Related papers: Superallowed Fermi beta decay
The precise determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements is very important, because it could be a clue to new physics beyond Standard Theory. This is particular true of $V_{ud}$, because it is the main contribution…
The limits on time-reversal invariant tensor-type weak currents from nuclear and neutron $\beta$ decays are evaluated including most recent experimental data. We find that $ -0.14 \times 10^{-2} < (C_T + C^\prime_T)/C_A < 1.4 \times 10^{-2}…
Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and…
We study the question whether the phenomenologically successful VMD approach to weak radiative hyperon decays can be made consistent with Hara's theorem and still yield the pattern of asymmetries exhibited by experimental data. It appears…
A precise measurement of the neutron decay $\beta$-asymmetry $A_0$ has been carried out using polarized ultracold neutrons (UCN) from the pulsed spallation UCN source at the Los Alamos Neutron Science Center (LANSCE). Combining data…
The Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix has traditionally been determined from the analysis of data in nuclear superallowed 0+ to 0+ transitions, neutron decay and pion beta decay. We show here that this element…
By making use of the isospin conservation by strong interaction, the Fermi $0\nu\beta\beta$ nuclear matrix element $M_{F}^{0\nu}$ is transformed to acquire the form of an energy-weighted double Fermi transition matrix element. This useful…
Neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay is related to many fundamental concepts in nuclear and particle physics beyond the standard model. Currently there are many experiments searching for this weak process. An accurate…
This presentation reviews the Standard Model formalism governing the weak decays of quarks, as embodied in the Cabibbo-Kobayashi-Maskawa (CKM) weak mixing matrix, and summarizes the experimental status and outlook. Two recent CLEO V_cb…
The experimental status of the Cabibbo-Kobayashi-Maskawa matrix is reviewed. Measurements discussed include B0_(s)-\bar{B}0_(s) mixing and several rare B and K decays with implications for |V_td| and |V_ts|. Extraction of |V_cb| and |V_ub|…
Ab initio calculations of the Gamow-Teller (GT) matrix elements in the $\beta$ decays of $^6$He and $^{10}$C and electron captures in $^7$Be are carried out using both variational and Green's function Monte Carlo wave functions obtained…
We analyze the cross section for inverse beta decay, focusing on the moderate energies (a few MeV to hundreds of MeV) relevant for reactor and supernova neutrinos. We discuss the updated evaluations of values and uncertainties in the cross…
An exactly solvable model for a description of the two-neutrino double beta decay transition of the Fermi type is considered. By using perturbation theory an explicit dependence of the two-neutrino double beta decay matrix element on the…
We analyze the recoil corrections in superallowed beta decays of $T=1$, $J^P=0^+$ nuclei by fixing the mean square charge weak radius model-independently using the data of multiple charge radii across the nuclear isotriplet. By comparing to…
A high-precision branching ratio measurement for the superallowed Fermi $\beta^{+}$ emitter $^{62}$Ga was performed with the Gamma-Ray Infrastructure for Fundamental Investigations of Nuclei (GRIFFIN) spectrometer at the Isotope Separator…
The current experimental determination of the absolute values of the CKM elements indicates that 2|Vub / Vcb/ Vus| = (1-z) with z given by z = 0.19 +(-) 0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the…
Our understanding of the weak mixing of quarks, described by the Cabibbo Kobayashi Maskawa (CKM) matrix, currently presents an anomaly. Thanks to major strides in both theory and experiment, improved precision in determinations of the first…
Limits on parameters describing physics beyond the Standard Model are presented. The most general Lorentz invariant effective Hamiltonian at the quark-lepton level involving vector, scalar and tensor operators has been used. The fits have…
We consider interpretations of the recent $\sim 3 \sigma$ reports by the CMS and ATLAS collaborations of a possible $X(\sim 750~{\rm GeV})$ state decaying into $\gamma \gamma$ final states. We focus on the possibilities that this is a…
We present a parameterization of the statistical rate function, f, for 20 superallowed 0+-to-0+ nuclear beta transitions between T=1 analog states, and for 18 superallowed "mirror" transitions between analog T=1/2 states. All these…