Related papers: Cosmological Constraints on Long-Lived Particles U…
We consider the effects on big bang nucleosynthesis (BBN) of the radiative decay of a long-lived massive particle. If high-energy photons are emitted after the BBN epoch ($t \sim 1 - 10^3$ sec), they may change the abundances of the light…
We study the growth of density perturbations in a universe with unstable dark matter particles. The mass (m_\nu) range 30 eV < m_\nu < 10 keV with lifetimes ($t_d$) in the range 10^7 sec < t_d < 10^16 sec are considered. We calculate the…
We examine the capacity of the Large Hadron Collider to determine the mean proper lifetime of long-lived particles assuming different decay final states. We mostly concentrate on the high luminosity runs of the LHC, and therefore, develop…
The positron anomaly recently reported by the cosmic-ray measurements can be explained by the decaying dark matter scenario, where it decays mainly into leptons with the lifetime of O(10^26) second. When the dark matter is a fermionic…
All extensions of the standard model that generate Majorana neutrino masses at the electro-weak scale introduce some "heavy" mediators, either fermions and/or scalars, weakly coupled to leptons. Here, by "heavy" we understand implicitly the…
We set conservative constraints on decaying dark matter particles with masses spanning a very wide range ($10^4-10^{16}$ GeV). For this we use multimessenger observations of cosmic-ray (CR) protons/antiprotons, electrons/positrons,…
In this Letter we report on a search for long-lived particles that decay into final states with two electrons or photons. Such long-lived particles arise in a variety of theoretical models, like hidden valleys and supersymmetry with…
The observation of long-lived particles at the LHC would reveal physics beyond the Standard Model, could account for the many open issues in our understanding of our universe, and conceivably point to a more complete theory of the…
Heavy neutral leptons (HNLs) are constrained by requirements of Big Bang Nucleosynthesis (BBN) as their decays significantly impact the formation of the primordial elements. We propose here a model where the primary decay channel for the…
While the paradigm of a weakly interacting massive particle (WIMP) has guided our search strategies for dark matter in the past decades, their null-results have stimulated growing interest in alternative explanations pointing towards…
We present a novel framework capable of addressing the dark matter problem through freeze-in and freeze-out mechanisms, separately or together, depending on the region of the parameter space considered. In the dark matter dynamics, the…
Since dark matter is only known to have gravitational interactions, it may plausibly decay to gravitons on cosmological timescales. Although such a scenario can be easily realized, there are currently no known limits on this possibility…
At present, the strongest upper limit on $\sum m_{\nu}$, the sum of neutrino masses, is from cosmological measurements. However, this bound assumes that the neutrinos are stable on cosmological timescales, and is not valid if the neutrino…
We revisit a cosmological constraint on dark matter decaying into dark radiation at late times. In Enqvist et al. (2015), we mainly focused on the effects of decaying dark matter (DDM) on the cosmic microwave background (CMB) and nonlinear…
A computer code to simulate temporal evolution of overdensities in a one-dimensional Universe is presented for didactic purposes. The formation of large scale structures in this one-dimensional universe can be studied both in matter or…
It is attractive to suppose for several astrophysical reasons that the universe has close to the critical density in light (~30 eV) neutrinos which decay radiatively with a lifetime of ~10^{23} sec. In such a cosmology the universe is…
The positron anomaly recently reported by the cosmic-ray measurements suggests that, if explained by the decay of dark matter particle, the decay source is closely linked up with the leptonic sector of the standard model. It is observed…
We update cosmological constraints on two decaying dark matter models in light of BOSS-DR12 data analyzed under the Effective Field Theory of Large-Scale Structures (EFTofLSS) formalism, together with Planck, Pantheon and other BOSS…
Popular extensions of the standard model of particle physics feature new fields and symmetries which could, for example, dynamically generate neutrino masses from $B-L$ spontaneous symmetry breaking. If a new light scalar that decays into…
We consider the effects of a massive, unstable neutrino on the evolution of large--scale structure and anisotropies in the cosmic microwave background. Comparison with large--scale structure data allows us to rule out a wide range of masses…