Search

In 2017, LHCb collaboration reported their first observation of the rare decays B s → ϕ (f 0 (980) / f 2 (1270) →) π + π - and the evidence of B 0 → ϕ (f 0 (980) / f 2 (1270) →) π + π - . Motivated by this, we study these quasi-two-body decays in the perturbative QCD approach. The branching fractions, CP asymmetries and the polarization fractions are calculated. We find that within the appropriate two-meson wave functions, the calculated branching fractions are in agreement with the measurements of LHCb. Based on the narrow-width approximation, We also calculate the branching fractions of the quasi-two-body B d , s → ϕ (f 0 (980) / f 2 (1270) →) π 0 π 0 and B d , s → ϕ (f 2 (1270) →) K + K - , and hope the predictions to be tested in the ongoing LHCb and Belle II experiments. Moreover, the processes B d , s → ϕ f 2 (1270) are also analyzed under the approximation. We note that the CP asymmetries of these decays are very small, because these decays are either penguin dominant or pure penguin processes. [ABSTRACT FROM AUTHOR]

The compact material irradiation facility (CMIF) is a current project in China that will provide a compact deuteron-beryllium neutron source. The target of this facility will be an intense and compact Isotope Decay-At-Rest (IsoDAR) neutrino source. In this paper, we propose to test the sterile neutrino hypothesis using CMIF as the neutrino source. At CMIF platform, the electron antineutrino production rate can be up to 2.0 × 10 19 per day. When paired with an 80 t liquid scintillator detector to study short baseline electron antineutrino disappearance, the inverse beta decay (IBD) event rate is large enough to investigate the parameter ranges of interest for neutrino anomalies. Our sensitivity analysis shows that a short baseline experiment at this platform will provide a very competitive sterile neutrino search, especially in the high- Δ m 2 region ( Δ m 2 > 10 eV 2 ). [ABSTRACT FROM AUTHOR]

Motivated by the observations of the decays B 0 → K 0 ∗ (1430) 0 f 0 (980) and B 0 → K 2 ∗ (1430) 0 f 0 (980) from BaBar collaboration, we study the B 0 (+) → K 0 , 2 ∗ (1430) 0 (+) f 0 (980) / σ decays in the perturbative QCD approach for the first time. In the absence of reliable nonperturbative wave functions we only assume the scalar meson f 0 (980) and σ are two-quark ground states. In our calculations, these decays are all dominated by the hard-scattering emission and annihilation diagrams, while the factorizable emission diagrams are forbidden or suppressed heavily by the vector decay constants. Furthermore, the branching fractions are sensitive to the mixing between f 0 (980) and σ . Comparing our results with the experimental data, a large mixing angle θ is favored. Taking θ = 145 ∘ , the orders of branching fractions of B → K 0 ∗ (1430) 0 σ , B → K 2 ∗ (1430) 0 σ and B → K 0 , 2 ∗ (1430) 0 f 0 (980) are predicted to be 10 - 4 , 10 - 5 and 10 - 6 , respectively, which can be measured in the current experiments such as LHCb and Belle-2. In addition, although these decays are penguin dominant, the mixing also leads to large direct CP asymmetries in these decays. With the precise data in future, our results could shed light on the inner structure of the scalar mesons and can be used to determine the mixing angle of the σ - f 0 (980) system. [ABSTRACT FROM AUTHOR]