospin states of the same compound nucleus (CN). Yadrovsky [1] suggested this possibility in 1975. Yadrovsky obtained the fission widths for two reaction data sets, namely 206Pb(α,f) and 209Bi(p,f), both leading to same CN, and concluded that “a nucleus remembers the isospin value of the nuclear states leading to fission”. We obtain the fission decay widths for both the T0 + ½ and T0 − ½ states of CN by using two appropriate reaction data sets. We then compare the fission widths for the two isospin states of CN. More specifically, we have chosen the combination of 206Pb(α,f) and 209Bi(p,f) same as presented in Yadrovsky’s paper [1] in this study. A significant difference between the ratios of fission decay widths to total decay widths for different isospin values suggests that isospin plays an important role in fission.

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9

DURGANANDINI, P. "SU(2) WZW THEORIES WITH HERMITIAN PERTURBATIONS." Modern Physics Letters A 06, no. 36 (November 30, 1991): 3349–58. http://dx.doi.org/10.1142/s0217732391003869.

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We show the existence of higher order conserved quantities of isospin 1 (with spin 0,2,4,6,…) and isospin 0,2 (with spin 1,3,5,7,…) for the k=2 SU(2) WZW theory perturbed by the singlet combination of the isospin 1 primary field. We also show the possible existence of conserved isospin 0 current with spin 3 in the k→∞ limit. We also analyze these theories for finite k(≥3) and show that at least by counting arguments there exist no higher conserved quantities in these cases.

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10

Liu, He, and Jun Xu. "Isospin Effect on Baryon and Charge Fluctuations from the pNJL Model." Universe 7, no. 1 (December 31, 2020): 6. http://dx.doi.org/10.3390/universe7010006.

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We have studied the possible isospin corrections on the skewness and kurtosis of net-baryon and net-charge fluctuations in the isospin asymmetric matter formed in relativistic heavy-ion collisions at RHIC-BES energies, based on a 3-flavor Polyakov-looped Nambu–Jona–Lasinio model. With typical scalar–isovector and vector–isovector couplings leading to the splitting of u and d quark chiral phase transition boundaries and critical points, we have observed considerable isospin effects on the susceptibilities, especially those of net-charge fluctuations. Reliable experimental measurements at even lower collision energies are encouraged to confirm the observed isospin effects.

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11

Al-Khudair, Falih H. "Investigation of isospin excited and mixed-symmetry states in even–even N = Z nuclei." International Journal of Modern Physics E 27, no. 08 (August 2018): 1850065. http://dx.doi.org/10.1142/s0218301318500659.

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Mixed-symmetry and isospin excited states are typical of the interacting boson model with isospin (IBM-3). With a view to look for such states, levels scheme of the IBM-3 dynamical symmetry is discussed. A systematic investigation in the proton and neutron degrees of freedom of the energy levels has been carried out. A sequence of isospin excitation bands has been identified. We have analyzed the wave functions and given the symmetrical labeling of the states. The transition probabilities between the isospin excitation states of model limits are analyzed in terms of isoscalar and isovector decompositions. The present calculations suggest that a combination of isospin excitation and mixed-symmetry states can provide substantial information on the structure of nuclear states. Calculations for [Formula: see text] and [Formula: see text] nuclei are presented and compared with the results of the shell model and available experimental data.

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12

BONNEAU, LUDOVIC, JULIEN LE BLOAS, PHILIPPE QUENTIN, JOHANN BARTEL, and DANIEL STROTTMAN. "ISOSPIN MIXING IN THE HIGHER TAMM-DANCOFF APPROXIMATION." International Journal of Modern Physics E 18, no. 04 (April 2009): 951–57. http://dx.doi.org/10.1142/s0218301309013099.

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We present a formalism to study the isospin content of a nuclear state in the framework of the Higher Tamm-Dancoff Approximation. This formalism is then applied to the description of even-even N = Z nuclei. Finally a schematic two-level model provides some insight into the isospin-mixing mechanism at work and the impact of the pairing correlations on the isospin-mixing parameter.

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13

Khunjua, Tamaz, Konstantin Klimenko, and Roman Zhokhov. "Dense quark matter with chiral and isospin imbalance: NJL-model consideration." EPJ Web of Conferences 191 (2018): 05015. http://dx.doi.org/10.1051/epjconf/201819105015.

