Revisiting the Ω(2012)\Omega(2012) as a hadronic molecule and its strong decays

Recently, the Belle collaboration measured the ratios of the branching fractions of the newly observed $\Omega(2012)$ excited state. They did not observe significant signals for the $\Omega(2012) \to \bar{K} \Xi^*(1530) \to \bar{K} \pi \Xi$ decay, and reported an upper limit for the ratio of the three body decay to the two body decay mode of $\Omega(2012) \to \bar{K} \Xi$. In this work, we revisit the newly observed $\Omega(2012)$ from the molecular perspective where this resonance appears to be a dynamically generated state with spin-parity $3/2^-$ from the coupled channels interactions of the $\bar{K} \Xi^*(1530)$ and $\eta \Omega$ in $s$-wave and $\bar{K} \Xi$ in $d$-wave. With the model parameters for the $d$-wave interaction, we show that the ratio of these decay fractions reported recently by the Belle collaboration can be easily accommodated.Comment: Published version. Published in Eur.\ Phys.\ J.\ C {\bf 80}, 361 (2020

Structure Analysis of Molybdenum, Osmium, and Iridium Organometallic Compound and of an Organic Charge-Transfer Salt.

The crystal and molecular structures of four compounds have been determined by X-ray diffraction. Red crystals of 2,6-bis (1-(2,2-dimethylpropanimino)ethyl) pyridine tetracarbonylmolybdenum(0), Mo(CO)\sb4(C\sb{19}N\sb3H\sb{31}), are orthorhombic, Pbca, Z = 8, a = 16.625(6), b = 17.185(3), c = 17.438(3) A; R = 0.0375 over 317 variables and 1454 observed reflections. Mo coordination is distorted octahedral with the organic ligand bonded to the metal at two of three possible Lewis base sites. Crystals of bis(triphenylphosphine)carbonyl (2,2-dicyanoethylidenamino)iridium(I), Ir(PPh\sb3)\sb2(CO)(C\sb4N\sb3), are triclinic, P1, Z = 2, a = 11.615(9), b = 12.562(9), c = 16.976(12) A, $\alpha$ = 91.24(7), $\beta$ = 99.46(5), $\gamma$ = 114.91(6)\sp\circ; R = 0.0473 over 185 parameters and 2383 observed reflections. One cyano group of the 2,2-dicyanoethylidenamino (TCM) ligand is disordered. On the basis of least squares refinement and quantum mechanical calculations of several models, it is concluded that the TCM anion, when coordinated to Ir, has an excited state pyramidal geometry. Bright yellow crystals of bis(ethylene)(hexamethylbenzene)osmium(0), OS(C\sb2H\sb4)\sb2(C\sb6Me\sb6), are triclinic, P1, a = 7.776(2), b = 9.162(3), c = 12.113(2) A, $\alpha$ = 71.53(2), $\beta$ = 78,72(1), $\gamma$ = 62.46(2)\sp\circ; R = 0.028 over 209 variables and 3766 observed reflections. Both the ethylene groups and the hexamethylbenzene are $\pi$-complexed to Os. The symmetry of the hexamethylbenzene has been reduced from D\sb6h to C\sb2v as a result of d$\pi$-p$\pi$* back bonding. The deformation parameters of the ethylene groups are large indicating strong d$\pi$-p$\pi$* back bonding of these ligands. Black, lustrous crystals of a new non-superconducting phase of bis(bis-ethylenedithiatetrathiafulvalenium)diiodoaurate(I), (BEDT-TTF)\sb2AuI\sb2, are orthorhombic, Pbcm, Z = 4, a = 6.799(3), b = 14.820(3), c = 32.836(6) A; R = 0.064 over 177 variables and 1638 observed reflections. Short intermolecular S-S contact distances, characteristic of these salts, are observed. However, the packing mode in this orthorhombic salt is different from that in the superconducting phase. The crystal structure of another new phase of (BEDT-TTF)\sb2AuI\sb2 has been only partially determined due to twinning. The present structural model gives R = 0.120 over 1848 reflections in a triclinic lattice, a = 5.728(2), b = 9.045(3), c = 16.351(9) A, $\alpha$ = 91.91, $\beta$ = 97.56, $\gamma$ = 103.28\sp\circ. Ab initio quantum mechanical calculations have been carried out on bis-ethylenedithiatetrathiafulvalene (ET) and tetramethyltetrathselenafulvalene (TMTSF). Orbital coefficients and HOMO density plots are presented as part of a long term study of the band structure of organic superconductors

catena-Poly[[bis­(nitrato-κO)copper(II)]-μ-1,4-bis­(4,5-dihydro-1,3-oxazol-2-yl)­benzene-κ2 N:N′]

