We analyse how dark matter (DM) can be produced in the early universe, working in the framework of a hidden sector charged under a U(1)' gauge symmetry and interacting with the Standard Model through kinetic mixing. Depending on the masses of the dark matter particle and of the dark photon, as well as on the hidden U(1)' gauge coupling and the kinetic mixing parameter, we classify all the distinct regimes along which the observed dark matter relic density can be accounted for. We find that 9 regimes are potentially operative to produce the DM particles and this along 5 distinct dynamical mechanisms. Among these, 4 regimes are new and correspond to regimes in which the DM particles are produced by on-shell dark photons. One of them proceeds along a new dynamical mechanism, which we dub sequential freeze-in. We argue that such regimes and the associated dynamical mechanisms are characteristic of DM models for which, on top of the Standard Model and the dark sector, there are other massive, but relatively light particles -- akin to the dark photon -- that interact both with the SM and the DM sectors.
We point out an earlier implementation of the "freeze-in" mechanism for the production of very weakly-interacting dark matter. We also clarify a footnote given in 0911.1120 regarding this eariler paper.
We compare dark matter production from the thermal bath in the early universe with its direct production through the decay of the inflaton. We show that even if dark matter does not possess a direct coupling with the inflaton, Standard Model loop processes may be sufficient to generate the correct relic abundance.
We discuss certain features of the low energy effective interactions of axion supermultiplet, which are relevant for axino cosmology, and examine the implication to thermal production of axino in the early Universe.
We present a new mechanism for generating the observed dark matter energy density, through resonant production of vector dark matter during inflation. Resonant amplification of the vector dark matter is achieved through Mathieu instabilities induced by an oscillatory coupling with the inflaton, which can occur as early as 11.9 e-folds before the end of inflation. Successful dark matter production is possible for a wide range of inflationary Hubble rates and vector mass scales. This scenario generates both helicity states of the vector dark matter density in contrast to other tachyonic producti…
In the framework of hypercolor scenario of multicomponent Dark Matter, inelastic interaction of high energy photons with the Dark Matter candidates is considered. This reaction results in production of energetic leptons and neutrinos, and the Dark Matter particles also can be boosted. Total and differential cross sections have been calculated. The search of correlations between detected signals of high-energy photons and neutrinos can give an information on the Dark Matter scenario and dynamics.
We study nonthermal production of baryon and dark matter. If we extend the MSSM by introducing some singlet chiral superfields so as to enlarge the conserved global symmetry, the abundance of the baryon and the dark matter in the universe may be explained as the charge asymmetry of that symmetry. In such a case, the baryon energy density and the dark matter energy density in the present universe can be correlated each other and take the similar order values naturally.
A concise summary of out-of-equilibrium dark matter production during post-inflationary reheating is presented. We show that the dark matter relic abundance is in general sensitive to the thermalization rate of the inflaton decay products, and the evolution of the temperature of the subsequently thermalized radiation. We discuss how smoking-gun signals, such as monochromatic neutrinos or gamma-ray lines, or Lyman-$α$ data, can help constrain out-of-equilibrium DM models.
The dark photon is a new gauge boson which arises from an extra U'(1) gauge symmetry. In this paper, a novel dark photon production mechanism based on MeV-scale $γ$-$γ$ collider is considered: $γγ\rightarrow γA'$. With the aid of PACKAGE-X, differential cross section of $γγ\rightarrow γA'$ is obtained, as a function of the kinetic mixing parameter $\varepsilon$ and dark photon mass $m_{A'}$. Taking the light-by-light scattering as background, the constraints on the dark photon parameter space for different time intervals in a MeV-scale $γ$-$γ$ collider are also given.
We reconsider non-thermal production of WIMP dark matter in a systematic way and using a numerical code for accurate computations of dark matter relic densities. Candidates with large pair annihilation rates are favored, suggesting a connection with the anomalies in the lepton cosmic-ray flux detected by Pamela and Fermi. Focussing on supersymmetric models we will consider the impact of non-thermal production on the preferred mass scale for dark matter neutralinos. We have also developed a new formalism to solve the Boltzmann's equation for a system of coannihilating species without assuming k…
We consider the production of dark matter in association with a pair of top quarks, mediated by a scalar or pseudoscalar particle in a generic Simplified Model. We demonstrate that the difference of azimuthal angle between the two leptons $Δϕ_{ll}$, in the dileptonic top decay mode, can directly probe the CP-properties of the mediator. We estimate the constraints to strength and CP-structure of dark matter production for these well-motivated Simplified Models from the LHC Run II.
