Chiral Perturbation Theory for phi -> rho gamma gamma and phi -> omega gamma gamma

We predict differential decay distributions for phi->rho gamma gamma and phi -> omega gamma gamma using chiral perturbation theory. We also consider the isospin violating decay phi -> omega pi^0. Experimental information on these decays can be used to determine couplings in the heavy vector meson chiral Lagrangian.Comment: It was shown by P. Ko et al., hep-ph/9510205 (Phys. Lett. B366 (1996) 287), that there is a etaprime pole contribution that dominates over what we calculate

A Renormalization Group Improved Calculation of Top Quark Production near Threshold

The top quark cross section close to threshold in $e^+e^-$ annihilation is computed including the summation of logarithms of the velocity at next-to-next-to-leading-logarithmic order in QCD. The remaining theoretical uncertainty in the normalization of the total cross section is at the few percent level, an order of magnitude smaller than in previous next-to-next-to-leading order calculations. This uncertainty is smaller than the effects of a light standard model Higgs boson.Comment: changed figures, added reference

Pion Interactions in the X(3872)

We consider pion interactions in an effective field theory of the narrow resonance X(3872), assuming it is a weakly bound molecule of the charm mesons D^{0} \bar D^{*0} and D^{*0} \bar D^{0}. Since the hyperfine splitting of the D^{0} and D^{*0} is only 7 MeV greater than the neutral pion mass, pions can be produced near threshold and are non-relativistic. We show that pion exchange can be treated in perturbation theory and calculate the next-to-leading-order correction to the partial decay width \Gamma[X \to D^0 \bar D^{0} \pi^0].Comment: 26 pages, 11 figures, revtex4, to appear in Phys. Rev.

Semiclassical Meson-Baryon Dynamics from Large-Nc QCD

The large-$N_c$ limit of the meson-baryon effective Lagrangian is shown to reduce to a semiclassical field theory. A chiral bag structure emerges naturally in the $N_c\rightarrow \infty$ limit. A possible connection between the chiral bag picture and the Skyrme model is discussed. The classical meson-baryon theory is used to reproduce the $M_\pi^3$ non-analytic correction to the baryon mass obtained previously as a loop correction in chiral perturbation theory.Comment: (13 pages, 1 figure, uses harvmac and uufiles), UCSD/PTH 94-1

Dynamical Polarizabilities of SU(3) Octet of Baryons

We present calculations and an analysis of the spin-independent dipole electric and magnetic dynamical polarizabilities for the lowest in mass SU(3) octet of baryons. These extensive calculations are made possible by the recent implementation of semi-automatized calculations in Chiral Perturbation Theory which allows evaluating dynamical spin-independent electromagnetic polarizabilities from Compton scattering up to next-to-the-leading order. Our results are in good agreement with calculations performed for nucleons found in the literature. The dependencies for the range of photon energies up to 1 GeV, covering the majority of the meson photo production channels, are analyzed. The separate contributions into polarizabilities from the various baryon meson clouds are studied.Comment: 10 pages, 7 figures, extended analysis of hyperon polarizabilitie

Exotic baryons from a heavy meson and a nucleon - Positive parity states -

We study heavy baryons with exotic flavor quantum numbers formed by a heavy meson and a nucleon (DbarN and BN) with positive parity. One pion exchange interaction, providing a tensor force, dominates as a long range force to bind the DbarN and BN ystems. In the heavy quark mass limit, pseudoscalar meson and vector meson are degenerate and the binding mechanism by the tensor force analogous to that in the nuclear systems becomes important. As a result, we obtain the DbarN and BN resonant states in the J^P=1/2^+, 3/2^+ and 5/2^+ channels with I=0

UKF based estimation approach for DVR control to compensate voltage swell in distribution systems

AbstractThe Dynamic Voltage Restorer (DVR) is identified as the best solution for mitigation of voltage sag and swell related problems in the much taped distribution system. The compensation performance of the DVR very much depends on its control algorithm. In the paper, an estimation method based on Unscented Kalman Filter (UKF) is proposed for mitigating the voltage swell concern. The proposed UKF based estimation technique is used to assist the control algorithm for generating reference signals of Voltage Source Converter (VSC) of DVR. DVR presents the compensation voltage as output which is included in the connected line. With this estimation method, voltage swell issues are discovered with accuracy and faster performance to retract out the swell problem in sensitivity load linked distribution systems. In MATLAB/Simulink platform the suggested method is executed and its performance is assessed and contrasted with the Linear Kalman Filter (LKF) and Extended Kalman Filter (EKF)

