Relativistic corrections to J/ψJ/\psi exclusive and inclusive double charm production at B factories

In order to clarify the puzzling problems in double charm production, relativistic corrections at order $v^{2}$ to the processes $e^{+}e^{-}\to J/\psi+\eta_{c}$ and $e^{+}e^{-}\to J/\psi+c\bar{c}$ at B factories are studied in non-relativistic quantum chromodynamics. The short-distance parts of production cross sections are calculated perturbatively, while the long-distance matrix elements are estimated from $J/\psi$ and $\eta_c$ decays up to errors of order $v^4$. Our results show that the relativistic correction to the exclusive process $e^{+}e^{-}\to J/\psi+\eta_{c}$ is significant, which, when combined together with the next-to-leading order $\alpha_{s}$ corrections, could resolve the large discrepancy between theory and experiment; whereas for the inclusive process $e^{+}e^{-}\to J/\psi+c\bar{c}$ the relativistic correction is tiny and negligible. The physical reason for the above difference between exclusive and inclusive processes largely lies in the fact that in the exclusive process the relative momentum between quarks in charmonium substantially reduces the virtuality of the gluon that converts into a charm quark pair, but this is not the case for the inclusive process, in which the charm quark fragmentation $c\to J/\psi+c$ is significant, and QCD radiative corrections can be more essential.Comment: Version to appear in PRD. In the summary an explicit statement added: "for the J/\psi eta_c cross section the relativistic correction alone gives an enhancement factor of 1.7 while the combination of relativistic correction with QCD radiative correction results in a much larger enhancement factor of 9". One reference added. A few typos correcte

Search for excited charmonium states in e+e−e^+e^- Annihilation at s=10.6\sqrt{s}=10.6 GeV

We suggest searching for excited charmonium states in $e^+e^-$ annihilation via double charmonium production at $\sqrt{s}=10.6$ GeV with $B$ factories, based on a more complete leading order calculation including both QCD and QED contributions for various processes. In particular, for the C=+ states, the $\chi_{c0}(nP)$ (n=2,3) and $\eta_c(mS)$ (m=3,4) may have appreciable potentials to be observed; while for the C=- states, the $\eta_ch_c$ production and especially the $\chi_{c1}h_c$ production might provide opportunities for observing the $h_c$ with higher statistics in the future. A brief discussion for the X(3940) observed in the double charmonium production is included.Comment: 13 pages and 8 figures in PRD version; QED contribution added; experimental and theoretical developments since 2004 summarized; references adde

QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems

We review the developments of QCD multipole expansion and its applications to hadronic transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compsred with updated experimental results.Comment: 23 pages, 7 figures. Some typos corrected, and 3 references adde

The Causal Boundary of spacetimes revisited

We present a new development of the causal boundary of spacetimes, originally introduced by Geroch, Kronheimer and Penrose. Given a strongly causal spacetime (or, more generally, a chronological set), we reconsider the GKP ideas to construct a family of completions with a chronology and topology extending the original ones. Many of these completions present undesirable features, like those appeared in previous approaches by other authors. However, we show that all these deficiencies are due to the attachment of an ``excessively big'' boundary. In fact, a notion of ``completion with minimal boundary'' is then introduced in our family such that, when we restrict to these minimal completions, which always exist, all previous objections disappear. The optimal character of our construction is illustrated by a number of satisfactory properties and examples.Comment: 37 pages, 10 figures; Definition 6.1 slightly modified; multiple minor changes; one figure added and another replace

N -Methyl-D-Aspartate-Mediated Injury Enhances Quisqualic Acid-Stimulated Phosphoinositide Turnover in Perinatal Rats

