Related papers: Atomic parity violation and the HERA anomaly
An excess of events at large Q2 with a positron in the final state has been observed at HERA which, if confirmed, would be a signal of new physics. It is not clear at present if a signal of comparable rate is also seen in the charged…
Data from HERA, LEP and the Tevatron, as well as from low energy experiments are used to constrain the scale of possible electron-quark contact interactions. Some models are found to describe the existing experimental data much better than…
The R parity odd renormalizable Yukawa interactions of quarks and leptons with the scalar superpartners have the ability to violate the baryon and lepton numbers, change the hadron and lepton flavors and make the lightest supersymmetric…
We explore the possible interpretation of the large-$Q^2$ anomaly reported by the H1 and ZEUS collaborations in terms of stop squark production off a strange quark in the proton via an R-violating interaction. This "strange stop"…
Recent advances in interpreting the most accurate to-date measurement of atomic parity violation in Cs are reviewed. The inferred nuclear weak charge, Q_W = - 72.65(28)_expt (36)_theor, agrees with the prediction of the standard model at 1…
The advantage of searching for violation of Time Reversal Invariance in neutron induced reactions using relative measurements of Time and Parity violating effects is discussed. This approach gives the enhancement of $T$-violating effects by…
Recent results of searches for new physics at HERA using the complete data sample corresponding to about 0.5/fb per experiment are reviewed. Searches for leptoquarks, isolated leptons (electrons, muons and taus) and a generic search for new…
In this paper we pursue a consistent leptoquark interpretation for HERA anomalies in the framework of Technicolor. We find that: (a) one F=0 scalar Technicolor leptoquark $P_3^{'}$ with a mass of 200 GeV can provide the required…
The parity violating longitudinal asymmetry ${\cal A}$ is calculated for quasielastic electron scattering. We use a variety of relativistic mean field models for the response of nuclear matter and $^{12}$C at a momentum transfer of q=550…
In the Standard Model the process $q\bar{q}\rightarrow q\bar{q}V$ (where $V=W^\pm,Z^0$ or $\gamma$) can occur via gluon exchange and also via $W^\pm$ or $Z^0$ exchange. The corresponding chromodynamic and electroweak amplitudes can…
In light of new data on neutron distributions from experiments with antiprotonic atoms [ Trzcinska {\it et al.}, Phys. Rev. Lett. 87, 082501 (2001)], we reexamine the role of nuclear-structure uncertainties in the interpretation of…
I review the bounds on the $R$-parity-violating supersymmetric Yukawa couplings from the considerations of proton stability, $n$--$\bar{n}$ oscillation, $\nu_e$-Majorana mass, neutrino-less double $\beta$ decay, charged-current…
Non-Standard-Model parity violation may be occurring in LHC collisions. Any such violation would go unseen, however, as searches are for it are not currently performed. One barrier to searches for parity violation is the lack of…
A summary of the recent searches for anomalous single top-quark production and lepton flavour violation in high energy ep collisions is presented. Single top-quark production via an anomalous flavour changing neutral current gamma-u-t…
We study the effects of virtual leptoquarks on charged current and neutral current processes at the $ep$ collider HERA. We present the areas of parameter space that can be excluded at HERA by searching for deviations from Standard Model…
Many explanations for the excess high-Q^2 $e^+p \to e^+X$ events from H1 and ZEUS at HERA have been proposed each with criticisms. We propose a new method to distinguish different models by looking at a new distribution which is insensitive…
We present calculations of nuclear-spin-dependent and nuclear-spin-independent parity violating amplitudes in Ba, Ra, Ac+, Th and Pa. Parity nonconservation in these systems is greatly enhanced due to the presence of very close electronic…
Supersymmetric models without conservation of R-parity are reviewed and low-energy constraints on the extra trilinear couplings listed. Current searches at the LEP, Tevatron and HERA colliders are then summed up. Prospects for further…
The supersymmetric extension of the Standard Model can contain interactions violating the so-called R-parity symmetry. Such couplings would lead to the lepton and/or baryon number violation and modify deeply the phenomenology of…
In the framework of the minimal supersymmetric standard model with an R-parity breaking coupling of the scalar top quark (stop) we investigate production processes and decay properties of the stop at HERA energies. The model is…