We review the existing proposals to detect relic neutrinos using the coherent scattering of a neutrino wind on a test mass. By considering the transformation of the neutrino momentum between reference frames, we demonstrate that the induced acceleration scales with the square of the neutrino mass for unclustered neutrinos, contrary to the existing literature. In addition, we show that there is a large contribution to this effect from coherent neutrino-electron scattering, which can exceed the neutrino-nucleus component by nearly an order of magnitude. Unfortunately, we find that even with this enhancement there are no existing experiments or proposals capable of detecting relic neutrinos using this method.
We consider the possibility of detecting relic anti-neutrinos by their resonant absorption in a nucleus, which can undergo electron capture. This possibility appears quite realistic in view of recent developments in Penning Trap Mass Spectrometry and cryogenic micro-calorimetry.
An updated luminosity staging baseline for CLIC is presented. Assuming accelerator ramp-up and up-time scenarios that are harmonized with those of other potential future colliders, CLIC will deliver 1 ab^-1 at sqrt(s)=380 GeV, 2.5 ab^-1 at sqrt(s)=1.5 TeV, and 5 ab^-1 at sqrt(s)=3 TeV. The complete programme will take 25-30 years. The baseline scenario for luminosity sharing between the two electron beam polarisation states is also discussed. Updated Higgs coupling sensitivities are given for this new luminosity staging baseline.
The light relic density affects the thermal and expansion history of the early Universe leaving a number of observable imprints. We focus on the primordial abundances of light elements produced during the process of Big Bang nucleosynthesis which are influenced by the light relic density. Primordial abundances can be used to infer the density of light relics and thereby serve as a probe of physics beyond the Standard Model. We calculate the observational uncertainty on primordial light element abundances and associated quantities that would be required in order for these measurements to achiev…
A new set of supersymmetric benchmark scenarios has recently been proposed in the context of the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking masses, taking into account the constraints from LEP, $b \to s γ$ and $g_μ- 2$. These points have previously been used to discuss the physics reaches of different accelerators. In this paper, we discuss the prospects for discovering supersymmetric dark matter in these scenarios. We consider direct detection through spin-independent and spin-dependent nuclear scattering, as well as indirect detection through relic annihilations to n…
We revisit the big bang nucleosynthesis (BBN) limits on primordial magnetic fields and/or turbulent motions accounting for the decaying nature of turbulent sources between the time of generation and BBN. This leads to larger estimates for the gravitational wave (GW) signal than previously expected. We address the detection prospects through space-based interferometers (for GWs generated around the electroweak energy scale) as well as pulsar timing arrays and astrometric missions (for GWs generated around the quantum chromodynamics energy scale).
We present a complete phenomenological prospectus for thermal relic neutralinos. Including Sommerfeld enhancements to relic abundance and halo annihilation calculations, we obtain direct, indirect, and collider discovery prospects for all neutralinos with mass parameters $M_1,M_2,|μ| < 4$ TeV, that freeze out to the observed dark matter abundance, with scalar superpartners decoupled. Much of the relic neutralino sector will be uncovered by the direct detection experiments Xenon1T and LZ, as well as indirect detection with CTA. We emphasize that thermal relic higgsinos will be found by next-gen…
Improved Big Bang Nucleosynthesis constraints on decaying massive relics
Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器）；Dipartimento di Fisica, Sapienza Università di Roma & Sezione INFN Roma1（罗马第一大学物理系与INFN罗马一分部）；Service de Physique Théorique, Université Libre de Bruxelles（布鲁塞尔自由大学理论物理服务处）；CP3-Origins, University of Southern Denmark（南丹麦大学CP3起源中心）
