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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…

High Energy Physics - Phenomenology · Physics 2014-11-18 Javier Ferrandis

The matrix element Vud of the CKM matrix can be determined by two independent measurements on neutron decay: the neutron lifetime tau and the ratio of coupling constants lambda, which is most precisely determined by measurements of the beta…

Nuclear Experiment · Physics 2011-07-21 Bastian Märkisch

In this work, we propose two possibilities of CPT-odd and Lorentz-violating (LV) nonminimal couplings in the Electroweak sector. These terms are gauge-invariant and couple a fixed 4-vector to the physical fields of the theory. After…

High Energy Physics - Phenomenology · Physics 2017-04-19 Victor E. Mouchrek-Santos , Manoel M. Ferreira

We discuss low-energy and collider constraints on the effective couplings characterizing non-standard charged current interactions. A direct comparison of low-energy and LHC probes can be performed within an effective theory framework, when…

High Energy Physics - Phenomenology · Physics 2015-06-11 Vincenzo Cirigliano , Martín González-Alonso , Michael L. Graesser

Precision measurements at low energy search for physics beyond the Standard Model in a way complementary to searches for new particles at colliders. In the weak sector the most general $\beta$ decay Hamiltonian contains, besides vector and…

Nuclear beta decays between (J^pi,T) = (0^+,1) analog states yield the best value for the Vud element of the Cabibbo-Kobayashi-Maskawa matrix. Current world data establish the corrected Ft values of 14 separate superallowed transitions to a…

Nuclear Experiment · Physics 2018-07-04 J. C. Hardy , I. S. Towner

A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix (CKM) is presented. This paper is an update of the results published in [1]. The experimental constraints imposed by the measurements of \epsilon_K, V_{ub}/V_{cb},…

High Energy Physics - Experiment · Physics 2010-11-23 F. Parodi , P. Roudeau , A. Stocchi

We report results from an experiment designed to test the conserved vector current (CVC) hypothesis by measuring the shape of the $\beta$-decay spectrum for the allowed $0^+\rightarrow 1^+$ ground state decay of $^{14}$O. Measurements of…

Nuclear Experiment · Physics 2015-06-23 E. A. George , P. A. Voytas , G. W. Severin , L. D. Knutson

The current value of Vud is determined from superallowed beta-decay experiments. Other methods, briefly summarised here, have to overcome specific experimental hurdles before they are competitive. However, the nuclear results do depend on a…

Nuclear Theory · Physics 2011-08-15 I. S. Towner , J. C. Hardy

We study the available data on exclusive leptonic and semileptonic $c\to s\ell^+\nu$ decays within the Standard Model and beyond. Our analysis accounts for theory correlations between the relevant hadronic matrix elements through…

High Energy Physics - Phenomenology · Physics 2024-12-03 Carolina Bolognani , Méril Reboud , Danny van Dyk , K. Keri Vos

Using an effective field theory approach, we study the new physics (NP) corrections to muon and beta decays and their effects on the extractions of V_ud and V_us. Assuming nearly flavor blind NP interactions we find that the CKM-unitarity…

High Energy Physics - Phenomenology · Physics 2011-02-14 Martín González-Alonso

A new measurement of the half-life of the positron emitter 10C has been made. The 10C decay belongs to the set of superallowed 0+ -> 0+ beta-decays whose Ft values offer stringent tests of the Conserved Vector Current (CVC) hypothesis and…

Nuclear Experiment · Physics 2009-11-30 K. K. H. Leung

The hypothesis is scrutinized that the weak interaction of hadronic systems at low energies is dominated by the coupling of the pseudoscalar, vector, and axial-vector mesons to the weak gauge bosons. The strength of the weak coupling of the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Peter Lichard

For many decades, the main source of information on the top-left corner element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix $V_{ud}$ were superallowed nuclear beta decays with an impressive 0.01\% precision. This precision, apart…

Nuclear Theory · Physics 2024-04-22 Mikhail Gorchtein , Chien Yeah Seng

Vector-like top partners with electric charge $+2/3$ are predicted in many extensions of the Standard Model and are actively searched for at the LHC through their electroweak decays $T\to Wb$, $Zt$, and $Ht$. More general scenarios,…

High Energy Physics - Phenomenology · Physics 2026-04-16 Mohammad Sahraei , Yasaman Hosseini , Mojtaba Mohammadi Najafabadi

We reinterpret publicly available $K^+ \to \pi^+ \nu \bar{\nu}$ data collected by NA62 from 2016 to 2024 to constrain the fundamental vectorial coupling of the QCD axion to down and strange quarks. Using a fully reproducible likelihood…

High Energy Physics - Phenomenology · Physics 2026-03-05 Diego Guadagnoli , Axel Iohner , Cristina Lazzeroni , Diego Martinez Santos , Joel C. Swallow , Claudio Toni

We test the models of vacuum energy interacting with cold dark matter and try to probe the possible deviation from the $\Lambda$CDM model using current observations. We focus on two specific models, $Q=3\beta H\rho_{\Lambda}$ and $Q=3\beta…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-15 Yun-He Li , Jing-Fei Zhang , Xin Zhang

We report the first direct measurement of the $^{14}\text{O}$ superallowed Fermi $\beta$-decay $Q_{EC}$-value, the last of the so-called "traditional nine" superallowed Fermi $\beta$-decays to be measured with Penning trap mass…

The leptonic and semileptonic decay propertis of Bc mesons are studied in a QCD potential model. The CKM element for the leptonic decay is calculated by evaluating its decay constant. With the help of the Isgur-Wise function, the form…

High Energy Physics - Phenomenology · Physics 2025-11-17 K K Pathak , S Bhattacharya , T Das

It has been proposed to determine the CKM matrix element |V_ub| in a model-independent way from a combination of rare and semileptonic B and D decays near the zero recoil point. An essential ingredient in such a determination is a heavy…

High Energy Physics - Phenomenology · Physics 2011-01-27 Benjamin Grinstein , Dan Pirjol