Related papers: $Z$ Boson Decay into Light and Darkness
In this paper, we investigate the Higgs boson decay process $H\to f\bar{f}Z\to f\bar{f}\mu^-\mu^+$, where $f$ denotes any light fermions, at the next-to-leading order (NLO) accuracy. The calculation is performed within the framework of…
A search is performed for a Higgs boson, decaying into two photons, using the L3 data collected at centre of mass energies between $\sqrt s$ = 189 and 202 GeV, corresponding to an integrated luminosity of 400 pb$^{-1}$. The processes…
In this paper, we present an improved calculation for the decay rate of the rare $Z$-boson decay into $J/\psi + J/\psi$. This decay is dominated by the photon fragmentation mechanism, i.e., the transition $Z\to J/\psi + \gamma^{*}$ followed…
Models in which the 750 GeV resonance ($S$) decays to two light axion-like particles (ALPs $a$), which in turn decay to collimated photons mimicking the observed signal, are motivated by Hidden Valley scenarios and could also provide a…
Collider search for dark matter production has been performed over the years based on high pT standard model signatures balanced by large missing transverse energy. The mono-Z boson production with leptonic decay has a clean signature with…
We interpret the recent excess in a rare decay of the Higgs boson, $H\to Z\gamma$, using a light axion-like particle (ALP) in the massrange $0.05 - 0.1$ GeV.The dominant decay of such a light ALP is into a pair of collimated photons, whose…
The couplings of the Standard Model sector to the scale invariant degrees of freedom can open the possibility to study dark photons (DP). The Dalitz-like decay of the (Higgs-like) scalar boson into a single photon and DP is studied. The…
The realization that first- and second-generation Yukawa couplings can be probed by decays of the Higgs boson to a meson in association with a photon has renewed interest in such rare exclusive decays. We present here a detailed study of…
We present new calculations of the leading-order one-loop amplitude and the decay rate for $H\to \nu \bar{\nu} \gamma$ within the standard model, employing reduction to a set of basic Passarino-Veltman functions resulting in more concise…
A search for heavy resonances decaying to a pair of Z bosons is performed using data collected with the CMS detector at the LHC. Events are selected by requiring two oppositely charged leptons (electrons or muons), consistent with the decay…
We study the Bose symmetry violation through the decays of heavy vector bosons at high energies. In particular, the decay of a Z'-boson into two photons where one of the photons is the vector unparticle in the scale invariant sector is…
Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…
A search is presented for resonances decaying to a Z boson and a photon. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, and…
In many theories of physics beyond the Standard Model, from extra dimensions to Hidden Valleys and models of dark matter, Z' bosons mediate between Standard Model particles and hidden sector states. We study the feasibility of observing…
A light meta-stable dark photon decaying into collimated electron/positron pair can fake a photon, either converted or unconverted, at the LHC. The detailed object identification relies on the specifics of the detector and strategies for…
A search is presented for a heavy resonance decaying into either a pair of Z bosons or a Z boson and a W boson (ZZ or WZ), with a Z boson decaying into a pair of neutrinos and the other boson decaying hadronically into two collimated quarks…
We study flavor changing neutral current decays of $B$ and $K$ mesons in the dark $U(1)_D$ model, with the dark photon/dark $Z$ mass between 10 MeV and 2 GeV. Although the model provides an improved fit (compared to the standard model) to…
We report the results of a search for a heavy neutral gauge boson Z' decaying into the dielectron final state using data corresponding to an integrated luminosity of 5.4 fb-1 collected by the D0 experiment at the Fermilab Tevatron Collider.…
Lorentz symmetry forbids decays of massive spin-1 particle like the $Z^0$ into two massless photons, a result known as the Landau-Yang theorem. But it is known that infrared effects can break Lorentz invariance. Employing the construction…
Experimentalists have long sought a method that allows them to control as they like the branching ratios of an unstable particle decay and direct some decay to follow one specific desired channel without another. The powerful laser could…