Related papers: On decays of Z' into unparticle stuff
We discuss the very rare, exclusive hadronic decays of a Z boson into a meson and a photon. The QCD factorization approach allows to organize the decay amplitude as an expansion in powers of $\Lambda_{\rm QCD}/m_Z\,$, where the leading…
Using the most general, model independent form of the effective Hamiltonian rare decays (B -> l^+ l^- gamma (l=mu, tau)) are studied. The sensitivity of the photon energy distribution and branching ratio to the new Wilson coefficients is…
We study the localized tachyon condensation in their mirror Landau-Ginzburg picture. We completely determine the decay mode of an unstable orbifold $C^r/Z_n$, $r=1,2,3$ under the condensation of a tachyon with definite R-charge and mass by…
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…
The decays of a scalar particle, of either parity, into two photons or into two gravitons are evaluated. The effective interactions are of the form $\phi FF, \phi F\tilde{F}$ or $\phi RR,\phi R\tilde{R}$; in particular, Higgs boson decay…
We investigate the rare baryonic ${\Lambda}_b\rightarrow{\Lambda}l^+ l^-$ decays in a non-universal $Z'$ model, which is one of the well-motivated extensions of the standard model (SM). Considering the effects of $Z'$-mediated…
The radiative decays of $b$-baryons facilitate the direct measurement of photon helicity in $b\to s\gamma$ transitions thus serving as an important test of physics beyond the Standard Model. In this paper we analyze the complete angular…
We consider the decay of positronium to a neutrino-antineutrino accompanied by a single photon. Since the neutrino pair go undetected, this appears as a single photon decay of positronium. These decay channel are mediated through the…
In this paper and within the standard Glashow-Weinberg-Salam model of electroweak interactions, we study theoretically the leptonic decay of the $W^{-}$-boson $(W^{-}\rightarrow \ell^{-}\bar{\nu}_{\ell})$ in the presence of a circularly…
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…
A class of extra dimensional models with a warped metric predict tunneling of a massive particle localized on our brane and escaping into additional dimensions. The experimental signature of this effect is the disappearance of the particle…
We propose a simplified model to study the possible new heavy diphoton resonance from cascade decay of a heavier particle at colliders, which may be related to the dark matter or other new physics beyond the standard model.…
Using the most general, model independent effective Hamiltonian, the rare B_s ->\gamma \nu \bar{\nu} decay with polarized photon is studied. The sensitivity of the branching ratio and photon polarization to the new Wilson coefficients are…
All real and virtual infrared singularities in the standard analysis of the perturbative Quantum Electrodynamics (like that of Yennie-Frautschi-Suura) are associated with photon emissions from the external legs in the scattering process.…
The two newly observed hidden-bottom mesons Zb(10610) and Zb'(10650) with quantum numbers J(P) = 1(+) are considered as hadronic molecules composed of BB(*) and B(*)B(*), respectively. We give predictions for the widths of the strong…
We study the collider phenomenology of a neutral gauge boson $Z'$ arising in minimal but anomalous $\mathrm{U}(1)$ extensions of the Standard Model (SM). To retain gauge invariance of physical observables, we consider cancellation of gauge…
Two-level boson systems displaying a quantum phase transition from a spherical (symmetric) to a deformed (broken) phase are studied. A formalism to diagonalize Hamiltonians with $O(2L+1)$ symmetry for large number of bosons is worked out.…
The decay of photoexcited quantum systems (examples are photodissociation of molecules and autoionization of atoms) can be viewed as a half-collision process (an incoming photon excites the system which subsequently decays by dissociation…
The radiative recombination of a free electron into an excited state of a bare, high-Z ion is studied, together with its subsequent decay, within the framework of the density matrix theory and Dirac's relativistic equation. Special…
We study models that produce a Higgs boson plus photon ($h^0 \gamma$) resonance at the LHC. When the resonance is a $Z'$ boson, decays to $h^0 \gamma$ occur at one loop. If the $Z'$ boson couples at tree-level to quarks, then the $h^0…