相关论文: Can Four-fermion Contact Interactions at One-loop …
The recent measurement of atomic parity violation in cesium atoms shows a $2.3\sigma$ deviation from the standard model prediction. We show that such an effect can be explained by four-fermion contact interactions with specific chiralities…
The most severe constraints on quark-lepton four-fermion contact interactions come from the agreement of atomic parity violation measurements with the Standard Model. In this letter I note that for contact interactions which arise in…
We investigate the role of four-fermion interactions, rotational and particle-hole asymmetries, and their interplay in three-dimensional systems with a quadratic band touching point by virtue of the renormalization group approach, which…
A contact four-fermion interaction between light quarks and electrons has been evoked as a possible explanation for the excess of events observed by HERA at high-$Q^2$. We explore the 1-loop effects of such interaction in $\Gamma(Z^0 \to…
The charge asymmetry in top quark production at hadron colliders is sensitive to beyond-the-Standard-Model four-fermion interactions. In this study we compare the sensitivity of cross-section and charge asymmetry measurements to effective…
Recent high-precision measurements of atomic parity-nonconserving transitions between the 6S and 7S states of cesium allow for a determination of the weak nuclear charge with a precision of 1.3%, providing an improved test of the standard…
Dipole interactions encode a rich variety of phenomena, such as radiative decays and electric dipole moments in both quark and lepton sectors, which probe physics beyond the Standard Model up to very high energy scales; due to…
Non-standard scenarios described by effective contactlike interactions can be revealed only by searching for deviations of the measured observables from the Standard Model (SM) predictions. If deviations were indeed observed within the…
The parity violation in cesium atom is analysed in the framework of the models based on the SU(3)_C X SU(3)_L X U(1)_N gauge group. It is shown that in the minimal version, the main contribution to a deviation of weak charge \Delta Q_W due…
We discuss the possibility of explaining the excess in the cross section at high-Q^2 recently found at HERA in terms of four-fermion effective interactions. To avoid the constraints from low-energy data, we select three special cases in…
Fermion compositeness, and other types of new physics that can be described by the exchange of very massive particles, can manifest themselves as the result of an effective four-fermion contact interaction. In the case of the processes…
We establish constraints on a general four-fermion contact interaction from precise measurements of electroweak parameters. We compute the one-loop contribution for the leptonic $Z$ width, anomalous magnetic, weak-magnetic, electric and…
Exchange of two neutrinos (as well as other fermions) generates a long-range parity-violating (PV) potential of the form $\sim G^2/r^5$, with characteristic range $\hbar/(2m_\nu c)$. In atomic systems the corresponding matrix elements…
We investigate the constraints on four-Fermi contact interactions from low-energy lepton-quark and lepton-lepton scattering experiments --- polarization asymmetries in electron (muon)-nucleon scattering experiments, cesium and thallium atom…
Non-standard physics which can be described by effective four fermion interactions may be an additional source of CP violation in the neutrino propagation. We discuss the detectability of such a CP violation at a neutrino factory. We assume…
Understanding the correlation effects in unconventional topological materials, in which the fermion excitations take unusual dispersion, is an important topic in recent condensed matter physics. We study the influence of short-range…
The four fermion contact interactions, required to explain the anomalous HERA result, could come from the exchange of new heavy (probably composite) resonances. Depending on their charges and quantum numbers, one gets different scenarios…
The production of several vector bosons in $\gamma\gamma$-interactions is the best place to search directly for any anomalous behavior of triple and quartic couplings. A few anomalous quartic boson operators are considered in the paper. A…
The contributions of non-standard four-neutrino contact interactions to electroweak observables are considered at the one-loop level by using the effective quantum field theory. The analysis is done in terms of three unknown parameters: the…
New-physics (NP) constraints on first-generation quark-lepton interactions are particularly interesting given the large number of complementary processes and observables that have been measured. Recently, first hints for such NP effects…