Related papers: $A_{LR}$, Negative $S$, and Extended Gauge Models
In light of the recent measurements of the top quark forward-backward asymmetry at the Fermilab Tevatron experiment, which in some regions of the parameter space shows a discrepancy of 3$\sigma$ compared to the SM prediction, we analyze top…
We analyze the bounds on the set of four "non-blind" anomalous gauge couplings that will be derived, in absence of deviations from the Standard Model predictions, from near future measurements at LEP2 and at the TEVATRON. The bounds are…
We report new direct measurements of the $Z^0$-lepton coupling asymmetry parameters $A_e$, $A_{\mu}$ and $A_{\tau}$, with polarized $Z^0$'s collected by the SLD detector at the SLAC Linear Collider. The parameters are extracted from the…
The Large Hadron Collider has a potential to probe the scale of left-right symmetry restoration and the associated lepton number violation. Moreover, it offers hope of measuring the right-handed leptonic mixing matrix. We show how this,…
Recent experimental results from the CDF collaboration which study the top forward-backward asymmetry have strengthened the case that new physics is playing a role in t-tbar production. Here we propose a set of measurements, built from the…
We study a gauge $B-L$ extension of the standard model of quarks and leptons with unconventional charges for the singlet right-handed neutrinos, and extra singlet scalars, such that a residual $Z_3$ symmetry remains after the spontaneous…
A sizable charge asymmetry in top quark pair production has been observed at the Tevatron. The experimental results seem to exceed systematically the Standard Model theory predictions by a significant amount and have triggered a large…
The left-right model is a gauge theory of electroweak interactions based on the gauge symmetry SU(2)_R . The main motivations for this model are that it gives an explanation for the parity violation of weak interactions, provides a…
Left-Right Models (LRM) attempt at giving an understanding of the violation of parity (or charge-conjugation) by the weak interactions in the SM through a similar description of left- and right-handed currents at high energies. The…
LEP determines $\sin^2 \theta_{\rm eff}$, by combining the various asymmetry measurements to be $0.2321 \pm 0.0005$. On the other hand, the left-right asymmetry as measured at SLC corresponds to \seff = $0.2292 \pm 0.0010$. I will discuss…
We evaluate the predictions of the left-right symmetry model based on $SU(2)\otimes U(1)$ gauge group with one bidoublet and one doublet Higgs fields on the parity violation, charged leptons and neutrinos masses. Parity violation in the…
Key electroweak measurements performed by the SLD collaboration at the SLC are described and recent results given. The left-right cross-section asymmetry, $A_{LR}$, has been updated to include the 1996 data. It remains the single most…
Motivated by the difference between SLD's recent measurement of ALR and the corresponding LEP results, we explore which kinds of new particles can (1) contribute dominantly to new physics through oblique corrections, (2) produce negative…
We revisit the issue of the limit on the scale of Left-Right symmetry breaking. We focus on the minimal SU(2)_L x SU(2)_R x U(1)_B-L gauge theory with the seesaw mechanism and discuss the two possibilities of defining Left-Right symmetry as…
We suggest the use of a universality-breaking observable based on lepton asymmetries as derived from the left-right asymmetry and the $\tau$ polarization at the $Z$ peak, which can efficiently constrain the parameter space of unified…
Lepton charge asymmetries can be used as an alternative means of searching for new physics. They are interesting because they are small in the Standard Model and therefore, necessarily evidence new physics. In this work we explore the use…
We consider how the measurement of top polarization at the Tevatron can be used to characterise and discriminate among different new physics models that have been suggested to explain the anomalous top forward-backward asymmetry reported at…
In a left-right gauge model of particle interactions, the left-handed fermion doublet (nu,e)_L is connected to its right-handed counterpart (n,e)_R through a scalar bidoublet so that e_L pairs with e_R, and nu_L with n_R to form mass terms.…
A sizeable charge asymmetry in top quark pair production has been observed at the Tevatron. The experimental results seem to exceed systematically the Standard Model theory predictions by a significant amount and have triggered a large…
We present new constraints on Lorentz symmetry (LS) violations with lunar laser ranging (LLR). Those constraints are derived in the standard-model extension (SME) framework aiming at parameterizing any LS deviations in all sectors of…