相关论文: Constraints on the Universal Contact Interaction

The matter content of the Standard Model admits a global symmetry due to the generational structure of the spectrum respected by all interactions except for fermion couplings to the Higgs doublet. This symmetry is identified as the largest…

Searches for physics beyond the Standard Model are reported from electron-proton collisions at a center of mass energy of 318 GeV. Results on a completely model independent search for deviations from Standard Model predictions at large…

The Standard Model of electroweak interactions is shown to include a gauge theory for the observed scalar and pseudoscalar mesons. This is done by exploiting the consequences of embedding the SU(2)left X U(1) group into the chiral group of…

Signals of physics beyond the Standard Model at HERA have been searched for by the H1 and ZEUS collaborations. Results are reported about searches of contact interaction effects, leptoquarks, R-parity violating squarks, excited fermions and…

We examine the potential of constraining possible nondecoupling effects of heavy neutrinos and Higgs bosons at LEP and SLC that may show up in the nonoblique part of the $Zl_il_j$ couplings. We analyze this type of new-physics interactions…

We study the effective interactions induced by loops of extra-dimensional gravitons and show the special role of a specific dimension-6 four-fermion operator, product of two flavour-universal axial currents. By introducing an ultraviolet…

We elucidate and extend the conditions that map gauge-Yukawa theories at low energies into time-honoured gauged four-fermion interactions at high energies. These compositeness conditions permit to investigate theories of composite dynamics…

In this talk, I summarize a global analysis on electron-quark contact interactions using the updated NC DIS data at HERA, Drell-yan production at the Tevatron, total hadronic cross sections at LEP, atomic parity violation measurement, low…

Using the constraint on the single top production cross-section obtained at the HERA collider, $\sigma(ep \to e t X)$, we evaluate an upper limit on oupling constant of the anomalous top quark interaction with a gluon via flavor-changing…

We look for a mechanism that removes without numerical fine tuning the strong constraint imposed by the flavor changing neutral current interaction of leptoquark exchange. If n x n degenerate leptoquarks couple universally to n generations…

Arguments coming from Quantum Field Theory are supplemented with a 1-loop perturbative calculation to settle the non-unitarity of mixing matrices linking renormalized mass eigenstates to bare flavor states for non-degenerate coupled…

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…

Highly accurate results from frequency measurements on neutral hydrogen molecules H_2, HD and D_2 as well as the HD^+ ion can be interpreted in terms of constraints on possible fifth-force interactions. Where the hydrogen atom is a probe…

The prospects of physics beyond the standard model in deep inelastic scattering are reviewed, emphasizing the search for contact interactions, for leptoquarks and for supersymmetry with R-parity violation. R-parity violating supersymmetry…

We consider $e e q q$ contact interactions as a possible origin of an excess of events above Standard Model predictions in $e^+ p \to e^+ jet$ at high $Q^2$ observed by the H1 and ZEUS collaborations at HERA. The HERA data prefer chirality…

We define a new class of $Z'$ models with neutral flavor-changing interactions at tree level in the down-quark sector. They are related in an exact way to elements of the quark mixing matrix due to an underlying flavored $U(1)'$ gauge…

We consider lepton-antilepton annihilation into a fermion-antifermion pair at variable c.m. energy. We propose for this process a simple parametrization of the virtual effects of the most general model of new physics of…

In the framework of the Standard Model Effective Field Theory, we compare the lower bounds on the scale of new physics possibly contributing to the $f\bar{f}h$ effective couplings, obtained from the measurements of different observables,…

By introducing a set of new triplet leptons (with nonzero hypercharge) that can Yukawa couple to their Standard Model counterparts, new sources of tree-level flavor changing currents are induced via mixing. In this work, we study some of…

We present a functional renormalization group investigation of an Euclidean three-dimensional matrix Yukawa model with U(N) symmetry, which describes N = 2 Weyl fermions that effectively interact via a short-range repulsive interaction.…