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Isospin asymmetry is the well-known property of dense quark matter, which exists in the compact stars and is produced in heavy ion collisions. On the other hand, the chiral imbalance between left- and right- handed quarks is another highly anticipated phenomenon that could occur in the dense quark matter. To investigate quark matter under these conditions, we take into account baryon – μB, isospin – μI and chiral isospin – μI5 chemical potentials and study QCD phase portrait using NJL4 model generalized to two massive quarks that could condense into the pion condensation. We have shown that the chiral isospin chemical potential μI5 generates pion condensation in isospin asymmetric quark matter. Also, we have investigated discrete symmetry (duality) between chiral and pion condensates in the case of massless quarks, which stay relatively instructive even if the quarks have bare mass. To describe hot dense quark matter, in addition to the above-mentioned chemical potentials, we introduce non-zero temperatures into consideration.

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14

TRIPATHI, R., A. BONASERA, S. WUENSCHEL, L. W. MAY, Z. KOHLEY, P. MARINI, A. MCINTOSH, et al. "ROLE OF QUASIPROJECTILE ISOSPIN ASYMMETRY IN NUCLEAR FRAGMENTATION." International Journal of Modern Physics E 21, no. 03 (March 2012): 1250019. http://dx.doi.org/10.1142/s021830131250019x.

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Fragment yield data, selected with different values of the isospin asymmetry of the quasiprojectile from 78, 86 Kr +58, 64 Ni reactions at E lab = 35 MeV/nucleon, have been analyzed within the framework of Landau free energy approach. Fits to the free energy data indicated the system to be in the regime of a first-order phase transition. The plot of free energy versus isospin asymmetry of the fragments showed a systematic change with increasing isospin asymmetry of the fragmenting source. This observation demonstrated the role of quasiprojectile isospin asymmetry as an external field which governed the minima positions in the free energy plot. The position of the central minimum was found to be in close agreement with the average isospin asymmetry of the fragments calculated excluding neutrons and protons. Significant deviations from the free energy plot were observed for N = Z fragments, particularly for the lighter ones, which could be corrected after inclusion of odd–even effects in the analysis. Analysis of yield data of N = Z nuclei gave a reasonable estimate of temperature. Analysis of free energy data gated with excitation energy of the fragmenting source showed a dependence of fit parameters of Landau free energy equation on the excitation energy as well as isospin asymmetry of the source.

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15

He, Lianyi, Meng Jin, and Pengfei Zhuang. "Effect of UA(1) Breaking on Chiral Phase Structure and Pion Superfluidity at Finite Isospin Chemical Potential." Modern Physics Letters A 22, no. 07n10 (March 28, 2007): 637–43. http://dx.doi.org/10.1142/s0217732307023237.

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We investigate the isospin chemical potential effect in the frame of SU(2) Nambu-Jona-Lasinio model. When the isospin chemical potential is less than the vacuum pion mass, the phase structure with two chiral phase transition lines does not happen due to UA(1) breaking of QCD. When the isospin chemical potential is larger than the vacuum pion mass, the ground state of the system is a Bose-Einstein condensate of charged pions.

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16

SPEHLER, D., and G. C. MARQUES. "UNIFIED ELECTROWEAK MODEL BASED ON SPACE–TIME AND ISOSPIN SYMMETRIES." International Journal of Modern Physics A 20, no. 01 (January 10, 2005): 175–98. http://dx.doi.org/10.1142/s0217751x05019452.

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We propose a spinorial approach to the unified electroweak interactions, in which no use is made of spontaneous symmetry breakdown. No scalar particles are needed in order to break the symmetry. No reference is made to gauge symmetry. Our approach stresses the role of space–time and isospin symmetries in the build up of the electroweak model. Internal degrees of freedom, such as isospin, are incorporated in the theory by using spinors carrying isospin indices. All vector bosons are described by a rank 2 field in the spinorial and the isospinorial indices. Leptons are accomodated in a rank 1 spinor field and in a rank 2 isospin field as well. The dynamical variables of the theory are the chiral and isochiral components of these fields.

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17

SATUŁA, W., J. DOBACZEWSKI, W. NAZAREWICZ, M. BORUCKI, and M. RAFALSKI. "ISOSPIN MIXING IN THE VICINITY OF THE N = Z LINE." International Journal of Modern Physics E 20, no. 02 (February 2011): 244–51. http://dx.doi.org/10.1142/s0218301311017582.

