The dependence of eccentricity scaled elliptic flow on the partonic cross section in $\mathrm{Au}+\mathrm{Au}$ collisions at relativistic heavy ion collider (RHIC) energy $\sqrt{s_{\mathit{NN}}}=200\hspace{0.5em}\mathrm{GeV}$ with impact parameter $b=8\hspace{0.5em}\mathrm{fm}$ is analyzed using a multiphase transport (AMPT) model. It is shown that the dependence of eccentricity scaled elliptic flow on the partonic cross section could be described well by a formula suggested by Bhalerao et al. The eccentricity scaled elliptic flow of the parton is $19\%~27\%$ lower than its ‘hydrodynamic limit.' The hadronization of the parton through coalescence and hadronic dynamics (decay, collision) could influence the obtained deviation of eccentricity scaled elliptic flow of the hadron from its ‘hydrodynamic limit.' The hadronic final state interactions and hadronization reduce the extracted ‘hydrodynamic limit’ by 20% and also reduce the deviation from the ‘hydrodynamic limit’ by 26%.

Although at small Bjorken $x$ gluons originated from different nucleons in a nucleus overlap in the longitudinal direction, most of them are still well separated in the transverse plane and therefore cannot fuse. For this reason the gluon density in nuclei cannot drop at small $x$ below a certain bottom bound, which we evaluated in a model independent manner assuming the maximal strength of gluon fusion. We also calculated gluon shadowing in the saturated regime using the Balitsky-Kovchegov equation and found the nuclear ratio to be well above the unitarity bound. The recently updated analysis of parton distributions in nuclei [1], including BNL Relativistic Heavy Ion Collider (RHIC) data on high-$p_T$ hadron production at forward rapidities, led to strong gluon shadowing. Such strong shadowing and therefore the interpretation of the nuclear modification of the $p_T$ spectra in $dA$ collisions at RHIC seem to be inconsistent with this unitarity bound.

The electric dipole polarizabilities of ${}^3\mathrm{H}$, ${}^3\mathrm{He}$, and ${}^4\mathrm{He}$ are calculated directly using the Schrödinger equation with the latest generation of two- and three-nucleon interactions. These polarizabilities are necessary to obtain accurate nuclear-polarization corrections for transitions involving $S$ waves in one- and two-electron atoms. Our results are compared to previous results, and it is shown that direct calculations of the electric polarizability of ${}^4\mathrm{He}$ using modern nuclear potentials are smaller than published values calculated using experimental photoabsorption data. The status of this topic is assessed in the context of precise measurements of transitions in one- and two-electron atoms.

Excited states in the extremely neutron-deficient isotope ${}^{172}\mathrm{Hg}$ have been established for the first time. The ${}^{96}\mathrm{Ru}({}^{78}\mathrm{Kr},2n)$ reaction was employed to populate excited states in ${}^{172}\mathrm{Hg}$ with a cross section $\sigma \approx 15$ nb. The highly selective recoil-decay tagging (RDT) technique was used to obtain clean in-beam $\gamma$-ray spectra for ${}^{172}\mathrm{Hg}$. The yrast ground-state band has tentatively been established up to $I=6\hspace{0.5em}\hslash$. The data have been interpreted within the framework of total Routhian surface and quasiparticle random phase approximation calculations.

It is shown that Kramers’ fission width, originally derived for a system with constant inertia, can be extended to systems with a deformation-dependent collective inertia, which is the case for nuclear fission. The predictions of Kramers’ width for systems with variable inertia are found to be in very good agreement with the stationary fission widths obtained by solving the corresponding Langevin equations.

Fission fragment angular distributions have been measured in the reactions ${}^{16}\mathrm{O}+{}^{188}\mathrm{Os}$ and ${}^{28}\mathrm{Si}+{}^{176}\mathrm{Yb}$ to investigate the contribution from noncompound nucleus fission. Parameters for statistical model calculations were fixed using fission cross section data in the ${}^{16}\mathrm{O}+{}^{188}\mathrm{Os}$ reaction. Experimental anisotropies were in reasonable agreement with those calculated using the statistical saddle point model for both reactions. The present results are also consistent with those of mass distribution studies in the fission of ${}^{202}\mathrm{Po}$, formed in the reactions with varying entrance channel mass asymmetry. However, the present studies do not show a large fusion hindrance as reported in the pre-actinide region based on the measurement of evaporation residue cross section.

