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<jats:title>Abstract</jats:title> <jats:p>This study set out to investigate charged vector particles tunneling via horizons of a pair of accelerating rotating charged NUT black holes under the influence of quantum gravity. To this end, we use the modified Proca equation incorporating generalized uncertainty principle. Applying the WKB approximation to the field equation, we obtain a modified tunneling rate and the corresponding corrected Hawking temperature for this black hole. Moreover, we analyze the graphical behavior of the corrected Hawking temperature <jats:inline-formula> <jats:tex-math><?CDATA $T'_{H}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_1_015104_M1.jpg" xlink:type="simple" /> </jats:inline-formula> with respect to the event horizon for the given black hole. By considering quantum gravitational effects on Hawking temperatures, we discuss the stability analysis of this black hole. For a pair of black holes, the temperature <jats:inline-formula> <jats:tex-math><?CDATA $T'_{H}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_1_015104_M2.jpg" xlink:type="simple" /> </jats:inline-formula> increases with the increase in rotation parameters <jats:italic>a</jats:italic> and <jats:inline-formula> <jats:tex-math><?CDATA $\omega $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_1_015104_Z-20191114132000.jpg" xlink:type="simple" /> </jats:inline-formula>, correction parameter <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_44_1_015104_M3.jpg" xlink:type="simple" /> </jats:inline-formula>, black hole acceleration <jats:inline-formula> <jats:tex-math><?CDATA $\alpha$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_1_015104_M4.jpg" xlink:type="simple" /> </jats:inline-formula>, and arbitrary parameter <jats:italic>k</jats:italic>, and decreases with the increase in electric <jats:italic>e</jats:italic> and magnetic charges <jats:italic>g</jats:italic>. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>From April to July 2018, a data sample at the peak energy of the <jats:inline-formula> <jats:tex-math><?CDATA $ \varUpsilon \left( {4{\rm{S}}} \right)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_021001_M1.jpg" xlink:type="simple" /> </jats:inline-formula> resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be ( <jats:inline-formula> <jats:tex-math><?CDATA $ 496.3 \pm 0.3 \pm 3.0)\;{\rm pb}^{-1}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_021001_M2.jpg" xlink:type="simple" /> </jats:inline-formula>, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The production of <jats:inline-formula> <jats:tex-math><?CDATA $\varXi _{cc}^ {++}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M2.jpg" xlink:type="simple" /> </jats:inline-formula> baryons in proton-proton collisions at a centre-of-mass energy of <jats:inline-formula> <jats:tex-math><?CDATA $\sqrt{s}=13\;{\rm{TeV}}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M3.jpg" xlink:type="simple" /> </jats:inline-formula> is measured in the transverse-momentum range <jats:inline-formula> <jats:tex-math><?CDATA $4 \lt p_{\rm{T}} \lt 15\;{\rm{GeV}}/c$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M4.jpg" xlink:type="simple" /> </jats:inline-formula> and the rapidity range <jats:inline-formula> <jats:tex-math><?CDATA $2.0 \lt y \lt 4.5$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M5.jpg" xlink:type="simple" /> </jats:inline-formula>. The data used in this measurement correspond to an integrated luminosity of <jats:inline-formula> <jats:tex-math><?CDATA $1.7\;{\rm{fb}}^{-1}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M6.jpg" xlink:type="simple" /> </jats:inline-formula>, recorded by the LHCb experiment during 2016. The ratio of the <jats:inline-formula> <jats:tex-math><?CDATA $\varXi _{cc}^ {++}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M7.jpg" xlink:type="simple" /> </jats:inline-formula> production cross-section times the branching fraction of the <jats:inline-formula> <jats:tex-math><?CDATA $\varXi _{cc}^ {++} \to \varLambda _c^ + K^-\pi^+ \pi^+$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M8.jpg" xlink:type="simple" /> </jats:inline-formula> decay relative to the prompt <jats:inline-formula> <jats:tex-math><?CDATA $\varLambda _c^ + $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M9.jpg" xlink:type="simple" /> </jats:inline-formula> production cross-section is found to be <jats:inline-formula> <jats:tex-math><?CDATA $(2.22\pm 0.27 \pm 0.29)\times 10^{-4}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M10.jpg" xlink:type="simple" /> </jats:inline-formula>, assuming the central value of the measured <jats:inline-formula> <jats:tex-math><?CDATA $\varXi _{cc}^ {++}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_022001_M11.jpg" xlink:type="simple" /> </jats:inline-formula> lifetime, where the first uncertainty is statistical and the second systematic. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The thermalization process of the holographic entanglement entropy (HEE) of an annular domain is investigated in the Vaidya-AdS geometry. We determine numerically the Hubeny-Rangamani-Takayanagi (HRT) surface, which may be a hemi-torus or two disks, depending on the ratio of the inner radius to the outer radius of the annulus. More importantly, for some fixed ratio of the two radii, the annulus undergoes a phase transition, or a double phase transition, during thermalization from a hemi-torus to a two-disk configuration, or vice versa. The occurrence of various phase transitions is determined by the ratio of the two radii of the annulus. The rate of entanglement growth is also investigated during the thermal quench. The local maximal rate of entanglement growth occurs in the region with a double phase transition. Finally, if the quench process is sufficiently slow, which may be controlled by the thickness of the null shell, the region with a double phase transition vanishes.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The constituent quark model is used to compute the ground and excited state masses of <jats:italic>QQQ</jats:italic>baryons containing either <jats:italic>c</jats:italic> or <jats:italic>b</jats:italic>quarks. The quark model parameters previously used to describe the properties of charmonium and bottomonium states were used in this analysis. The non-relativistic three-body bound state problem is solved by means of the Gaussian expansion method which provides sufficient accuracy and simplifies the subsequent evaluation of the matrix elements. Several low-lying states with quantum numbers <jats:inline-formula> <jats:tex-math><?CDATA $ J^P=\frac{1}{2}^\pm, \frac{3}{2}^\pm, \frac{5}{2}^\pm$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023102_M1.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ \frac{7}{2}^+$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023102_M2.jpg" xlink:type="simple" /> </jats:inline-formula> are reported. We compare the results with those obtained by the other theoretical formalisms. There is a general agreement for the mass of the ground state in each sector of triply heavy baryons. However, the situation is more puzzling for the excited states, and appropriate comments about the most relevant features of our comparison are given. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the contributions of intermediate bottomonium-like <jats:inline-formula> <jats:tex-math><?CDATA $Z_b$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M2.jpg" xlink:type="simple" /> </jats:inline-formula> states and the bottom meson loops in the heavy quark spin flip transitions <jats:inline-formula> <jats:tex-math><?CDATA $\Upsilon(4S) \to h_b(1P,2P) \pi^+\pi^-$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M3.jpg" xlink:type="simple" /> </jats:inline-formula>. Depending on the constructive or destructive interferences between the <jats:inline-formula> <jats:tex-math><?CDATA $Z_b$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M4.jpg" xlink:type="simple" /> </jats:inline-formula>-exchange and the bottom meson loops mechanisms, we predict two possible branching ratios for each process: <jats:italic>BR</jats:italic> <jats:inline-formula> <jats:tex-math><?CDATA $_{\Upsilon(4S) \to h_b(1P)\pi^+\pi^-}\simeq\big(1.2^{+0.8}_{-0.4}\times10^{-6}\big)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M5.jpg" xlink:type="simple" /> </jats:inline-formula> or <jats:inline-formula> <jats:tex-math><?CDATA $\big( 0.5^{+0.5}_{-0.2}\times10^{-6}\big)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M6.jpg" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math><?CDATA $ {{BR}}_{\Upsilon(4S) \to h_b(2P)\pi^+\pi^-}\simeq \big(7.1^{+1.7}_{-1.1}\times10^{-10}\big)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_Z-20191120133111.jpg" xlink:type="simple" /> </jats:inline-formula> or <jats:inline-formula> <jats:tex-math><?CDATA $\big( 2.4^{+0.2}_{-0.1}\times10^{-10}\big)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M8.jpg" xlink:type="simple" /> </jats:inline-formula>. The contribution of the bottom meson loops is found to be considerably larger than that of the <jats:inline-formula> <jats:tex-math><?CDATA $Z_b$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M9.jpg" xlink:type="simple" /> </jats:inline-formula>-exchange in the <jats:inline-formula> <jats:tex-math><?CDATA $\Upsilon(4S) \to h_b(1P) \pi\pi$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M10.jpg" xlink:type="simple" /> </jats:inline-formula> transitions, while its decay rates are not comparable to those of heavy quark spin conserved <jats:inline-formula> <jats:tex-math><?CDATA $\Upsilon(4S) \to \Upsilon(1S,2S) \pi\pi$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M11.jpg" xlink:type="simple" /> </jats:inline-formula> processes. We also predict the contribution of the charm meson loops in the branch fractions of <jats:inline-formula> <jats:tex-math><?CDATA $\psi(3S,4S) \to h_c(1P)\pi\pi$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023103_M12.jpg" xlink:type="simple" /> </jats:inline-formula>. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the semileptonic decays <jats:inline-formula> <jats:tex-math><?CDATA $B_c^- \to (\eta_c, J/\psi) l ^- \bar{\nu}_l$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M2.jpg" xlink:type="simple" /> </jats:inline-formula> using the PQCD factorization approach with the newly defined distribution amplitudes of the <jats:inline-formula> <jats:tex-math><?CDATA $B_c$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M3.jpg" xlink:type="simple" /> </jats:inline-formula> meson and a new kind of parametrization for extrapolating the form factors which takes into account the recent lattice QCD results. We find the following main results: (a) the PQCD predictions of the branching ratios of the <jats:inline-formula> <jats:tex-math><?CDATA $B_c \to (\eta_c,J/\psi) l \bar{\nu}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M4.jpg" xlink:type="simple" /> </jats:inline-formula> decays are smaller by about 5%-16% when the lattice results are taken into account in the extrapolation of the relevant form factors; (b) the PQCD predictions of the ratio <jats:inline-formula> <jats:tex-math><?CDATA $R_{\eta_c}, R_{ J/\psi}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M5.jpg" xlink:type="simple" /> </jats:inline-formula> and of the longitudinal polarization <jats:inline-formula> <jats:tex-math><?CDATA $P_{\tau}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M6.jpg" xlink:type="simple" /> </jats:inline-formula> are <jats:inline-formula> <jats:tex-math><?CDATA $R_{\eta_c}=0.34\pm 0.01, R_{J/\psi}=0.28\pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M7.jpg" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math><?CDATA $P_{\tau}(\eta_c) = 0.37\pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M8.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $P_{\tau}(J/\psi) = -0.55 \pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M9.jpg" xlink:type="simple" /> </jats:inline-formula>; and (c) after including the lattice results, the theoretical predictions slightly change: <jats:inline-formula> <jats:tex-math><?CDATA $R_{\eta_c}=0.31\pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M10.jpg" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math><?CDATA $ R_{ J/\psi}=0.27\pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M11.jpg" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math><?CDATA $P_{\tau}( \eta_c) = 0.36 \pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M12.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $P_{\tau}( J/\psi) = -0.53\pm 0.01$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M13.jpg" xlink:type="simple" /> </jats:inline-formula>. The theoretical predictions of <jats:inline-formula> <jats:tex-math><?CDATA $R_{ J/\psi}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023104_M14.jpg" xlink:type="simple" /> </jats:inline-formula> agree with the measurements within the errors. The other predictions could be tested by the LHCb experiment in the near future. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Dark sector may couple to the Standard Model via one or more mediator particles. We discuss two types of mediators: the dark photon <jats:inline-formula> <jats:tex-math><?CDATA $ A^{\prime} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M1.jpg" xlink:type="simple" /> </jats:inline-formula> and the dark scalar mediator <jats:inline-formula> <jats:tex-math><?CDATA $ \phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M2.jpg" xlink:type="simple" /> </jats:inline-formula>. The total cross-sections and various differential distributions of the processes <jats:inline-formula> <jats:tex-math><?CDATA $ e^{+} e^{-} \rightarrow q \bar{q} A^{\prime} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M3.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ e^{+} e^{-} \rightarrow q \bar{q} \phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M4.jpg" xlink:type="simple" /> </jats:inline-formula> ( <jats:inline-formula> <jats:tex-math><?CDATA $ q = u,\; d,\; c,\; s $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M5.