We study the feebly interacting massive particle dark matter whose production processes are significantly affected by the phase evolution and the complicated thermal corrections to the vector boson. We calculate the freeze-in processes to obtain the correct dark matter relic density by enumerating all the possible $1 \leftrightarrow 2$ and $2 \leftrightarrow 2$ processes. The predicted gravitational waves emitted by the first-order phase transitions and the cosmic strings are evaluated.
We evaluate the prospects for finding evidence of dark matter production at the Large Hadron Collider. We consider WIMPs and superWIMPs, weakly- and superweakly-interacting massive particles, and characterize their properties through model-independent parameterizations. The observed relic density then implies lower bounds on dark matter production rates as functions of a few parameters. For WIMPs, the resulting signal is indistinguishable from background. For superWIMPs, however, this analysis implies significant production of metastable charged particles. For natural parameters, these rates m…
Associated production of a dark particle and a photon, represented as a mono-$γ$ event, is a promising channel to probe particle contents and dynamics in the dark sector. In this paper we study properties of the mono-$γ$ production of a vector dark matter at future $e^+e^-$ colliders. The photon-like and Pauli operators, as well as triple gauge bosons interactions involving the dark matter, are considered in the framework of Effective Field Theory. We show that, comparing to the Pauli operator, the triple gauge bosons couplings are much more interesting at high energy collider. Beam polarizati…
Universidad de Granada（格拉纳达大学）；Universidad de Coimbra（科英布拉大学）；Jožef Stefan Institute（约瑟夫·斯蒂芬研究所）；Institute for Fundamental Physics of the Universe (IFPU)（宇宙基础物理研究所）
We will review the main aspects of a mechanism for the contemporary generation of the baryon and Dark Matter abundances from the out-of-equilibrium decay of a Wimp-like mother particle and briefly discuss a concrete realization in a Supersymmetric scenario.
Many extensions of the SM contain hidden sectors which are uncharged under the SM gauge group. The simplest model with an additional $U(1)$ group predicts the existence of the new gauge boson, dark photon $Z_D$. In this work we consider single production of dark photon $Z_D$ at the LHC and study its discovery potential via the process $pp\rightarrow Z_Dγ\rightarrow llγ$. After simulating the signal as well as the relevant backgrounds, the numerical results show that the signal of $Z_D$ might be detected at the 14TeV LHC.
We consider the production of right-handed (RH) sneutrino dark matter in a model of Dirac neutrino where neutrino Yukawa coupling constants are very small. Dark matter RH sneutrinos are produced by scatterings and decays of thermal particles in the early Universe without reaching thermal equilibrium due to the small Yukawa couplings. We show that not only decays of thermal particles but also the thermal scatterings can be a dominant source as well as non-thermal production in a scenario with light sneutrinos and charged sleptons while other supersymmetric particles are heavy. We also discuss t…
Dark matter (DM) interacting only gravitationally with the standard model could have been produced in the early universe by Hawking evaporation of primordial black holes (PBH). This mechanism is viable in a large range of DM mass, spanning up to the Planck scale. However, DM is also unavoidably produced by the irreducible UV gravitational freeze-in. We show that the latter mechanism sets strong bounds, excluding large regions of the parameter space favored by PBH production.
