Related papers: Lepton number violating four-body tau lepton decay…
We point out that lepton number violation is possible even if neutrinos are Dirac particles. We illustrate this by constructing a simple model that allows for lepton number violation by four units only. As a consequence, neutrinoless double…
Using data collected with the BaBar detector between 1999 and 2001, we describe a preliminary search for the neutrinoless decay Tau to Mu Gamma. This data sample includes data collected both on and off the Upsilon(4S) resonance and…
Using data collected with the OPAL detector at LEP, we have searched for the processes e+e- -> Z0 -> p e-, p mu- and the charge conjugate final-states. These would violate the conservation of the baryon-number B, lepton-number L and the…
We present two recent developments on lepton flavour violation in the MSSM. 1) The supersymmetric seesaw mechanism can be realized through the exchange of heavy SU(2)_W-triplet states, rather than `right-handed' neutrinos. In this scenario…
We systematically investigate baryon number violating (BNV) nucleon decays into one lepton ($e,\mu,\nu/\bar\nu$) and two pseudoscalar mesons ($\pi\pi,\pi\eta,\pi K$) within the low-energy effective field theory (LEFT) framework. By…
The $\nu_M{\rm SM}$ is defined as the SM extended to include dimension-5 operators. In this model neutrino masses violate lepton number, and two parameters of the lepton mixing matrix, the Majorana phases, are yet to be constrained. One…
In this work we study the short-range contributions that induce effective lepton number violating (LNV) interactions. We obtain a full set of constraints on the effective short-range couplings from a large variety of low-energy $|\Delta L|=…
We calculate the rates for the charged lepton flavour violating decays l_i -> l_j gamma, tau -> l pi, tau -> l eta, tau -> l eta', mu^- -> e^- e^+ e^-, the six three body leptonic decays tau^- -> l_i^- l_j^+ l_k^- and the rate for mu-e…
Lepton-flavor-violating decays of the type L->l gamma gamma (mu->e gamma gamma, tau->e gamma gamma, and tau->mu gamma gamma) are proposed as new probes of R-parity-violating supersymmetry. Non-penguin diagrams with a sneutrino that decays…
Within the resonance chiral theory, we have studied the process of a tau lepton decaying into a vector resonance plus a pseudo-Goldstone meson and a tau neutrino. Two kinds of processes are discussed: (a) tau- --> (rho pi-,omega pi-, phi…
We investigate leptonic decays $D_s \to \tau \nu_\tau$ and $B^+ \to \tau \nu_\tau$ in R-parity violating (RPV) supersymmetric standard model. Taking account of interference between the s-channel slepton exchange and the $t$-channel squark…
The effect of lepton transverse polarization in the B^0 --> D^- l^+ nu_l, B^+ --> bar(D^0) l^+ nu_l decays (l= tau, mu) is analyzed within the framework of Standard Model in the leading order of HQET. It is shown that the non-zero…
The possible Majorana nature of neutrinos leads to lepton-number-violating effects such as neutrinoless double beta decay. The standard study of this process involves mass-dependent matrix elements which, although easy to use, might be…
We present a search for the decay B+ -> tau+ nu using 288 inverse femtobarns of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed semileptonic B decay…
One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests comparing…
We study the lepton-flavor-violating reaction $\mu^+ e^- \to e^+ e^-$ within two extensions of the standard model that include heavy neutrinos. The reaction is studied in the low energy limit in the form of muonium decay $M\to e^+ e^-$ and…
We review the recent developments in the field of nuclear double beta decay, which is presently an important topic in both nuclear and particle physics. The mechanism of lepton number violation within the neutrinoless double beta decay is…
If CP is violated in any decay process involving leptons it will signify the existense of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. We…
Realistic predictions are made for the rates of lepton flavour violating Higgs boson decays, tau --> mu gamma, mu --> e gamma, Bs --> mu+mu-, Bs --> tau mu and tau --> 3mu, via a top-down analysis of the Minimal Supersymmetric Standard…
We investigate the lepton flavor violation decays, $\tau \to \mu\gamma$, $\tau \to e\gamma$ and $\mu \to e\gamma$, in the framwork of a squential fourth generation model with a heavy fourth neutrino, $\nu'$. Using the recent experimental…