3,281 research outputs found

    Adiabatic Electroweak Baryogenesis Driven by an Axion-like Particle

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    An axion-like particle (ALP) offers a new direction in electroweak baryogenesis because the periodic nature enables it to trigger a strong first-order phase transition insensitively to the decay constant ff. For ff much above TeV, the ALP-induced electroweak phase transition is approximately described by adiabatic processes, distinguishing our scenario for electroweak baryogenesis from the conventional ones. We show that, coupled to the electroweak anomaly, the ALP can naturally realize spontaneous electroweak baryogenesis to solve the matter-antimatter asymmetry problem for ff in the range between about 10510^5 GeV and 10710^7 GeV. In such an ALP window, the CPCP violation for baryogenesis is totally free from the experimental constraints, especially from the recently improved limit on the electron electric dipole moment. Future searches for ALPs could probe our scenario while revealing the connection between electroweak symmetry breaking and baryogenesis.Comment: 12 pages, 5 figures, appendices added, published versio

    Nanoscale Heat Transfer from Magnetic Nanoparticles and Ferritin in an Alternating Magnetic Field

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    Recent suggestions of nanoscale heat confinement on the surface of synthetic and biogenic magnetic nanoparticles during heating by radio frequency-alternating magnetic fields have generated intense interest because of the potential utility of this phenomenon for noninvasive control of biomolecular and cellular function. However, such confinement would represent a significant departure from the classical heat transfer theory. Here, we report an experimental investigation of nanoscale heat confinement on the surface of several types of iron oxide nanoparticles commonly used in biological research, using an all-optical method devoid of the potential artifacts present in previous studies. By simultaneously measuring the fluorescence of distinct thermochromic dyes attached to the particle surface or dissolved in the surrounding fluid during radio frequency magnetic stimulation, we found no measurable difference between the nanoparticle surface temperature and that of the surrounding fluid for three distinct nanoparticle types. Furthermore, the metalloprotein ferritin produced no temperature increase on the protein surface nor in the surrounding fluid. Experiments mimicking the designs of previous studies revealed potential sources of the artifacts. These findings inform the use of magnetic nanoparticle hyperthermia in engineered cellular and molecular systems

    Dark matter filtering-out effect during a first-order phase transition

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    If the mass of dark matter is generated from a cosmological phase transition involving the nucleation of bubbles, the corresponding bubble walls can filter out dark matter particles during the phase transition. Only particles with sufficient momentum to overcome their mass inside the bubbles can pass through the walls. As a result, the dark matter number density after the phase transition has a suppression factor expโก(โˆ’Mฯ‡/2ฮณ~T)\exp(-M_\chi/2\tilde \gamma T), where Mฯ‡M_\chi is the dark matter mass, and ฮณ~\tilde \gamma and TT are the Lorentz factor and temperature of the incoming fluid in the bubble wall rest frame, respectively. Under certain assumptions, we show that the filtering-out process can naturally provide a large suppression consistent with the observed dark matter density for a wide range of dark matter masses up to the Planck scale. Since the first-order phase transition is the decisive ingredient in our mechanism, a new connection is made between heavy dark matter scenarios and gravitational wave observations.Comment: 6 pages, 2 figures, minor change, presentation improve

    Finite rings with identity having GL(2m) as the group of units

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    ์ฃผ์–ด์ง„ ํ™˜์— ์žˆ์–ด์„œ ๊ฐ€์—ญ์› ์ „์ฒด์˜ ์ง‘ํ•ฉ์€ ๊ณฑ์…‰๊ตฐ์„ ์ด๋ฃฌ๋‹ค. ์ด ๊ณฑ์…ˆ๊ตฐ์ด ์ˆœํšŒ์ธ ์œ ํ•œํ™˜์€ ๊ทธ ๊ตฌ์กฐ๊ฐ€ ์™„์ „ํžˆ ๊ฒฐ์ •๋œ๋‹ค๋Š” ๊ฒƒ์€ ์ด๋ฏธ ์•Œ๋ ค์ ธ ์žˆ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋‹ค์Œ ์ •๋ฆฌ๋ฅผ ์ฆ๋ช…ํ•œ๋‹ค. ์ •๋ฆฌ (3. 1) ๊ฐ€์—ญ์› ์ „์ฒด๋กœ ์ด๋ฃจ์–ด์ง„ ๊ณฑ์…‰๊ตฐ์ด ์ผ๋ฐ˜์„ ํ˜•๊ตฐ GLโ‚‚(2m)๊ณผ ๋™ํ˜•์ธ ์œ ํ•œํ™˜ R์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค. ์ฆ‰, Rโ‰…Mโ‚‚(2m)โŠ•Zโ‚‚โŠ•โ€ฆโ€ฆโŠ•Zโ‚‚

    Rheological method for alpha test evaluation of developing superplasticizers' performance: Channel flow test

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    Advance in high-range water-reducing admixture revolutionizes the workability and constructability of conventional vibrated concrete as well as self-consolidating concrete. Its need from construction fields has increased, and consequently a variety of new-type polycarboxylates, base polymers for the admixture, are being formulated in these days. Synthesizing new polymers needs a quick, but reliable, test to evaluate its performance on concrete. The test is also asked for selecting the best applicable brand of them before a test concrete will be mixed. This paper proposes a channel flow test and its usage for the purpose. The proposed procedure for the test includes the mix proportion of a test mortar, the test method, and rheological interpretation of the test results.ope

    Nanoscale Heat Transfer from Magnetic Nanoparticles and Ferritin in an Alternating Magnetic Field

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    Recent suggestions of nanoscale heat confinement on the surface of synthetic and biogenic magnetic nanoparticles during heating by radio frequency-alternating magnetic fields have generated intense interest because of the potential utility of this phenomenon for noninvasive control of biomolecular and cellular function. However, such confinement would represent a significant departure from the classical heat transfer theory. Here, we report an experimental investigation of nanoscale heat confinement on the surface of several types of iron oxide nanoparticles commonly used in biological research, using an all-optical method devoid of the potential artifacts present in previous studies. By simultaneously measuring the fluorescence of distinct thermochromic dyes attached to the particle surface or dissolved in the surrounding fluid during radio frequency magnetic stimulation, we found no measurable difference between the nanoparticle surface temperature and that of the surrounding fluid for three distinct nanoparticle types. Furthermore, the metalloprotein ferritin produced no temperature increase on the protein surface nor in the surrounding fluid. Experiments mimicking the designs of previous studies revealed potential sources of the artifacts. These findings inform the use of magnetic nanoparticle hyperthermia in engineered cellular and molecular systems
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