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The fission decay mechanism of various 212,213,215,217At⁎ isotopes formed in tightly (3,4He) and loosely bound (6,8He) projectile induced reactions on 209Bi target, is studied within the framework of dynamical cluster-decay model (DCM), over a wide range of excitation energies spread across the Coulomb barrier. By optimizing appropriate neck-length parameter ΔR, the fission cross-sections are calculated for 212,213,215At⁎ compound nuclei (CN) at above barrier energies, where some experimental data is available. The DCM calculations are extended at below barrier region for these nuclei, and for one more reaction 8He+209Bi→217At⁎, using the systematics of 212,213,215At⁎ isotopes. The magnitude of fission cross-sections increase with the addition of neutrons in the He-projectile (or say in the At compound nucleus since the target nucleus of each reaction is same). To obtain better description of fission dynamics involved for neutron-deficient and neutron-rich He-induced reactions, the fragmentation potential and prefromation probability P 0 of decaying fragments are analyzed along with corresponding barrier tunneling probability P. The fission fragment mass distributions are explored for all ‘At’ isotopes, and most probable fission fragments are identified. It has been observed that asymmetric fission forms the predominant decay mode for all isotopes, although a minor hump with very small preformation factor appears around symmetric fragments for lighter 212,213At⁎ nuclei. Finally, the N/Z dependence of fission cross-sections and most probable decaying fragments is explored in view of fragmentation structure and related cross-sectional yields.

The fission mass distribution of Z=104-120 superheavy nuclei formed in 238U-induced reactions is investigated using the dynamical cluster decay approach. The cross-section for the formation of symmetric fragments with masses A 2 ± 20 of 274Hs⁎, 286Cn⁎, 286Fl⁎, and 302120⁎ nuclei are calculated over a wide energy spectrum by rationalizing the neck-length parameter (ΔR). The calculations are carried out by including the quadrupole ( β 2 i )-deformation of the fragments using hot and cold optimum orientation approaches. Within hot orientation criteria, symmetric fission distribution is observed for 274Hs⁎ nucleus which becomes highly asymmetric in nature for 302120⁎ compound system. The lead (Pb)-peaks originating due to quasi-fission process start competing while going from 274Hs⁎ to 302120⁎ nucleus. Additionally, the role of cold orientation approach is also explored for these nuclei which show the opposite trend in the mass distribution while going from Z=108 to Z=120 superheavy system. Further, the fission and asymmetric quasi-fission cross-sections are predicted for various entrance channels i.e. 58Fe+244Pu, 54Cr+248Cm, and 50Ti+249Cf and compared with experimentally available data of 64Ni+238U reaction to identify the favorable projectile-target combination for the synthesis of Z=120 nucleus. The results show that because of larger fusion probability, 50Ti+249Cf reaction seems to provide a favorable option for the synthesis of Z=120 superheavy nucleus.

The global α -nucleus optical model is studied based on the nucleon self-energies in an Dirac-Brueckner-Hartree-Fock (DBHF) approach. The newly developed nucleon-nucleus optical model CTOM derived from DBHF, is used as the basis to consistently generate the real and imaginary potentials of the α -nucleus optical potential by double-folding model. The same range correction a of the improved local density approximation (ILDA) in CTOM is adopted, which is also suitable to modify the nucleon interaction range in α -nucleus systems. To get better description of experimental data, the re-normalization factors ( N R , N I ) are introduced in α -nucleus scattering calculations, and the individual optimized ( N R , N I ) for all nuclei and energies are searched out under the guidance of χ 2 criterion. We systematically explore the energy dependence of N R and N I by considering the α elastic scattering from 12 C to 208 Pb at incident energies below 120 MeV / nucleon and a simple exponential function is extracted. With this global α -nucleus optical potential, a reasonable description of all available experimental data for α scattering from nuclei is achieved.

We present an explanation for the abnormally large diffuseness parameter of the Woods-Saxon (WS) potential in heavy-ion fusion reactions based on the thermal considerations of the ion-ion potential. Within the framework of the temperature-dependent (TD) form of the proximity potential 2010, we systematically explored the role of the thermal effects in the fusion excitation functions of a significant number of the heavy-ion fusion reactions. The obtained results reveal that the proximity potential supplemented with temperature effects has been successful in reproducing the fusion excitation data for various considered systems. Based on the TD nucleus-nucleus potentials, we extract the equivalent diffuseness parameter of the WS potential. The extracted values are ranging between 0.63 fm and 1.09 fm. We also show the diffuseness parameter follows a regular decreasing trend with increase of the temperature T .

In this paper, we study odd-A nuclei. To do this study we use the controlled single particle concept which involves an even-even core and a single particle that is controlled by the core. Assuming that the core can be expressed by the γ-rigid Bohr Hamiltonian for γ = 30 ∘ we want to study such a system. Therefore, the Hamiltonian of the odd-A nucleus is constructed then eigenfunction and eigenvalues related to the system are derived. To examine the results, 189Ir has been considered as an experimental candidate for our study. Theoretical predictions of energy rates and B(E2) transition rates are compared with experimental reports. The results show a good agreement with experimental data.

