1,660 research outputs found
Power Counting and Perturbative One Pion Exchange in Heavy Meson Molecules
We discuss the possible power counting schemes that can be applied in the
effective field theory description of heavy meson molecules, such as the
X(3872) or the recently discovered Zb(10610) and Zb(10650) states. We argue
that the effect of coupled channels is suppressed by at least two orders in the
effective field theory expansion, meaning that they can be safely ignored at
lowest order. The role of the one pion exchange potential between the heavy
mesons, and in particular the tensor force, is also analyzed. By using
techniques developed in atomic physics for handling power-law singular
potentials, which have been also successfully employed in nuclear physics, we
determine the range of center-of-mass momenta for which the tensor piece of the
one pion exchange potential is perturbative. In this momentum range, the one
pion exchange potential can be considered a subleading order correction,
leaving at lowest order a very simple effective field theory consisting only on
contact-range interactions.Comment: 21 pages, 1 figur
A Lattice Test of 1/N_c Baryon Mass Relations
1/N_c baryon mass relations are compared with lattice simulations of baryon
masses using different values of the light-quark masses, and hence different
values of SU(3) flavor-symmetry breaking. The lattice data clearly display both
the 1/N_c and SU(3) flavor-symmetry breaking hierarchies. The validity of 1/N_c
baryon mass relations derived without assuming approximate SU(3)
flavor-symmetry also can be tested by lattice data at very large values of the
strange quark mass. The 1/N_c expansion constrains the form of discretization
effects; these are suppressed by powers of 1/N_c by taking suitable
combinations of masses. This 1/N_c scaling is explicitly demonstrated in the
present work.Comment: 13 pages, 20 figures; v2 version to be published in PR
The Heavy Quark Spin Symmetry Partners of the X(3872)
We explore the consequences of heavy quark spin symmetry for the charmed
meson-antimeson system in a contact-range (or pionless) effective field theory.
As a trivial consequence, we theorize the existence of a heavy quark spin
symmetry partner of the X(3872), with , which we call X(4012) in
reference to its predicted mass. If we additionally assume that the X(3915) is
a heavy spin symmetry partner of the X(3872), we end up predicting a
total of six molecular states. We also discuss the error
induced by higher order effects such as finite heavy quark mass corrections,
pion exchanges and coupled channels, allowing us to estimate the expected
theoretical uncertainties in the position of these new states.Comment: 18 pages; final version accepted for publicatio
Maturity Pattern of Assets and Liabilities: a Case Study of Canara Bank
This paper discusses the issues in relating to the maturity pattern of asset and liabilities of the bank i.e. Canara bank under study. It examines the maturity patterns of both assets and liabilities under different time buckets and analyses the implication of different mismatches.It also throws on the impact of an overall gap on bank's profitability and liquidity and elaborates on various categories of risk that require to be managed. The data had been collected from the secondary sources such as annual reports of Canara Bank, reports and websites etc. It has been found in the study that proper liability mix technique is a successful tool for minimizing the risk
Exotic mesons with double charm and bottom flavor
We study exotic mesons with double charm and bottom flavor, whose quark
configuration is \bar{Q}\bar{Q}qq. This quark configuration has no annihilation
process of quark and antiquark, and hence is a genuinely exotic states. We take
a hadronic picture by considering the molecular states composed of a pair of
heavy mesons, such as DD, DD* and D*D* for charm flavor, and BB, BB* and B*B*
for bottom flavor. The interactions between heavy mesons are derived from the
heavy quark effective theory. All molecular states are classified by I(J^P)
quantum numbers, and are systematically studied up to the total angular
momentum J \leq 2. By solving the coupled channel Schrodinger equations, due to
the strong tensor force of one pion exchanging, we find bound and/or resonant
states of various quantum numbers.Comment: 24 pages, 3 figure
Purification, physicochemical and regulatory properties of serine hydroxymethyltransferase from sheep liver
Serine hydroxymethyltransferase (EC 2.1.2.1) was purified from the cytosolic fraction of sheep liver by ammonium sulphate fractionation, CM-Sephadex chromatography, gel filtration using Ultrogel ACA 34 and Blue Sepharose affinity chromatography. The homogeneity of the enzyme was rigorously established by Polyacrylamide gel and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, isoelectrofocusing, ultracentrifugation, immunodiffusion and Immunoelectrophoresis. The enzyme was a homotetramer with a molecular weight of 210,000 ± 5000. The enzyme showed homotropic cooperative interactions with tetrahydrofolate (nH = 2.8) and a hyperbolic saturation pattern with L-serine. At the lowest concentration of tetrahydrofolate used (0.2 mM), only 5% of the added folate was oxidized during preincubation and assay. ThenH value was independent of the time of preincubation. Preincubation of the enzyme with serine resulted in a partial loss of the cooperative interactions (nH =1.6) with tetrahydrofolate. The enzyme was regulated allosterically by interaction with nicotinamide nucleotides; NADH was a positive effector while NAD+ was a negative allosteric effector. The subunit interactions were retained even at the temperature optimum of 60‡C unlike in the case of the monkey liver enzyme, where these interactions were absent at higher temperatures. D-Cycloserine, a structural analogue of serine caused a sigmoid pattern of inhibition, in contrast with the observations on the monkey liver enzyme. Cibacron blue F3GA completely inhibited the enzyme and this inhibition could be reversed by tetrahydrofolate. Unlike in the monkey liver enzyme, NAD+ and NADH gave considerable protection against this inhibition. The sheep liver enzyme differs significantly in its kinetic and regulatory properties from the serine hydroxymethyltransferases isolated from other sources
Wess-Zumino Terms in Supersymmetric Gauge Theories
The Wess-Zumino term is constructed for supersymmetric QCD with two colors
and flavors, and is shown to correctly reproduce the anomalous Ward identities.
Supersymmetric QCD is also shown not to have topologically stable skyrmion
solutions because of baryon flat directions, which allow them to unwind. The
generalization of these results to other supersymmetric theories with quantum
modified constraints is discussed.Comment: 4 pages (revtex
Study of analgesics usage in third trimester of pregnancy and its ill effects on pregnancy course and outcome
Background: Pregnancy is a special physiological state. Pregnancy care is one of the greatest challenges in medicine as it demands a special care in the use of drugs because of altered physiology. At least 10 percent of birth defects are thought to result from maternal drug exposures. NSAIDS are one of the most commonly used medications during pregnancy (17%) to treat painful events during pregnancy.Methods: A prospective observational study was conducted after taking approval from the Institutional ethical committee and study was conducted for a period of one year. Antenatal clinics and inpatients wards of department of obstetrics and Gynaecology were visited and all the pregnant women with exposure to analgesics during third trimester and at the time of labour were included in the study. Information regarding the analgesics exposure either prescribed by the physician or self-medicated was collected.Results: Total 1520 pregnant women were included in the study over a period of one year. Analgesic exposure was seen in 77.1% of pregnant women during labour. Most common analgesic used to relieve labour pain was tramadol. 22.9% pregnant women were exposed to analgesics during third trimester, among them exposure to paracetamol was observed in 14% of pregnant women and to tramadol in 8.9%. Indications for usage of these analgesics during pregnancy were fever with myalgia (45.8%), false labour pain (37%), and headache (11.4%).Conclusions: Study showed that there is a positive association between analgesics exposure during third trimester of pregnancy particularly to paracetamol exposure and preterm delivery. Association between paracetamol exposure and low birth weight was also observed in this study but this finding could be due to more number of preterm deliveries which could not be ruled out in this study. Further studies have to be conducted to confirm the association since there are only limited numbers of studies done till now
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