School of Physics and Material Science

We studied the statistical model of nucleons consisting of sea having various quark-gluon Fock states in addition to valence quarks. Using statistical consideration and taking 86% of the total Fock states contributing to the low energy properties of nucleon, we aim to find the contributions to these properties coming from the scalar, vector and tensor sea. We checked its validity against the assumption where the contributions from scalar and tensor sea have been suppressed and justified to be unimportant. We took the approximation that sea is getting a zero contribution from H 0 G 10 and H 1 G 10 in three gluon states. Under the above considerations, the calculated magnetic moment, spin distribution and weak decay coupling constant ratio for proton and neutron states have been tabulated. We hereby confirm that the suppression of the scalar and tensor sea leads to modification in the parameters of the nucleons showing deviation from the experimental data.

The spin distributions, weak decay matrix elements for strange baryon octets with SU(3) breaking effects is studied. We systematically apply operator formalism along with statistical method to study J P = 1 2 + strange baryon octets for their low energy properties. Baryon is taken as an ensemble of quark-gluon Fock states in sea with three valence quarks to have spin-1/2, color-1 and flavor-8 quantum numbers. Detailed balance principle is applied to calculate the probabilities of each Fock states, with the inclusion of mass correction of strange quark in order to check the SU(3) breaking in weak decays constants and spin distributions. A dominant contribution from the vector sea is verified as compared to scalar and tensor sea, also the symmetry breaking correction leads to the deviations in the value of axial vector matrix elements ratio F D from experimental values by 17%. Present framework suggests a stronger base to choose statistical model with detailed balance principle to verify the experimental and theoretical values available and hence provide a deeper understanding to the strange baryon structure. Symmetry breaking effects lead to reduction in the values of axial matrix elements. Its contribution has a significant role in determining the validity of present approach.

The spin structure of lambda has its special importance in analyzing the spin content of other hadrons. Assuming hadrons as a cluster of quarks and gluons (generally referred as valence and sea), statistical approach has been applied to study spin distribution of lambda among quarks. We apply the principle of detailed balance to calculate the probability of various quark–gluon Fock states and check the impact of SU(3) breaking on these probabilities particularly in sea for the Fock states containing strange quark. The flavor probability when multiplied by spin and color multiplicities of these quark–gluon Fock states results in estimating the individual contributions from valence and sea. We conclude that breaking in symmetry significantly affects the polarization of quarks inside the hyperons.

We treat the hadrons as an ensemble of quark-gluon Fock states where contributions from sea-quarks and gluons can be studied in detail for the properties of low lying baryons. Statistical model is applied to calculate individual probabilities from various scalar, vector and tensor sea components in flavor, spin and color subspaces for each quark-gluon Fock state. The mass of strange quark is imposed in terms of constraints to the availability of strange quarks in the sea and free energy of gluons in conformity with experimental indications. We calculate multiplicities for different sets of Fock states to compute the role of strange sea for cascade doublet Ξ + , and Ξ -. The low energy properties like magnetic moment, weak decay matrix elements and axial coupling constant ratios have been studied. The incorporation of strange quark gluon sea is discussed and they found to affect the results by almost 46% . The results provide deeper understanding for baryon structure thereby motivating experiments for further inspection, especially the spin distribution among the quarks and gluons.

Probabilities of various Fock states with strange and nonstrange quark-gluon sea contents are calculated to probe the hadronic structure. Particularly for nucleon, we find various contributions to the low energy properties from scalar, vector and tensor sea in addition to three valence quarks. We focus on the importance of individual sea contributions to the low energy parameters of nucleon by taking the strange and non strange quark-gluon content to the hadron sea. We confirm that the extended Fock space wavefunction is capable of explaining the experimental results where vector sea plays a crucial role in studying hadronic structure while scalar and tensor sea appears to be less dominating due to quark-spin flip process but cannot be neglected. Some of the properties like spin distribution and g A /g V ratio seem to be the most affected by the change in the statistically determined coefficients. Detailed analysis includes different approximations within the statistical approach to test the validity of the model chosen. Phenomenological implication of such sea affecting these properties is also discussed and the results are compared with the experiments.

Within the framework of heavy quark effective theory and chiral perturbation theory, masses and splittings of heavy charm mesons are studied. A mass formula is used for comprehensive analysis of low lying charm meson states.The variation of mass splittings and spin splittings with respect to various symmetry conserving and symmetry breaking parameters have also been focussed.

Statistical approach for proton and neutron have been used to study the low energy properties of nucleons. Nucleons is assumed as a composite system of three quarks and "sea" where sea is assumed to be in S-wave consisting of quark-antiquark pairs (u]\bar{u},d\bar{d} only) and gluons. Here the contributions from scalar, vector and tensor sea is taken into consideration to find

The theory of heavy meson masses, in which the symmetries of heavy and light quarks are exploited, can be used to describe the low energy interaction among heavy mesons to a better extent. The spin-flavor symmetry leads to many interesting relations between the properties of hadrons containing a heavy quark. The most direct consequences concern the spectroscopy of such states. We use such symmetries to explore some of the states of B-meson and predictions are found to be in agreement with the experimental data.

The statistical model is implemented to find the magnetic moments of all octet baryons. The well-known sum rules like GMO and CG sum rules has been checked in order to check the consistency of our approach. The small discrepancy between the results suggests the importance of breaking in SU(3) symmetry.