The nucleus-nucleus potentials evaluated in the double-folding and energy density approximations with and without the contributions of the kinetic energy of the nucleons are discussed in detail. The nuclear part of nucleus-nucleus potentials obtained in the double-folding approach is close to the one calculated in the energy density approximation without the contributions of the kinetic energy. The cross-sections of fusion around the barrier and elastic scattering are calculated for the systems 16O + 208Pb, 40Ca + 40Ca, 16O + 56Fe, 16O + 92Zr using the total nucleus-nucleus interaction. It is shown that taking into account the contribution of kinetic energy to the potential allows simultaneously describes the experimental cross sections of the fusion and elastic scattering.

The low-lying dipole strength of the deformed nucleus 156Gd was investigated in the energy region from 3.1 MeV to 6.2 MeV using the method of nuclear resonance fluorescence (NRF). The NRF experiments were performed at the Darmstadt High Intensity Photon Setup (DHIPS) at Technische Universitat Darmstadt using unpolarized continuous-energy bremsstrahlung and at the High-Intensity γ-ray Source (HIγS) at Duke University using quasi-monoenergetic and linearly-polarized photon beams. The combination of both experiments allows to separate electric and magnetic contributions and to determine absolute transition strengths for individual excited states as well as averaged quantities over narrow excitation energy regions. The investigated energy regions cover the region of the scissors mode as well as the low-energy part of the Pygmy Dipole Resonance. This is the first experiment where both of these excitation modes as well as the region in between has been successfully studied in a deformed heavy nucleus using the NRF method.

Using dynamical cluster-decay model, the time scale of fission and light charged particles emitted in the decay of Hf⁎ and Pt⁎ nuclei is estimated. The decay analysis is carried out for isotopes and isobars of 170,174Hf⁎ and 170,174Pt⁎ nuclei. The structural information from the excited Hf⁎ and Pt⁎ nuclei is extracted using the fragmentation potential and preformation probability, which in turn accordingly influence the cross section yields. The cross sections of evaporation residue and fission-fragments are calculated by optimizing the neck length ΔR with in the frame work of dynamical cluster-decay model (DCM). The neck length ΔR provides significant information about the shape elongation of decaying fragments and in turn provides an insight of the reaction time scale. Applying momentum conservation, the velocity and time scale of fission fragments is calculated for 170Hf⁎ nucleus at temperature T = 2.011 MeV , which comes out of the order of ( 0.7 – 1 ) × 10 − 21 s and the same for light charged particle is 0.5 × 10 − 21 s.

The measurements of open charm production was proposed as an important tool to investigate the properties of hot and dense matter formed in nucleus-nucleus collisions as well as to provide the means for model independent interpretation of the existing data on $\text{J}/\psi$ suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150$A$ GeV/$c$ allowed to validate the general concept of D$^0$ meson detection via its D$^0 \to \pi^+ + K^-$ decay channel and delivered a first indication of open charm production. The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented., Comment: Quark Matter 2018 proceedings Submitted to Nuclear Physics A

The magnetic dipole ( M 1) response of the 169 Tm nucleus is investigated from a theoretical point of view. The theoretical tool used in this study is the Rotational Invariant Quasiparticle Phonon Nuclear Model (RI-QPNM) which gives a possibility to eliminate spurious contributions in the M 1 spectrum. In the framework of this model, both the low-lying and high-lying parts of the M 1 excitation spectrum of 169 Tm are calculated. The result shows that the low-lying excitations have almost pure orbital character and can be interpreted as scissors mode, whereas the high-lying transitions can be read as spin-flip mode because of its spin nature. The reduced transition probability summed up in the energy range 2–4 MeV is found to be B ( M 1 ↑ ) = 3.040 μ N 2 which agrees with the available experimental data. The fragmentation of the low-energy M 1 strength is also well reproduced. This is also the first study in which both the low-lying and high-lying M 1 spectrum of the 169 Tm nucleus is theoretically investigated.

A survey of even–even nuclei in the nuclear chart showed regularities in the values of the ratio Q ( 2 1 + ) / ( B ( E 2 ) for each nucleus for which independent measurements of both the electric quadrupole moment of the 2 1 + state, Q ( 2 1 + ) , and the reduced transition probability B ( E 2 ; 0 1 + → 2 1 + ) exist. As predicted by the rotational model, this ratio was found to be close to unity for the deformed nuclei in the rare-earth region. For non-rotational nuclei the absolute value of this ratio is almost always considerably lower. This latter observation can be interpreted within different models for different classes of nuclei as illustrated by a set of schematic IBA model calculations. A general mixing model and simple geometrical models are also suitable for collective non-rotational nuclei. Near magic nuclei a mechanism within the seniority scheme is compatible with the observed small value of R Q B .

