Related papers: Double beta decay of sigma^- hyperons
As a result of the helicity suppression effect, within the Standard Model the rare decay channel $B_s \to e^+ e^-$ has a decay probability which is five orders of magnitude below current experimental limits. Thus, any observation of this…
Under the working hypothesis that the structure of a bound hadron is modified by its interactions with other hadrons, one may expect to see changes in carefully chosen observables. In the light of a recent proposal to measure the axial…
We present a novel mode of neutrinoless double beta decay with emission of a light Majoron-like scalar particle phi. We assume it couples via an effective seven-dimensional operator with a (V+A) lepton current and (V+-A) quark currents…
We consider all possible scalar bilinears, which couple to two fermions of the standard model. The various baryon and lepton number violating couplings allowed by these exotic scalars are studied. We then discuss which ones are constrained…
The existence of large \nu_\mu-\nu_\tau mixing suggests the likelihood of large smuon-stau mixing in supersymmetric models, leading to \mu and \tau number violation. In addition to interesting signatures in slepton and neutralino production…
We review the detection of the Delta L=2 semileptonic meson decays of the form M(+) -> M'(-) lepton(+) lepton(-) that we studied in a previous work, mediated by a Majorana neutrino with a mass in the range between the masses of the initial…
We consider the most generic situation in models where the electroweak symmetry is broken by the condensation of a strongly coupled fermion sector, such as for instance a fourth generation. We study the scalar content resulting from the…
We present a detailed discussion on neutrinoless double beta decay $(0\nu \beta \beta)$ within left-right symmetric models based on the gauge symmetry of type $SU(2)_L \times SU(2)_R \times U(1)_{B-L}$ as well as $SU(3)_L \times SU(3)_R…
The LEGEND experiment is looking for the extremely rare neutrinoless double beta ($0\nu\beta\beta$) decay of $^{76}$Ge using isotopically-enriched high-purity germanium (HPGe) detectors. The detection of this process would imply that the…
The extension of the Standard Model by right handed neutrinos with masses in the GeV range can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the universe via leptogenesis. It has…
We analyze leptogenesis in a supersymmetric triplet seesaw scenario that explains the observed neutrino masses, adopting a phenomenological approach where the decay branching ratios of the triplets and the amount of CP--violation in its…
In this work we show that the implementation of spontaneous breaking of the lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast neutrino decay with majoron emission and generates a bunch of new contributions to…
We investigate the differential branching ratio, branching ratio, differential forward-backward asymmetry, the forward-backward asymmetry of the lepton pair and the lepton polarization asymmetry of the exclusive $B\to \tau^+ \tau^- \gamma$…
The combined CMS and ATLAS analysis of \(h \to Z\gamma\) reveals a \(2\sigma\) excess over the Standard Model (SM) prediction, hinting at potential new physics. In contrast, the observed agreement of \(\mu_{\gamma\gamma}\) with the SM…
We study the implications for Two Higgs Doublet Models of the recent announcement at the LHC giving a tantalizing hint for a Higgs boson of mass 125 GeV decaying into two photons. We require that the experimental result be within a factor…
The Higgs-portal lepton flavor violation is studied in a vectorlike lepton model. For evading the constraints from rare $Z\to \ell^\pm_i \ell^\mp_j$ decays, we introduce two triplet vectorlike leptons, $(1,3)_{-1}$ and $(1,3)_{0}$. The…
Neutrinoless double beta decay ($0\nu\beta\beta$) is a rare process which could take place if neutrinos are Majorana fermions: the observation of this decay would provide unambiguous evidence for the existence of new Physics beyond the…
Hadronic decays of the $\tau$ lepton provide a clean source to study hadron dynamics in an energy regime dominated by resonances, with the interesting information captured in the spectral functions. Recent results on exclusive channels are…
Searches for $B$ mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either $\Lambda_c$ or $\Lambda$ and the lepton is a muon or an electron. These decays violate both baryon and lepton number…
The present experimental status in the search for neutrinoless double beta decay is reviewed, with emphasis on the first indication for neutrinoless double beta decay found in the Heidelberg-Moscow experiment, giving first evidence for…