Narrow Results

Variational calculations are carried out with a multiconfiguration-interaction wave function to obtain the relativistic energies of the 1s² 2 ln l ¹S(m)(n =2–6, m1–5) states for the beryllium isoelectronic sequence (Z =4–10). Relativistic corrections and the mass polarization effects are evaluated with the first-order perturbation theory. The identifications of the energy levels for 1s² 2 ln l ¹S(m)(n =2–6, m1–5) states in the Be-like ions are reported. The oscillator strengths, transition rates and wavelengths are also calculated. The calculated results are compared with other theoretical and experimental data in the literature.

Time evolution of the cities and languages is considered in terms of multiplicative noise¹ and fragmentation² processes; where power law (Pareto-Zipf law)³ and slightly asymmetric log-normal (Gauss)⁴ distribution result for the size distribution of the cities and for that of the languages, respectively. The cities and the languages are treated differently (and as connected; for example, the languages split in terms of splitting the cities, etc.) and thus two distributions are obtained in the same computation at the same time. Evolutions of lifetimes and families for the cities and the languages are also studied. We suggest that the regularities may be evolving out of randomness, in terms of the relevant processes.

We study a model for freeway traffic which includes strong noise taking into account the fluctuations of individual driving behavior. The model shows emergent traffic jams with a self-similar appearance near the throughput maximum of the traffic. The lifetime distribution of these jams shows a short scaling regime, which gets considerably longer if one reduces the fluctuations when driving at maximum speed but leaves the fluctuations for slowing down or accelerating unchanged. The outflow from a traffic jam self-organizes into this state of maximum throughput.

We present the more recent measurements of the B hadrons lifetimes and its ratios, performed using 250 pb^-1 of the Run II data collected with the DØ detector at Tevatron.

Heavy flavor baryons are attractive systems for testing effective theories for weak lifetime and decay systematics. Recently, new experimental results have mitigated one historic problem in the weak lifetime systematics and continued another. The charm baryon system continues to show new high mass, narrow states well isolated from one another. The spectroscopy of these states will challenge new advances in lattice gauge theoretic calculations of baryon structure. Double charm baryons still are seen only by SELEX, which showed a new candidate. High-sensitivity searches by BELLE and BaBar show only featureless background.

We present a review of heavy flavor physics results from the CDF and DØ Collaborations operating at the Fermilab Tevatron Collider. A summary of results from Run 1 is included, but we concentrate on legacy results of charm and b physics from Run 2, including results up to Summer 2014.

From femtosecond spectroscopy (fs-spectroscopy) of metals, electrons and phonons reequilibrate nearly independently, which contrasts with models of heat transfer at ordinary temperatures ($T>100$ K). These electronic transfer models only agree with thermal conductivity $(k)$ data at a single temperature, but do not agree with thermal diffusivity $(D)$ data. To address the discrepancies, which are important to problems in solid state physics, we separately measured electronic (ele) and phononic (lat) components of $D$ in many metals and alloys over $\sim$290–1100 K by varying measurement duration and sample length in laser-flash experiments. These mechanisms produce distinct diffusive responses in temperature versus time acquisitions because carrier speeds $(u)$ and heat capacities $(C)$ differ greatly. Electronic transport of heat only operates for a brief time after heat is applied because $u$ is high. High $D_{\mathrm{\text{ele}}}$ is associated with moderate $T$, long lengths, low electrical resistivity, and loss of ferromagnetism. Relationships of $D_{\mathrm{\text{ele}}}$ and $D_{\mathrm{\text{lat}}}$ with physical properties support our assignments. Although $k_{\mathrm{\text{ele}}}$ reaches $\sim 20\times k_{\mathrm{\text{lat}}}$ near 470 K, it is transient. Combining previous data on $u$ with each $D$ provides mean free paths and lifetimes that are consistent with $\sim 298$ K fs-spectroscopy, and new values at high $T$. Our findings are consistent with nearly-free electrons absorbing and transmitting a small fraction of the incoming heat, whereas phonons absorb and transmit the majority. We model time-dependent, parallel heat transfer under adiabatic conditions which is one-dimensional in solids, as required by thermodynamic law. For noninteracting mechanisms, $k\cong \mathrm{\Sigma }{C}_i{k}_i\mathrm{\Sigma }{C}_i/(\mathrm{\Sigma }{C}_i^2)$. For metals, this reduces to $k=k_{\mathrm{\text{lat}}}$ above $\sim$20 K, consistent with our measurements, and shows that Meissner’s equation $(k\cong k_{\mathrm{\text{lat}}}+k_{\mathrm{\text{ele}}})$ is invalid above $\sim$20 K. For one mechanism with multiple, interacting carriers, $k\cong \mathrm{\Sigma }{C}_i{k}_i/(\mathrm{\Sigma }{C}_i)$. Thus, certain dynamic behaviors of electrons and phonons in metals have been misunderstood. Implications for theoretical models and technological advancements are briefly discussed.