Alpha($^{4}$He)-cluster models have often been used to describe light nuclei. Towards the application to multi-cluster systems involving heavy clusters, we study the relative wave functions of the $\alpha+^{16}$O and $\alpha+^{40}$Ca systems generated from phase-shift-equivalent potentials. In general, a potential between clusters is deep accommodating several redundant bound states which should be removed in an appropriate way. To avoid such a complicated computation, we generate a shallow-singular potential by using supersymmetric transformations from the original deep potential. Changes in the relative wave functions by the transformations are quantified with electric-multipole transitions which give a different radial sensitivity to the wave function depending on their multipolarity. Despite the fact that the original and transformed potentials give exactly the same phase shift, some observables are unfavorably modified. A possible way to obtain a desired supersymmetric potential is proposed., Comment: 30 pages, 9 figures, to appear in Nucl. Phys. A

We have studied the α-decay properties of superheavy nuclei Z = 118 in the range 275 ≤ A ≤ 325 . Most of the predicted, unknown nuclei in the range 291 ≤ A ≤ 301 were found to have α-decay chains. Of these the nuclei 293−301118 were found to have long half-lives and hence could be sufficient to detect them if synthesized in a laboratory. Fusion barries for different projectile-target combinations to synthesis superheavy nuclei Z = 118 are studied and are also represented in simple relations. We have also studied the evaporation residue cross section, compound nucleus formation probability (PCN) and survival probability ( P Surv ) of different projectile-target combinations to synthesis superheavy element Z = 118 . The selected most probable projectile-target combinations are Ca+Cf, Ti+Cm, Sc+Bk, V+Am, Cr+Pu, Fe+U, Mn+Np, Ni+Th and Kr+Pb. We have formulated simple relations for maximum evaporation residue cross sections and its corresponding energies. This helps to identify the projectile-target combinations quickly. Hence, we have identified the most probable projectile-target combinations to synthesis these superheavy nuclei. We hope that our predictions may be a guide for the future experiments in the synthesis of more isotopes of superheavy nuclei Z = 118 .

We use the well-known Wentzel–Kramers–Brillouin (WKB) barrier penetration probability to calculate α-decay branching ratios for ground and excited states of heavy even–even nuclei of Fermium ( 248 – 254 Fm), Californium ( 244 – 252 Cf), Curium ( 238 – 248 Cm) and Plutonium ( 234 – 244 Pu) with 94 ≤ Z p ≤ 100. We obtained the branching ratios for the excited states of daughter nucleus by the α-decay energy (Qα), the angular momentum of α-particle ( l α ), and the excitation probability of the daughter nucleus with the excitation energy of state l in the daughter nucleus (i.e. E l ⁎ ). α-Decay half-lives have been evaluated by using the proximity potential model for the heavy even–even nuclei. We have reported the half-lives and compared the results with the experimental data. The theoretical branching ratios of α-transitions in our calculation are found to agree with the available experimental data well for 0 → + 0+, 0 → + 2+, 0 → + 4+, 0 → + 6+ and 0+ → 8+ α-transitions.

In the framework of the energy density method with the use of the wave function of the two-center shell model, the influence of the simultaneous account for the Pauli exclusion principle and the monopole and quadrupole polarizations of nuclei on the nuclear part of the potential of their interaction by the example of the Ca 40 + Ca 40 system is considered. The calculations performed in the framework of the adiabatic approximation show that the consideration of the Pauli exclusion principle and the polarization of nuclei, especially the quadrupole one, essentially affects the nucleus–nucleus interaction potential.

Using the extended fragmentation theory, the compactness of hot and cold fusion reactions is analyzed for odd-Z nuclei ranging Z = 105 – 117 . The calculations for the present work are carried out at T = 0 MeV and l = 0 ħ , as the temperature and angular momentum effects remain silent while addressing the orientation degree of freedom (i.e. compact angle configuration). In the hot fusion, 48Ca (spherical) + actinide (prolate) reaction, the non-equatorial compact (nec) shape is obtained for Z = 113 nucleus. On the other hand, Z > 113 nuclei favor equatorial compact (ec) configuration. The distribution of barrier height ( V B ) illustrate that the ec-shape is obtained when the magnitude of quadrupole deformation of the nucleus is higher than the hexadecupole deformation. In other words, negligible or small −ve β 4 -deformations support ec configurations. On the other hand, large (+ve) magnitude of the β 4 -deformation suggests that the configuration appears for compact angle θ c 90 ° , leading to nec structure. Similar deformation effects are observed for Bi-induced reactions, in which not belly-to-belly compact (nbbc) configurations are seen at θ c = 42 ° . In addition to the effect of β 2 and β 4 -deformations, the exclusive role of octupole deformations ( β 3 ) is also analyzed. The β 3 -deformations do not follow the reflection symmetry as that of β 2 and β 4 , leading to the possible occurrence of compact configuration within 0° to 180° angular range.

The dynamics of α -induced reactions are worked out over an incident beam energy E α ∼ 10 – 15 MeV using targets of different masses. The decay patterns of odd mass compound systems 117 Sb ⁎ , 145 Pm ⁎ and 191 Ir ⁎ formed in α + 113 In, α + 141 Pr and α + 187 Re reactions are investigated in view of n-evaporation data. The methodology of collective clusterization is applied by optimizing the neck-length parameter Δ R and the DCM calculated cross-sections find nice agreement with the experimental data. The resulting compound systems with A C N = 117 – 191 cover a wide range of compound nucleus mass, and hence give an opportunity to explore various aspects related to the dynamics involved. Moreover the neutron–proton asymmetry dependence is explored in terms of the Bulk constant ( α ) (in the liquid drop binding energy expression) and radius term R i and its consequent influence on the fragmentation structure of these compound systems is investigated.

