Related papers: Constraints on Extra Gauge Bosons in e gamma Colli…
One of the necessary steps in constructing high precision option of KKMC was to install the double bremsstrahlung matrix element for the process e+ e- to nu_e bar nu_e into the scheme of Coherent Exclusive Exponentiation. The process is…
In the context of topcolor-assisted techicolor($TC2$) models, we investigate the feasibility of detecting the non-universal gauge boson $Z^{'}$ in the future high-energy linear $e^{+}e^{-}$ collider($LC$) experiments by performing…
We construct a new gauged $U(1)_\ell$ lepton number model which is anomaly-free for each SM generation. The active neutrino masses are radiatively generated with a minimal scalar sector. The phenomenology and collider signals are studied.…
A new exclusion limit for the electromagnetic production of a light U(1) gauge boson {\gamma}' decaying to e^+e^- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the…
We obtain bounds for the mass of the extra neutral gauge boson, ${Z^\prime}$, predicted by two versions of ${SU (3)_C \times SU (3)_L \times U (1)_X}$ model, namely one corresponding to its minimal version and another where the neutrinos…
We consider theories where lepton flavor is violated, in particular concentrating on the four fermion operator consisting of three electrons and a tau. Strong constraints are available from existing searches for tau -> eee, requiring the…
In this study, we explore the non-standard $\nu\bar{\nu}\gamma \gamma$ couplings parametrized by dimension-seven operators via $e^{+}e^{-} \to \nu\bar{\nu}\gamma$ process at the FCC-ee/CEPC and $\mu^{+}\mu^{-}\to\nu\bar{\nu}\gamma$ process…
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 investigate the potential for detecting and studying Higgs bosons in $\gamma\gamma$ and $e\gamma$ collisions at future linear colliders with energies below a TeV. Our study incorporates realistic $\gamma\gamma$ spectra based on available…
We study the sensitivity of the processes `e+ e- -> lepton (l) neutrino (v) quark (u) antiquark (d)', where the lepton is an electron or a muon, on the non-standard trilinear gauge couplings (TGC), using the optimal observables method at…
We recall how a new light gauge boson emerged in Supersymmetric extensions of the Standard Model with an extra singlet superfield, and how it could behave very much as a light pseudoscalar, with the corresponding symmetry broken at a scale…
A model with $L_{\mu} -L_{\tau}$ gauge symmetry is the least constrained model as a resolution to the disagreement of the muon anomalous magnetic moment between the theoretical predictions and the experimental results. In this paper, we…
We study the process e+e- -->nu nubar gamma to search for its sensitivity to the extra gauge bosons Z_2, Z_3 and W_2 which are suggested by the little Higgs models. We find that the ILC with sqrt(s)=0.5 TeV and CLIC with sqrt(s)=3 TeV cover…
Strong interactions between pairs of the K+ K- and K0 K0bar mesons can be studied in radiative decays of phi(1020) mesons. We present a theoretical model of the reactions e+ e- --> phi --> K+ K- gamma and e+ e- --> phi --> K0 K0bar gamma.…
Our aim is to establish some signatures of the extra gauge boson ${Z^\prime}$, predicted in two versions of ${SU (3)_C \times SU (3)_L \times U (1)_X}$ model and to show possible differences between these signatures. First, by considering…
Data collected at centre-of-mass energies of 181-184 GeV by ALEPH at LEP corresponding to an integrated luminosity of 56.9 pb-1, are analysed in a search for pair-produced charged Higgs bosons H+-. Three analyses are employed to select the…
We consider the possibility of new physics giving rise to effective interactions of the form $e^+e^-Hf \bar f$, where $f$ represents a charged lepton $\ell$ or a (light) quark $q$, and $H$ the recently discovered Higgs boson. Such vertices…
The session on precision studies of electroweak interactions is summarized. The contributions address the bilinear, trilinear, quartic as well as heavy-quark interactions of the electroweak gauge bosons. This makes up a picture of the…
A sensitivity of the collider FCC-hh to anomalous quartic gauge couplings (aQGCs) of neutral bosons in lead-lead collisions is studied. Examining diphoton production, the bounds on aQGCs at $5\sigma$ and 95\% C.L. are obtained depending on…
We explore quark interactions mediated by new gauge bosons of masses in the 0.3 - 50 GeV range. A tight upper limit on the gauge coupling of light Z' bosons is imposed by the anomaly cancellation conditions in conjunction with collider…