分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: Recently, the evidence for gamma-ray emission has been found in the $Fermi$-LAT observation for the outer halo of Andromeda galaxy (M31). The dark matter (DM) annihilation offers a possible explanation on the gamma-ray radiation. In this work, we focus on the dark matter annihilation within minispikes around intermediate-mass black holes (IMBHs) with masses ranging from $100~\mathrm{M_\odot}$ to $10^6~\mathrm{M_\odot}$. When the thermal annihilation relic cross section $\left\langle \sigma v \right\rangle = 3 \times 10^{-26}~\mathrm {cm} ^{3}\;\mathrm {s} ^{-1}$ is adopted, we conduct an investigation on the population of IMBHs in the spherical halo area of M31. We find that there could be more than 65 IMBHs with masses of $ 100~ \mathrm{M_\odot}$ surrounded by the DM minispikes as the remnants of Population III stars in the M31 spherical halo, and it is almost impossible for the existence of minspikes around IMBHs with masses above $10^4~ \mathrm{M_\odot}$ which could be formed by the collapse of primordial cold gas, for both dark matter annihilation channels $b\bar{b}$ and $\tau^{+}\tau^{-}$. The properties of dark matter have been further explored with the simulation of these two scenarios for IMBHs formation.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: A series of dynamical anomalies in the orbits of distant trans-Neptunian objects points to a new celestial body (usually named Planet Nine) in the solar system. In this draft, we point out that a mirror planet captured from the outer solar system or formed in the solar system is also a possible candidate. The introduction of the mirror matter model is due to an unbroken parity symmetry and is a potential explanation for dark matter. This mirror planet has null or fainter electromagnetic counterparts with a smaller optical radius and might be explored through gravitational effects.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: The $W$-boson mass ($m_{W}=80.4335 \pm 0.0094 \mathrm{GeV}$) measured by the Collider Detector at Fermilab collaboration is greater than the standard model (SM) prediction at a confidence level of $7\sigma$, strongly suggesting the presence of new particles or fields. In the literature, various new particles and/or fields have been introduced to explain the astrophysical and experimental data, and their presence, in principle, may also enhance the $W$-boson mass. In this study, we investigate axion-like particle (ALP), dark photon (DP), and chameleon dark energy (DE) models for a solution to the $W$-boson mass excess. We find that the ALP and DP interpretations have been significantly narrowed down by global electroweak fits. The possibility of attributing the $W-$boson mass anomaly to the chameleon DE is ruled out by other experiments.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: A series of dynamical anomalies in the orbits of distant trans-Neptunian objects points to a new celestial body (usually named Planet Nine) in the solar system. In this draft, we point out that a mirror planet captured from the outer solar system or formed in the solar system is also a possible candidate. The introduction of the mirror matter model is due to an unbroken parity symmetry and is a potential explanation for dark matter. This mirror planet has null or fainter electromagnetic counterparts with a smaller optical radius and might be explored through gravitational effects.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: Some models such as the Nebula-Relay hypothesis, predict that the ancestors of Earth's life once lived in molecular clouds. Where does the energy come from for creatures in molecular clouds? In this draft, we proposed a new bioenergetic mechanism that is driven by the cosmic ray ionization of hydrogen molecules. Protons are naturally produced in this scenario, which may be the origin of chemiosmosis. Based on this bioenergetics mechanism, we speculate that LUCA is one type of biological hydrogen microbe.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: The chiral puzzle of biological molecules is thought to be closely related to the origin of life and is still a mystery so far. Previously, we proposed a new model on the origin of life, Nebula-Relay hypothesis, which assumed that the life on Earth originated at the planetary system of the Sun's predecessor star and then filled in the pre-solar nebula after its death. As primitive lives existed in the pre-solar nebula for a long time, did the chiral biomolecules form during this period? We explore such a possibility in this work and find that the ultra-low temperature environment of molecular clouds is beneficial to generating the chiral polymer chain of biological molecules.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: The $W$-boson mass ($m_{W}=80.4335 \pm 0.0094 \mathrm{GeV}$) measured by the Collider Detector at Fermilab collaboration is greater than the standard model (SM) prediction at a confidence level of $7\sigma$, strongly suggesting the presence of new particles or fields. In the literature, various new particles and/or fields have been introduced to explain the astrophysical and experimental data, and their presence, in principle, may also enhance the $W$-boson mass. In this study, we investigate axion-like particle (ALP), dark photon (DP), and chameleon dark energy (DE) models for a solution to the $W$-boson mass excess. We find that the ALP and DP interpretations have been significantly narrowed down by global electroweak fits. The possibility of attributing the $W-$boson mass anomaly to the chameleon DE is ruled out by other experiments.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: Some models such as the Nebula-Relay hypothesis, predict that the ancestors of Earth's life once lived in molecular clouds. Where does the energy come from for creatures in molecular clouds? In this draft, we proposed a new bioenergetic mechanism that is driven by the cosmic ray ionization of hydrogen molecules. Protons are naturally produced in this scenario, which may be the origin of chemiosmosis. Based on this bioenergetics mechanism, we speculate that LUCA is one type of biological hydrogen microbe.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: A modified version of panspermia theory, named Nebula-Relay hypothesis or local panspermia, is introduced to explain the origin of life on Earth. Primitive life, acting as the seeds of life on Earth, originated at pre-solar epoch through physicochemical processes and then filled in the pre-solar nebula after the death of pre-solar star. Then the history of life on the Earth can be divided into three epochs: the formation of primitive life in the pre-solar epoch; pre-solar nebula epoch; the formation of solar system and the Earth age of life. The main prediction of our model is that primitive life existed in the pre-solar nebula (even in the current nebulas) and the celestial body formed therein (i.e. solar system).
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: 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 $m_W$. Moreover, the corresponding bino-like neutralino dark matter mass is in the $\sim 180-280$ GeV range. Interestingly, the favored DM mass region can soon be entirely probed by ongoing direct detection experiments like PandaX-4T, XENONnT, LUX-ZEPLIN, and DARWIN.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: 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 $m_W$. Moreover, the corresponding bino-like neutralino dark matter mass is in the $\sim 180-280$ GeV range. Interestingly, the favored DM mass region can soon be entirely probed by ongoing direct detection experiments like PandaX-4T, XENONnT, LUX-ZEPLIN, and DARWIN.