Owing to its doubly magic nature having equal numbers of protons and neutrons, the 40Ca nuclear scattering can be successfully described by the optical model that assumes a spherical nuclear potential. Therefore, optical model analysis was employed to calculate the elastic scattering cross section for p + 40 Ca interaction at energies from 9 to 22 MeV as well as the polarization at energies from 10 to 18.2 MeV. New optical model parameters (OMPs) were proposed based on the best fitting to experimental data. It is found that the best fit OMPs depend on the energy by smooth relationships. The results were compared with other OMPs sets regarding their chi square values ( χ 2 ). The obtained OMP's set was used to calculate the volume integral of the potentials and the root mean square (rms) value of nuclear matter radius of 40Ca. In addition, 40Ca bulk nuclear matter properties were discussed utilizing both the obtained rms radius and the Thomas–Fermi rms radius calculated using spherical Hartree–Fock formalism employing Skyrme type nucleon–nucleon force. The nuclear scattering SCAT2000 FORTRAN code was used for the optical model analysis.

An optical potential constructed using the p ¯ N scattering amplitudes derived from the 2009 version of the Paris N ¯ N potential is applied in calculations of p ¯ quasi-bound states in selected nuclei across the periodic table. A proper self-consistent procedure for treating energy dependence of the amplitudes in a nucleus appears crucial for evaluating p ¯ binding energies and widths. Particular attention is paid to the role of P -wave amplitudes. While the P -wave potential nearly does not affect calculated p ¯ binding energies, it reduces considerably the corresponding widths. The Paris S -wave potential supplemented by a phenomenological P -wave term yields in dynamical calculations p ¯ binding energies B p ¯ ≈ 200 MeV and widths Γ p ¯ ∼ 200 – 230 MeV, which is very close to the values obtained within the RMF model consistent with p ¯ -atom data.

The decay of various compound nuclei formed via exotic neutron-rich 9Li projectile is studied within the dynamical cluster-decay model (DCM). Following the earlier work of one of us (RKG) and collaborators (M. Kaur et al. (2015) [1] ), for an empirically fixed neck-length parameter Δ R e m p , the only parameter in the DCM, at a given incident laboratory energy E L a b , we are able to fit almost exactly the (total) fusion cross section σ f u s = ∑ x = 1 6 σ x n for 9Li projectile on 208Pb and other targets, with σ f u s depending strongly on the target mass of the most abundant isotope and its (magic) shell structure. This result shows the predictable nature of the DCM. The neck-length parameter Δ R e m p is fixed empirically for the decay of 217At⁎ formed in 9Li + 208Pb reaction at a fixed laboratory energy E L a b , and then the total fusion cross section σ f u s calculated for all other reactions using 9Li as a projectile on different targets. Apparently, this procedure could be used to predict σ f u s for 9Li-induced reactions where experimental data are not available. Furthermore, optimum choice of “cold” target-projectile combinations, forming “hot” compact configurations, are predicted for the synthesis of compound nucleus 217At⁎ with 8Li + 209Pb as one of the target-projectile combination, or another ( t , p ) combination 48Ca + 169Tb, with a doubly magic 48Ca, as the best possibility.

A comparative analysis of intermediate mass fragments (IMFs) and light particles (LPs) [equivalently, evaporation residues (ERs)] in the decay of 26,27,28,29 Al ⁎ has been carried out for reactions O 16 + 10 , 11 B and O 18 + 10 , 11 B at the energy range 1 MeV ≤ E / A ≤ 4 MeV , within dynamical cluster decay model (DCM) of collective clusterisation approach. We find that, for IMFs having Z = 3 , 4 , 5 and 6 , the range of mass minima are ∑ i = 5 8 A i , ∑ i = 8 9 A i , ∑ i = 9 13 A i and ∑ i = 11 15 A i , respectively. With increase in the mass of compound nuclei, Z = 6 becomes more prominent as compared to its neighboring fragments which is also observed in the experimental data. The LPs cross sections ( σ L P s ) in the decay of 26–29 Al ⁎ are also estimated. We find that the value of ∑ P 0 of LPs for 26,27 Al ⁎ is less as compared to that for 28,29 Al ⁎ , contrary to the value of ∑ P . Eventually, the cross sections for LPs are having higher contribution in the decay of 28,29 Al ⁎ in agreement with the experimental data. As expected for light mass nuclei, the σ L P s for 26,27 Al ⁎ find better comparison with experimental data for spherical considerations rather than β 2 deformations. We also conform Bohr's hypothesis via the entrance channel independence for compound nucleus 28 Al ⁎ formed through O 18 + 10 B and F 19 + 9 Be channels at an excitation energy E C N ⁎ ∼ 44 MeV , by having a unique choice of neck length parameter Δ R for both the reactions.

The O (g.s.) 16 + 8 Be (g.s.) structure of the ground state of 24Mg nucleus has been probed experimentally using direct knockout reaction Mg 24 ( O 16 , 2 16 O ) 8 Be in the quasi free scattering kinematics domain. The direct 16O-cluster knockout finite range prediction indicates a fair amount of O (g.s.) 16 + 8 Be (g.s.) component in the Mg (g.s.) 24 .

We investigate properties of bound and resonance states in the Λ 9 Be nucleus. To reveal the nature of these states, we use a three-cluster 2 α + Λ microscopic model. The model incorporates Gaussian and oscillator basis functions and reduces a three-cluster Schrodinger equation to a two-body like many-channel problem with the two-cluster subsystems ( Λ 5 He and 8Be) being in a bound or a pseudo-bound state. Influence of the cluster polarization on the energy and widths of resonance states in Λ 9 Be and on elastic and inelastic Λ 5 He +α scattering is analyzed.

