Right-Handed Vector V and Axial A Couplings in Weak Interactions

arXiv (Cornell University), 2007

Any theory that have a global spontaneously broken theory will imply the existence of very light neutral bosons or massless bosons (sometimes called Majorons). For most of these models we have neutrino-Majoron couplings, that appear as additional branching ratios in decays of mesons, W bosons and leptons. Here we present updated limits on the couplings for the electron and muon neutrino flavours and present for the first time bounds on tau neutrino-Majoron couplings.

Annals of Physics, 1983

We consider the Born approximation scattering, by electrons, of neutrinos (and antineutrinos) of the muon and of the electron types; the general Lagrangian respecting lepton locality is used. Throughout, we study only differential cross sections as the experimental observables. Some tests previously proposed for "neutrino identity" or Lorentz structure of the neutral weak interaction are reexamined. We find that, in general, these relations cannot uniquely answer the question of Lorentz structure. Similarly, in general, one cannot estblish whether the tinal neutral lepton is completely identical with, or "partly identical" with, or completely different from, the initial neutrino; identity allows a difference in helicity. In several experimental situations, one can exclude the possibility of a complete non-identity. In one experimental situation, assuming pe universality, one can establish that the final and the initial neutrinos are completely identical, even in their helicity. "Does an interference between neutral currents and the (V-A) charged current exist in v, e '-)-scattering ?" Certain tests can answer this question completely if pe universality is assumed. Without Fe universality, the answer is "destructive interference" if an observable (A,) turns out to be less than 4; A, = 4 would exclude a constructive interference. Assuming neutrino identity, time-reversal invariance for the helicity flipping types (S, P, T), and ye universality, certain simple combinations of observables were previously noted to determine the (V, A) neutral interaction couplings of the neutrino to the electron. With our general formalism, that determination is seen not to require the first two assumptions. Also, the couplings concerned are seen to be only the "diagonal" ones-which refer to that part of the final state in which the final neutrino is identical with the iniitial one. Keeping in view a recent experimental situation, the following question is answered: "When will the lack of enough events for Fe-scattering (or, similarly, ve-scattering) become a threat to lepton locality ?" Some additional consequences of pe universality are noted.

Journal of Modern Physics, 2010

This work deals with the interaction of neutrino with the nucleon considering data taken from different experiments. It is assumed that the interaction of neutrino with nucleons go through the intermediate vector boson (IVB) which may be the W or Z with effective mass of the order of 80 GeV. The neutrino wave function is obtained via perturbation technique to calculate the weak leptonic current. On the other hand, the quark current is estimated using the measured experimental data of deep inelastic scattering of neutrino-nucleon interaction. Eventually the total interaction transition matrix is calculated as a function of momentum transfer square, q 2 and qualitatively compared with the available experimental data. Besides, a comparative study is also done to explore the influence of the target composition during the neutrino weak interactions. In this context an investigation of neutrino-proton and neutrino-neutron interactions are carried out to calculate the deep inelastic cross section in both cases.

Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012

Physical Review D

In neutrino-nucleus interactions, a proton produced with a correlated pion might exhibit a leftright asymmetry relative to the lepton scattering plane even when the pion is absorbed. Absent in other proton production mechanisms, such an asymmetry measured in charged-current pionless production could reveal the details of the absorbed-pion events that are otherwise inaccessible. In this study, we demonstrate the idea of using final-state proton left-right asymmetries to quantify the absorbed-pion event fraction and underlying kinematics. This technique might provide critical information that helps constrain all underlying channels in neutrino-nucleus interactions in the GeV regime.

Physical Review D, 2017

We examine lepton flavor violating (LFV) interactions for heavy right-handed neutrinos that exist in most of the standard model extensions that address dark matter (DM) and neutrino mass at the loop level. In order to probe the collider effect of these LFV interactions, we impose the assumption that the model parameters give the right values of the DM relic density and fulfill the constraints from the LFV processes α → β γ and α → 3 β. We also investigate the possibility of probing these interactions, and hence the right-handed neutrino, at leptonic colliders through different final state signatures.

Journal of High Energy Physics, 2013

We consider nonstandard interactions of neutrinos with electrons arising from a new light spin-1 particle with mass of tens of GeV or lower and couplings to the neutrinos and electron. This boson is not necessarily a gauge boson and is assumed to have no mixing with standard-model gauge bosons. Adopting a modelindependent approach, we study constraints on the flavor-conserving and -violating couplings of the boson with the leptons from a number of experimental data. Specifically, we take into account the (anti)neutrinoelectron scattering and e + e − → ννγ measurements and keep explicitly the dependence on the new particle mass in all calculations. We find that one of the two sets of data can provide the stronger constraints, depending on the mass and width of the boson.

2007

Any theory that have a global spontaneously broken symmetry will imply the existence of very light neutral bosons or massless bosons (sometimes called Majorons). For most of these models we have neutrino-Majoron couplings, that appear as additional branching ratios in decays of mesons and leptons. Here we present an updated limits on the couplings between the electron, muon and tau neutrinos and Majorons. For such we analyze the possible effects of Majoron emission in both meson and lepton decays. In the latter we also include an analysis of the muon decay spectrum. Our results are |geα| 2 < 5.5 × 10 −6 , |gµα| 2 < 4.5 × 10 −5 and |gτα| 2 < 5.5 × 10 −2 at 90 % C. L., where α = e, µ, τ .

Eprint Arxiv Hep Ph 0201280, 2002

Given the eventuality of neutrino and muon factories in the foreseeable future, all possible 2 → 2 processes involving two neutrinos, whether Dirac or Majorana ones, and two charged fermions are considered on the basis of the most general Lorentz invariant four-fermion effective interaction possible, in the limit of massless particles. Such a parametrization should enable the assessment of the sensitivity to physics beyond the Standard Model, including the eventual discrimination between the Dirac or Majorana character of neutrinos, of specific experimental beam and detector designs.

Physical Review D - PHYS REV D, 2002

R-parity violation in the supersymmetric standard model can be the source of neutrino masses and mixing. We analyze the neutrino mass matrix coming from either bilinear or trilinear R-parity violation and its collider signatures, assuming that the atmospheric and solar neutrino data are explained by three active neutrino oscillations. Taking the gauge mediated supersymmetry breaking mechanism, we show that the lightest neutralino decays well inside the detector and the model could be tested by observing its branching ratios in the future colliders. In the bilinear model where only the small solar neutrino mixing angle can be accommodated, the relation, $10^3$ BR($\nu e^\pm \tau^\mp$) $\sim$ BR($\nu \mu^\pm \tau^\mp$) $\approx$ BR($\nu \tau^\pm \tau^\mp$), serves as a robust test of the model. The large mixing angle solution can be realized in the trilinear model which predicts BR($\nu e^\pm \tau^\mp$) $\sim$ BR($\nu \mu^\pm \tau^\mp$) $\sim$ BR($\nu \tau^\pm \tau^\mp$). In either ca...