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We present the isospin- and angular-momentum-projected nuclear density functional theory (DFT) and its applications to the isospin-breaking corrections to the superallowed β-decay rates in the vicinity of the N = Z line. A preliminary value obtained for the Cabibbo–Kobayashi–Maskawa matrix element, |Vud| = 0.97463(24), agrees well with the recent estimate by Towner and Hardy [Phys. Rev.C77, 025501 (2008)]. We also discuss new opportunities to study the symmetry energy by using the isospin-projected DFT.

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18

LIU, JIAN-YE, YONG ZHONG XING, HANG LIU, WEN-JUN GUO, and XI GUO LEE. "ENTRANCE CHANNEL EFFECTS ON THE ISOSPIN FRACTIONATION AT INTERMEDIATE ENERGY HEAVY ION COLLISIONS." International Journal of Modern Physics E 14, no. 04 (June 2005): 587–97. http://dx.doi.org/10.1142/s0218301305003430.

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We investigate the dependence of isospin fractionation degree on the entrance channel condition, which includes the impact parameter, the beam energy, the mass and the neutron–proton ratio of the colliding system as well as quantifying the gas phase and the liquid phase by using the isospin dependent quantum molecular dynamics model. We found that the isospin fractionation degree increases markedly with the enhancements of the neutron–proton ratio of system and the beam energy; however, it decreases with increasing system mass as well as slowly increases with the enhancement of the impact parameter. In particular, the property for the sensitive dependence of isospin fractionation degree on the symmetry potential and its weak dependence on the in-medium nucleon–nucleon cross-section is preserved for all the neutron-rich systems and all the impact parameters in the relative lower beam energy region. In this case, the isospin fractionation degree for all the neutron-rich systems can be directly compared with the experimental data to extract the information on the symmetry potential in the relative lower beam energy region.

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19

CHAKRABORTY, S., B. SAHOO, and S. SAHOO. "ISOSPIN DEPENDENCE OF THE SATURATION PROPERTIES OF ASYMMETRIC NUCLEAR MATTER IN NONRELATIVISTIC MEAN FIELD MODEL." International Journal of Modern Physics E 21, no. 09 (September 2012): 1250079. http://dx.doi.org/10.1142/s0218301312500796.

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A phenomenological momentum dependent interaction (MDI) is considered to describe the equation of state (EOS) for isospin asymmetric nuclear matter (ANM), where the density dependence of the nuclear symmetry is the basic input. In this interaction, the symmetry energy shows soft dependence of density. Within the nonrelativistic mean field approach we calculate the nuclear matter fourth-order symmetry energy E sym, 4 (ρ). Our result shows that the value of E sym, 4 (ρ) at normal nuclear matter density ρ0( = 0.161 fm -3) is less than 1 MeV conforming the empirical parabolic approximation to the EOS of ANM at ρ0. Then the higher-order effects of the isospin asymmetry on the saturation density ρ sat (β), binding energy per nucleon K sat (β) and isobaric incompressibility K sat (β) of ANM is being studied, where [Formula: see text] is the isospin asymmetry. We have found that the fourth-order isospin asymmetry β cannot be neglected, while calculating these quantities. Hence the second-order K sat , 2 parameter basically characterizes the isospin dependence of the incompressibility of ANM at saturation density.

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20

Lee, Bum-Hoon, Shahin Mamedov, and Chanyong Park. "Nucleon mass splitting in the isospin medium." International Journal of Modern Physics A 29, no. 29 (November 20, 2014): 1450170. http://dx.doi.org/10.1142/s0217751x1450170x.

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Using the AdS/CFT correspondence, we investigate a nucleon mass splitting and pion–nucleon coupling in the isospin medium. We find that there exists a nucleon mass splitting which is exactly given by the half of the meson mass splitting because nucleon has the half isospin charge of the charged mesons. In addition, we also investigate the pion–nucleon and four pion interactions which requires the modification of the known Abelian-type unitary gauge fixing because of the non-Abelian structure of the isospin medium. After finding the non-Abelian unitary gauge fixing, we find that in the isospin medium the couplings only for π0 π0 π+ π- and π0 π0π0 π0 of four pion interactions shift, while there is no pion–nucleon coupling splitting in spite of the nucleon's and meson's mass splittings.

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21

Selva, Giovanni, Xavier Roca-Maza, and Gianluca Colò. "Isospin Symmetry Breaking Effects on the Mass-Radius Relation of a Neutron Star." Symmetry 13, no. 1 (January 16, 2021): 144. http://dx.doi.org/10.3390/sym13010144.

