With the recent possible signal of dark matter from the CDMS II experiment, the Z' mass of a new version of the dark left-right gauge model (DLRM II) is predicted to be at around a TeV. As such, it has an excellent discovery prognosis at the operating Large Hadron Collider.
The Standard Model of particle interactions is extended to include fermion doublets (n,e)_R transforming under the gauge group SU(2)_R such that n is a Dirac scotino (dark-matter fermion), with odd R parity. Based on recent CDMS data, it is shown how this new dark left-right model (DLRM2) favors a Z' gauge boson at around 1 or 2 TeV and be observable at the LHC. The new W_R gauge bosons may also contribute significantly to lepton-flavor-changing processes such as mu to e gamma and mu-e conversion in a nucleus or muonic atom.
The left-right twin Higgs model predicts a light stable scalar \hat{S}, which is a candidate for WIMP dark matter. We study its scattering on nucleon and find that the cross section is below the CDMS II upper bound but can reach the SuperCDMS sensitivity. Then we study the Higgs phenomenology by paying special attention to the decay h -> \hat{S} \hat{S} which is strongly correlated with the dark matter scattering on nucleon. We find that such an invisible decay can be sizable, which can severely suppress the conventional decay modes like h->VV (V=W,Z) and h->b\bar{b}. On the other hand, compar…
We show that mostly right-handed Dirac sneutrino is a viable supersymmetric light dark matter candidate. While the Dirac sneutrino scattering with nuclei is dominantly through the $Z$ boson exchange and is stringently constrained by the invisible decay width of $Z$ boson, it is possible to realize a large enough cross section with nucleon to account for possible signals observed at direct dark matter searches such as CDMS II-Si or CoGeNT. Even if the XENON100 limit is taken into account, a small part of signal region for CDMS II-Si events remains outside the excluded region by XENON100.
We add a singlet right handed neutrino plus a charged and a neutral singlet scalars to the standard model. This extension includes a discrete symmetry such that we obtain a heavy sterile neutrino which couples only to the electron and the new scalars. In this sense the singlet neutrino does not mix with ordinary ones and thus has no effect on Big Bang Nucleosynthesis. However, such sterile neutrino can be in equilibrium with electroweak particles in the early Universe due to its couplings to electrons and also because the Higgs boson mixes with the singlet scalars. We obtain that the sterile n…
Decay processes $B\rightarrow D_{\left(s\right)}^{\left(*\right)}h$ ($h=π,ρ$) are studied in the framework of the confined covariant quark model using the naïve factorization assumption. We observe that the theoretical results on branching fractions have tendency to systematically exceed the experimental numbers. Such a behavior has already been seen for similar processes by other authors.
We have performed the calculations for the nonleptonic $Ξ_b^- \rightarrow π^- \ Ξ_c^0 (2790) \left(J=\frac{1}{2}\right)$ and $Ξ_b^- \rightarrow π^- \ Ξ_c^0 (2815) \left(J=\frac{3}{2}\right)$ and the same reactions replacing the $π^-$ by a $D_s^-$. At the same time we evaluate the semileptonic rates for $Ξ_b^- \rightarrow \barν_l l \ Ξ_c^0 (2790)$ and $Ξ_b^- \rightarrow \barν_l l \ Ξ_c^0 (2815)$. We look at the reactions from the perspective that the $Ξ_c^0 (2790)$ and $Ξ_c^0 (2815)$ resonances are dynamically generated from the pseudoscalar-baryon and vector-baryon interactions. We evaluate ra…
The radiative baryonic decay $\mathcal{B}^{*}\left(\frac{3}{2}\right)\to\mathcal{B}\left(\frac{1}{2}\right)+γ$ is a magnetic dipole $(M1)$ transition. It requires the transition magnetic moment $μ_{\mathcal{B}\left(3/2\right)\to\mathcal{B}\left(1/2\right)}$. The transition magnetic moments for the helicities $1/2$ and $3/2$ are evaluated in the frame work of constituent quark model in which the intrinsic spin and the magnetic moments of quarks $u,d$ and $s$ play a key role. Within this framework, the radiative decays $Δ^{+}\to p +γ$, $Σ^{*0}\to Λ+γ$, $Σ^{*+}\to Σ^{+}+γ$ and $Ξ^{*0}\to Ξ^{0}+γ$…
We propose an effective left-right-right-left model with a parity breaking scale around a few TeV. One of the main achievements of the model is that the mirror fermions as well as the mirror gauge sector simultaneously could be at TeV scale. It is shown that the most dangerous quadratic divergence of the SM Higgs boson involving the top quark in the loop is naturally suppressed, and begins at three loop. The model postpones the fine-tuning of the mass of the SM Higgs boson up to a sufficiently high scale. The model explains the smallness of the neutrino masses whether they are Dirac or Majoran…
In a class of left-right symmetric models for linear seesaw, a neutrinoless double beta decay induced by the left- and right-handed charged currents together will only depend on the breaking details of left-right and electroweak symmetries. This neutrinoless double beta decay can reach the experimental sensitivities if the right-handed charged gauge boson is below the 100 TeV scale.