Dark matter associated visible particle production at high energy colliders provides a unique way to determine the microscopic properties of the dark matter. We investigate a pair of fermionic dark matter particles associated with a b-jet production at the LHC, through a mediator which couples to standard model or dark matter particles via either a vector or axial-vector coupling. The calculation is performed by implementing these simplified models in the FeynRules/MadGraph5 aMC@NLO framework. In our calculation, next-to-leading order QCD corrections and parton-shower effects are considered. W…
We derive precision predictions for the production of dark-matter particles recoiling against a jet with large transverse momentum at the LHC. The dark-matter fermions are described within a simplified model and couple to the Standard Model via a vector mediator. Our predictions for the mono-jet signature include the resummation of the leading and next-to-leading threshold logarithms. The corresponding matching coefficient is evaluated at NLO. The resummed result is matched to the fixed-order NLO cross section obtained from the MadGraph framework. We discuss numerical results for several bench…
This paper reports preliminary results of a study of the HA production process in e+e- collisions at a 1 TeV linear collider and their implication in the study of dark matter at particle colliders. The analysis is carried out using full Geant-4 simulation and reconstruction for the LDC detector model.
Experiments using proton beams at high luminosity colliders and fixed target facilities provide impressive sensitivity to new light weakly coupled degrees of freedom. With these experiments in mind, we revisit the production of dark vectors and scalars via proton bremsstrahlung, making use of a model that describes the underlying nucleon scattering cross-section in the forward direction due to pomeron exchange. We compare the resulting distributions and rates with those obtained via variants of the Fermi-Weizsacker-Williams approximation, and provide production rate distributions for a range o…
A pseudo Nambu-Goldstone boson (pNGB) is a natural candidate of dark matter in that it avoids the severe direct detection bounds. We show in this paper that the pNGB has another different and interesting face with a higher symmetry breaking scale. Such large symmetry breaking is motivated by various physics beyond the standard model. In this case, the pNGB interaction is suppressed due to the Nambu-Goldstone property and the freeze-out production does not work even with sufficiently large portal coupling. We then study the pNGB dark matter relic abundance from the out-of-equilibrium production…
We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into axinos to account respectively for the baryon asymmetry and the dark matter of the universe. The Q ball decays well before the big bang nucleosynthesis so that it is not affected by the decay. We show the region of the parameters which realizes this scenario.
We investigate the phenomenology of a dark matter scenario containing two generations of the dark matter particle, differing only by their mass and their couplings to the other particles, akin to the quark and lepton sectors of the Standard Model. For concreteness, we consider the case where the two dark matter generations are Majorana fermions that couple to a right-handed lepton and a scalar mediator through Yukawa couplings. We identify different production regimes in the multi-flavor dark matter scenario and we argue that in some parts of the parameter space the heavier generation can play…
Pion bremsstrahlung in the splitting function formalism and the dark photon production
Institute for Nuclear Research of the Russian Academy of Sciences（俄罗斯科学院核物理研究所）；Landau Phystech School of Physics and Research, Moscow Institute of Physics and Technology（莫斯科物理科学与技术大学朗道物理与技术学院）；Institute of Theoretical and Mathematical Physics, Lomonosov Moscow State University（莫斯科国立大学理论与数学物理研究所）
We describe the implementation of four models for production of dark matter or as- sociated particles at the LHC based on the simplest extensions of the Standard Model. The first kind of models include dark matter production via s-channel mediators. This includes production in association with a jet for a vector boson (Z') or scalar (S) mediator as well as mono-higgs production via associated hZ' production. We implement the simplest t-channel mediator in the form of a scalar with leptonic quantum numbers and completely generic Yukawa couplings to the dark matter fermion and a right-handed SM …
We consider LHC searches for dark matter in the mono-Higgs channel using the tools of effective field theory. This channel takes unique advantage of the presence of $SU(2)_L$ breaking in those operators to avoid the need for any initial-state radiation, usually necessary to tag the production of invisible particles. We find that sensitivities to parameters describing dark matter interactions with standard model particles are comparable to those from monojet searches for a subset of the usually-considered operators, and we present for the first time bounds from collider searches on operators wh…
The Inert Doublet Model(IDM) is one of the simplest extensions beyond Standard Model(SM) with an extended scalar sector, which provide a scalar dark matter particle candidate. In this paper, we investigate the double charged Higgs production at $γγ$ collider. By scanning the whole parameter space, we obtain the parameter points corresponding to the correct relic abundance of dark matter. After applying all theoretical and experimental constraints, the parameter space for the existence of dark matter is extremely restricted. We perform the analysis for the signal of $H^+H^-$ production in the I…
A gamma line signal in cosmic-ray observation would be found when Higgs is produced at rest or almost rest by DM annihilation because of decay of 126 GeV Higgs into two gamma. This line signal gives a constraint on Higgs production cross section by DM. We examine this point with simple analysis in this work.