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Isospin symmetry breaking effects on the mass-radius relation of a cold, non-accreting neutron star are studied on the basis of two Skyrme Energy Density Functionals (EDFs). One functional contains isospin symmetry breaking terms other than those typically included in Skyrme EDFs while its counterpart is of standard form. Both functionals are based on the same fitting protocol except for the observables and pseudo-observables sensitive to the isospin symmetry breaking channel. The quality of those functionals is similar in the description of terrestrial observables but choosing either of them has a non-negligible effect on the mass-radius relation and tidal deformability of a neutron star. Further investigations are needed to clarify the effects of isospin symmetry breaking on these and other observables of neutron stars that are, and will become, available.

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22

Di Toro, M., S. J. Yennello, and B. A. Li. "Isospin flows." European Physical Journal A 30, no. 1 (October 2006): 153–63. http://dx.doi.org/10.1140/epja/i2006-10113-x.

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23

Balachandran, A. P., B. Rai, G. Sparano, and A. M. Srivastava. "Isospin balls." Physical Review Letters 59, no. 8 (August 24, 1987): 853–56. http://dx.doi.org/10.1103/physrevlett.59.853.

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24

Bijnens, Johan, and Fredrik Borg. "Isospin breaking in decays I: strong isospin breaking." Nuclear Physics B 697, no. 1-2 (October 2004): 319–42. http://dx.doi.org/10.1016/j.nuclphysb.2004.07.011.

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25

Nayak, Ranjit. "Kaon Isospin Fluctuations in ALICE at the LHC." Proceedings 10, no. 1 (April 12, 2019): 22. http://dx.doi.org/10.3390/proceedings2019010022.

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The first measurements of isospin fluctuations in the kaon sector is presented in Pb-Pb collisions at s N N = 2.76 TeV. A robust statistical observable was used to extract the isospin fluctuations of neutral and charged kaons as a function of collision centrality. The results show a significant variation in the behaviour of ν d y n in data when compared to Monte-Carlo models such as HIJING and AMPT. The deviation from 1/n scaling in data indicates possible isospin fluctuation in the kaon sector in heavy ion collisions.

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26

Gaitanos, T., G. Ferini, M. Colonna, M. Di Toro, and H. H. Wolter. "Isospin Effects on Subthreshold Particle Production." HNPS Proceedings 14 (December 5, 2019): 7. http://dx.doi.org/10.12681/hnps.2240.

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The production/absorption rate of particles in compressed and heated asymmetric matter is studied using a Relativistic Mean Field (RMF) transport model with an isospin dependent collision term. We show that the K+/K° ratio reflects the isospin effects on the production rates just because of the large sensitivity around the threshold. The results are very promising with respect to the possibility of a direct link between particle production data in exotic Heavy Ion Collisions (HIC) and the isospin dependent part of the Equation of State (EoS) at high baryon densities.

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27

DMITRAŠINOVIĆ, V., KEITARO NAGATA, and ATSUSHI HOSAKA. "CHIRAL PROPERTIES OF BARYON INTERPOLATING FIELDS." Modern Physics Letters A 23, no. 27n30 (September 30, 2008): 2381–84. http://dx.doi.org/10.1142/s0217732308029423.

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We study the chiral transformation properties of all possible local (non-derivative) interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We derive and use the relations/identities among the baryon operators with identical quantum numbers that follow from the combined color, Dirac and isospin Fierz transformations. These relations reduce the number of independent baryon operators with any given spin and isospin. The Fierz identities also effectively restrict allowed baryon chiral multiplets. It turns out that the chiral multiplets of the baryons are equivalent to their Lorentz representation.

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28

Lü, Gang, and Qin-Qin Zhi. "Direct CP Violation from Isospin Symmetry Breaking Effects for the Decay Process B-s→P(V)π0 in PQCD." Advances in High Energy Physics 2019 (May 21, 2019): 1–14. http://dx.doi.org/10.1155/2019/6927130.

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We investigate the direct CP violation for the decay process of B-s→P(V)π0 (P,V refer to the pseudoscalar meson and vector meson, resp.) via isospin symmetry breaking effects from the π0-η-η′ mixing mechanism in PQCD factorization approach. Isospin symmetry breaking arises from the electroweak interaction and the u-d quark mass difference by the strong interaction, which are known to be tiny. However, we find that isospin symmetry breaking at the leading order shifts the CP violation due to the new strong phases.

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29

HANHART, CHRISTOPH. "ISOSPIN BREAKING IN HADRONIC REACTIONS." International Journal of Modern Physics A 20, no. 02n03 (January 30, 2005): 543–45. http://dx.doi.org/10.1142/s0217751x05021737.