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:italic>b</jats:italic> quarks) are discussed. We focus on the study of the invisible <jats:inline-formula> <jats:tex-math><?CDATA $ A^{\prime} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M7.jpg" xlink:type="simple" /> </jats:inline-formula> due to the cleaner background at future <jats:inline-formula> <jats:tex-math><?CDATA $ e^{+} e^{-} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M8.jpg" xlink:type="simple" /> </jats:inline-formula> colliders. It is found that the kinematic distributions of the two-jet system could be used to identify (or exclude) the dark photon and the dark scalar mediator, as well as to distinguish between them. We further study the possibility of a search for dark photons at a future CEPC experiment with <jats:inline-formula> <jats:tex-math><?CDATA $ \sqrt{s} = 91.2 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M9.jpg" xlink:type="simple" /> </jats:inline-formula> GeV and 240 GeV. With CEPC running at <jats:inline-formula> <jats:tex-math><?CDATA $ \sqrt{s} = $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M10.jpg" xlink:type="simple" /> </jats:inline-formula> 91.2 GeV, it would be possible to perform a decisive measurement of the dark photon (20 GeV <jats:inline-formula> <jats:tex-math><?CDATA $ \lt m_{A^{\prime}} \lt $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M11.jpg" xlink:type="simple" /> </jats:inline-formula> 60 GeV) in less than one operating year. The lower limits of the integrated luminosity for the significance <jats:inline-formula> <jats:tex-math><?CDATA $ S/\sqrt{B} = $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M12.jpg" xlink:type="simple" /> </jats:inline-formula> 2 <jats:inline-formula> <jats:tex-math><?CDATA $ \sigma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M13.jpg" xlink:type="simple" /> </jats:inline-formula>, 3 <jats:inline-formula> <jats:tex-math><?CDATA $ \sigma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M14.jpg" xlink:type="simple" /> </jats:inline-formula> and 5 <jats:inline-formula> <jats:tex-math><?CDATA $ \sigma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_023105_M15.jpg" xlink:type="simple" /> </jats:inline-formula> are presented. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Elastic scattering of <jats:sup>10</jats:sup>Be on a <jats:sup>208</jats:sup>Pb target was measured at <jats:inline-formula> <jats:tex-math><?CDATA $ E_{\rm Lab} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024001_M1.jpg" xlink:type="simple" /> </jats:inline-formula> = 127 MeV, which corresponds to three times the Coulomb barrier. The secondary <jats:sup>10</jats:sup>Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou. The angular distribution of elastic scattering in the <jats:sup>10</jats:sup>Be + <jats:sup>208</jats:sup>Pb system shows a typical Fresnel diffraction peak. Optical model analysis of the angular distribution was performed using the Woods-Saxon, double-folding and global potentials. With the global potential, different density distributions were used. The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The level structure in neutron-deficient nucleus <jats:sup>91</jats:sup>Ru was investigated via the <jats:sup>58</jats:sup>Ni (<jats:sup>36</jats:sup>Ar, 2<jats:italic>p</jats:italic>1<jats:italic>n</jats:italic> <jats:inline-formula> <jats:tex-math><?CDATA $\gamma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M5.jpg" xlink:type="simple" /> </jats:inline-formula>) <jats:sup>91</jats:sup>Ru reaction at a beam energy of 111 MeV. Charged particles, neutrons, and <jats:inline-formula> <jats:tex-math><?CDATA $\gamma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M8.jpg" xlink:type="simple" /> </jats:inline-formula>-rays were emitted in this reaction and detected by the DIAMANT CsI ball, Neutron Wall, and the EXOGAM Ge clover array, respectively. In addition to the previously reported levels in <jats:sup>91</jats:sup>Ru, new low-to-medium spin states were observed. Angular correlation and linear polarization measurements were performed to unambiguously determine spins and parities of the excited states in <jats:sup>91</jats:sup>Ru. The low-spin states of <jats:sup>91</jats:sup>Ru exhibit a scheme of multi-quasiparticle excitations, which is very similar to that of the neighboring <jats:inline-formula> <jats:tex-math><?CDATA $N=47$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M12.jpg" xlink:type="simple" /> </jats:inline-formula> isotone. These excitations have been interpreted in terms of the shell model. The calculations performed in the configuration space <jats:inline-formula> <jats:tex-math><?CDATA $(p_{3/2},f_{5/2},p_{1/2},g_{9/2})$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M13.jpg" xlink:type="simple" /> </jats:inline-formula> reproduce the experimental excitation energies reasonably well, supporting the interpretation of the newly assigned positive-parity states in terms of the three quasiparticle configurations <jats:inline-formula> <jats:tex-math><?CDATA $\pi(g_{9/2})^{-2} \nu(g_{9/2})^{-1}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M14.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $\nu (g_{9/2})^{-3}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_44_2_024002_M15.jpg" xlink:type="simple" /> </jats:inline-formula>. </jats:p>