The breaking of parity, a fundamental symmetry between left and right is best understood in the framework of left-right symmetric extension of the standard model. We show that the production of a heavy right-handed neutrino at the proposed Large Hadron-Electron Collider (LHeC) could give us the most simple and direct hint of the scale of this breaking in left-right symmetric theories. This production mode gives a lepton number violating signal with $ΔL=2$ which is very clean and has practically no standard model background. We highlight that the right-handed nature of $W_R$ exchange which defi…
We propose four left-right symmetric extensions of several chiral 3-3-1 models. Although they have some common features they also have important difference due to different representation content.
We discuss various experimental tests of the left-right symmetric model possible to perform in the next generation linear colliders. We consider processes which provide sensitive probes of the basic ingredients of the model: right-handed gauge bosons, right-handed Majorana neutrinos, lepton number violating interactions and triplet Higgs scalars. A supersymmetric version of the left-right model is also studied and some distinctive experimental tests for it is proposed. One of the main messages of this talk is to emphasize the usefulness of the collision modes $e^-e^-$, $e^-γ$ and $γγ$ for the …
In left-right symmetric seesaw models an eight-fold degeneracy among the right-handed neutrino mass matrices is known to exist. We use stability and viability of leptogenesis as criteria in order to discriminate among the degenerate solutions and to partially lift the eight-fold degeneracy.
We present a systematic approach to solve analytically for the right-handed quark mixings in the minimal left-right symmetric model which generally has both explicit and spontaneous CP violations. The leading-order result has the same hierarchical structure as the left-handed CKM mixing, but with additional CP phases originating from a spontaneous CP-violating phase in the Higgs vev. We explore the phenomenology entailed by the new right-handed mixing matrix, particularly the bounds on the mass of $W_R$ and the CP phase of the Higgs vev.
The complete list of electroweak chiral Lagrangian up to order of p4 for left-right symmetric models with a neutral light higgs is provided. The connection of these operators to left and right gauge boson mixings and masses is made and their contribution to conventional generalized electroweak chiral Lagrangian with a neutral light higgs included in is estimated.
The difference between left- and right-handed particles is perhaps one of the most puzzling aspects of the Standard Model (SM). In left-right models (LRMs) the symmetry between left- and right-handed particles can be restored at high energy. Due to this symmetry these models are quite predictive with regards to experimental observables, making them interesting beyond the SM candidates. Here we discuss the more symmetric LRMs, the experimental constraints, and the fine-tuning present in the Higgs sector.
We study flavor-changing neutral current and CP violations in the minimal supersymmetric left-right model. We calculate the beyond-standard-model contributions to the neutral kaon mixing $ΔM_K$ and $ε$, and find possible to have a numerical cancelation between the contributions from the right-handed gauge boson and supersymmetric box diagram. With the cancelation, the right-handed $W$-boson mass scale can be lowered to about 2 TeV, well within the search limit of LHC.
We show that the lightest right-handed sneutrino in TeV scale supersymmetric B-L model with inverse seesaw mechanism is a viable candidate for cold dark matter. We find that it accounts for the observed dark matter relic abundance in a wide range of parameter space. The spin-independent cross section of B-L right-handed sneutrino is consistent with the recent results CDMS II and XENON experiments and it is detectable in future direct detection experiments. Although the B-L right-handed sneutrinos annihilate into leptons, the PAMELA results can not be explained in this model unless a huge boost…
The decays of $η$ and $η^\prime$ mesons provide unique opportunities for testing the properties of low energy Quantum Chromodynamics and for the search of new physics beyond the Standard Model. However, recent experimental results on the rare decays of $η^{\left(\prime\right)}\rightarrowπ^0\left(η\right)γγ$ cannot be self-consistently described by the combination of the Vector Meson Dominance and Linear Sigma Model employing the same set of parameters. We show that this tension can be attributed to the presence of a leptophobic dark photon $\mathcal{B}$, and find representative values of the p…
Strong decays of $X\left( 3915\right) $ are analyzed from two quark model descriptions of $X\left( 3915\right) $, a conventional one in terms of the Cornell potential and an unconventional one from a Generalized Screened potential. We conclude that the experimental suppression of the OZI allowed decay $X\left( 3915\right) \rightarrow D\overline{D}$ might be explained in both cases as due to the momentum dependence of the decay amplitude. However, the experimental significance of the OZI forbidden decay $X\left( 3915\right) \rightarrowωJ/ψ$ could favor an unconventional description.
We give exact formulas for the right-handed analog of the CKM matrix in the minimal Left-Right symmetric theory, for the case when the Left-Right symmetry is generalized Parity as in the original version of the theory. We derive its explicit form and give a physical reason for the known and surprising fact that the right-handed mixing angles are close in value to the CKM ones, in spite of the Left-Right symmetry being badly broken in nature. We exemplify our results on the production of the right-handed charged gauge boson and the computation of the neutral K meson mass difference.
Two renormalization group invariant quantities in quantum chromodinamics (QCD), defined in Euclidean space,namely, Adler D-function of electron-positron annihilation to hadrons and Bjorken polarized deep-inelastic scattering sum rule, are considered. It is shown, that the 5-th order corrections to them in $\overline{MS}$-like renormalization prescriptions, proportional to Riemann $ζ$-function $ζ\left(4\right)$, can be restored by the transition to the C-scheme, with the $β$-function, analogous to Novikov, Shifman, Vainshtein and Zakharov exact $β$-function in $\mathcal{N}=1$ supersymmetric gau…