SIGMA MESON AND PROPERTIES OF NUCLEAR MATTER

We have calculated the saturation observables of symmetric nuclear matter and nuclear symmetry energy in the framework of Brueckner-Hartree-Fock (BHF) formalism with Bonn-B potential as two-body interaction, including modification of hadronic parameter inside nuclear medium. We have found that it is possible to understand all the saturation observables of symmetric nuclear matter by incorporating in-medium modification of the parameters of sigma meson alone. Linear density dependent reduction of σ-nucleon coupling constant by about 6.8% and density independent reduction σ-meson mass by about 3.5% is sufficient to understand nuclear matter saturation observables. We find with the calculated symmetry energy that neutron skin thickness of 208Pb is 0.20 fm and the radius of 1.4 solar mass neutron stars as 11.98 ± 0.75 km.

IS THERE ANY PUZZLE OF NEW PHYSICS IN B → Kπ DECAYS?

Due to re-parametrization invariance of decay amplitudes, any single new physics (NP) amplitude arising through either the electro-weak penguin (EWP) or the color-suppressed tree amplitude can be embedded simultaneously into both the color-suppressed tree and the EWP contribution in B → Kπ decays. We present a systematic method to extract each standard model (SM)-like hadronic parameter as well as new physics parameters in analytic way, so that one can pinpoint them once experimental data are given. Using the currently available experimental data for B → Kπ modes, we find two possible analytic results: one showing the large SM-like color-suppressed tree contribution and the other showing the large SM-like EWP contribution. The magnitude of the NP amplitude and its weak phase are quite large. For instance, we find |PNP/P′| = 0.39 ± 0.13, φNP = 92° ± 15° and δNP = 7° ± 26°, which are the ratio of the NP-to-SM contribution, the weak and the strong phase of the NP amplitude, respectively. We also investigate the dependence of the NP contribution on the weak phase γ and the mixing induced CP asymmetry of B0 → KSπ0, respectively