Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Two low-lying unbound states in <jats:sup>16</jats:sup>C are investigated by deuteron inelastic scattering in inverse kinematics. Besides the 2 <jats:inline-formula> <jats:tex-math><?CDATA $ ^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054001_M1.jpg" xlink:type="simple" /> </jats:inline-formula> state at 5.45 MeV previously measured in a 1<jats:italic>n</jats:italic> knockout reaction, a new resonant state at 6.89 MeV is observed for the first time. The inelastic scattering angular distributions of these two states are well reproduced by the distorted-wave Born approximation (DWBA) calculation with an <jats:italic>l</jats:italic> = 1 excitation. In addition, the spin-parities of the unbound states are discussed and tentatively assigned based on shell model calculations using the modified YSOX interaction. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The cross sections of the <jats:sup>121</jats:sup>Sb <jats:inline-formula> <jats:tex-math><?CDATA $ (n, 2n) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M1.jpg" xlink:type="simple" /> </jats:inline-formula> <jats:sup>120</jats:sup>Sb<jats:sup>m</jats:sup> and <jats:sup>123</jats:sup>Sb <jats:inline-formula> <jats:tex-math><?CDATA $ (n, 2n) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M2.jpg" xlink:type="simple" /> </jats:inline-formula> <jats:sup>122</jats:sup>Sb reactions were measured at 12.50, 15.79 and 18.87 MeV neutron energies relative to the standard <jats:sup>27</jats:sup>Al <jats:inline-formula> <jats:tex-math><?CDATA $ (n,\alpha ) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M3.jpg" xlink:type="simple" /> </jats:inline-formula> <jats:sup>24</jats:sup>Na monitor reaction using neutron activation and offline γ-ray spectrometry. Irradiation of the samples was performed at the BARC-TIFR Pelletron Linac Facility, Mumbai, India. The quasi-monoenergetic neutrons were generated via the <jats:sup>7</jats:sup>Li <jats:inline-formula> <jats:tex-math><?CDATA $ (p,n) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M4.jpg" xlink:type="simple" /> </jats:inline-formula> reaction. Statistical model calculations were performed by nuclear reaction codes TALYS (ver. 1.9) and EMPIRE (ver. 3.2.2) using various input parameters and nuclear level density models. The cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV energies. The effect of pre-equilibrium emission is also discussed in detail using different theoretical models. The present measured cross sections were discussed and compared with the reported experimental data and evaluation data of the JEFF-3.3, ENDF/B-VIII.0, JENDL/AD-2017 and TENDL-2019 libraries. A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis method. Furthermore, a systematic study of the <jats:inline-formula> <jats:tex-math><?CDATA $ (n, 2n) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M5.jpg" xlink:type="simple" /> </jats:inline-formula> reaction cross section for <jats:sup>121</jats:sup>Sb and <jats:sup>123</jats:sup>Sb isotopes was also performed within 14–15 MeV neutron energies using various systematic formulae. This work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in the <jats:inline-formula> <jats:tex-math><?CDATA $ (n, 2n) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054002_M6.jpg" xlink:type="simple" /> </jats:inline-formula> reaction channel. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>New cross sections of the <jats:sup>183</jats:sup>W(<jats:italic>n,α</jats:italic>)<jats:sup>180m</jats:sup>Hf, <jats:sup>186</jats:sup>W(<jats:italic>n,d</jats:italic>*)<jats:sup>185</jats:sup>Ta, <jats:sup>182</jats:sup>W(<jats:italic>n,p</jats:italic>)<jats:sup>182</jats:sup>Ta, <jats:sup>184</jats:sup>W(<jats:italic>n,p</jats:italic>)<jats:sup>184</jats:sup>Ta, <jats:sup>182</jats:sup>W(<jats:italic>n</jats:italic>,2<jats:italic>n</jats:italic>)<jats:sup>181</jats:sup>W, <jats:sup>184</jats:sup>W(<jats:italic>n</jats:italic>,<jats:italic>α</jats:italic>)<jats:sup>181</jats:sup>Hf, and <jats:sup>186</jats:sup>W(<jats:italic>n</jats:italic>,<jats:italic>α</jats:italic>)<jats:sup>183</jats:sup>Hf reactions were measured in the neutron energy range of 13.5-14.8 MeV via the activation technique to improve the database and resolve discrepancies. Monoenergetic neutrons in this energy range were produced via the T(<jats:italic>d</jats:italic>,<jats:italic>n</jats:italic>)<jats:sup>4</jats:sup>He reaction on a solid Ti-T target. The activities of the irradiated monitor foils and samples were measured using a well-calibrated high-resolution HPGe detector. Theoretical calculations of the excitation functions of the seven nuclear reactions mentioned above in the neutron energies from the threshold to 20 MeV were performed using the nuclear theoretical model program TALYS-1.9 to aid new evaluations of cross sections on tungsten isotopes. The experimental data obtained were analyzed and compared with that of previous experiments conducted by other researchers, and with the evaluated data available in the five major evaluated nuclear data libraries of IAEA (namely ENDF/B-VIII.0 or ENDF/B-VII.0, JEFF-3.3, JENDL-4.0u+, CENDL-3.2, and BROND-3.1 or ROSFOND-2010), and the theoretical values acquired using TALYS-1.9 nuclear-reaction modeling tools. The new cross section measurements agree with those of some recent experiments and theoretical excitation curves at the corresponding energies. The consistency of the theoretical excitation curves based on TALYS-1.9 with these experimental data is better than that of the evaluated curves available in the five major nuclear data libraries of IAEA. