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  • Cosmological parameter estimation from CMB and X-ray clusters after Planck

    分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-09-27

    摘要: We update the cosmological parameter estimation for three non-vanilla models by a joint analysis of CCCP X-ray cluster, the newly released Planck CMB data as well as some external data sets, such as baryon acoustic oscillation measurements from the 6dFGS, SDSS DR7 and BOSS DR9 surveys, and Hubble Space Telescope H0 measurement. First of all, we nd that X-ray cluster data sets strongly favor a non-zero summed neutrino mass at more than 3 con dence level in these non-vanilla models. And then, we reveal some tensions between X-ray cluster and Planck data in some cosmological parameters. For the matter power spectrum amplitude 8, X-ray cluster data favor a lower value compared with Planck. Because P of the strong 8 m degeneracy, this tension could beyond 2 con dence level when the P summed neutrino mass m is allowed to vary. For the CMB lensing amplitude AL, the addition of X-ray cluster data results in a 3 deviation from the vanilla model. Furthermore, Planck+X-ray data prefer a large Hubble constant and phantom-like dark energy equation of state, which are in 2 tension with those from WMAP7+X-ray data. Finally, we nd that these tensions/descrepencies could be relaxed in some sense by adding a 9% systematic shift in the cluster mass functions.

  • Galaxy: A Decade of Realising CWFR Concepts

    分类: 计算机科学 >> 计算机科学的集成理论 提交时间: 2022-11-28 合作期刊: 《数据智能(英文)》

    摘要: Despite recent encouragement to follow the FAIR principles, the day-to-day research practices have not changed substantially. Due to new developments and the increasing pressure to apply best practices, initiatives to improve the efficiency and reproducibility of scientific workflows are becoming more prevalent. In this article, we discuss the importance of well-annotated tools and the specific requirements to ensure reproducible research with FAIR outputs. We detail how Galaxy, an open-source workflow management system with a web-based interface, has implemented the concepts that are put forward by the Canonical Workflow Framework for Research (CWFR), whilst minimising changes to the practices of scientific communities. Although we showcase concrete applications from two different domains, this approach is generalisable to any domain and particularly useful in interdisciplinary research and science-based applications.

  • Does Dark Matter Solve the Hubble Tension Puzzle?

    分类: 天文学 >> 星系和宇宙学 提交时间: 2025-02-06

    摘要: The Hubble constant H0 defines the rate of expansion of the Universe. Currently there are three conflicting values of the Hubble constant. The Planck team (Ade et al 2014), the Carnegie-Chicago team (Freedman et al 2019), and the SHoES team (Riess et al 2016) have all produced values that disagree beyond their errors. The SHoES team has shown that the Hubble constant is increasing in recent times (Riess et al 1998) reflecting an increase or acceleration in the rate of expansion of the Universe. Baruch (2024a) “Are Stellar Distance Measurements Opening a Window into New Physics?” has reviewed recent data of the SHoES team (Riess et al 2021) where Hubble telescope photometric data for two groups of Cepheids at different distances was linked to Gaia parallax measurements of the same stars. It is shown “beyond reasonable doubt” how for this unique set of precise data the zero-point correction can be eliminated and a wavelength independent (colourless) extinction of light across the Milky Way galaxy revealed. This current paper seeks out the cause of this extinction and shows that the data of Freedman et al 2019 neatly fits a wavelength independent extinction when the cause of the extinction is attributed to dark matter. The extinction coefficients are derived. All the Riess and the Freedman values of the Hubble constant are shown to agree with the Planck Satellite (Ade et al 2014) value within the error bars when the differences are attributed to dark matter extinction. The recent time acceleration in the expansion of the Universe also is shown to be a function of intergalactic dark matter extinction. The key properties required of the dark matter are defined.

  • Are Stellar Distance Measurements Opening a Window into New Physics

    分类: 天文学 >> 星系和宇宙学 提交时间: 2025-01-24

    摘要: This paper derives a mathematical analysis of the apparent conflict between photometrically based and parallax distance measurements. The best photometrically based distance measurements using the Hubble telescope when compared with the algorithm corrected Gaia parallax measurements do not agree. The algorithm corrected Gaia parallax measurements are quoted by the Gaia team as correct to within a few mico arcseconds, but Riess et al (2021) subtract a further ten micro arc-seconds from each Cepheid parallax. These further corrections to the Gaia data eliminate the conflict and support the Hubble tension derived by Riess et al (2021). There is no conflict in the Hubble photometric and Gaia parallax distances in the Riess et al (2022) paper. Riess et al (2022) use earlier Gaia derived cluster distances and adopt a zero point correction derived from the photometry. The mathematical analysis shows that an alternative method of eliminating the conflict indicates a tiny attenuation of light in the Milky Way. It is argued that this attenuation of the light is completely wavelength-independent. All photometry is equally effected by this wavelength independent attenuation, which requires new physics. Photometry cannot be used to reveal any new physics due to the absorption being wavelength independent. It is shown that when the wavelength independent absorption is included in calculating the absolute magnitude of Cepheids it removes the Hubble tension.