Previous work in our laboratory demonstrated that ischemic-hypoxic brain injury in postnatal day 7 rats causes a substantial increase in phosphoinositide (PPI) turnover stimulated by the glutamate analogue quisqualic acid (QUIS) in the hippocampus and striatum. To examine this phenomenon in more detail, we performed similar experiments after producing injury by unilateral intracerebral injections of the glutamate analogue N -methyl-D-aspartate (NMDA). The 7-day-old rodent brain is hypersensitive to NMDA neurotoxicity and NMDA injection causes histopathology that closely resembles that produced by ischemia-hypoxia. NMDA, 17 nmol in 0.5 Μl, was injected into the right posterior striatum of 7-day-old rat pups and they were killed 3 days later. Hippocampal or striatal tissue slices were prepared from ipsilateral and contralateral hemispheres from vehicle-injected control and from noninjected control rat pups. Slices were then incubated with myo -[ 3 H]inositol plus glutamate agonists or antagonists in the presence of lithium ions and [ 3 H]inositol monophosphate ([ 3 H]IP 1 ) accumulation was measured. The glutamate agonists, QUIS, L-glutamic acid, and ( RS )-Α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, stimulated greater [ 3 H]IP 1 release in tissue ipsilateral to the NMDA injection compared with that in the contralateral side and in control pups. The glutamate antagonists, D,L-2-amino-7-phosphonoheptanoic acid, 3-[(+)-2-carboxypiperazin-4-yl]-propyl-l-phosphoric acid, kynurenic acid, and 6,7-dinitroquinoxaline-2,3-dione did not inhibit QUIS-stimulated [ 3 H]IP 1 release. The enhanced PPI turnover in the lesioned tissue was specific to glutamate receptors because carbachol (CARB) failed to elicit preferential enhanced stimulation. To investigate the possibility that alterations in the release of endogenous neurotransmitters had a role in potentiating QUIS-stimulated PPI turnover after NMDA injection, we examined the effect of tetrodotoxin. Tetrodotoxin (0.5 Μ M ) did not alter QUIS-or CARB-stimulated PPI hydrolysis in the lesioned or unlesioned tissue. The influence of extracellular calcium concentration on QUIS-stimulated [ 3 H]IP 1 formation was also examined after the NMDA lesion. Moderate reduction of calcium in the buffer (1 Μ M ) enhanced the lesion effect. Low calcium buffer enhanced QUIS-stimulated PPI turnover in the lesioned hippocampal slices, but reduced QUIS stimulation in contralateral slices and controls. In contrast, CARB-stimulated PPI turnover was not enhanced in low Ca 2+ buffer. A similar pattern of Ca 2+ dependency was observed in striatal slices. Calcium-free (<10 n M ) buffer suppressed PPI turnover in all groups. These studies demonstrate that NMDA-induced excitotoxic injury in neonatal rats causes a selective enhancement of QUIS-stimulated PPI turnover that resembles the effects of ischemia-hypoxia. In addition, we found that agonist-stimulated PPI turnover is sensitive to the in vitro Ca 2+ concentration. These changes could reflect altered coupling of non-NMDA receptors to phospholipase C activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65991/1/j.1471-4159.1992.tb08337.x.pd

Coulomb drag between quantum wires with different electron densities

We study the way back-scattering electron--electron interaction generates Coulomb drag between quantum wires with different densities. At low temperature $T$ the system can undergo a commensurate-- incommensurate transition as the potential difference $|W|$ between the two wires passes a critical value $\Delta$, and this transition is reflected in a marked change in the dependence of drag resistivity on $W$ and $T$. At high temperature a density difference between the wires suppresses Coulomb drag induced by back scattering, and we use the Tomonaga--Luttinger model to study this suppression in detail.Comment: 6 pages, 4 figure

Pendekatan Multiple Overhead Rates Pada JOC System Di PT. Mgt

PT MGT is a garment company that manufactures various types of outerwear men. The process ofmanufacture or finishing of products based on the production schedule (order from the marketingdepartment). Product costing applied by companies is accumulating direct materials cost (fabricsand accessories), direct labor cost, overhead cost, washing materials cost, and retro cost. Thecompany used actual costing system to measure the production cost, so that the management cannotknow production cost reporting at any time. Job-order costing systems is the answer for thecompay's necessity to calculating the product cost. The authors will describe job-order costingsystems step by step. There is a difference between company's calculation version with the authorsproposed. The results of calculations performed by company to AX 037 MTWQ is Rp43, 907.28while using the job-order system is Rp42, 162.35. The results of calculations performed by companyto RPBC 073 CH / K is Rp27, 553.09, while using the job-order system is Rp23, 895.49. Thedifference is due to the differences in classification and overhead cost allocation method usingmultiple rates

Giant oscillations in a triangular network of one-dimensional states in marginally twisted graphene

The electronic properties of graphene superlattices have attracted intense interest that was further stimulated by the recent observation of novel many-body states at "magic" angles in twisted bilayer graphene (BLG). For very small ("marginal") twist angles of 0.1 deg, BLG has been shown to exhibit a strain-accompanied reconstruction that results in submicron-size triangular domains with the Bernal stacking. If the interlayer bias is applied to open an energy gap inside the domain regions making them insulating, marginally-twisted BLG is predicted to remain conductive due to a triangular network of chiral one-dimensional (1D) states hosted by domain boundaries. Here we study electron transport through this network and report giant Aharonov-Bohm oscillations persisting to temperatures above 100 K. At liquid helium temperatures, the network resistivity exhibits another kind of oscillations that appear as a function of carrier density and are accompanied by a sign-changing Hall effect. The latter are attributed to consecutive population of the flat minibands formed by the 2D network of 1D states inside the gap. Our work shows that marginally twisted BLG is markedly distinct from other 2D electronic systems, including BLG at larger twist angles, and offers a fascinating venue for further research.Comment: 11 pages, 8 figure