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We apply the recently proposed RMF (BCS)* ansatz to study the charge radii of the potassium isotopic chain up to <jats:sup>52</jats:sup>K. It is shown that the experimental data can be reproduced rather well, qualitatively similar to the Fayans nuclear density functional theory, but with a slightly better description of the odd–even staggerings (OES). Nonetheless, both methods fail for <jats:sup>50</jats:sup>K and to a lesser extent for <jats:sup>48,52</jats:sup>K. It is shown that if these nuclei are deformed with a <jats:inline-formula> <jats:tex-math><?CDATA $ \beta_{20}\approx-0.2 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054101_M1.jpg" xlink:type="simple" /> </jats:inline-formula>, then one can obtain results consistent with experiments for both charge radii and spin-parities. We argue that beyond-mean-field studies are needed to properly describe the charge radii of these three nuclei, particularly for <jats:sup>50</jats:sup>K. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The generalized liquid-drop model (GLDM) with the microscopic shell correction from relativistic Hartree-Fock (RHF) calculations is used to explore the <jats:italic>α</jats:italic>-decay of superheavy nuclei. The known nuclei with <jats:inline-formula> <jats:tex-math><?CDATA $ Z = 106-118 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M2.jpg" xlink:type="simple" /> </jats:inline-formula> are chosen as examples for testing. The calculated half-lives of <jats:italic>α</jats:italic>-decay agree with the experimental data better than those from the GLDM with the shell correction in the Weizs <jats:inline-formula> <jats:tex-math><?CDATA $ {\rm {\ddot{a}}} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M3.jpg" xlink:type="simple" /> </jats:inline-formula>cker-Skyrme model. Moreover, the influence of the decay energy <jats:inline-formula> <jats:tex-math><?CDATA $ Q_{\alpha} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M4.jpg" xlink:type="simple" /> </jats:inline-formula> on <jats:italic>α</jats:italic>-decay is investigated. It is determined that the <jats:inline-formula> <jats:tex-math><?CDATA $ Q_{\alpha} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M5.jpg" xlink:type="simple" /> </jats:inline-formula> values obtained from the WS4 model with radial basis function (RBF) correction match the experimental data optimally. Owing to these advantages, the GLDM with the RHF shell correction and WS4+RBF <jats:inline-formula> <jats:tex-math><?CDATA $ Q_{\alpha} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M6.jpg" xlink:type="simple" /> </jats:inline-formula> values is adopted to predict the <jats:italic>α</jats:italic>-decay lifetime for the unknown superheavy nuclei with <jats:inline-formula> <jats:tex-math><?CDATA $ Z = 118-120 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M7.jpg" xlink:type="simple" /> </jats:inline-formula>. The trend of the available <jats:italic>α</jats:italic>-decay half-lives according to the neutron number is similar to the trends of the values from the GLDM calculation without shell correction as well as the universal decay law (UDL) formula. Comparably, the RHF shell correction depresses (raises) the <jats:italic>α</jats:italic>-decay lifetime for most nuclei with <jats:inline-formula> <jats:tex-math><?CDATA $ N \lt 186 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M8.jpg" xlink:type="simple" /> </jats:inline-formula> ( <jats:inline-formula> <jats:tex-math><?CDATA $ N\gt,186 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M9.jpg" xlink:type="simple" /> </jats:inline-formula>). In comparison with the half-lives of spontaneous fission, it can be concluded that the <jats:italic>α</jats:italic>-decay is dominant in the superheavy nuclei <jats:inline-formula> <jats:tex-math><?CDATA $ ^{281-304}118 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M10.jpg" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{284-306}119 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M11.jpg" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math><?CDATA $ ^{287-308}120 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054102_M12.jpg" xlink:type="simple" /> </jats:inline-formula>. These results are beneficial to the exploration of superheavy nuclei in experiments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Inspired by the recent observation of a very narrow state, called <jats:inline-formula> <jats:tex-math><?CDATA $ T_{cc}^+ $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M3.jpg" xlink:type="simple" /> </jats:inline-formula>, by the LHCb collaboration, the possible bound states and low-lying resonance states of the doubly-heavy tetraquark states <jats:inline-formula> <jats:tex-math><?CDATA $ cc\bar{u}\bar{d} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M4.jpg" xlink:type="simple" /> </jats:inline-formula> ( <jats:inline-formula> <jats:tex-math><?CDATA $ T_{cc} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M5.jpg" xlink:type="simple" /> </jats:inline-formula>) and <jats:inline-formula> <jats:tex-math><?CDATA $ bb\bar{u}\bar{d} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M6.jpg" xlink:type="simple" /> </jats:inline-formula> ( <jats:inline-formula> <jats:tex-math><?CDATA $ T_{bb} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M7.jpg" xlink:type="simple" /> </jats:inline-formula>) are searched in the framework of a chiral quark model with an accurate few-body method, the Gaussian expansion method. The real scaling method is also applied to identify the genuine resonance states. In the calculation, the meson–meson structure, diquark–antidiquark structure, and their coupling are all considered. The numerical results show: (i) For <jats:inline-formula> <jats:tex-math><?CDATA $ T_{cc} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M8.