In the minimal supersymmetric standard models, neutralino dark matter with mass of $m_χ\sim m_Z/2\sim 45$ GeV and $m_χ\sim m_h/2\sim 62$ GeV can have the thermal relic abundance $Ω_{χ_1}h^2\simeq 0.120$ via the $Z$- and Higgs-resonant annihilations, respectively, while avoiding all the current constraints. Phenomenology of such scenarios is determined only by three parameters, Bino mass $M_1$, Higgsino mass $μ$, and $\tanβ$, in the limit that all other supersymmetric particles and heavy Higgs bosons are decoupled. In this paper, we comprehensively study the constraints and future prospects of …
A model that can simultaneously explain Dark Matter relic density and the apparent matter anti-matter imbalance of the universe has been recently proposed. The model requires $b$-hadron branching fractions to Dark Matter at the per mille level. The $b$-hadrons decay to a dark sector baryon, $ψ_{\rm{DS}}$, which has a mass in the region $940$ MeV/c$^{2} \leq m(ψ_{\rm{DS}}) \leq 4430$ MeV/c$^{2}$. In this paper, we discuss the sensitivity of the LHCb experiment to search for this dark baryon, covering different types of topology and giving prospects for Runs 3 and 4 of the LHC, as well as for th…
Both active and sterile sub-eV neutrinos can form the cosmic neutrino background in the early Universe. We consider the beta-decaying (e.g., $^3$H) and EC-decaying (e.g., $^{163}$Ho) nuclei as the promising targets to capture relic neutrinos in the laboratory. We calculate the capture rates of relic electron neutrinos and antineutrinos against the corresponding beta decay or electron capture (EC) decay backgrounds in the (3+$N_{\rm s}$) flavor mixing scheme, and discuss the future prospect in terms of the PTOLEMY project. We stress that such direct measurements of hot DM might not be hopeless …
We present an analysis of the Dark S3 model in the heavy DM mass region, this model features an S3 symmetric extension of the scalar sector of the SM including a scalar $SU(2)$ doublet dark matter candidate. We use publicly available tools to compute, in addition to conventional physical constraints on the parameter space of the model, the Sommerfeld enhancement factors for the present day annihilation cross section and the likelihood profile for a simulation of an observation run by the Cherenkov Telescope Array of the Coma Berenices dwarf galaxy. Our results disfavour masses above $\sim$5 Te…
Unlike its minimal counterpart, the Next to Minimal supersymmetric Standard Model (NMSSM) allows the possibility that the lightest neutralino could have a mass as small as $\sim 1 {\rm GeV}$ while still providing a significant component of relic dark matter (DM). Such a neutralino can provide an invisible decay mode to the Higgs as well. Further, the observed SM-like Higgs boson ($H_{125}$) could also have an invisible branching fraction as high as $\sim 19\%$. Led by these facts, we first delineate the region of parameter space of the NMSSM with a light neutralino ($M_{{\tildeχ}_{1}^{0}} < 62…
If dark matter is composed of primordial black holes, such black holes can span an enormous range of masses. A variety of observational constraints exist on massive black holes, and black holes with masses below $10^{15}\,\mathrm{g}$ are often assumed to have completely evaporated by the present day. But if the evaporation process halts at the Planck scale, it would leave behind a stable relic, and such objects could constitute the entirety of dark matter. Neutral Planck-scale relics are effectively invisible to both astrophysical and direct detection searches. However, we argue that such reli…
The proposed Circular Electron Positron Collider (CEPC), with a center-of-mass energy $\sqrt{s} = 240$ GeV, will primarily serve as a Higgs factory. At the same time, it can offer good opportunities to search for new physics phenomena at low energy, which can be challenging to discover at hadron colliders, but well motivated by some theoretical models developed to explain, e.g., the relic abundance of dark matter. This paper presents sensitivity studies of chargino pair production, considering scenarios for both a Bino-like and a Higgsino-like neutralino as the lightest supersymmetric particle…