Open charm hadrons with strange quark have been discovered in recent years but non-strange part have been somewhat ignored. We aim to calculate ground and excited low lying states charm meson masses using mass formulae developed in heavy hadron chiral perturbation theory. Also various parameters in one loop mass formulae are analyzed graphically within their respective ranges. We here provide the more constrained fits for different parameters. Spin and mass splittings are also calculated

Open charm hadrons with strange and non-strange mesons have been discovered in recent years. We study the spectra of several newly observed resonances by different collaborations like BaBar [2]and LHCb [3] etc. Using an effective Lagrangian approach based on heavy quark symmetry and chiral dynamics, we explore the strong decay widths and branching ratios of various resonances and suggest their J p values. We try to fit the experimental data to find the coupling constants involved in the strong decays through pseudoscalar mesons. The present work also discusses about the possible spin-parity assignments of recently observed states by LHCb collaboration. The tentative assignment of newly discovered state D * J (3000) can be natural parity states (0 -, 1 + , 2 -, 3 + ....) while D J (3000) can be identified with unnatural parity states like (0 + , 1 -, 2 + , 3 -....). Therefore, the missing doublets 2S,1D,1F,2P and 3S can be thought of filled up with these states. We study the two-body strong decay widths and branching ratios of missing doublets and plot branching ratios vs mass of decaying particle. These plots are used to analyze all assignments to D J (3000) deeply and various possibilities for J P values.

The current status and some perspectives of the phenomenology of massive neutrinos is reviewed. We start with the phenomenology of neutrino oscillations in vacuum and in matter. We summarize the results of neutrino experiments using solar, atmospheric. The fundamental theory of flavor changing neutrinos that has confirmed the neutrino oscillations and the various parameters affecting these oscillations have been discussed in detail. Specifically we will take the solar and atmospheric neutrino case. The oscillation plots will be discussed in detail, based on their behavior in vacuum and matter. Both normal and inverted mass hierarchy hypotheses are tested and both are consistent with observation. Finally the sensitivity of theta 13 over these probability oscillations has been analyzed and commented.

Open charm hadrons with strange and non-strange mesons have been discovered in recent years. We study the spectra of several newly observed resonances by different collaborations like BaBar [2]and LHCb [3] etc. Using an effective Lagrangian approach based on heavy quark symmetry and chiral dynamics, we explore the strong decay widths and branching ratios of various resonances and suggest their J p values. We try to fit the experimental data to find the coupling constants involved in the strong decays through pseudoscalar mesons. The present work also discusses about the possible spin-parity assignments of recently observed states by LHCb collaboration. The tentative assignment of newly discovered state D * J (3000) can be natural parity states (0 -, 1 + , 2 -, 3 + ....) while D J (3000) can be identified with unnatural parity states like (0 + , 1 -, 2 + , 3 -....). Therefore, the missing doublets 2S,1D,1F,2P and 3S can be thought of filled up with these states. We study the two-body strong decay widths and branching ratios of missing doublets and plot branching ratios vs mass of decaying particle. These plots are used to analyze all assignments to D J (3000) deeply and various possibilities for J P values.

We present the mass formula for heavy-light charm meson at one loop, using heavy quark effective theory. Formulating an effective Lagrangian, the masses of the ground state heavy mesons have been studied in the heavy quark limit, including leading corrections from finite heavy quark masses and nonzero light quark masses, using a constrained fit for the eight equations with 11 parameters including three coupling constants g, h, and g . Masses determined using this approach are fitted to the experimentally known decay widths to estimate the strong coupling constants, showing a better match with available theoretical and experimental data.

The theory of heavy meson masses, in which the symmetries of heavy and light quarks are exploited, can be used to describe the low energy interaction among heavy mesons to a better extent. The spin-flavor symmetry leads to many interesting relations between the properties of hadrons containing a heavy quark. The most direct consequences concern the spectroscopy of such states. We use such symmetries to explore some of the states of B-meson and predictions are found to be in agreement with the experimental data.

Neutrino oscillation is the new physics beyond standard model. In this paper we have revisited the issue of neutrino oscillation in simple and delicate manner. Starting from the fundamental quantum mechanical treatment for the neutrinos, we calculated the probabilities for the neutrino oscillating within three flavors. Normal and inverted hierarchy have been taken into account for the solar and atmospheric cases, in vacuum and matter. The probabilities have been plotted for all the cases and discussed.

We studied the statistical model of nucleons consisting of sea having various quark-gluon Fock states in addition to valence quarks. Using statistical consideration and taking 86% of the total Fock states contributing to the low energy properties of nucleon, we aim to find the contributions to these properties coming from the scalar, vector and tensor sea. We checked its validity against the assumption where the contributions from scalar and tensor sea have been suppressed and justified to be unimportant. We took the approximation that sea is getting a zero contribution from ‫ܪ‬ ‫ܩ‬ ଵ and ‫ܪ‬ ଵ ‫ܩ‬ ଵ in three gluon states. Under above considerations, the calculated magnetic moment, spin distribution and weak decay coupling constant ratio for proton and neutron states have been tabulated. We hereby confirm that the suppression of the scalar and tensor sea leads to modification in the parameters of the nucleons showing deviation from the experimental data.

An operator formalism is used on the wavefunction of baryons to compute their charge radii and quadrupole moments. Total anti-symmetric wavefunction in spin, color and flavor space is framed for $J^P=\frac{1}{2}^+$ nucleons and $J^P=\frac{3}{2}^+$ hyperons. To understand the importance of sea, statistical model is used in conjugation with the detailed balance principle. Within the statistical approach, the importance of sea with quarks and gluons are studied using the relevant probabilities that are associated with spin, flavor, and color space. The present work also focuses on individual contributions of valence and sea which contains terms of scalar, vector and tensor sea. The obtained results are in agreement with available theories and few experimental outcomes. Our computed results may provide important information for upcoming experimental findings.

consistent with the chiral symmetry. The Lagrangian effectively describes the strong interaction of heavy-light mesons with the pseudo scalar goldstone boson at low energies. B meson masses in the heavy quark effective theory are given in terms of a single non-perturbative parameter