Decay D→K(∗)ℓ+νℓ{\mathit{D} \to} {{\mathit K}^{(*)}}{{\mathit \ell}^{+}}{{\mathit \nu}_{{{{\mathit \ell}}}}} in covariant quark model

We study the leptonic and semileptonic $D$-meson decays (${{\mathit D} \to} {{\mathit \ell}^{+}}{{\mathit \nu}_{{{{\mathit \ell}}}}}$ and ${\mathit{D} \to} {{\mathit K}^{(*)}}{{\mathit \ell}^{+}}{{\mathit \nu}_{{{{\mathit \ell}}}}}$) in the framework of covariant quark model with built-in infrared confinement. We compute the required form factors in the entire kinematical momentum transfer region. The calculated form factors are used to evaluate the branching fractions of these transitions. We determine the following ratios of the partial widths: $\Gamma ({{\mathit D}^{0}} \rightarrow {{\mathit K}^{-}}{{\mathit e}^{+}}{{\mathit \nu}_{{e}}})/\Gamma({{\mathit D}^{+}} \rightarrow {{\overline{\mathit K}}^{0}}{{\mathit e}^{+}}{{\mathit \nu}_{{e}}}) = 1.02$, $\Gamma({{\mathit D}^{0}} \rightarrow {{\mathit K}^{-}}{{\mathit \mu}^{+}}{{\mathit \nu}_{{\mu}}})/\Gamma({{\mathit D}^{+}} \rightarrow {{\overline{\mathit K}}^{0}}{{\mathit \mu}^{+}}{{\mathit \nu}_{{\mu}}}) = 0.99$ and $\Gamma({{\mathit D}^{+}} \rightarrow {{\overline{\mathit K}}^{0}}{{\mathit \mu}^{+}}{{\mathit \nu}_{{\mu}}}) / \Gamma({{\mathit D}^{+}} \rightarrow {{\overline{\mathit K}}^{0}}{{\mathit e}^{+}}{{\mathit \nu}_{{e}}}) = 0.97$ which are in close resemblance with the iso-spin invariance and experimental results.Comment: 20 pages, 6 tables, 7 figure

QQˉQ\bar Q (Q∈{b,c}Q\in \{b, c\}) spectroscopy using Cornell potential

The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schr\"odinger equation to obtain their mass spectra using only four parameters namely quark mass ($m_c$, $m_b$) and confinement strength ($A_{c\bar c}$, $A_{b\bar b}$). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited $S$, $P$, $D$ and $F$ states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available experimental observations and results from other theoretical models. We also compute mass spectra and life time of the $B_c$ meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and $B_c$ mesons are in tune with available experimental data and other theoretical approaches

Masses and decay modes of charmonia using a confinement model

The masses of charmonium s and p-states, pseudoscalar and vector decay constants, leptonic, hadronic as well as radiative decay widths for charmonia have been computed in the framework of extended harmonic confinement model without any additional parameters. The outcome in comparison with other contemporary theoretical and experimental results is presented.Comment: Submitted to AIP for proceedings of International Workshop on Theoretical High Energy Physics held at IIT Roorkee, INDIA during 15-20 March, 200

Superconductivity in 2-2-3 system Y2Ba2Cu2O(8+delta)

Researchers synthesized a new high T(sub c) 2-2-3 superconductor Y2Ba2Cu3O(8+delta) by a special preparation technique and characterized it by ac-susceptibility measurements. Diamagnetism and Meissner effect sets in at low fields and superconducting transition onsets at 90 K. The systematic investigation of the real and imaginary components of ac-susceptibility as a function of temperature and applied ac magnetic field reveals that the magnetic behavior is that of a granular type superconductor

Coupled Supersymmetry and Ladder Structures Beyond the Harmonic Oscillator

The development of supersymmetric (SUSY) quantum mechanics has shown that some of the insights based on the algebraic properties of ladder operators related to the quantum mechanical harmonic oscillator carry over to the study of more general systems. At this level of generality, pairs of eigenfunctions of so-called partner Hamiltonians are transformed into each other, but the entire spectrum of any one of them cannot be deduced from this intertwining relationship in general -- except in special cases. In this paper, we present a more general structure that provides all eigenvalues for a class of Hamiltonians that do not factor into a pair of operators satisfying canonical commutation relations. Instead of a pair of partner Hamiltonians, we consider two pairs that differ by an overall shift in their spectrum. This is called coupled supersymmetry. In that case, we also develop coherent states and present some uncertainty principles which generalize the Heisenberg uncertainty principle. Coupled SUSY is explicitly realized by an infinite family of differential operators which admit orthonormal bases of eigenfunctions of generalized harmonic oscillators.Comment: 18 pages, 3 figure