Group theoretic method for the systematic study of five-quark states with meson-baryon ($q\overline{q}\text{−}{q}^3$) configuration is developed. The calculation of matrix elements of many-body Hamiltonian is simplified by transforming the physical bases (meson-baryon quark cluster bases) to symmetry bases (group chain classified bases), where the fractional parentage expansion method can be used. Three quark models, the Glashow-Isgur naive model, the Salamanca chiral quark model, and the quark delocalization color screening model, are used to show the general applicability of the method and general results of constituent quark models for five-quark states are given. The method is also useful in the study of the five-quark components effect in baryon structure, the calculation of meson-baryon scattering, and the meson-baryon open channel coupling effect on baryon resonances. The physical contents of different model configurations for the same five-quark system can also be compared through the transformation between different physical bases to the same set of symmetry bases.

Neutrino-induced reactions on ${}^{56}\mathrm{Fe}$ and ${}^{56}\mathrm{Ni}$ are investigated based on a new shell-model Hamiltonian for $\mathit{pf}$ shell. The calculated charged current reaction cross section on ${}^{56}\mathrm{Fe}$ induced by decay-at-rest (DAR) neutrinos is shown to be consistent with the observation. The Gamow-Teller strength in ${}^{56}\mathrm{Ni}$ is found to be more spread compared to previous calculations and result in a considerably large branching ratio for the proton knock-out channel. As a consequence of this, the production yields of heavy elements such as ${}^{55}\mathrm{Mn}$ in population III stars are shown to be enhanced for the new Hamiltonian.

We use the continuum discretized coupled channel (CDCC) method to investigate the effects of breakup coupling on ${}^8\mathrm{B}+{}^{58}\mathrm{Ni}$ elastic scattering. We evaluate angular distributions at several collision energies and show that our theoretical results are in excellent agreement with the recent data of Aguilera et al. [Phys. Rev. C 79, 021601(R) (2009)]. We show that nuclear excitations of the target have a weak influence on the elastic angular distributions but that the inclusion of continuum-continuum couplings is essential to reproduce the data.

We study effects of eccentricity fluctuations on the elliptic flow coefficient $v_2$ at midrapidity in both $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV by using a hybrid model that combines ideal hydrodynamics for space-time evolution of the quark gluon plasma phase and a hadronic transport model for the hadronic matter. For initial conditions in hydrodynamic simulations, both the Glauber model and the color glass condensate model are employed to demonstrate the effect of initial eccentricity fluctuations originating from the nucleon position inside a colliding nucleus. The effect of eccentricity fluctuations is modest in semicentral $\mathrm{Au}+\mathrm{Au}$ collisions, but significantly enhances $v_2$ in $\mathrm{Cu}+\mathrm{Cu}$ collisions.

High spin states in ${}^{134}\mathrm{I}$ were identified for the first time based on measurements of prompt $\gamma$ rays from the spontaneous fission of ${}^{252}\mathrm{Cf}$ at Gammasphere. Five excited levels with five deexciting transitions were observed. The mass number was assigned based on the intensity of transitions in the complementary Rh fragments. Angular correlations for the first two transitions in ${}^{134}\mathrm{I}$ and for high spin states in ${}^{133,135,136}\mathrm{I}$ were performed, but were not sufficient to firmly assign the spins and parities in ${}^{134}\mathrm{I}$.

The single-particle spectral function of ${}^{56}\mathrm{Ni}$ has been computed within the framework of self-consistent Green's functions theory. The Faddeev random phase approximation method and the $G$ matrix technique are used to account for the effects of long- and short-range physics on the spectral distribution. Large-scale calculations have been performed in spaces including up to ten oscillator shells. The chiral ${\mathrm{N}}^3\mathrm{LO}$ interaction is used together with a monopole correction that accounts for eventual missing three-nucleon forces. The single-particle energies associated with nucleon transfer to valence $1p0f$ orbits are found to be almost converged with respect to both the size of the model space and the oscillator frequency. The results support that ${}^{56}\mathrm{Ni}$ is a good doubly magic nucleus. The absolute spectroscopic factors to the valence states on $A=55,57$ are also obtained. For the transition between the ground states of ${}^{57}\mathrm{Ni}$ and ${}^{56}\mathrm{Ni}$, the calculations nicely agree with heavy-ion knockout experiments.

Excited states in the $N=90$ and $N=91$ Pt nuclei have been investigated using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. These nuclei were populated via the reactions ${}^{92}\mathrm{Mo}({}^{78}\mathrm{Kr},2n)$ and ${}^{94}\mathrm{Mo}({}^{78}\mathrm{Kr},3n)$ at 335 and 348 MeV, respectively. The recoil-decay tagging technique has been used to correlate prompt $\gamma$ radiation with the characteristic $\alpha$ decays of ${}^{168}\mathrm{Pt}$ and ${}^{169}\mathrm{Pt}$. A $\gamma \text{−}\gamma$ analysis has allowed a level scheme for ${}^{168}\mathrm{Pt}$ to be reported for the first time and the level scheme for ${}^{169}\mathrm{Pt}$ to be extended. The excitation energies of the proposed positive-parity yrast states of ${}^{168}\mathrm{Pt}$ are compared with calculations based on the interacting boson model and found to be in excellent agreement. These data show a continuation of the trend toward vibrational nuclei as the $N=82$ shell gap is approached. In addition, new excited states constituting two decay paths have been discovered in ${}^{169}\mathrm{Pt}$.