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ T_{bb} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M9.jpg" xlink:type="simple" /> </jats:inline-formula>, only <jats:inline-formula> <jats:tex-math><?CDATA $ I(J^P) = 0(1^+) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M10.jpg" xlink:type="simple" /> </jats:inline-formula> states are bound in different quark structures. The binding energy varies from a few MeV for the meson–meson structure to over 100 MeV for the diquark–antidiquark structure. For example, for <jats:inline-formula> <jats:tex-math><?CDATA $ T_{cc} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M11.jpg" xlink:type="simple" /> </jats:inline-formula>, in the meson–meson structure, there exists a weakly bound molecule <jats:inline-formula> <jats:tex-math><?CDATA $ DD^* $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M12.jpg" xlink:type="simple" /> </jats:inline-formula> state around 3841.4 MeV, 1.8 MeV below the <jats:inline-formula> <jats:tex-math><?CDATA $ D^0D^{*+} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M13.jpg" xlink:type="simple" /> </jats:inline-formula>, which may be a good candidate for the observed state by LHCb; however in the diquark–antidiquark structure, a deeper bound state with mass 3700.9 MeV is obtained. When considering the structure mixing, the energy of system decreases to 3660.7 MeV and the shallow bound state disappears. (ii) Besides bound states, several resonance states for <jats:inline-formula> <jats:tex-math><?CDATA $ T_{QQ}(Q = c, b) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M14.jpg" xlink:type="simple" /> </jats:inline-formula> with <jats:inline-formula> <jats:tex-math><?CDATA $ I(J^P) = 1(0^+), 1(1^+), 1(2^+), 0(1^+) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054103_M15.jpg" xlink:type="simple" /> </jats:inline-formula> are proposed. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Balitsky-Kovchegov equations in projectile and target rapidity representations are analytically solved for fixed and running coupling cases in the saturation domain. Interestingly, we find that the respective analytic <jats:italic>S</jats:italic>-matrices in the two rapidity representations have almost the same rapidity dependence in the exponent in the running coupling case, which provides a method to explain why the equally good fits to HERA data were obtained when using three different Balitsky-Kovchegov equations formulated in the two representations. To test the analytic outcomes, we solve the Balitsky-Kovchegov equations and numerically compute the ratios between these dipole amplitudes in the saturation region. The ratios are close to one, which confirms the analytic results. Moreover, the running coupling, collinearly-improved, and extended full collinearly-improved Balitsky-Kovchegov equations are used to fit the HERA data. We find that all of them provide high quality descriptions of the data, and the <jats:inline-formula> <jats:tex-math><?CDATA $ \chi^2/\mathrm{d.o.f} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054104_M1.jpg" xlink:type="simple" /> </jats:inline-formula> obtained from the fits are similar. Both the analytic and numerical calculations imply that the Balitsky-Kovchegov equation at the running coupling level is robust and has a sufficiently strong predictive power at HERA energies; however, higher order corrections could be significant for future experiments, such as those at the EIC or LHeC. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Naturally occurring <jats:italic>α</jats:italic> emitters with extremely long half-lives are investigated using the latest experimental data. Within the time-dependent perturbation theory, <jats:italic>α</jats:italic> decay with a rather narrow width is treated as a quasi-stationary problem by dividing the potential between the <jats:italic>α</jats:italic> particle and daughter nucleus into a stationary part and a perturbation. The experimental <jats:italic>α</jats:italic> decay half-lives of seven available long-lived <jats:italic>α</jats:italic> emitters with <jats:inline-formula> <jats:tex-math><?CDATA $ T^{\rm{total}}_{1/2} \gt, 10^{14} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M1.jpg" xlink:type="simple" /> </jats:inline-formula> y are reproduced with a good accuracy. It is also found that the deformation effect should be treated carefully for long-lived nuclei, especially with low <jats:inline-formula> <jats:tex-math><?CDATA $ Q_\alpha $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M2.jpg" xlink:type="simple" /> </jats:inline-formula> values. Predictions of the <jats:italic>α</jats:italic> decay half-lives of twenty