In the title coordination polymer, [Cu(NO3)2(C12H12N2O2)]n, the CuII ion, situated on an inversion center, is coordinated by two O atoms from two nitrate anions and two N atoms from two 1,4-bis­(4,5-dihydro-1,3-oxazol-2-yl)benzene (L) ligands in a distorted square-planar geometry. Each L ligand also lies across an inversion center and bridges two CuII ions, forming a polymeric chain running along the [101] direction. The three O atoms of the nitrate group are disordered over two positions in a 3:2 ratio

Modeling of polyethylene, poly(l-lactide), and CNT composites: a dissipative particle dynamics study

Dissipative particle dynamics (DPD), a mesoscopic simulation approach, is used to investigate the effect of volume fraction of polyethylene (PE) and poly(l-lactide) (PLLA) on the structural property of the immiscible PE/PLLA/carbon nanotube in a system. In this work, the interaction parameter in DPD simulation, related to the Flory-Huggins interaction parameter χ, is estimated by the calculation of mixing energy for each pair of components in molecular dynamics simulation. Volume fraction and mixing methods clearly affect the equilibrated structure. Even if the volume fraction is different, micro-structures are similar when the equilibrated structures are different. Unlike the blend system, where no relationship exists between the micro-structure and the equilibrated structure, in the di-block copolymer system, the micro-structure and equilibrated structure have specific relationships

N 1,N 2-Bis(6-methyl-2-pyrid­yl)formamidine

In the crystal structure of the title mol­ecule, C13H14N4, the two pyridyl rings are not coplanar but twisted about the C—N bond with an inter­planar angle of 71.1 (1)°. In the crystal, the mol­ecules form dimers, situated on crystallographic centres of inversion, which are connected via a pair of N—H⋯N hydrogen bonds. C—H⋯π-electron ring inter­actions are also present in the crystal structure. The title mol­ecule adopts an s–cis–anti–s–cis conformation in the solid state

Radiative decays of the neutral Zc(3900)Z_c(3900) and Zc(4020)Z_c(4020)

We study the radiative decays $Z_c(3900)/Z_c(4020) \to \gamma \chi_{cJ}(\gamma\chi_{cJ}^\prime)$ ($J=0, 1, 2$), with the assumption that the $Z_c(3900)$ and $Z_c(4020)$ couple strongly to $D\bar D^* +c.c$ and $D^*{\bar D}^*$ channel, respectively. By considering the contributions of intermediate charmed mesons triangle loops within an effective Lagrangian approach, it is shown that the calculated partial widths of $Z_c(3900) \to \gamma \chi_{cJ}$ are about a few hundreds keVs, while the obtained partial widths $Z_c(4020) \to \gamma \chi_{cJ}$ are about tens of keVs. The predicted partial widths of $Z_c(3900)\to\gamma\chi_{c0,1}^\prime$ are less than 1 keV, which mainly due to the very small phase space. For $Z_c(4020)\to\gamma\chi_{c0,2}^\prime$, the calculated partial widths are usually smaller than 1 keV. For the $Z_c(4020)\to\gamma\chi_{c1}^\prime$ process, the obtained partial widths can reach up to the order of 10 keV. Furthermore, the dependence of these ratios between different decay modes on the masses of $Z_c(3900)$ or $Z_c(4020)$ are also investigated, which may be a good quantity for the experiments. It is hoped that these calculations here could be tested by future experiments.Comment: 9 pages, 6 figures. Accepted by Physical Review

Stateless Two-Stage Multiple Criteria Scheduling in Nuclear Medicine

Examination in nuclear medicine exhibits scheduling difficulties due to its intricate clinical issues, such as varied radiopharmaceuticals for different diseases, machine preparation and length of scan, and patients’ and hospital’s criteria and/or limitations. Many scheduling methods exist but are limited for nuclear medicine. In this paper, we present stateless two-stage scheduling to cope with multiple criteria decision making. The first stage mostly deals with patients’ conditions. The second stage concerns more the clinical condition and its correlations with patients’ preference which presents more complicated intertwined configurations. A greedy algorithm is proposed in the second stage to determine the (time slot and patient) pair in linear time. The result shows practical and efficient scheduling for nuclear medicine