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In the standard model the isospin symmetry is broken by electro magnetic interactions as well as the difference in the quark masses. Given a systematic scheme that allows to disentangle these two effects it is possible to get direct access to properties of QCD from low and medium energy hadronic reactions. Recently interest in isospin breaking reactions has revived due to the measurement of a forward–backward asymmetry in pn→dπ0 as well as the total cross section for dd→απ0—both quantities vanish in an isospin symmetric world. The current status of the theoretical analysis for these reactions is disucssed. In addition, I will briefly discuss how the isospin violating a0(980)-f0(980) transition amplitude can be studied in dd and pn induced production reactions—a quantity that is believed to reveal important information on the nature of these lightest scalar mesons.

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30

Quinonez, Michael, Arun Kingan, and Larry Zamick. "Manifestations of isospin in nearest neighbor spacing distributions for the f-p model space." International Journal of Modern Physics E 26, no. 10 (October 2017): 1750060. http://dx.doi.org/10.1142/s0218301317500604.

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The strong interactions are charge independent. If we limit ourselves to the strong interactions, we have the isospin [Formula: see text] as a good quantum number. Here, we consider the lack of level repulsion of states of different isospin and how this effect manifests in nearest neighbor spacing (NNS) histograms, which provide a visual and statistical context in which to study distributions of energy level spacings. In particular, we study nucleons in the [Formula: see text] model space for the nucleus [Formula: see text]. We also compare NNS distributions produced in the isospin formalism to distributions produced in the proton–neutron formalism.

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31

YOSHIKAWA, TADASHI. "THE VERTEX CORRECTIONS IN TECHNICOLOR MODEL WITHOUT EXACT CUSTODIAL SYMMETRY." Modern Physics Letters A 10, no. 22 (July 20, 1995): 1601–12. http://dx.doi.org/10.1142/s0217732395001721.

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We discuss the effects of isospin breaking which appear in the vertex corrections for [Formula: see text], Zτ+τ− and Wντ in a one-family technicolor model without exact custodial symmetry. By means of the effective Lagrangian approach we compute the vertex corrections for [Formula: see text], Zττ and Wτν. When the isospin symmetry in technilepton sector is not exact and there are a few lighter technivector mesons that are composed by technileptons, the technivector mesons contribute to the vertex corrections. It would be the evidence of the isospin breaking when the difference of the vertex corrections between Zττ and Wτν is measured.

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32

SALEHI, NASRIN, and ALI AKBAR RAJABI. "PROTON STATIC PROPERTIES BY USING HYPERCENTRAL CONSTITUENT QUARK MODEL AND ISOSPIN." Modern Physics Letters A 24, no. 32 (October 20, 2009): 2631–37. http://dx.doi.org/10.1142/s0217732309031016.

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The static properties of protons are useful for understanding the quark structure of the proton. In his work we have introduced the hypercentral constituent quark model and isospin dependent potentials. Here constituent quarks interact with each other via a potential in which we have taken into account the three-body force effect and the standard two-body potential contributions. According to our model the static properties of protons containing u and d quarks are better than the other models and closer to experimental results. The two key ingredients of this improvement are the effective quark–gluon hypercentral potentials, and hyperfine interaction and isospin dependence potential. Recently, Schrödinger equation has been solved by Giannini but we have solved the Dirac equation exact analytically and we have shown that a considerable improvement in the description of the static properties of proton is obtained with an isospin dependent potential and the complete interaction including spin and isospin terms reproduces the position of the quark.

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33

Yang, Li, and Xin-Jian Wen. "Asymmetric magnetized QCD matter realized by scalar and instanton-induced interactions." International Journal of Modern Physics A 33, no. 21 (July 30, 2018): 1850123. http://dx.doi.org/10.1142/s0217751x18501233.

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In a strong magnetic field utilizing a two-flavor NJL model, the isospin symmetry and asymmetry can be realized by altering the fraction parameter [Formula: see text] of the two kinds of interactions, i.e. the scalar coupling and instanton-induced coupling. As [Formula: see text] increases, the [Formula: see text] quark mass decreases while [Formula: see text] quark mass increases monotonously. The two mass lines cross at [Formula: see text] with an isospin symmetry mass [Formula: see text]. Even in the flavor-decoupled state, i.e. the strong isospin asymmetry, the [Formula: see text] and [Formula: see text] mass lines can have a common mass at a critical temperature [Formula: see text]. As the magnetic field becomes stronger, the [Formula: see text] will move towards the chiral restoration phase. The strong isospin asymmetry will lead to a split of the pseudocritical temperatures for [Formula: see text] and [Formula: see text] quarks, which can be reflected by the two peaks of the specific heat and sound velocity.

