Related papers: Single- and multi-photon final states with missing…
New resonances with masses of order a few ${\rm TeV}$ might be discovered at the LHC. We show that no resonance that couples to electrons only through Standard Model interactions can decay to both $e^+e^-$and $\gamma \gamma$ with…
A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to…
New observables \sigma_\pm for the process e^+e^-\to\mu^+\mu^- allow one to get more direct information on additional Z' boson effects than what is obtained from the canonical ones, \sigma and A_{FB}. Their deviations from the Standard…
In the framework of the Standard Model with lepton mixing the radiative decay $\nu_i \rightarrow \nu_j \gamma$ of a neutrino of high ($E_\nu \sim 100 \, GeV$) and super-high ($E_\nu \ge 1 \, TeV$) energy is investigated in the Coulomb field…
A search for supersymmetric particles in events with large missing transverse momentum, heavy flavor jet candidates and no leptons (e,\mu) in {\surd}s = 7 TeV proton-proton collisions is presented. In a data sample corresponding to an…
We utilize the lepton number violation signal process $p\, e^- \to \tau^+ jjj$ to search for heavy Majorana neutrinos at future proton-electron colliders. The LHeC (FCC-eh) is considered to run with an electron beam energy of 60 GeV, a…
We compute next-to-leading power corrections in the zero-jettiness variable for the production of colorless final states at hadron colliders at next-to-leading order in QCD. To assess if the process-independence of leading power…
Low energy phenomenology of the unparticle physics associated with an exact scale invariant sector possessing a non-trivial infrared fixed point at a higher energy scale is explored for both electron-positron and hadronic colliders. Feynman…
It has already been shown that the energy flow distributions in tagged events disagree with those predicted by QCD models, generating serious systematic errors in the unfolding of the photon structure function $F_{2}^{\gamma}$. This new…
The existence of a new, photon-like, massive particle, the gamma' or dark photon, is postulated in several extensions of the Standard Model. These models are often advocated to explain some recent puzzling astrophysical observations, as…
A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV.…
High energy, high luminosity, future lepton colliders, circular or linear, may possibly give us hint about fundamental laws of Nature governing at very short distances and very short time intervals, the same which have brought our Universe…
We summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, we evaluate the capabilities of various $e^+e^-$, $p\bar p$ and $pp$ colliders to discover evidence for supersymmetric particles.…
A high-energy $e^+e^-$ Linear Collider has been considered since a long time as an important complement to the LHC. Unprecedented precision measurements as well as the exploration of so far untouched phase space for direct production of new…
The Standard Model of particle physics has been remarkably successful in describing present experimental results. However, it is assumed to be only a low-energy effective theory which will break down at higher energy scales, theoretically…
A search for new physics in events featuring a single photon and missing transverse momentum is presented, using proton-proton $\sqrt{s}$ = 13 TeV collision data corresponding to an integrated luminosity of 101 fb$^{-1}$ collected by the…
Hadronic final states in e+e- annihilitions at centre-of-mass energies from 14GeV up to 189GeV are studied in order to test recent predictions for power corrections to the mean values as well as the distributions of event shape variables.
We study the potential impacts of a new type of particle collider -- an $e\mu$ collider -- on the search for new physics beyond the Standard Model. As our first attempt for exploring its physics potential, we demonstrate that the the $e\mu$…
We propose a simple extension of the Standard Model (SM) by adding an extra U(1) symmetry which is hidden from the SM sector. Such a hidden U(1) has not been considered before, and its existence at the TeV scale can be explored at the LHC.…
Electroweak processes with four fermions in the final state were measured extensively at LEP-2 in e+e- collisions with centre-of-mass energies up to 209 GeV. By combining the results obtained by Aleph, Delphi, L3 and Opal, the predictions…