TOWARDS RESILIENCE IN CHENNAI

Global mean temperatures have increased, average sea levels have risen, snow cover has decreased, glaciers and icecaps have started to melt, thunderstorms and torrential rains have occurred in dry areas, all pointing towards climate change. NASA has mentioned that majority of the climate scientists agree that these indicators of climate-warming trends over the past century are mostly due to human activities. The United Nations has endorsed this position and forecasted that around 50 million people will become environmental refugees by the end of this decade (UNEP, 2005). Due to this, most of the world is debating how to reduce greenhouse emissions that cause climate change and how to build resilience to the inevitable effects of climate change through various climate summits. Even though the awareness of building resilience in cities exists around the world, developing nations are facing challenges in building resilient cities due to over population and unplanned growth in the process of rapid urbanisation and economic development.One such example is Chennai, a coastal city in India. Though the city has experienced major floods in 1943, 1978, and 2005; the recent unprecedented rainfall in the fall of 2015 caused by the El Nino phenomenon had collapsed Chennai with flash floods. This presented an Indian context of climate change crisis – which is a consequence of expanding cities over existing environmental systems thereby damaging them severely. The city of Chennai, from Pre Independence to Post Independence, has been filling natural ponds, lakes and marshes to expand the city to allow closer proximity to the city centre for economic development. While these actions have resulted in increased flooding during rain, conditions of water scarcity has been observed during summer. Hasty urbanization has given no regard to the traditional system of planning which had once respected nature and combated floods and droughts through the various cultural practices and taboos practiced by the people. Thus, it is essential to look back at the planning trajectory of Chennai and to recognise methods used traditionally in the region to survive the environmental disaster, making the city flood resilient. This research explores the possibilities of alternative and sustainable approaches for resilient urban development using the environmental disaster of Chennai’s 2015 flood as a case study. This examination uncovers the traditional, the British Raj-era, the post-Independence, and the contemporary development context in order to understand the local context for where and when coastal human settlement negatively impacted the natural system.As Eliot Scalar said, “adaptation is the key. If we need to reverse climate change, we first have to survive long enough to do that”- Century of the city- No time to loose (Rockefeller Foundation, 2008)

Quantum loops in the Resonance Chiral Theory: improving the vector form factor

Quantum loops in the Resonance Chiral Theory are needed to improve the implementation of non-perturbative QCD. Furthermore, the one-loop computations can predict chiral low-energy couplings at next-to-leading order, a very appealing task. We present a first calculation of the vector form factor of the pion at subleading order in the 1/N_C expansion. From the analysis of the result at large energies we justify the requirement of considering short-distance constraints from form factors with resonances in the final state. The long-distance limit of our results allows to get a next-to-leading order estimate of \ell_6.Comment: Talk given at the International Workshop e+e- Collisions from phi to J/psi, 27th February-2nd March (2006), Novosibirsk (Russia

Tablet misoprostol as a cervical priming agent prior to surgical abortion

Background: Every effort to promote effective contraceptive methods as well as emergency contraception is being made, still there would be a need and place for termination of pregnancy. Objective of present study was to evaluate and to know the efficacy and adverse effects of tablet misoprostol 400 micro gram as a cervical priming agent administered either by oral or vaginal route, 3 hours before MTP.Methods: Prospective randomized not blinded study carried out for two years at Government Tertiary care level hospital, OBG Department, Mangalore on 100 women with gestational age up to 12 weeks requesting for surgical abortion.Results: In both the groups there was no significant statistical difference with respect to age (p=0.44), parity and gestational age (p=0.59). With respect to baseline cervical dilatation significant statistical difference was not observed in both the groups. Baseline dilatation of the cervix was 8.0 mm versus 8.2 mm (p value=0.55). Baseline cervical dilatation was ≥7mm in 90% of women when tab misoprostol was given by oral route and 94% with vaginal route. There was no significant statistical difference with respect to side effects (p value>0.05) except nausea (p=0.01) found in both the groups. Gastro Intestinal side effects were more in oral misoprostol group, but it was not statistically significant.Conclusions: Oral route is an effective alternative to vaginal route. Oral route is preferred over vaginal route because women can do self-administration at home and there was no internal examination discomfort