Dark matter may be coupled to dark radiation: light degrees of freedom that mediate forces between dark sector particles. Cosmological constraints favor dark radiation that is colder than Standard Model radiation. In models with fixed couplings between dark matter and the Standard Model, these constraints can be difficult to satisfy if thermal equilibrium is assumed in the early universe. We construct a model of asymmetric reheating of the visible and dark sectors from late decays of a long-lived particle (for instance, a modulus). We show, as a proof-of-principle, that such a model can popula…
Recently, the XENON1T experiment has reported an excess in the electronic recoil events. The excess is consistent with the interpretation of absorption of 3keV bosonic dark matter, for example, hidden photon dark matter with kinetic mixing of the order of $10^{-15}$. We point out that the minimally gravitational production provides a viable mechanism for obtaining a correct relic hidden photon abundance. We present parameter dependence of the hidden photon dark matter abundance on the inflationary scale $H_{\rm inf}$ and also the reheating temperature $T_{\rm R}$. We show that the inflationary…
The dark matter in the universe can be in the form of a superheavy matter species (WIMPZILLA). Several mechanisms have been proposed for the production of WIMPZILLA particles during or immediately following the inflationary epoch. Perhaps the most attractive mechanism is through gravitational particle production, where particles are produced simply as a result of the expansion of the universe. In this paper we present a detailed numerical calculation of WIMPZILLA gravitational production in hybrid-inflation models and natural-inflation models. Generalizing these findings, we also explore the d…
In this work, we investigate the effects of first-order phase transitions on the singlet fermionic dark matter in the scotogenic model. It is known that this dark matter candidate tends to conflict with the relevant constraints such as the neutrino oscillation data and charged lepton flavor violating processes if its thermal production mechanism is assumed. We find that the dark matter production mechanisms are modified by first-order phase transitions at some specific parameter regions, where the phase transitions can be one-step or two-step depending on the parameters. If the phase transitio…
We explore the LHC phenomenology of an extension of warped higgsless models. The model is supersymmetric in the bulk and on the IR brane as introduced in [arXiv:0805.1379], corresponding to an emergence of a supersymmetric spectrum in the composite sector of the higgsless model. In particular, the lightest neutralino is rendered stable by an R parity and serves as a realistic cold dark matter candidate. The observation of missing energy signals at the LHC from LSP and NLSP production in association with third generation quarks is discussed based on simulations using WHIZARD.
The stability of the dark matter particle could be attributed to the remnant $Z_2$ symmetry that arises from the spontaneous breaking of a global U(1) symmetry. This plausible scenario contains a Goldstone boson which, as recently shown by Weinberg, is a strong candidate for dark radiation. We show in this paper that this Goldstone boson, together with the CP-even scalar associated to the spontaneous breaking of the global U(1) symmetry, plays a central role in the dark matter production. Besides, the mixing of the CP-even scalar with the Standard Model Higgs boson leads to novel Higgs decay c…
It has been shown that the longitudinal mode of a massive vector boson can be produced by inflationary fluctuations and account for the dark matter content of the Universe. In this work we examine the possibility of instead producing the transverse mode via the coupling $ϕF \tilde F$ between the inflaton and the vector field strength. Such a coupling leads to a tachyonic instability and exponential production of one transverse polarization of the vector field, reaching its maximum near the end of inflation. At production the mass is negligible and the vectors add up coherently to form a dark e…
We consider the possibility that the dark matter particle is a scalar WIMP messenger associated to neutrino mass generation, made stable by the same symmetry responsible for the radiative origin of neutrino mass. We focus on some of the implications of this proposal as realized within the singlet-triplet scotogenic dark matter model.We identify consistent parameter sets consistent both with neutrino mass and the observed dark matter abundance. Finally we characterize the expected phenomenological profile of heavy Higgs boson physics at the LHC as well as at future linear Colliders.
