相关论文: Probing conversion-driven freeze-out at the LHC
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…
We propose a novel scenario to obtain the correct relic abundance for thermally under-produced dark matter. This scenario utilizes a strongly first-order phase transition at temperature $T_{\rm PT}$ that gives rise to dark matter mass $m$.…
We study an extension of the singlet-scalar Higgs portal featuring a dark vector $V_\mu$ and a real scalar $\phi$. The vector is a dark matter (DM) candidate, while $\phi$ is long-lived and decays via higher-dimensional operators. We…
Dark matter scenarios are being tested at the LHC in the general-purpose experiments through promptly decaying states. In parallel, new dedicated detectors have been proposed for the LHC to probe dark matter portal theories predicting…
Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark…
We revisit dark-matter production through freeze-in and freeze-out by solving the Boltzmann equations at the level of the phase-space distribution $f(p,t)$. Using the $2\to2$ annihilation and the $1\to2$ decay processes for illustration, we…
Dark Matter relic density generation through \textit{freeze-in} mechanism where dark matter particles interact feebly with visible sector particles, is an alternative approach to well-studied and most popular \textit{freeze-out} paradigm.…
Predictivity of many non-thermal dark matter (DM) models is marred by the gravitational production background. This problem is ameliorated in models with lower reheating temperature $T_R$, which allows for dilution of gravitationally…
Dark Matter (DM) may belong to a hidden sector that is only feebly interacting with the Standard Model (SM) and may have never been in thermal equilibrium in the Early Universe. In this case, the observed abundance of dark matter particles…
Soft displaced leptons are representative collider signatures of compressed dark sectors with feeble couplings to the standard model. Prime targets are dark matter scenarios where co-scattering or co-annihilation sets the relic abundance…
Models in which the dark matter is very weakly coupled to the observable sector may explain the observed dark matter density, either as a "superWIMP" or as "asymmetric dark matter." Both types of models predict displaced vertices at…
If the dark matter is produced in the early universe prior to Big Bang nucleosynthesis, a modified cosmological history can drastically affect the abundance of relic dark matter particles. Here, we assume that an additional species to…
We propose a new strategy to look for long-lived particles (LLP) at the LHC. The LLPs are produced at one experiment, but its decay products are detected by a detector at another experiment. We use a confining Hidden Valley scenario as a…
A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops…
Displaced vertices are relatively unusual signatures for dark matter searches at the LHC. We revisit the model of pseudo-Dirac dark matter (pDDM), which can accommodate the correct relic density, evade direct detection constraints, and…
Long-lived particles have become a new frontier in the exploration of physics beyond the Standard Model. In this paper, we present the implementation of four types of long-lived particle searches, viz. displaced leptons, disappearing track,…
A search for long-lived particles decaying in the outer regions of the CMS silicon tracker or in the calorimeters is presented. The search is based on a data sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the CMS…
We propose a systematic programme to search for long-lived neutral particle signatures through a minimal set of displaced searches requiring significant missing transverse energy (dMETs). Our approach is to extend the well-established dark…
Galaxy clusters are promising targets for indirect dark matter searches. Gamma-ray signatures from the decay or annihilation of dark matter particles inside these clusters could be observable with the Fermi Large Area Telescope (LAT). Based…
We have developed a set of four fully coupled Boltzmann equations to precisely determine the relic density and temperature of dark matter by including three distinct sectors: dark matter, light scalar, and standard model sectors. The…