  • Does the CMB have a Dark Secret?

    分类: 天文学 >> 星系和宇宙学 分类: 天文学 >> 星系和宇宙学 提交时间: 2025-05-27

    摘要: It is suggested that the formation of dark matter binaries would produce radiation in the same way that the formation of hydrogen atoms does in HII regions. A hydrogen HII region like the Orion Nebula with its Lyman alpha radiation is considered as a model for dark matter particles combining into binaries. This conjecture is considered in detail and it is found to provide a surprising fit to the Planck data isotropy and dipole. It could be regarded as an alternative explanation. A precise mass for the dark matter particle would be 10.7 ZeV (1.07 x 1013 GeV). Examination of the Plank structure of the CMB also suggests there is further physics to be revealed. Observational tests are suggested to check the role of dark matter in the Galaxy Halo.

  • Wavelength-Independent Extinction in the Milky Way, Is it new physics?

    分类: 天文学 >> 星系和宇宙学 提交时间: 2025-02-21

    摘要: The paper Baruch (2025a) shows that there is an apparent wavelength-independent extinction coefficient of 0.06 magnitudes per kiloparsec across the Milky Way. Baruch 2025b) shows that the Hubble constant values of Riess et al (2016, 2018a and 2018b), Freedman et al (2019) and the Planck satellite (Ade et al 2014) coincide if the extinction coefficient is a function of the density of dark matter. This wavelength-independent extinction has a frequency threshold between 160Ghz and 300 Thz. This paper seeks a possible process by which dark matter can absorb light.The current data on dark matter is reviewed to determine how dark matter could act as a wavelength-independent absorber of light in the visible frequencies. The discussion of the role of inertia and momentum in general relativity and its relationship with the other forces since the Einstein paper on General Relativity of 1915 is reviewed. It is conjectured that for a pair of gravitationally bound dark matter particles a photon with sufficient momentum would effectively “ionise” the pair, releasing the two dark matter particles, and absorbing the photon. The approximate mass of the dark matter particle is derived. It is suggested that this dark matter extinction provides real data to help settle the role of inertia and momentum in General Relativity. A test for the “ionisation” process is suggested.

  • Supersymmetry explanation of the Fermi Galactic Center excess and its test at LHC run II

    分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28

    摘要: We explore the explanation of the Fermi Galactic Center excess (GCE) in the next-to-minimal supersymmetric Standard Model. We systematically consider various experimental constraints including the dark matter (DM) relic density, DM direct detection result

  • Could Dark Matter Heavy Neutrinos produce Spin Flip Radiation?

    分类: 天文学 >> 星系和宇宙学 提交时间: 2025-05-18

    摘要: There is a clear indication that dark matter in the Milky Way absorbs a tiny amount of light in the visible parts of the spectrum, (Baruch 2025a, and 2025b) . In Baruch (2025c) it is conjectured that this is caused by dark matter forming binary pairs which are destroyed (ionised) by the momentum of photons in the visible parts of the spectrum. This paper examines whether the dark matter binaries will also radiate photons. Can a binary form of dark matter with two spin half fermions produce spin flip radiation in the same way that hydrogen does with the 21cm line? It is shown that any such spin flip radiation would be very faint due to the excessively long half life of the suggested binary form of dark matter.

  • Interpreting the galactic center gamma-ray excess in the NMSSM

    分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28

    摘要: In the Next-to-Minimal Supersymmetric Standard Model (NMSSM), all singlet-dominated particles including one neutralino, one CP-odd Higgs boson and one CP-even Higgs boson can be simultaneously lighter than about 100 GeV. Consequently, dark matter (DM) in the NMSSM can annihilate into multiple final states to explain the galactic center gamma-ray excess (GCE). In this work we take into account the foreground and background uncertainties for the GCE and investigate these explanations. We carry out a sophisticated scan over the NMSSM parameter space by considering various experi- mental constraints such as the Higgs data, B-physics observables, DM relic density, LUX experiment and the dSphs constraints. Then for each surviving parameter point we per- form a fit to the GCE spectrum by using the correlation matrix that incorporates both the statistical and systematic uncertainties of the measured excess. After examining the properties of the obtained GCE solutions, we conclude that the GCE can be well explained by the pure annihilations χ ̃01χ ̃01 → b ̄b and χ ̃01χ ̃01 → A1Hi with A1 being the lighter singlet- dominated CP-odd Higgs boson and Hi denoting the singlet-dominated CP-even Higgs boson or SM-like Higgs boson, and it can also be explained by the mixed annihilation χ ̃01χ ̃01 → W+W−,A1H1. Among these annihilation channels, χ ̃01χ ̃01 → A1Hi can provide the best interpretation with the corresponding p-value reaching 0.55. We also discuss to what extent the future DM direct detection experiments can explore the GCE solutions and conclude that the XENON-1T experiment is very promising in testing nearly all the solutions.