In this work, the conducting properties of graphene lattice with a particular concentration of defect (5% and 10%) has been studied. The real space block recursion method introduced by Haydock et al. has been used in presence of the random distribution of defects in graphene. This Green function based method is found to be more powerful than the usual reciprocal based methods which need artificial periodicity. Different resonant states appear because of the presence of topological and local defects are studied within the framework of Green function.

The low-lying states of ⁷¹Ge have been studied the via the ⁷¹Ga (p,n γ)⁷¹Ge reaction using proton beam energies of 2.5–4.3 MeV. The angular distributions have been used to assign the spins and the multipole mixing ratios using statistical theory for compound nuclear reactions. The ambiguity in the spin values for the various levels has been removed. The multipole mixing ratios for a few γ-transitions have been newly measured. The lifetimes of the levels at 747.0, 808.0, 831.1, 1377.8, 1406.6, 1414.4, 1422.1, 1558.8 and 1566.1 keV excitation energies have been measured for the first time using the Doppler shift attenuation method.

The separation energy and half-life of some heavy proton emitting nuclei, and the single-particle structure of unbound ¹¹N, have been evaluated by implementing a careful numerical treatment to solve the Schrödinger equation in a continuum discretization context. The basic scheme behind the method consists in using the ground-state proton emitter in connection with an isolated single-particle resonance.

The excited states of ⁷³As have been investigated via the ⁷³Ge(p, nγ)⁷³As reaction with proton beam energies from 2.5–4.3 MeV. The lifetimes of the levels at 769.6, 860.5, 1177.8, 1188.7, 1274.9, 1344.1, 1557.1 and 1975.2 keV excitation energies have been measured for the first time using the Doppler shift attenuation method. The angular distributions have been used to assign the spins and the multipole mixing ratios using statistical theory for compound nuclear reactions. The ambiguity in the spin values for the various levels has been removed. The multipole mixing ratios for eight γ-transitions have been newly measured.

This study reports the $\alpha$-decay half-lives of 39 transfermium isotopes with $Z=105-113$, most of which have not been observed. The half-lives were calculated using micro–macroscopic approaches and semi-empirical formulae, applying current $\alpha$-decay Q-values from the latest mass database, AME2016. These results were compared to predicted values in previous works to evaluate the efficiency of and difference between various calculation methods. We found that the $\alpha$-resonance approach used in a previous study is not appropriate to predict though most other approaches are mutually consistent. An uncertainty of 70% was observed in the present theoretical calculations, similar to that observed in measurements. A Q-value uncertainty of 10% can lead to a large variation of 3 orders of magnitude in predicted $\alpha$-decay half-life. We also found that the dominance of either $\alpha$ decay or spontaneous fission is unclear for the isotopes with $Z=105$–$108$, whereas most of the nuclei of $Z=109$–$113$ can be clearly identified as $\alpha$ emitters. Finally, we provide the updated $\alpha$-decay half-lives for the isotopes of interest, including their uncertainties and corresponding decay modes.

Proton radioactivity of neutron-deficient nuclei with atomic numbers $Z=51$–91 and mass number 104–211 is investigated using the analytical super-asymmetric fission (ASAF) model — a model used to study $\alpha$-decay and cluster radioactivity since 1984. The experimental $Q_p$ values are compared with calculated ones based on WS4 (Y. Z. Wang et al., 2014–2015), and in few cases KTUY05 (H. Koura et al., 2005) mass models. Proton drip-line and neutron drip-line are determined using the WS4 mass model. We compare the calculated results with experimental half-lives, showing good agreement.

