相关论文: Bounds on Four-Fermion Contact Interactions Induce…
We review the low energy constraints on type I see-saw extensions of the Standard Model in which the scale of new physics, associated to lepton number violation, can be probed at current collider searches. In such scenarios, the flavour…
The interactions between two octet baryons are studied at low energies using lattice QCD (LQCD) with larger-than-physical quark masses corresponding to a pion mass of $m_{\pi}\sim 450$ MeV and a kaon mass of $m_{K}\sim 596$ MeV. The…
Assuming that the leptons and quarks other than top are massless at tree level, we show that their masses may be induced by loops involving the top quark. As a result, the generic features of the fermion mass spectrum arise from…
Using string scattering amplitudes of open bosonic string on a single $D$-brane, we construct a local field theoretical action for tachyon fields. Cubic local interactions between various particles, belonging to the particle spectrum of…
The capability of string theories to reproduce at low energy the observed pattern of quark and lepton masses and mixing angles is examined, focusing the attention on orbifold constructions, where the magnitude of Yukawa couplings depends on…
We investigate the fermions of the standard model without a Higgs scalar. Instead, we consider a non-local four-quark interaction in the tensor channel which is characterized by a single dimensionless coupling $f$. Quantization leads to a…
A new mechanism for generating neutrino masses without a high-energy mass scale is proposed. The mechanism needs a fundamental mass scale M in the 100-1000 TeV region and a minimal field content beyond the Standard Model one containing a…
We propose a random matrix model as a representation for $D=1$ open strings. We show that the model is equivalent to $N$ fermions with spin in a central potential that also includes a long-range ferromagnetic interaction between the…
We propose using the general structure and properties of conformal field theory amplitudes, in particular those defined on surfaces with boundaries, to explore effective string theory amplitudes for some hadronic processes. Two examples are…
Very recently, we proposed an explanation of the discrepancy between the measured anomalous magnetic moment of the muon and the Standard Model (SM) prediction in which the dominant contribution to $(g-2)_\mu$ originates in Kaluza-Klein (KK)…
We explore the capability of the Tevatron and LHC to place limits on the possible existence of flavor-independent $q \bar q \gamma\gamma$ contact interactions which can lead to an excess of diphoton events with large invariant masses.…
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…
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 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 constrain general Dirac neutrino interactions based on the Standard Model Effective Field Theory framework extended with right-handed neutrinos $N$ (SMNEFT) using deep inelastic and coherent elastic neutrino scattering, nuclear beta…
Interactions between electrons in one-dimension are fully described at low energies by only a few parameters of the Tomonaga-Luttinger model which is based on linearisation of the spectrum. We consider a model of spinless fermions with a…
We recently proposed a spontaneous A$_{4}$ flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The main features of this choice are the…
Unitarity of longitudinal weak vector boson scattering implies an upper bound on the scale of electroweak symmetry breaking, $\Lambda_{EWSB}\equiv \sqrt{8\pi}v\approx$ 1 TeV. Appelquist and Chanowitz have derived an analogous upper bound on…
Simple models are proposed where the baryon and lepton number are gauged and spontaneously broken near the weak scale. The models use a fourth generation that is vector-like with respect to the strong, weak and electromagnetic interactions…
In this work we investigate the implication of low-energy precision measurements on the quark-lepton charged currents in general neutrino interactions with sterile neutrinos in effective field theories. The physics in low-energy…