The generation of lepton asymmetry below the electroweak scale has a considerable impact on production of dark matter sterile neutrinos. Oscillations or decays of the heavier sterile neutrinos in the neutrino minimal standard model can give rise to the requisite lepton asymmetry, provided the masses of the heavier neutrinos are sufficiently degenerate. We study the renormalization group evolution of the mass difference of these singlet fermions to understand the degree of necessary fine-tuning. We construct an example of the model that can lead to a technically natural realization of this low-…
If the preon structure of quarks, leptons and gauge bosons will be proved then in the Universe during relativistic phase transition the production of nonperturbative preon condensates has been occured collective excitations of which are perceived as pseudogoldstone bosons. Dark matter consisting of pseudogoldstone bosons of familon type contains a "hot" component from massless particles and a "cold" (nonrelativistic) component from massive particles. It is shown that such dark matter was undergone to two relativistic phase transitions temperatures of which were different. In the result of thes…
The proposed DarkQuest beam dump experiment, a modest upgrade to the existing SeaQuest/SpinQuest experiment, has great potential for uncovering new physics within a dark sector. We explore both the near-term and long-term prospects for observing two distinct, highly-motivated hidden sector benchmark models: heavy neutral leptons and Higgs-mixed scalars. We comprehensively examine the particle production and detector acceptance at DarkQuest, including an updated treatment of meson production, and light scalar production through both bremsstrahlung and gluon-gluon fusion. In both benchmark model…
In the context of Self-Interacting Dark Matter as a solution for the small-scale structure problems, we consider the possibility that Dark Matter could have been produced without being in thermal equilibrium with the Standard Model bath. We discuss one by one the following various dark matter production regimes of this kind: freeze-in, reannihilation and dark freeze-out. We exemplify how these mechanisms work in the context of the particularly simple Hidden Vector Dark Matter model. In contrast to scenarios where there is thermal equilibrium with the Standard Model bath, we find two regimes wh…
We discuss the production of radiation and dark matter assuming a time-dependent inflaton decay rate during the reheating period. It is shown that the time dependence of the inflaton decay rate can substantially modify the reheating dynamics. As an illustration, a leading interaction between the inflaton $ϕ$ and the Higgs doublet ${\boldsymbol h}$ of the form $ϕ|{\boldsymbol h}|^2$ was adopted. In the presence of such interaction, the Higgs doublet acquires a $ϕ$-dependent mass which generates vacuum-expectation-value due to inflaton oscillations and breaks the Standard Model gauge symmetry. T…
Since the gravitational interaction is universal, any particle that ever existed, if kinematically accessible, has to be produced through her. We explore the possibility that dark matter is generated purely from gravitational scatterings together with heavy Majorana right-handed neutrinos that are long-lived. Their late decay could inject significant entropy into the thermal bath, diluting both the dark matter abundance and the cosmic baryon asymmetry, thereby imposing various constraints on the reheating dynamics. Additionally to the entropy injection, long-lived right-handed neutrinos could …
Weakly interacting dark matter particles can be pair-produced at colliders and detected through signatures featuring missing energy in association with either QCD/EW radiation or heavy quarks. In order to constrain the mass and the couplings to standard model particles, accurate and precise predictions for production cross sections and distributions are of prime importance. In this work, we consider various simplified models with s-channel mediators. We implement such models in the FeynRules/MadGraph5_aMC@NLO framework, which allows to include higher-order QCD corrections in realistic simulati…
We investigate the QCD next-to-leading order (NLO) corrections to the production of a pair of fermionic dark matter particles associated with a W boson production through a mediator which couples to standard model particles via either a vector or axial-vector coupling at the LHC. We find that the QCD NLO corrections reduce the dependence of the total cross sections on the factorization and renormalization scales, and the $K$-factors increase with the increment of the dark matter mass. We also provide the LO and QCD NLO corrected distributions of the transverse momenta $p_T^μ$ of final muon and…
We examine a scenario for freeze-in production of dark matter, which occurs due to the large thermal correction to the mass of a decaying mediator particle present in the thermal bath of the early Universe. We show that the decays, which are kinematically forbidden otherwise, can open up at very high temperatures and dominate the dark matter production. We explore such forbidden production of dark matter in the minimal $U(1)_{B-L}$ model, comparing dark matter phenomenology in the context of forbidden frozen-in with the standard picture.