Angular distributions of projectile-like fragments (PLFs) have been measured in the reaction ${}^{19}\mathrm{F}+{}^{66}\mathrm{Zn}$ at $E_{\mathrm{lab}}=61,82,92$, and 109 MeV to understand their formation in the low energy domain ($\hspace{0.5em}\lesssim 7$ MeV nucleon). In this energy range, maximum angular momentum ‘$l_{\max }$’ in the reaction is lower than or close to the critical or limiting angular momentum for complete fusion ‘$l_{\lim }$(CF).’ The sum-rule model was modified to explain the cross sections of PLFs in the present study. For the first time, the modified sum-rule model, with a competition of incomplete fusion (ICF) reaction with complete fusion below $l_{\lim }$(CF) reasonably reproduced the cross sections of PLFs in the beam energy range of the present study. It was observed that the cross sections of lighter PLFs fall more rapidly with decreasing beam energy compared to those of heavier PLFs, suggesting a change in the reaction mechanism from heavier to lighter PLFs. Transfer probabilities for peripheral collisions were calculated within the framework of a semiclassical formalism. The parameters of the nuclear potential required for the calculation of transfer probability were obtained by fitting the elastic scattering data measured in the present work. Calculated transfer probabilities were significantly lower compared to the corresponding experimental values, suggesting a significant overlap of the projectile and the target nuclei in incomplete fusion reactions. The present analysis showed that the overlap of the projectile and the target nuclei increases with increasing mass transfer at a given beam energy and for a given PLF, overlap increases with increasing beam energy.

We present results for the measurement of $\varphi$ meson production via its charged kaon decay channel $\varphi \to K^{+}{K}^{-}$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=62.4,130$, and 200 GeV, and in $p+p$ and $d+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV from the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC). The midrapidity ($\left|y\right|<0.5$) $\varphi$ meson transverse momentum ($p_T$) spectra in central $\mathrm{Au}+\mathrm{Au}$ collisions are found to be well described by a single exponential distribution. On the other hand, the $p_T$ spectra from $p+p$, $d+\mathrm{Au}$, and peripheral $\mathrm{Au}+\mathrm{Au}$ collisions show power-law tails at intermediate and high $p_T$ and are described better by Levy distributions. The constant $\varphi /K^{-}$ yield ratio vs beam species, collision centrality, and colliding energy is in contradiction with expectations from models having kaon coalescence as the dominant mechanism for $\varphi$ production at RHIC. The $\Omega /\varphi$ yield ratio as a function of $p_T$ is consistent with a model based on the recombination of thermal $s$ quarks up to $p_T~4$ GeV/$c$, but disagrees at higher transverse momenta. The measured nuclear modification factor, $R_{d\mathrm{Au}}$, for the $\varphi$ meson increases above unity at intermediate $p_T$, similar to that for pions and protons, while $R_{\mathit{AA}}$ is suppressed due to the energy loss effect in central $\mathrm{Au}+\mathrm{Au}$ collisions. Number of constituent quark scaling of both $R_{\mathrm{cp}}$ and $v_2$ for the $\varphi$ meson with respect to other hadrons in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV at intermediate $p_T$ is observed. These observations support quark coalescence as being the dominant mechanism of hadronization in the intermediate $p_T$ region at RHIC.

Inclusive measurements of pion production in proton-proton collisions in the forward direction were undertaken at 400 and 600 MeV at the cooler synchrotron (COSY) at Forschungszentrum Julich using the Big Karl spectrograph. The high resolution in the ${\pi }^{+}$ momentum ensured that there was an unambiguous separation of the $\mathit{pp}\to {\pi }^{+}d/{\pi }^{+}\mathit{pn}$ channels. Using these and earlier data, the ratio of the production cross sections could be followed through the Δ region and compared with the predictions of final state interaction theory. Deviations are strongly influenced by long-range terms in the production operator and the tensor force in the final $\mathit{pn}$ system. These have been investigated in a realistic $\mathit{pp}\to {\pi }^{+}d/{\pi }^{+}\mathit{pn}$ calculation that includes $S\rightleftharpoons D$ channel coupling between the final nucleons. A semiquantitative understanding of the observed effects is achieved.