The α + 15 O cluster structure in astrophysically important 19Ne nucleus has been investigated within the framework of the shifted Deng-Fan potential model. The Nikiforov-Uvarov (NU) method is applied to reproduce the rotational bands of α + 15 O configuration. The lifetimes of the 9 / 2 − and 7 / 2 − resonance states of 19Ne populated in the O 15 ( α , γ ) reaction are also calculated by employing this local potential cluster model. Good agreement is found between the calculated and the experimental spectra, especially our calculations have produced the correct spins and parities of states at 4.14 and 4.20 MeV. Our results suggest that the shifted Deng-Fan potential is applicable to describe cluster-core structures in nuclei.

In this work, we have performed large-scale shell-model calculations for the first-forbidden $\beta ^{-}$ decay of $^{207}$Hg into the one-proton-hole nucleus $^{207}$Tl corresponding to the recently available experimental data from ISOLDE-CERN [T. A. Berry et al., Phys. Rev. C 101, 054311 (2020)]. We have used the one-particle one-hole ($1p$-$1h$) truncation for both protons and neutrons simultaneously across the doubly-shell closure at $^{208}$Pb in the final states of $^{207}$Tl. In our calculations, we have also considered the effect of mesonic enhancement $\epsilon _{\mathrm{mec}}=2.01\pm 0.05$ in the rank-0 for the axial-charge matrix element $\gamma _{5}$. Here, we have calculated the $\log ft$ values from the ground-state of $^{207}$Hg to the several excited states of $^{207}$Tl and obtained a good agreement between the calculated and the experimental data. In the experimental data spin and parity for some states are not yet confirmed, thus based on the shell-model results for the $\log ft$ values we have given the prediction for these states. This is the first theoretical calculation for the $\log ft$ values for these transitions., Comment: 16 pages, 2 figures, 2 tables

In this paper, we discuss an analytical description of a parity-doublet structure for an odd-A nucleus. We use the controlled single particle (CSP) concept to present the analytical model. In a parity-doublet structure, those bands consisting of states with opposite positive and negative parity appear. At first glance, it seems complex to present an analytical description, but the CSP concept enables us to present an analytical description of such an event. The calculated results are compared to the experimental data of Pm 151 , and there is a good agreement with calculated and experimental results.

The dynamical cluster decay model (DCM) is employed to explore the relative effect of sticking ( I S ) and non-sticking ( I N S ) limits of moment of inertia (MOI) in the decay of hot and rotating 214,216Rn⁎ compound nuclei, formed in 16,18O + 198Pt reactions. Beside this, the nuclear deformation effects i.e. quadrupole β 2 (static and dynamic) and higher order static deformations up to hexadecapole ( β 4 ) are duly incorporated and studied within DCM. The influence of both ‘ I N S / I S ’ addressing rotational energy component and ‘deformations’ is gauged through the barrier characteristics, preformation factor and barrier lowering effects. The experimentally given ER and ff data is addressed by optimizing the neck-length ΔR, that strongly depends on the limiting angular momentum, which in turn depends on the sticking or non-sticking limits of interaction. In addition to this, the influence of increase in energy and neutron number is probed in reference to ER survival probability of Rn compound nucleus. Finally, the ff cross-sections of 214,216Rn⁎ nuclei are predicted within sticking limit of moment of inertia as the same seems to be more suitable for such decay paths.

Despite intense theoretical and experimental investigation, the physical mechanisms governing the suppression of bound quark-antiquark states in nuclear collisions are not yet fully understood. While color screening in a plasma phase is expected to play a role, there are numerous other possible suppression mechanisms that do not require deconfinement, as well as effects on the heavy quark initial state in the nucleus which can also play a role. To study these effects, the PHENIX collaboration has used the flexibility of the RHIC accelerator complex to observe the evolution of open heavy flavor and quarkonia dynamics as both the projectile and target nuclei size are varied. Open heavy flavor in small collision systems can serve as the baseline for interpreting quarkonia production in the nuclear environment, and comparisons of the ψ ( 2 S ) with the ψ ( 1 S ) show that in rapidity regions with relatively high hadron density, the larger 2S state is preferentially more suppressed than the more tightly bound ψ ( 1 S ) . This suggests that late-stage mechanisms may be at least partially responsible for quarkonia suppression in nuclear collisions. In this talk, we will present results on excited-state quarkonia in p+p, p+Al, and p/d/3He+Au collisions and open heavy flavor in small systems, and discuss how these measurements impact our understanding of heavy quark behavior in the quark-gluon plasma.