naturally occurring nuclei are provided, namely, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{142} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M3.jpg" xlink:type="simple" /> </jats:inline-formula>Ce, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{145,146} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M4.jpg" xlink:type="simple" /> </jats:inline-formula>Nd, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{149} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M5.jpg" xlink:type="simple" /> </jats:inline-formula>Sm, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{156} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M6.jpg" xlink:type="simple" /> </jats:inline-formula>Dy, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{162,164} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M7.jpg" xlink:type="simple" /> </jats:inline-formula>Er, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{168} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M8.jpg" xlink:type="simple" /> </jats:inline-formula>Yb, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{182,183,184,186} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M9.jpg" xlink:type="simple" /> </jats:inline-formula>W, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{187,188,189,190} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M10.jpg" xlink:type="simple" /> </jats:inline-formula>Os, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{192,195} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M11.jpg" xlink:type="simple" /> </jats:inline-formula>Pt, and <jats:inline-formula> <jats:tex-math><?CDATA $ ^{204,206} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M12.jpg" xlink:type="simple" /> </jats:inline-formula>Pb. These nuclei are energetically unstable to <jats:italic>α</jats:italic> decay with low decay energies and extremely long decay half-lives. In particular, the candidates <jats:inline-formula> <jats:tex-math><?CDATA $ ^{187} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M13.jpg" xlink:type="simple" /> </jats:inline-formula>Os and <jats:inline-formula> <jats:tex-math><?CDATA $ ^{149} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054105_M14.jpg" xlink:type="simple" /> </jats:inline-formula>Sm are strongly recommended for future experiments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, the <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M1.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates in the magnetic field of a neutron star are investigated under different conditions of electron density, temperature, and decay energy. By considering the influence of magnetic field on the electron spectrum, we improve the Takahashi–Yokoi model and perform the calculations of <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M2.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates for the nickel (Ni) isotopes, which are the typical neutron-rich nuclei participating in the rapid neutron-capture process (<jats:italic>r</jats:italic>-process). It is found that the <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M3.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates are increased significantly in the extremely strong magnetic field ( <jats:inline-formula> <jats:tex-math><?CDATA $ B \gt, 10^{15} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M4.jpg" xlink:type="simple" /> </jats:inline-formula> G). Furthermore, we find oscillation of <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M5.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates with the increase of magnetic field strength, implying that the magnitude of <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M6.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates is closely related to not only the decay energy but also the environmental electron density. In contrast, the impact of temperature on the <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M7.jpg" xlink:type="simple" /> </jats:inline-formula> decay rates is found to be negligible in the range of <jats:inline-formula> <jats:tex-math><?CDATA $ 10^{7} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M8.jpg" xlink:type="simple" /> </jats:inline-formula> K <jats:inline-formula> <jats:tex-math><?CDATA $ \lt T\lt 10^{10} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_5_054106_M9.jpg" xlink:type="simple" /> </jats:inline-formula> K. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Large High Altitude Air Shower Observatory (LHAASO) has reported the measurement of photons with high energies of up to 1.42 PeV from twelve gamma-ray sources. We are concerned with the implications of the LHAASO data on the fate of Lorenz symmetry at such high energy levels; thus, we consider the interaction between gamma rays and photons in the cosmic microwave background (CMB) and compute the optical depth, mean free path, and survival probability of photons from these gamma-ray sources. Employing the threshold value predicted by standard special relativity, the lowest survival probability for observed gamma ray photons is found to be approximately 0.60, which is fairly high and implies that abundant photons with energies above the threshold may reach the Earth without Lorentz symmetry violation. We conclude that it is unreasonable to argue that Lorentz symmetry would be violated using current observations at the LHAASO.</jats:p>