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We investigate neutrinoless double-beta decay ($0\nu\beta\beta$) in minimal extensions of the Standard Model of particle physics where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass terms. We argue that…

High Energy Physics - Phenomenology · Physics 2024-10-28 W. Dekens , J. de Vries , D. Castillo , J. Menéndez , E. Mereghetti , V. Plakkot , P. Soriano , G. Zhou

Influence of the neutrino mass submatrix $M_L$ on the e-e- -> W-W- process is discussed. Taking into account various possible CP signatures of heavy neutrinos it is shown that, in some cases, nonzero $M_L$ substantially changes predictions…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Duka , J. Gluza , M. Zralek

We study two-neutrino ($2\nu\beta\beta$) and neutrinoless double-$\beta$ ($0\nu\beta\beta$) decays in the nuclear shell model and proton-neutron quasiparticle random-phase approximation (pnQRPA) frameworks. Calculating the decay half-life…

Nuclear Theory · Physics 2023-04-14 Lotta Jokiniemi , Beatriz Romeo , Pablo Soriano , Javier Menéndez

Violations of the $\Delta$I=1/2 rule are investigated in the nonmesonic weak hypernuclear decay using a weak $\Lambda$N$\to$NN transition potential based on meson exchange. While the weak $\Delta$I=3/2 matrix elements of baryons with…

Nuclear Theory · Physics 2009-10-30 A. Parreño , A. Ramos , C. Bennhold , K. Maltman

As shown in Ref.\cite{Rod09}, the Fermi nuclear matrix element $M^{0\nu}_F$ of neutrinoless double beta ($0\nu\beta\beta$) decay can be reconstructed if one is able to measure the isospin-forbidden single Fermi transition matrix element…

Nuclear Theory · Physics 2011-03-28 Vadim Rodin , Amand Faessler

Matrix elements of six-quark operators are needed to extract new physics constraints from experimental searches for neutron-antineutron oscillations. This work presents in detail the first lattice quantum chromodynamics calculations of the…

High Energy Physics - Lattice · Physics 2019-05-20 Enrico Rinaldi , Sergey Syritsyn , Michael L. Wagman , Michael I. Buchoff , Chris Schroeder , Joseph Wasem

We present the matrix elements for the semileptonic kaon decays $K_{l2\gamma}$ , $K_{l2l^+l^-}$, $K_{l2l'^+l'^-}$,$K_{l3}$, $K_{l3\gamma}$ and $K_{l4}$ at next-to-leading order, and $K_{e5}$ at leading order in Chiral Perturbation Theory…

High Energy Physics - Phenomenology · Physics 2009-09-25 J. Bijnens , G. Colangelo , G. Ecker , J. Gasser

We discuss the contributions of lepton-number-violating sources to neutrinoless double beta decay ($0\nu\beta\beta$). Assuming that these sources arise at scales well above the electroweak scale, they can be described within an effective…

High Energy Physics - Phenomenology · Physics 2019-06-13 W. Dekens

The neutrinoless double-beta decay process $nn\rightarrow ppee$ within the light Majorana-exchange scenario is studied using the relativistic pionless effective field theory (EFT) in finite-volume cubic boxes with the periodic boundary…

High Energy Physics - Lattice · Physics 2025-09-30 Y. L. Yang , P. W. Zhao

We revisit the process of inverse neutrino-less double beta decay (e e -> W W) at future linear colliders. The cases of Majorana neutrino and Higgs triplet exchange are considered. We also discuss the processes e mu -> W W and mu mu -> W W,…

High Energy Physics - Phenomenology · Physics 2015-03-17 Werner Rodejohann

Starting from chiral nuclear interactions, we evaluate the contribution of the leading-order contact transition operator to the nuclear matrix element (NME) of neutrinoless double-beta decay, assuming a light Majorana neutrino-exchange…

Nuclear Theory · Physics 2021-12-14 R. Wirth , J. M. Yao , H. Hergert

We investigate neutrinoless double-beta decay ($0\nu\beta\beta$) in the minimal extension of the standard model of particle physics, the $\nu$SM, where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass…

High Energy Physics - Phenomenology · Physics 2023-03-09 Wouter Dekens , Jordy de Vries , Emanuele Mereghetti , Javier Menéndez , Pablo Soriano , Guanghui Zhou

We present a calculation of the matrix elements of the most general set of DeltaS=2 dimension-six four-fermion operators. The values of the matrix elements are given in terms of the corresponding B-parameters. Our results can be used in…

High Energy Physics - Lattice · Physics 2009-10-31 C. R. Allton , L. Conti , A. Donini , V. Gimenez , L. Giusti , G. Martinelli , M. Talevi , A. Vladikas

We computed the $\Sigma^{-}\to n\pi^+e^-\ell^-$ ($\ell=e,\mu$), $\Xi^-\to \Lambda\pi^+e^-e^-$, and $\Lambda\to p\pi^+e^-e^-$ lepton number violating (LNV) hyperon decays mediated by a resonant Majorana neutrino. The expected hyperon…

High Energy Physics - Phenomenology · Physics 2023-04-12 Gerardo Hernández-Tomé , Diego Portillo-Sánchez , Genaro Toledo

An algebraic method for evaluating bare nucleon matrix elements of quark operators is proposed. Thereby, bare nucleon matrix elements are traced back to vacuum matrix elements. The method is similar to the soft pion theorem. Matrix elements…

High Energy Physics - Phenomenology · Physics 2010-03-19 Sven Zschocke , Burkhard Kampfer , Guenter Plunien

The generator coordinate method begins with the variational construction of a set of non-orthogonal mean-field states that span a subspace of the full many-body Hilbert space. These states are then often projected onto states with good…

Nuclear Theory · Physics 2021-12-08 A. M Romero , J. M. Yao , B. Bally , T. R. Rodríguez , J. Engel

We report ab initio benchmark calculations of nuclear matrix elements (NMEs) for neutrinoless double-beta ($0\nu\beta\beta$) decays in light nuclei with mass number ranging from $A=6$ to $A=22$. We use the transition operator derived from…

Nuclear Theory · Physics 2021-01-27 J. M. Yao , A. Belley , R. Wirth , T. Miyagi , C. G. Payne , S. R. Stroberg , H. Hergert , J. D. Holt

The semileptonic transition of $\Lambda_b$ baryon is studied using the Hypercentral constituent quark model. The six-dimensional hyperradial $Schr\ddot{o}dinger$ equation is solved in the variational approach to get masses and wavefunctions…

High Energy Physics - Phenomenology · Physics 2020-10-28 Kaushal Thakkar

Background: The discovery of neutrinoless double-beta ($0\nu\beta\beta$) decay would demonstrate the nature of neutrinos, have profound implications for our understanding of matter-antimatter mystery, and solve the mass hierarchy problem of…

Nuclear Theory · Physics 2017-02-09 L. S. Song , J. M. Yao , P. Ring , J. Meng

We evaluate the leading-order short-range nuclear matrix element for the neutrinoless double-beta ($0\nu\beta\beta$) decay of the nuclei most relevant for experiments, including $^{76}$Ge, $^{100}$Mo, $^{130}$Te and $^{136}$Xe. In our…

Nuclear Theory · Physics 2021-12-06 Lotta Jokiniemi , Pablo Soriano , Javier Menéndez