The decay mechanism of 217At⁎ formed in Li 9 + 208 Pb reaction is studied within the dynamical cluster-decay model (DCM) at various center-of-mass energies. The aim is to see the behavior of a light neutron-rich radioactive beam on a doubly-magic target nucleus for the (total) fusion cross section σ fus and the individual decay channel cross sections. Experimentally, only the isotopic yield of heavy mass residues At ⁎ 211 – 214 [equivalently, the light-particles (LPs) evaporation residue cross sections σ x n for x = 3 – 6 neutrons emission] are measured, with the fusion–fission (ff) component σ ff taken zero. For a fixed neck-length parameter ΔR, the only parameter in the DCM, we are able to fit σ fus = ∑ x = 1 6 σ x n almost exactly for 9Li on 208Pb at all E c . m . 's. However, the observed individual decay channels (3n–6n) are very poorly fitted, with unobserved channels (1n, 2n) and σ ff strongly over-estimated. Different ΔR values, meaning thereby different reaction time scales, are required to fit individually both the observed and unobserved evaporation residue channels (1n–6n) and σ ff , but then the compound nucleus (CN) contribution σ CN is very small ( 1 % ), and the non-compound nucleus (nCN) decay cross section σ nCN contributes the most towards total σ fus ( = σ CN + σ nCN ). Thus, the 9Li induced reaction on doubly-magic 208Pb is more of a quasi-fission-like nCN decay, which is further analyzed in terms of the statistical CN formation probability P CN and CN survival probability P surv . For the reaction under study, P CN 1 and P surv → 1 , in particular at above barrier energies.

We have studied the fusion cross section, survival cross section, fission cross section, compound nucleus formation probability ( P CN ) and survival probability ( P Surv ) of superheavy nuclei 126 307 , 126 318 , 126 319 , and 126 320 . Hence, we have identified the most probable projectile–target combination to synthesis these superheavy nuclei. From the detail study of these parameters, it is clear that for the superheavy nuclei 126 307 , the projectile target combinations such as 54Fe + 253Fm and 58Ni + 249Cf are most probable projectile target combination for synthesis. The projectile target combinations such as 64Ni + 254Cf and 80Se + 238U are most probable projectile target combination for the synthesis of 126 318 . The projectile target combinations such as 72Zn + 247Cm and 66Ni + 253Cf are most probable projectile target combination for synthesis the superheavy nuclei 126 319 . The projectile target combinations such as 66Ni + 254Cf and 82Se + 238U are most probable projectile target combination for synthesis the superheavy nuclei 126 320 . Thus, we hope that our predictions may be guide for the future experiments in the synthesis of superheavy nuclei Z = 126 .

In reference to recent experiment, the dynamical aspects of reactions forming even mass isotopes of 118,120,122Xe⁎ nuclei are examined using the collective clusterization approach and the l-summed Wong model. The role of excitation energy (or temperature), deformations, orientations and angular momentum etc. has been investigated for the 28Si + 90,92,94Zr reactions. In order to account for the role of deformations, the evaporation residue (ER) cross sections of 122Xe⁎ nucleus have been studied in reference to the available experimental data by using spherical as well as deformed fragmentation approach. We have used optimum and compact orientations respectively for β 2 alone and for β 4 included, which inturn provide nice agreement with the available experimental cross-sections. Also, the effect of isospin (N/Z ratio) of decay fragments has been explored in view of the fragmentation analysis and preformation probability of 118,120,122Xe⁎ nuclei. Additionally, the role of projectile nucleus is also explored by studying the fragmentation path of 118Xe⁎ nucleus in comparison to 123Ba⁎ system. Further, the ER cross-sections have been predicted for various even mass isotopes of 116,118,120,124Xe. In addition to this, to explore the fusion characteristics of 28Si + 90,92,94Zr reactions, the Wong model as well as the l-summed Wong model has also been employed. Here also, the role of deformation in formation of 122Xe⁎ nucleus has been examined and the calculated cross-sections find decent agreement with the experimental data.

A systematic study on α-decay half-life time, T α , of α-particle emission from a large number of deformed heavy and superheavy nuclei is presented. The calculations are employed in the framework of the density-dependent cluster model. The microscopic α-daughter nuclear interaction potential is calculated in the framework of the double-folding model with the realistic effective Michigan-three-Yukawa Reid nucleon–nucleon interaction. We study the neutron number variation of log T α and arranged different isotones at each neutron magic number according to their stability, in the sense that the more stable isotone corresponds to the lowest value of log T α . We found that the half-life time becomes minimum when the neutron or proton numbers of the corresponding daughter nucleus are magic. Moreover, the half-life time is maximum for parent nucleus with magicity. The nuclear stability is assumed to be proportional with the depth of the minimum value in log T α for the daughter nucleus or the height of its maximum value for the parent one. The neutron magic numbers predicted and confirmed from the present study are 126, 152, 162, 172, 184, 196, 202 and 212, most of them were deduced by other authors based on different methods.

The decay mechanism of compound system 61 Ni ⁎ formed in fast neutron induced reactions is explored within the collective clusterization approach of the Dynamical Cluster-decay Model (DCM) in reference to a recent experiment over an energy spread of E n = 1 – 100 MeV . The excitation functions for the decay of the compound nucleus 61 Ni ⁎ formed in the n + Ni 60 reaction show a double humped variation with incident beam energy where the peak at lower energy corresponds to α -emission while the one at higher energy originates from 2 p 2 n -emission. The experimentally observed transmutation of α -emission at lower energy into 2 p 2 n -emission at higher incident energies is explained on the basis of temperature dependence of the binding energies used within the framework of DCM. The cross-sections for the formation of the daughter nucleus 57 Fe after emission of α -cluster from the 61 Ni ⁎ nucleus are addressed by employing the neck length parameter (ΔR), finding decent agreement with the available experimental data. The calculations are done for non-sticking choice of moment of inertia ( I N S ) in the centrifugal potential term, which forms the essential ingredient in DCM based calculations. In addition to this, the effect of mass (and charge) of the compound nucleus is exercised in view of α and 2 p 2 n emission and comparative study of the decay profiles of compound systems with mass A = 17–93 is employed to get better description of decay patterns.