We explored $\gamma$-ray mean lifetimes of transitions $2^{+}\to 0^{+}$ state suggested by earlier researchers such as Grodzins [Phys. Lett. 2 (1962)], Bohr and Mettelson [Mat. Fys. Medd. Dan. Vid. Selsk 27 (1953) 1], Wang’s formula [Chin. J. Phys. 18 (1980) 151], and best global fit formulae [Phys. Rev. C 37 (1988) 805], equations accessible in the literature for nuclei ranging from ${}^{128}$Ce to ${}^{252}$Fm. Also, as compared to other equations accessible in the literature, the standard deviation observed utilizing Grodzins formula with regard to experiments was lower. We also forecasted $\gamma$-ray mean lifetimes of transitions $2^{+}\to 0^{+}$ state and $B(E2)$-values for nuclei ranging from ${}^{122}$Ce to ${}^{256}$Fm. Around 136 even–even nuclei’s mean lifetimes and $B(E2)$-values are predicted which are helpful in the Coulomb fission process.

A complex system consisting of k phases is considered in this study. Its functioning is such that the control shifts sequentially within different phases to complete their assigned task. Missiles, rockets and electronic exploders used to fire electric detonators are examples of such systems. The components in different subsystems are in a parallel configuration. Their lifetimes are assumed to be independent and identical random variables that follow exponential distribution. The distribution function of system operational time is obtained when all subsystem operational times are unobserved. The method of maximum likelihood is used to estimate unknown parameter of system operational time's distribution. An estimate of system reliability is provided through simulations.

We determine the wavefunctions of electrons bound to a positively charged mesoscopic metallic cluster covered by an insulating surface layer. The radius of the metal core and the thickness of the insulating surface layer are of the order of a couple of Ångström. We study, in particular, the electromagnetic decay of externally located electrons into unoccupied internally located states that exhibit a resonance behavior. This resonance structure has the consequence that the lifetime of the "mesoscopic atoms" may vary by up to six orders of magnitude depending on the values of the parameters (from seconds to years).

The synthesis of a phthalocyanine-porphyrin heteropentamer (zinc(II) tetra(5-phenoxy-10,15,20-triphenylporphyrin)) zinc(II) phthalocyanine, (ZnPc-(ZnTPP)₄), containing four units of zinc tetraphenylporphyrin linked to a central zinc phthalocyanine macrocycle via an ether linkage is reported. The photophysical parameters of the pentamer are reported in toluene and dimethyl sulfoxide (DMSO). The observed differences in the fluorescence behavior of the pentamer in the two solvents is explained in terms of emission from different states; charge transfer state in DMSO and locally excited state in toluene. The rate constants for fluorescence, intersystem crossing, internal conversion, and of charge and energy transfer are reported for the pentamer. Quantum yields for fluorescence, internal conversion, triplet state and of charge and energy transfer are also reported for the pentamer, ZnPc-(ZnTPP)₄ and the mixture of ZnPc and ZnTPP. The latter two parameters are higher in the pentamer compared to a mixture containing ZnPc and ZnTPP.

The deformation energy of ²⁹⁴118 is calculated by using the Yukawa-plus-exponential model and the shell and pairing corrections based on the two-center shell model. The α valley of ¹⁰⁶Te is clearly seen on the PES. The half-lives of α-emitters are determined by means of the analytical superasymmetric fission model, the universal curve, and a semiempirical formula based on fission theory (semFIS). The increased deviations in the neighbourhood of magic numbers of nucleons, present in other relationships, are smoothed out by semFIS, leading to the best fit with experimental results. The experimental lifetimes of 142 transuranium α-emitters including superheavies are compared with theoretical results.

Being influenced by both evolving collectivity and single-particle excitations, exotic nuclei beyond the ¹³²Sn are studied in several experimental attempts. Here, we present the systematics on recent isomeric lifetime studies on very-neutron rich ^136,140Sb and ¹⁴²I isotopes in the μs range using the EURICA spectrometer at the RIKEN/RIBF beam factory and first lifetime studies in the less-neutron-rich _136,138I isotopes in the sub-ns range using the EXILL/FATIMA spectrometer at the ILL.

Microscopic theories of alpha decay and cluster radioactivity explain these decay modes as a quantum tunneling of a preformed cluster at the nuclear surface. In the present work we show for the first time that in a spontaneous cold fission process the shell plus pairing corrections calculated with Strutinsky’s procedure may give a strong argument for preformation of a light fission fragment near the nuclear surface. It is obtained when the radius of the light fragment, R₂, is increased linearly with the separation distance, R, of the two fragments, while for R₂ = constant one gets the well known two hump potential barrier. Nuclear physics community also contributed to nanocluster physics by applying the macroscopic-microscopic method to explain the shell effects experimentally observed since 1984.