Search results for " MATRIX"
showing 10 items of 2053 documents
Lepton Transmutation in the Dualized Standard Model
2002
The successful explanation of fermion mixing and of the fermion mass hierarchy by the Dualized Standard Model (DSM) scheme is based on the premises of a fermion mass matrix rotating in generation space with changing scales at a certain speed, which could in principle lead to sizeable flavour-violation observable in high sensitivity experiments such as BaBar. However, a full perturbative calculation to 1-loop order reported here shows that this kinematical, flavour-violating effect of a rotating mass matrix is off-set in the DSM by parallel effects from rotating wave functions and vertices giving in the end only very small flavour-violations which are unlikely to be detectable by present exp…
Revealing the Majorana nature of heavy neutrinos via a heavy Higgs boson
1992
Abstract Analyzing several recently proposed models, based on simple extensions of the standard model (SM), with heavy Majorana neutrinos, it is shown that the change of detecting lepton number violation through their production and subsequent decays may be significantly enhanced, if a heavy Higgs boson with mass within a reasonably broad range is present.
Improved bounds on SUSY accompanied neutrinoless double beta decay
1998
Neutrinoless double beta decay induced by light Majorana neutrino exchange between two decaying nucleons with squark/slepton exchange inside one and W exchange inside the other nucleon (so-called vector-scalar exchange) gives stringent limits on R-parity violating interactions. We have extended previous work by including the tensor contribution to the transition rate. We discuss the improved limits on trilinear \Rp -MSSM couplings imposed by the current experimental limit on the $\znbb$ decay half-life of $^{76}$Ge.
Photo-transmutation of leptons
2001
By photo-transmutation of leptons we mean photon-lepton reactions of the following type: $\gamma l_\alpha \longrightarrow \gamma l_\beta$ with $l_\alpha \neq l_\beta$, occurring as a consequence of the lepton mass matrix changing its orientation (rotating) under changing scales. In this paper, we first discuss these reactions in general terms, then proceed to the calculation of their cross sections in two specific schemes, one within the framework of the conventional Standard Model, the other being the so-called Dualized Standard Model we ourselves advocate. Although the cross section obtained is generally small the calculation reveals certain special circumstances where these reactions may…
The solar LMA neutrino oscillation solution in the Zee model
2001
We examine the neutrino mass matrix in the version of Zee model where both Higgs doublets couple to the leptons. We show that in this case one can accommodate the large mixing angle (LMA) MSW solution of the solar neutrino problem, while avoiding maximal solar mixing and conflicts with constraints on lepton family number-violating interactions. In the simplified scenario we consider, we have the neutrino mass spectrum characterized by $m_1 \simeq m_2 \simeq \sqrt{\Delta m^2_\mathrm{atm}}/\sin 2\theta$ and $m_3/m_1 \simeq \cos 2\theta$, where $\theta$ is the solar mixing angle.
Neutrino mass hierarchy and Majorana CP phases within the Higgs triplet model at the LHC
2007
Neutrino masses may be generated by the VEV of an $SU(2)_L$ Higgs triplet. We assume that the doubly charged component of such a triplet has a mass in the range of several 100 GeV, such that it is accessible at LHC. Its decay into like-sign leptons provides a clean experimental signature, which allows for a direct test of the neutrino mass matrix. By exploring the branching ratios of this decay into leptons of various flavours, we show that within this model the type of the neutrino mass spectrum (normal, inverted or quasi-degenerate) might actually be resolved at the LHC. Furthermore, we show that within the Higgs triplet model for neutrino mass the decays of the doubly charged scalar into…
Study ofB−→DK−π+π−andB−→Dπ−π+π−decays and determination of the CKM angleγ
2015
We report a study of the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) decays, where the neutral D meson is detected through its decays to the K--/+pi(+/-) and CP -even K+K- and pi(+)pi(-) final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb(-1). We observe the first significant signals in the CP - even final states of the D meson for both the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) modes, as well as in the doubly Cabibbo suppressed D -> K+pi(-) final state of the B- -> D pi(-)pi(+)pi(-) decay. Evidence for the suppressed d…
Measurements of |Vcb|, form factors and branching fractions in the decays → ℓ and → ℓ
1997
Two samples of exclusive semileptonic decays, 579 B0 -> D*+l-νl events and 261 B0 -> D+l-νl events, are selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP. From the reconstructed differential decay rate of each sample, the product of the hadronic form factor F(ω) at zero recoil of the D(*)+ meson and the CKM matrix element Vcb are measured to be FD*+ (1) Vcb = (31.9 +/- 1.8stat +/- 1.9syst) × 10-3,FD+ (1) Vcb = (27.8 +/- 6.8stat +/- 6.5syst) × 10-3. The ratio of the form factorsFD+ (1) and FD*+ (1) is measured to beFD+ (1)/FD*+ (1) = 0.87 +/- 0.22stat +/- 0.21syst. A value of Vcb is extracted from the two samples, using theoretical constraints o…
Minimal Flavour Violation and Multi-Higgs Models
2010
We propose an extension of the hypothesis of Minimal Flavour Violation (MFV) to general multi-Higgs models without the assumption of Natural Flavour Conservation (NFC) in the Higgs sector. We study in detail under what conditions the neutral Higgs couplings are only functions of V-CKM and propose a MFV expansion for the neutral Higgs couplings to fermions
A large magnetic detector for the neutrino factory
2000
Abstract The physics opportunities of the neutrino factory have been the subject of a number of recent studies. It was shown that sensitive measurements of the angle θ 13 , of MSW effects, and of the sign of the atmospheric mass difference Δ m 23 2 are possible, and even CP violation in the neutrino mixing matrix may be within reach. The focus of interest is the oscillation ν e →ν μ , which leads in the well-defined neutrino beam of the neutrino factory to ‘wrong-sign’ muon events. In this paper, we show that a large magnetic detector will be capable of detecting with high efficiency and small backgrounds such wrong-sign muon events. We present a conceptual design of the apparatus and its p…