This work presents the nuclear level scheme (NLS) of 164Dy nucleus obtained from the 163Dy(n t h ,2γ) experiment. The latter has used a γ − γ coincidence spectrometer to measure the two-step gamma cascades corresponding to the decays from the compound state to 9 low-lying states of 164Dy, whose energies are 0.0, 73.393, 242.234, 761.815, 828.215, 915.991, 976.916, 1039.309, and 1122.774 keV. Based on the measured data, the 164Dy NLS, which consists of 64 primary gamma transitions and their corresponding intermediate levels, together with 132 secondary gamma transitions, has been constructed. Among these data, 20 primary gamma transitions, 51 intermediate levels, and 63 secondary gamma transitions are found to be the same as those currently exist in the Evaluated Nuclear Structure Data File (ENSDF) database. The remaining data, which include 44 primary transitions, 13 intermediate levels, and 69 secondary transitions, are therefore, considered as an update for the NLS of 164Dy. In particular, the spin values of 57 observed intermediate levels have been tentatively assigned by means of transition rules. Furthermore, the influence of the present experimental data on the nuclear level density and radiative strength function is also discussed.

By adding repulsive nuclear potential, in Gaussian shape and double-folding form with different values of repulsive surface diffuseness parameter, to the attractive double-folding nuclear potential (M3Y) the effect of repulsive core on alpha decay half-lives and decay parameters of some even-even alpha emitters were analyzed. Calculations were accomplished using WKB approximation by considering Bohr-Sommerfeld quantization condition. The results showed calculated half-lives with M3Y lay between obtained lower and upper limits by M3Y plus repulsive potential with short-range repulsive diffuseness a r e p = 0.01 fm and long-range one a r e p = 0.30 fm . As result of crucial role of quantization factor an increasing trend of half-lives were observed by increase of a r e p . Also good coincidence between theory and experiment was observed for a distinct a r e p which highlights the formation of alpha particle near surface of parent nucleus.

We study the effect of the strong quasi-classical gluon field produced in the pre-thermal equilibrium stage of ultra-relativistic heavy ion collisions (RHICs) on the evolution of heavy quarks. It is shown that this field leads to an initial enhancement of the nuclear modification factor (RAA) of charm quarks at large pT. After the further evolution in the QGP phase, we find a larger interaction strength, which is necessary to obtain the RAA measured in experiments, compared to the standard drag and diffusion dynamics without the inclusion of this pre-thermal equilibrium stage. Moreover, we find a larger final elliptic flow ν2 is obtained, that is quite close to the experimental measurements.

We present measurements of the nuclear modification factor R A A and azimuthal anisotropy v 2 for electrons from charm and bottom hadron decays at mid-rapidity ( | y | 0.35 ) and for inclusive J / ψ via the di-muon decay channel at forward-rapidity ( 1.2 | y | 2.2 ) in Au+Au collisions at s N N = 200 GeV . Charm and bottom decay electron R A A can be described by a T-Matrix model based on a strongly coupling QGP scenario ( 2 π T D = 4 ) as well as SUBATECH and DGLV models based on quark mass dependent energy loss. Finite charm and bottom decay electron v 2 are observed with significances of 3.5 and 1.1 σ. The charm decay electron v 2 is better described by the Langevin + viscous hydro calculation with coalescence than that without coalescence. The charm decay electron v 2 is larger than inclusive J / ψ v 2 with a significance of 0.7 σ. These observations hint that charm quarks are dragged by the medium and hadronize via coalescence with light-flavor quarks. Complete analyses of 36 billion Au+Au collision events from RHIC 2014 and 2016 runs increase the integrated luminosity by a factor of 8 for the charm and bottom decay electron R A A measurements, by a factor of 2 for the charm and bottom decay electron v 2 measurements, and by a factor of 5 for the inclusive J / ψ v 2 measurements.

I review recent work on the dynamics of critical fluctuations in nucleus-nucleus collisions, and describe how this work can inform the ongoing search for the critical point.

The suppression of production rates of heavy quarkonia in ion-ion collisions with respect to nucleon-nucleon collisions provide sensitive probes in studying the properties of the hot and dense matter formed in these collisions at high energies. However, the baseline for understanding the behavior in the hot medium should be determined from nucleon-nucleus collisions. The nucleon-nucleus collisions themselves are also important for studying the nature of modifications of the parton distributions in the nucleus. Based on the data collected by the ATLAS detector in 2013 at the LHC, we show the results of ϒ(nS) production in proton-lead collisions at s NN = 5.02 TeV . The measurements of ϒ(nS) production cross section, nuclear modification factors, excited-to-ground state ratios and self-normalized ratios are presented for the di-muon decay channel differentially as a function of p T , center-of-mass rapidity and event centrality.

Recent results from open heavy-flavor measurements in proton-proton ( pp ), proton/deuteron-nucleus ( p /d-A), and nucleus-nucleus collisions (A-A) at RHIC and at the LHC are presented. Predictions from theoretical models are compared with the data, and implications for the properties of the hot and dense medium produced in ultra-relativistic heavy-ion collisions are discussed.

