Scalar meson in dynamical and partially quenched two-flavor QCD: lattice results and chiral loops

This is an exploratory study of the lightest non-singlet scalar $q\bar q$ state on the lattice with two dynamical quarks. Domain Wall fermions are used for both sea and valence quarks on a 16^3*32 lattice with an inverse lattice spacing of 1.7 GeV. We extract the scalar meson mass 1.58(34) GeV from the exponential time-dependence of the dynamical correlators with $m_{val}=m_{sea}$ and N_f=2. Since this statistical error-bar from dynamical correlators is rather large, we analyze also the partially quenched lattice correlators with $m_{val}$ not equal $m_{sea}$. They are positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$. In order to understand this striking effect of partial quenching, we derive the scalar correlator within the Partially Quenched ChPT and find it describes lattice correlators well. The leading unphysical contribution in Partially Quenched ChPT comes from the exchange of the two pseudoscalar fields and is also positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$ at large t. After the subtraction of this unphysical contribution from the partially quenched lattice correlators, the correlators are positive and exponentially falling. The resulting scalar meson mass 1.51(19) GeV from the partially quenched correlators is consistent with the dynamical result and has appreciably smaller error-bar.Comment: 23 pages, 8 figure

Optimized OFDM Model Using CMA Channel Equalization for BER Evaluation

Orthogonal Frequency Division Multiplexing (OFDM) is a type of Multicarrier Modulation (MCM) technique in which entire bandwidth is divided into large number of small sub-carriers and each subcarrier is transmitted parallel to achieve higher data rates. It has various applications like Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB) and wireless LAN.OFDM technique is widely used in wireless communication system because of its very high data rate. The performance of FFT based OFDM system using Linear and cyclic channel coding and Constant Modulus Algorithm (CMA) equalizer is simulated using simulink model. The BER saving using the optimized proposed model with both linear and cyclic channel coding along with CMA equalizer is evaluated. The proposed work using cyclic channel coding with QPSK/QAM modulation and CMA as channel equalization under AWGN channel results in 52.6% and 96.3% BER reduction as compared to conventional OFDM model without channel coding, channel equalization and channel fading. So, CMA equalizer is used to enhance the performance of OFDM system

Extended Bandwidth Optimized and Energy Efficient Dynamic Source Routing Protocol in Mobile Ad-hoc Networks

With the increase in the evolution of wireless communication, the ad-hoc networks are gaining attention and are significantly becoming the technology solutions to the various problems. Mobile ad-hoc Networks (MANETs) are envisaged to grow as a main component in the today 4G architecture, and ad hoc networks are projected to be a significant element of the whole future wireless communication. The MANETs are infrastructure less, self-forming and self-organizing network in which there is no control of any centralized entity. The nodes are free to move around the network with dynamic topology. But this self formation, flexibility and scalability create many challenges and design constraints like hidden  terminal, limited bandwidth, limited energy of a node, unpredictable change in the topology etc. Bandwidth and energy are the scarce resources of the network. In order to effectively manage the consumption of bandwidth and energy, an algorithm is proposed which is the extension of traditional Dynamic Source Routing (DSR) reactive routing protocol. The extended protocol applies the mobile agents to carry the data. The proposed work is intended to optimize the bandwidth and making the protocol energy efficient

Sodium alginate microspheres for extending drug release: formulation and in vitro evaluation

In the present study, spherical microspheres of theophylline (TP) using sodium alginate as the hydrophilic carrier were prepared to prolong the release. The shape, surface and size characteristics were determined by scanning electron microscopy. The microspheres were found to be discreet and spherical in shape and had a smoother surface. The mean diameter of seven alginate microspheres formulations were between 7.6 ± 0.52 and 22.35 ±0.31 μm. It was observed that mean particle size of the microspheres increased with an increase in the concentration of polymer. The entrapment efficiency was found to be in the range of 70–93%. Optimized alginate microspheres were found to possess good sphericity, size and adequate entrapment efficiency. The in vitro release studies were carried out in pH progression media (pH 1.2, 2.5, 4.5, 7 and 7.4 solutions). Results indicated that percent drug release decreased with an increased alginate concentration. TP-loaded Alginate microspheres showed extended in vitro drug release thus use of microspheres potentially offers sustained release profile along with improved delivery of TP.Keywords: Extended drug delivery; Sodium alginate; Microspheres; Bronchial asthm

Supergravity Radiative Effects on Soft Terms and the μ\mu Term

We compute quadratically divergent supergravity one-loop effects on soft supersymmetry-breaking parameters and the $\mu$ term in generic hidden sector supergravity models. These effects can significantly modify the matching condition for soft parameters at the Planck scale and also provide several new sources of the $\mu$ term which are naturally of order the weak scale. We also discuss some phenomenological implications of these effects, particularly the violation of the scalar mass universality which may lead to dangerous FCNC phenomena, and apply the results to superstring effective supergravity models.Comment: 12 pages, REVTEX. One reference is adde

Role of Charm Factory in Extracting CKM-Phase Information via B --> DK

In this paper we study the impact of data that can be obtained from a Charm Factory on the determination of the CKM parameter gamma from decays of the form B -> D0 K where the D0 decays to specific inclusive and exclusive final states. In particular, for each exclusive final state $f$, the charm factory can determine the strong phase difference between D0-> f and D0-bar -> f by exploiting correlations in psi(3770)-> D0 D0-bar. This provides crucial input to the determination of gamma via the interference of B+- -> K+- D0 -> f with B+- -> K+- D0-bar -> f. We discuss how the method may be generalized to inclusive final states and illustrate with a toy model how such methods may offer one of the best means to determine gamma with 10^8-10^9 B-mesons.Comment: 12 pages, 7 figures, Version 2: Fixed typos; add reference; Version 3: fixed latex glitc

Correlation Functions of Hadron Currents in the QCD Vacuum Calculated in Lattice QCD

Point-to-point vacuum correlation functions for spatially separated hadron currents are calculated in quenched lattice QCD on a $16^3\times 24$ lattice with $6/g^2=5.7$. The lattice data are analyzed in terms of dispersion relations, which enable us to extract physical information from small distances where asymptotic freedom is apparent to large distances where the hadronic resonances dominate. In the pseudoscalar, vector, and axial vector channels where experimental data or phenomenological information are available, semi-quantitative agreement is obtained. In the nucleon and delta channels, where no experimental data exist, our lattice data complement experiments. Comparison with approximations based on sum rules and interacting instantons are made, and technical details of the lattice calculation are described.Comment: 31 pages in REVTeX (with 10 figures to be added using figures command), MIT CTP #214

Grand Unification of Quark and Lepton FCNCs

In the context of Supersymmetric Grand Unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link flavor changing neutral current and CP violating processes occurring in the leptonic and hadronic sectors. We study the correlation between flavor changing squark and slepton mass insertions in models \`a la SU(5). We show that the constraints coming from lepton flavor violation exhibit a strong impact on CP-violating B decays.Comment: 4 pages, 1 figur