To study the Gamow-Teller (GT) transitions to the $\mathit{pf}$-shell nucleus ${}^{64}\mathrm{Cu}$, the ${}^{64}\mathrm{Ni}({}^3\mathrm{He},t){}^{64}\mathrm{Cu}$ experiment was performed at the Research Center for Nuclear Physics (RCNP) Ring Cyclotron, Osaka, using a ${}^3\mathrm{He}$ beam of 140 MeV/nucleon. The outgoing tritons were momentum analyzed by the Grand Raiden spectrometer at $0^{°}$. A high energy resolution of 32 keV (full width at half-maximum) allowed the separation of individual levels in the excitation-energy region from 0 to 3.5 MeV. In addition to the ground state (gs), known to be a $J^{\pi }=1^{+}$ GT state, many low-lying states showed $L=0$ nature, suggesting that they are candidates for GT states. Because the GT strength $B(\mathrm{GT})$ for the gs transition is known from the $\beta$-decay measurement, the strengths for the excited states could be determined using the proportionality between the $B(\mathrm{GT})$ and the reaction cross section extrapolated to $q=0$ momentum transfer. At higher excitation energies, the level density becomes high and the so-called GT giant resonance dominates the spectrum. The lower and the upper limits of the strength contained in this energy region were estimated. Our results show that less than 55% of the strength predicted by the Ikeda sum rule is located in the excitation-energy region from 0 to 17 MeV.

We investigate the consequences of space-momentum correlations in quark phase-space distributions for coalescence processes at the hadronization transition. Thus far it has been proved difficult to reconcile such correlations with the empirically observed constituent quark number scaling (CQNS) at the Relativistic Heavy Ion Collider (RHIC). To address this problem we combine our earlier developed quark recombination model with quark phase-space distributions computed from relativistic Langevin simulations in an expanding quark-gluon plasma (QGP). Hadronization is based on resonance formation within a Boltzmann equation that recovers thermal equilibrium and obeys energy conservation in the quark-coalescence process, while the fireball background is adjusted to hydrodynamic simulations of semicentral $\mathrm{Au}\text{−}\mathrm{Au}$ collisions at RHIC. To facilitate the applicability of the Langevin process, we focus on strange and charm quarks. Their interactions in the QGP are modeled using leading-order perturbative QCD augmented by effective Lagrangians with resonances that smoothly merge into hadronic states formed at $T_c$. The interaction strength is adjusted to reproduce the empirical saturation value for the quark-elliptic flow, $v_{2,q}^{\mathrm{sat}}\simeq 7\text{−}8\%$. The resulting ϕ and $J/\psi$ elliptic flow recover CQNS over a large range in transverse momentum ($p_T$) within a few percent. As a function of transverse kinetic energy, both the quark spectra from the Langevin simulations and the meson spectra generated via resonance recombination recover CQNS from zero to at least $3\hspace{0.5em}\mathrm{GeV}$.

One of the few $p$ nuclei with an odd number of protons is ${}^{113}\mathrm{In}$. Reaction cross sections of ${}^{113}\mathrm{In}(\alpha ,\gamma ){}^{117}\mathrm{Sb}$ and ${}^{113}\mathrm{In}(\alpha ,n){}^{116}\mathrm{Sb}$ have been measured with the activation method at center-of-mass energies between 8.66 and 13.64 MeV, close to the astrophysically relevant energy range. The experiments were carried out at the cyclotron accelerator of ATOMKI. The activities were determined by off-line detection of the decay $\gamma$ rays with a HPGe detector. Measured cross sections and astrophysical $S$ factor results are presented and compared with statistical model calculations using three different $\alpha +$nucleus potentials. The comparison indicates that the standard rates used in the majority of network calculations for these reactions were too fast due to the energy dependence of the optical $\alpha$ potential at low energy.

The nuclei ${}^{131}\mathrm{I}$ and ${}^{133}\mathrm{I}$ have been populated in multinucleon transfer reactions between ${}^{136}\mathrm{Xe}$ ions and various targets, and their structure has been investigated by time-correlated $\gamma$-ray coincidence spectroscopy and the measurement of $\gamma$-ray angular correlations. A $19/2^{-}$ isomer at 1918 keV, with a half-life of 24(1) μs, has been identified in ${}^{131}\mathrm{I}$, as well as nanosecond isomers with $J^{\pi }=23/2^{+}$ in both isotopes. A $T_{1/2}=25(3)$ ns isomer at 4308 keV in ${}^{131}\mathrm{I}$ is suggested to have $J^{\pi }=(31/2^{-},33/2^{-})$ and is primarily attributed to the coupling of an odd proton in the $d_{5/2}$ or $g_{7/2}$ orbit with the $({\pi }^2){}_{0^{+}}(\nu h_{11/2}^{-3}{d}_{3/2}^{-1}){}_{{15}^{-}}$ configuration in ${}^{130}\mathrm{Te}$ responsible for the ${15}^{-}$ isomer in that nucleus. The observed level properties are compared with predictions of a shell-model calculation.