Collisions of identical nuclei at finite impact parameter have an unequal number of participating nucleons from each nucleus due to fluctuations. The event-by-event fluctuations have been estimated by measuring the difference of energy in the zero-degree calorimeters on either side of interaction vertex. The fluctuations affect the global variables such as the rapidity distributions, and the effect has been correlated with a measure of these fluctuations., Contribution to Quark Matter 2015, 4 pages, 8 figures

We report on the J/ψ production and polarization as a function of p T and x T , measured via the dielectron decay channel at mid-rapidity in p+p collisions at s = 500 GeV in the STAR experiment. The measured J/ψ p T spectrum is in agreement with NRQCD and CGC+NRQCD predictions, while the J/ψ polarization shows a trend towards longitudinal polarization with increasing p T . In addition, first measurements of the J/ψ production as a function of charged-particle multiplicity are presented at s = 500 GeV . A strong correlation between the J/ψ yield and charged-particle multiplicity is observed with a hint of J/ψ p T dependence.

The high-spin states in 86 Sr nucleus were populated using the 76 Ge( 13 C, 3n) reaction at a beam energy of 45 MeV. The γ – γ and γ – γ – γ coincidence measurements were used to establish the level scheme up to 10.9 MeV excitation energy and spin I π = 19 + . In our preliminary results reported earlier, a positive-parity dipole ( Δ I = 1 ) band based on the 6878-keV level having M1 γ -ray transitions was identified. In the present work, the γ -rays and their sequence have been established for this band. The band may have a magnetic rotational character. The spin-parity of the levels were assigned by measuring the Directional Correlations of the Oriented (DCO) nuclei and the polarization asymmetry. The polarization measurements were performed for the first time for the γ -ray transitions in this nucleus. The experimental band structures were compared with the shell-model calculations using two recent effective interactions, JUN45 and jj44b in the 1 p 3 / 2 , 0 f 5 / 2 , 1 p 1 / 2 , 0 g 9 / 2 model space. From the Tilted-Axis Cranking (TAC) calculations, the 4-qp π ( g 9 / 2 ) 2 ⊗ ν ( g 9 / 2 ) − 2 configuration is suggested for the lower-part of the ( Δ I = 1 ) band up to spin I π = 16 + and the 6-qp π [ ( g 9 / 2 ) 2 ( f 5 / 2 ) 1 ( p 1 / 2 ) 1 ] ⊗ ν ( g 9 / 2 ) − 2 configuration for the upper-part of the band.

The present paper proposes a modeling of the local even–odd effect based on the number of configurations in a nucleus undergoing fission at two stages along its fission path. One is the fissioning nucleus stage just after passing through the outer saddle point when the fragments are considered as pre-formed and the intrinsic energy is not yet shared. The other stage is at the end of the fission path when the scission is imminent. Then the intrinsic energy is already partitioned and the fragments are completely formed. The probability that a pre-formed fragmentation arrives at the end of the fission path (i.e. at scission) when the fragmentation is completely formed is expressed by the ratio of the number of configurations of the formed fragmentation to the one of pre-formed fragmentation. The local even–odd effect is defined as half of the difference between these normalized ratios corresponding to even-Z and odd-Z fragmentations. Both numbers of configurations in the fissioning nucleus, in which the fragments are pre-formed and completely formed, are calculated using level densities described by the constant temperature function (justified by the small values of the intrinsic energy before scission). The obtained local even–odd effect results describe well the experimental data, including the increase at asymmetry values corresponding to fragmentations in which one of the fragments is magic or double magic (i.e. fragmentations in which Z H = 50 and/or N H = 82 and very asymmetric fragmentations in which Z L = 28 ).

Starting from three-parameter Fermi distribution of nuclear densities, we used two formulas, for calculating the half-density radius, to study the effect of variation of radius of daughter nucleus on both α -decay half-life and α -preformation factor. We compared the results of the aforementioned two formulas with the corresponding results obtained from the nuclear densities of Hartree–Fock calculation derived from the BSk2 Skyrme force. We considered >60 isotopes of Po and Rn α -emitter elements and studied the variation of half-life and preformation factor with density parameters. We found that the variation of density parameters of daughter nuclei highly affects the calculated half-life and the extracted value of preformation factor, but the behavior of these two quantities with variation of parent neutron number is almost independent of the density parameters.

Levels of 188 Re populated in thermal neutron capture reaction with enriched 187 Re targets have been studied. Single γ -ray spectrum of 188 Re, measured with the high-resolution crystal diffraction spectrometer GAMS5, as well as γγ -coincidence experiments performed with high efficiency Ge detectors, allowed to develop model-independent level scheme of the doubly-odd 188 Re nucleus up to ∼ 1.5 MeV excitation energy. Analysis of the established 188 Re level scheme in terms of the quasiparticle-plus-rotor model indicates coexistence of axially-deformed and triaxial structures in the energy range above 400 keV.

Fission fragment mass–angle and mass ratio distributions have been measured for the 30Si + 180Hf reaction in the beam energy range 128–148 MeV. Quasifission signature is observed in this reaction, forming the compound system 210Rn. The results are compared with a very asymmetric reaction 16O + 194Pt, forming the same compound nucleus. Calculations assuming saddle point, scission point and DNS models have been performed to interpret the experimental results. The results strongly suggest the entrance channel dependence of quasifission in heavy ion collisions.