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34

OH, PHILLIAL. "SYMPLECTIC STRUCTURE OF ISOSPIN PARTICLES IN YANG-MILLS FIELDS." Modern Physics Letters A 07, no. 21 (July 10, 1992): 1923–30. http://dx.doi.org/10.1142/s0217732392001634.

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Using Dirac’s constraint analysis, we explore the Hamiltonian formalism of isospin particles in external Yang-Mills fields without kinetic and potential energy term. We consider an example of isospin particle in ’t Hooft-Polyakov magnetic monopole field and discuss possible quantization condition of magnetic charge in terms of geometric quantization.

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35

LE BLOAS, JULIEN, LUDOVIC BONNEAU, PHILIPPE QUENTIN, JOHANN BARTEL, and DANIEL STROTTMAN. "EFFECTS OF VIBRATIONAL AND PAIRING CORRELATIONS ON ISOSPIN MIXING IN THE HIGHER TAMM-DANCOFF APPROXIMATION." International Journal of Modern Physics E 19, no. 04 (April 2010): 568–74. http://dx.doi.org/10.1142/s0218301310014984.

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In the framework of the Higher Tamm-Dancoff Approximation which allows for a consistent treatment of pairing and quadrupole vibrational correlations preserving the particle-number symmetry and the Pauli principle, we compare the isospin content of ground and excited Kπ = 0+ states including either type of the above mentioned correlations using an approximate projection-after-variation technique for isospin. The pairing correlations are described with a delta interaction using the same strength in the T = 0 and T = 1 channels, whereas the vibrational correlations are treated with an isoscalar quadrupole-quadrupole interaction. As a first study, we apply this approach in the N = Z, even-even 16 O nucleus. For the same amount of correlations measured by the diffusivity of Fermi surface or depletion of particle-hole vacuum in the ground-state solution, we find very similar isospin mixing in the ground state for both types of correlations, but different patterns for the distribution in the calculated solutions of the expectation value of the square of the isospin operator.

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36

Del Nobile, Eugenio. "Halo-Independent Comparison of Direct Dark Matter Detection Data." Advances in High Energy Physics 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/604914.

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We review the halo-independent formalism that allows comparing data from different direct dark matter detection experiments without making assumptions on the properties of the dark matter halo. We apply this method to spin-independent WIMP-nuclei interactions, for both isospin-conserving and isospin-violating couplings, and to WIMPs interacting through an anomalous magnetic moment.

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37

TAKAISHI, TETSUYA. "DENSITY OF STATES METHOD AT FINITE ISOSPIN DENSITY." Modern Physics Letters A 19, no. 12 (April 20, 2004): 909–20. http://dx.doi.org/10.1142/s0217732304013805.

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The density of states method is applied for lattice QCD at a finite isospin density. The advantage of this method is that one can easily obtain results for various values of parameters (quark mass, coupling constant and the number of flavors). We compare results for the chiral condensate and the quark number density with those from the R-algorithm and find that they are in good agreement. By calculating the chiral condensate we obtain information on the phase structure for various quark flavors and isospin chemical potentials. We also show results for the chiral condensate at two different quark masses and at two different isospin densities which are not easily obtainable in the conventional Monte Carlo method.

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38

Moosavi Nejad, S. M., and A. Armat. "Determination of hyperon properties through the variational method considering the hyperfine interaction." International Journal of Modern Physics E 28, no. 10 (October 2019): 1950087. http://dx.doi.org/10.1142/s0218301319500873.

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Performing a fit procedure on the hyperon masses, we first determine the free parameters in the Cornell-like hypercentral potential between the constituent quarks of hyperons in their ground state. To this end, using the variational principle, we apply the hyperspherical Hamiltonian including the Cornell-like hypercentral potential and the perturbation potentials due to the spin–spin, spin–isospin and isospin–isospin interactions between constituent quarks. In the following, we compute the hyperon magnetic moments as well as radiative decay widths of spin-3/2 hyperons using the spin-flavor wave function of hyperons. Our analysis shows acceptable consistencies between theoretical results and available experimental data. This leads to reliable wave functions for hyperons at their ground state.

