arXiv subjects
Publications and source records attributed to Fayyazuddin.
Isospin analysis has been used to constrain the CP-asymmetries in B -> pi pi decays. In particular correlation between a weak phase θand a strong phase δis obtained. Further using the experimental values for the CP-average branching ratios, the following bounds on direct CP-asymmetries are obtained: -0.35+/- 0.22=< C_{π^+π^-}\leq 0; C_{π^0π^0}=-(2.4\pm 1.0) C_{π^+π^-}. Constraints on mixing induced CP-asymmetries are also discussed.
After some general remarks about SU_L(4) electroweak unification, the model is extended to SU_L(4)xU_X(1) to accomodate fractionally charged quarks. The unification scale is expected to be in TeV region. A right-handed Majorana neutrino along with known lepton are put in the fundamental representation of SU_L(4) with Y_X=0. The see-saw mechanism for neutrino masses and flavor mixing in neutrino sector is a natural feature of the model. The lepton number violating processes can occure through dilepton gauge bosons contained in the model.
Final state phases δ_f and δ_f' in B-> D pi, barD pi decays are shown to be equal i.e. δ=δ_f-δ_f' = 0. Thus CP-violating asymmetry A(t) is independent of final state phases. The estimate for the phases δ_f and δ_f' is also given.
The newly observed resonances D_{s_{1}}^* and D_{s_0} are discussed in a potential model. The relationship between the mass difference between p-states D_{s_1}^*(1^+), D_{s_0}(0^+) and s-states D_s^*(1^-), D_s(0^-) is also examined. Some remarks about the state D_1^*(1^+) and D_0(0^+) in the non- strange sectors are also made.
Electron--proton scattering in elastic and highly inelastic region is reviewed in a unified approach. The importance of parity--violating scattering due to electro--weak interference in probing the structure of proton is emphasized. The importance of longitudnal spin--spin asymmetry as well as parity violating longitudnal asymmetry to extract the structure functions of proton in both regions are discussed. The recoil polarization of proton in the elastic scattering is also discussed.
In this article we give an overview of CP-violation for both K^0 (\bar{K}^0 ), B^0 (\bar{B}^0), and B_s(\bar{B}_s) systems. Direct CP-violation and mixing induced CP-violation are discussed for K^0(\bar{K}^0), and B^0(\bar{B}^0) decays.
The final state interactions (FSI) in Delta S=-1, Delta C=\pm 1, decays of B-meson are discussed. The rescattering corrections are found to be of order of 15-20%. The strong interaction phase shifts are estimated and their effects on CP-asymmetry are discussed.
The decays \bar{B}-> \bar{K}D and \bar{B}-> \bar{K}\bar{D} taking into account final state interactions are discussed. These decays are described by four strong phases δ_0,δ_1,\barδ_0,\barδ_1 (subscripts 0 and 1 refers to I=0 and I=1 final states), one weak phase γand four real amplitudes. It is argued that strong interaction dynamics implies \barδ_1=0,δ_0=-δ_1. Rescattering has significant effects on weak amplitudes. Taking into account, rescattering, we find that direct CP--violating asymmetry in these decays may lie in the range \mp 0.023\sin γ\leq \QTR{cal}{A}_{1,2}\leq \mp 0.086\sin γ.
The time-dependent analysis of the decays $Λ_b\to Λ+D^0(t)$ and $Λ_b\to Λ+\bar{D}^0(t)$ is discussed. The effect of particle mixing due to time evolution of $D^0$ and $\bar{D}^0$ on the observables for these decays viz the branching ratio of decay widths and the asymmetry parameters $α,β$ and $γ$ are analysed. It is shown that it is possible to extract information about $(Δm/Γ)\sin \hatγ$ from the experimental data for these observables. Here $Δm=m_{D_1^0}-m_{D_2^0},Γ$ is the decay widths for $D^{\prime}s$ and $\hatγ$ is the weak phase.
The decays $\bar{B}\to \bar{K}D$ and $\bar{B}\to \bar{K}\bar{D}$ taking into account final state interactions are discussed. These decays are described by four strong phases $δ_0, δ_1, \tildeδ_0, \tildeδ_1$ (subscript 0 and 1 refer to I=0 and I=1 isospin final states), one weak phase $γ$ and four real amplitudes. Isospin constraints are taken into account. It is argued that strong interaction dynamics gives $δ_1\approx \tildeδ_1$. The four real amplitudes are estimated. Some observable consequences are discussed.
It is shown that interference of the amplitudes for the decays $Λ_b \to ΛD$ and $Λ_b \to Λ\bar{D}^0$ gives rise to CP-violation.
The two body non-leptonic $Λ_b$ decays are analyzed in factorization approximation, using quark model, $ξ= 1 / N_c$ as a free parameter. It is shown that the experimental branching ratio for $Λ_b \longrightarrow Λ{J/ψ}$ restricts $ξ$ and this ratio can be understood for a value of $ξ$ which lies in the range $ 0 \leq ξ\leq 0.5 $ suggested by two body B meson decays. The branching ratios for $Λ_b \longrightarrow Λ_{c} D^*_s(D_s) $ are predicted to be larger than the previous estimates. Finally it is pointed that CKM-Wolfenstein parameter $ρ^2 + η^2$, where $η$ is CP phase, can be determined from the ratio of widths of $Λ_b \longrightarrow Λ\bar{D}$ and $Λ_b \longrightarrow Λ{J/ψ}$ or that of $Λ_b \longrightarrow p D_s$ and $Λ_b \longrightarrow Λ_c D_s$ independent of the parameter $ξ$.