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Title: Baryogenesis from decaying magnetic helicity

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 94; Journal Issue: 6; Related Information: CHORUS Timestamp: 2016-09-06 18:11:42; Journal ID: ISSN 2470-0010
American Physical Society
Country of Publication:
United States

Citation Formats

Kamada, Kohei, and Long, Andrew J. Baryogenesis from decaying magnetic helicity. United States: N. p., 2016. Web. doi:10.1103/PhysRevD.94.063501.
Kamada, Kohei, & Long, Andrew J. Baryogenesis from decaying magnetic helicity. United States. doi:10.1103/PhysRevD.94.063501.
Kamada, Kohei, and Long, Andrew J. 2016. "Baryogenesis from decaying magnetic helicity". United States. doi:10.1103/PhysRevD.94.063501.
title = {Baryogenesis from decaying magnetic helicity},
author = {Kamada, Kohei and Long, Andrew J.},
abstractNote = {},
doi = {10.1103/PhysRevD.94.063501},
journal = {Physical Review D},
number = 6,
volume = 94,
place = {United States},
year = 2016,
month = 9

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevD.94.063501

Citation Metrics:
Cited by: 6works
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  • Many models of baryogenesis rely on anomalous particle physics processes to give baryon number violation. By numerically evolving the electroweak equations on a lattice, we show that baryogenesis in these models creates helical cosmic magnetic fields, though the helicity created is smaller than earlier analytical estimates. After a transitory period, electroweak dynamics is found to conserve the Chern-Simons number and the total electromagnetic helicity. We argue that baryogenesis could lead to magnetic fields of nano-Gauss strength today on astrophysical length scales. In addition to being astrophysically relevant, such helical magnetic fields can provide an independent probe of baryogenesis and CPmore » violation in particle physics.« less
  • Late-decaying string moduli dilute the baryon asymmetry of the Universe created in any previous era. The reheat temperature for such moduli is below a GeV, thus motivating baryogenesis at very low temperatures. We present an extension of the minimal supersymmetric standard model with TeV-scale colored fields that can yield the correct baryon asymmetry of the Universe in this context. Modulus decay, which reheats the Universe at a temperature below GeV, produces the visible sector fields and neutralino dark matter in nonthermal fashion. We discuss various possibilities for baryogenesis from TeV-scale colored fields and show that they can generate an acceptablemore » baryon asymmetry, while being compatible with phenomenological constraints like neutron-antineutron oscillation.« less
  • To investigate the characteristics of large-scale and long-term evolution of magnetic helicity with solar cycles, we use the method of Local Correlation Tracking to estimate the magnetic helicity evolution over solar cycle 23 from 1996 to 2009 using 795 MDI magnetic synoptic charts. The main results are as follows: the hemispheric helicity rule still holds in general, i.e., the large-scale negative (positive) magnetic helicity dominates the northern (southern) hemisphere. However, the large-scale magnetic helicity fluxes show the same sign in both hemispheres around 2001 and 2005. The global, large-scale magnetic helicity flux over the solar disk changes from a negativemore » value at the beginning of solar cycle 23 to a positive value at the end of the cycle, while the net accumulated magnetic helicity is negative in the period between 1996 and 2009.« less
  • We use daily full-disk vector magnetograms from Vector Spectromagnetograph on Synoptic Optical Long-term Investigations of the Sun system to synthesize the first Carrington maps of the photospheric vector magnetic field. We describe these maps and make a comparison of the observed radial field with the radial field estimate from line-of-sight magnetograms. Furthermore, we employ these maps to study the hemispheric pattern of current helicity density, H{sub c} , during the rising phase of solar cycle 24. The longitudinal average over the 23 consecutive solar rotations shows a clear signature of the hemispheric helicity rule, i.e., H{sub c} is predominantly negativemore » in the north and positive in the south. Although our data include the early phase of cycle 24, there appears to be no evidence for a possible (systematic) reversal of the hemispheric helicity rule at the beginning of the cycle as predicted by some dynamo models. Furthermore, we compute the hemispheric pattern in active region latitudes (-30 Degree-Sign {<=} {theta} {<=} 30 Degree-Sign ) separately for weak (100 G < |B{sub r} | < 500 G) and strong (|B{sub r} | > 1000 G) radial magnetic fields. We find that while the current helicity of strong fields follows the well-known hemispheric rule (i.e., {theta} {center_dot} H{sub c} < 0), H{sub c} of weak fields exhibits an inverse hemispheric behavior (i.e., {theta} {center_dot} H{sub c} > 0), albeit with large statistical scatter. We discuss two plausible scenarios to explain the opposite hemispheric trend of helicity in weak and strong field regions.« less
  • The conjecture that magnetic helicity (linked flux) is conserved in magnetized plasmas for time scales that are short compared to the resistive diffusion time is experimentally tested in the CTX spheromak (Phys. Rev. Lett. 45, 1264 (1980); 51, 39 (1983); Nucl. Fusion 24, 267 (1984)). Helicity is created electrostatically by current drawn from electrodes. The magnetized plasma then flows into a conducting flux conserver where the energy per helicity of the plasma is minimized and a spheromak is formed on a relaxation time scale of many Alfven times. The magnetic field strength of the equilibrium is subsequently increased and sustained.more » The amount of helicity created by the magnetized coaxial plasma source, the helicity content of the spheromak equilibrium, and the resistive loss of the helicity are measured to determine the balance of helicity between source and spheromak with a +- 16% uncertainty. In CTX the amount of energy that must be rapidly dissipated within the conducting boundary while conserving helicity in the process of sustaining the spheromak is experimentally controllable, and has varied from 1.8 times the spheromak magnetic energy to greater than 10 times. The relaxation, or minimization of the energy-to-helicity ratio, determines the gross structure (the normalized spatial profile) of the spheromak, while the conservation of helicity itself determines the magnitude and time dependence of the magnetic fields of the spheromak equilibrium. Helicity balance tests are done by individually varying the sign and magnitude of the source voltage and flux, and by observing sustainment of spheromaks with fields opposing those of the source. A threshold for helicity injection from the source is measured and related to the source and entrance region size. During times short compared to resistive« less