The flagship measurement of the JUNO experiment is the determination of the neutrino mass ordering. Here we revisit its prospects to make this determination by 2030, using the current global knowledge of the relevant neutrino parameters as well as current information on the reactor configuration and the critical parameters of the JUNO detector. We pay particular attention to the non-linear detector energy response. Using the measurement of $θ_{13}$ from Daya Bay, but without information from other experiments, we estimate the probability of JUNO determining the neutrino mass ordering at $\ge$ …
We work with a UV conformal U(1)' extension of the Standard Model, motivated by the hierarchy problem and recent collider anomalies. This model admits fermionic vector portal WIMP dark matter charged under the U(1)' gauge group. The asymptotically safe boundary conditions can be used to fix the coupling parameters, which allows the observed thermal relic abundance to constrain the mass of the dark matter particle. This highly restricts the parameter space, allowing strong predictions to be made. The parameter space of several UV conformal U(1)' scenarios will be explored, and both bounds and p…
We discuss the singlet-doublet fermion dark matter model with CP-violation. In this model, the CP-violation generates a pseudo-scalar interaction of dark matter with the SM-Higgs boson. Thanks to the pseudo-scalar interaction, the model can evade the strong constraint from the dark matter direct detection experiments while keeping the success of the thermal relic scenario. The CP-violation also predicts signals in dark matter indirect detection experiments and electric dipole moments (EDM) that can be as large as the current upper bound. We investigate the constraints and prospects of the dire…
The pseudoscalar resonance or "A-funnel" in the Minimal Supersymmetric Standard Model~(MSSM) is a widely studied framework for explaining dark matter that can yield interesting indirect detection and collider signals. The well-known Galactic Center excess (GCE) at GeV energies in the gamma ray spectrum, consistent with annihilation of a $\lesssim 40$ GeV dark matter particle, has more recently been shown to be compatible with significantly heavier masses following reanalysis of the background. In this paper, we explore the LHC and direct detection implications of interpreting the GCE in this e…
An electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM) with masses of a few hundred GeV can account for variety of experimental data, assuming the lightest neutralino to be the lightest supersymmetric (SUSY) particle: the non-observation at the LHC searches owing to their small production cross sections, the results for the (upper limit of the) Dark Matter (DM) relic abundance and the DM Direct Detection (DD) limits. Such a light EW sector can in particular explain the reinforced $4.2\,σ$ discrepancy between the experimental result for $(g-2)_μ$, and its Standard Model …
Multi-Component Dark Matter Systems and Their Observation Prospects
在一个三分量的暗物质系统中，除了考虑标准的暗物质湮灭外，还考虑了暗物质粒子的转换和半湮灭。我们发现DM的残余丰度对这些非标准DM湮灭过程非常敏感，这是最近发现的双组分DM系统。为了考虑一个三分量DM系统的具体模型，我们在Ma的辐射跷跷板模型中加入一个Majorana费米子χ和一个实标量玻色子χ，得到一个Z_2 \times Z '_2 DM稳定对称性，其中DM粒子是惰性的希格斯玻色子玻色子，χ和χ。它示出了如何允许的参数空间，以前获得的情况下的χ和χ，变化。这个模型中的半湮灭过程产生单色中微子。估计了冰立方对这些来自太阳的单色中微子的观测率。来自太阳的高能单色中微子的观测可能表明一个多组分DM系统。
We present an updated analysis of the CMSSM and the NUHM using the latest experimental data and numerical tools. We map out favored regions of Bayesian posterior probability in light of data from the LHC, flavor observables, the relic density and dark matter searches. We present some updated features with respect to our previous analyses: we include the effects of corrections to the light Higgs mass beyond the 2-loop order using FeynHiggs v2.10.0; we include in the likelihood the latest limits from direct searches for squarks and gluinos at ATLAS with ~20/fb; the latest constraints on the spin…
Two experiments from the Fermilab, E989 and CDF II, have reported two anomalies for muon $g-2$ and $W$-boson mass that may indicate the new physics at the low energy scale. Here we examine the possibility of a common origin of these two anomalies in the Next-to-Minimal Supersymmetric Standard Model. Considering various experimental and astrophysical constraints such as the Higgs mass, collider data, flavor physics, dark matter relic density, and direct detection experiments, we find that lighter electroweakinos and sleptons can generate sufficient contributions to muon $g-2$ and $m_W$. Moreove…