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39

Bayar, M., and V. R. Debastiani. "a0(980)–f0(980) mixing in χc1 decay." EPJ Web of Conferences 199 (2019): 04009. http://dx.doi.org/10.1051/epjconf/201919904009.

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We investigate the isospin breaking in the ${\chi _{c1}} \to {\pi ^0}{\pi ^ + }{\pi ^ - }$ and ${\chi _{c1}} \to {\pi ^0}{\pi ^0}\eta $ decays and its relation to the a0(980) – f0(980) mixing, which was measured by the BESIII Collaboration. The isospin violation is introduced through the use of different masses for the charged and neutral kaons, either in the propagators of pairs of mesons created in the χc1 decay, or in the propagators inside the T matrix. We find that the most important effect in the total amplitude is the isospin breaking inside the T matrix which is essential to get a good agreement with the experimental measurement of the mixing.

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40

JI, XIAOBIN. "N* PRODUCTION FROM J/ψ DECAYS AT BES." International Journal of Modern Physics A 20, no. 08n09 (April 10, 2005): 1834–37. http://dx.doi.org/10.1142/s0217751x05023438.

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The πN system in [Formula: see text] is limited to be pure isospin 1/2 due to isospin conservation. This is a big advantage in studying N*→πN from the J/ψ decays, compared with πN and γN experiments which mix isospin 1/2 and 3/2 for πN system. Based on the 58 million J/ψ data collected at the Beijing Electron Positron Collider, [Formula: see text] and other decay channels are analyzed. In the decay [Formula: see text], three peaks show up very clearly at 1400 MeV/c2, 1500 MeV/c2 and 1670 MeV/c2 in the πN invariant mass spectrum with additional peak around 2030 MeV/c2 which may be caused by a new N* resonance.

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41

Achasov, N. N., and G. N. Shestakov. "New information on the strong isospin symmetry breaking in the reactions of the a00(980) and f0(980) resonance production." EPJ Web of Conferences 212 (2019): 03002. http://dx.doi.org/10.1051/epjconf/201921203002.

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We discuss the isotopic symmetry breaking as a tool of studying the production mechanisms and nature of light scalar mesons. The anomalous isospin breaking effects can appear not only due to the $ a_0^0(980) - {f_0}(980) $ mixing, but also for any mechanism of the production of the $ \bar{K} $ pairs with a definite isospin in the S wave.

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42

LIU, J. Y., HUAN FENG HAO, YONG ZHONG XING, WEI ZUO, and XI GUO LEE. "INFLUENCES OF THE ISOSPIN-DEPENDENCE OF IN-MEDIUM NUCLEON–NUCLEON CROSS-SECTION AND MOMENTUM DEPENDENT INTERACTION ON ISOSCALING PARAMETER." International Journal of Modern Physics E 17, no. 04 (April 2008): 645–53. http://dx.doi.org/10.1142/s0218301308010052.

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Influences of the isospin-dependent in-medium nucleon–nucleon cross-section [Formula: see text] and momentum-dependent interaction (MDI) on the isoscaling parameter α are investigated for two central collisions 40 Ca + 40 Ca and 60 Ca + 60 Ca . These collisions are with isospin dependent quantum molecular dynamics in the beam energy region from 40 to 60 MeV/nucleon. The isotope yield ratio R21(N, Z) for the above two central collisions depends exponentially on the neutron number N and proton number Z of isotopes, with an isoscaling. In particular, the isospin-dependent [Formula: see text] and MDI induce an obvious decrease of the isoscaling parameter α. The mechanism of the decreases of α by both [Formula: see text] and MDI are studied respectively.

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43

Nurmukhamedov, A. M. "The restoration of Wigner’s SU(4)-symmetry in the superheavy nucleus and its correlation with the problem “island of stability”, or does the “island of stability” exist?" Modern Physics Letters A 31, no. 27 (August 28, 2016): 1650145. http://dx.doi.org/10.1142/s0217732316501455.

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This paper reviews the history and stages of experimental verification of the hypothesis of Wigner’s spin–isospin SU(4)-symmetry restoration in the field of heavy atomic nuclei and its implications on hypothesis of the “island of stability”. Energies of [Formula: see text]-decay of a number of [Formula: see text]-chains of new superheavy nuclei were calculated based on Wigner’s mass formula without contribution of spin–orbit interaction that correspond to the restoration of Wigner’s spin–isospin symmetry. Calculated energies of the [Formula: see text]-decay fit the experimental data better than other theoretical approaches. It is concluded that there is a need to continue theoretical research of the “island of stability” taking into account mechanisms of restoration of Wigner’s spin–isospin SU(4)-symmetry.

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44

Lam, Yi Hua, and Nadezda A. Smirnova. "Isospin Non-Conservation in Shell Model Approach and Applications*." EPJ Web of Conferences 178 (2018): 05006. http://dx.doi.org/10.1051/epjconf/201817805006.

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Up to now, empirical shell-model Hamiltonians for valence space calculations provide the most accurate description of the low-energy spectra and individual transitions of sd- and pf-shell nuclei. These features made them of particular importance for the description of the isospin-symmetry-breaking phenomena, such as energy splitting of the isobaric multiplets or isospin-forbidden transition rates. In this contribution, we demonstrate the applications of a recently constructed isospin non-conserving (INC) Hamiltonian in sd shell [Lam et al. Phys. Rev. C 87, 054304 (2013)]. First, we explore the partial decay scheme of 24Si and discuss the states affected by the Thomas-Ehrman shift. Second, we show the accuracy of the INC Hamiltonian for the description of the mirror energy differences.

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45

XU, JUN, LIE-WEN CHEN, BAO-AN LI, and HONG-RU MA. "ISOSPIN AND MOMENTUM DEPENDENCE OF LIQUID-GAS PHASE TRANSITION IN HOT ASYMMETRIC NUCLEAR MATTER." International Journal of Modern Physics E 17, no. 09 (October 2008): 1917–26. http://dx.doi.org/10.1142/s0218301308010891.

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The liquid-gas phase transition in hot neutron-rich nuclear matter is investigated within a self-consistent thermal model using different interactions with or without isospin and/or momentum dependence. The boundary of the phase-coexistence region is shown to be sensitive to the density dependence of the nuclear symmetry energy as well as the isospin and momentum dependence of the nuclear interaction.

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46

Gomes, J. F., G. M. Sotkov, and A. H. Zimerman. "Solitons with isospin." Nuclear Physics B 714, no. 3 (May 2005): 179–216. http://dx.doi.org/10.1016/j.nuclphysb.2005.02.024.

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47

Dabrowski, J. "Isospin oscillations inΣ12C." Journal of Physics G: Nuclear Physics 13, no. 4 (April 1987): L45—L49. http://dx.doi.org/10.1088/0305-4616/13/4/003.

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48

Mirkes, E., and R. Urech. "Isospin violation in." European Physical Journal C 1, no. 1 (1998): 201. http://dx.doi.org/10.1007/s100520050073.

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49

Gaarde, Carl. "Spin-isospin excitations." Nuclear Physics A 507, no. 1 (January 1990): 79–98. http://dx.doi.org/10.1016/0375-9474(90)90570-c.

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50

MESQUITA, A., M. RAZEIRA, C. A. Z. VASCONCELLOS, and F. FERNÁNDEZ. "THE ROLE OF ANTIKAON CONDENSATES IN THE ISOSPIN ASYMMETRY OF NEUTRON STARS." International Journal of Modern Physics D 19, no. 08n10 (August 2010): 1553–56. http://dx.doi.org/10.1142/s0218271810017688.

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We study the effects of the scalar-isovector light mesons on the isospin asymmetry and phase transition of hadronic matter to hadronic matter with a condensate of antikaons, using an effective model with derivative couplings. In our formalism, nucleons interact through the exchange of σ, ω, ϱ, δ, and ς mesons in the presence of electrons and muons to accomplish electric charge neutrality and beta equilibrium. The phase transition to the antikaons condensate was implemented through the Gibbs conditions combined with the mean-field approximation, giving rise to a mixed phase of coexistence between nucleon matter and the condensed antikaons. As expected, our results indicate that the scalar-isovector mesons increase the range of the mixed phase–space, they operate for restoring isospin symmetry and they reduce the value of the effective nucleon mass, independently of the depth of the optical potential for antikaons. Also as expected the increase of the depth of optical potential favors the population of antikaons. Our results predict the density threshold of birth of the K-antikaons. The most expressive result of our calculation is the abrupt change in the isospin asymmetry due to the presence of the condensate. Moreover, we have found that scalar-isovector mesons increase the fraction of protons and reduced the fraction of neutrons in the system, since these mesons couple with the conserved isovector current of baryons and thus the minimum in the energy of the system corresponds to saturated isospin states (symmetric in isospin). Finally, we have found as expected that these mesons produce the stiffness of the EoS.

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