Electroweak Sphaleron in a Magnetic field

Abstract

Using lattice simulations we calculate the rate of baryon number violating processes, the sphaleron rate, in the Standard Model with an external (hyper)magnetic field for temperatures across the electroweak cross-over, focusing on the broken phase. Additionally, we compute the Higgs expectation value and the pseudocritical temperature. The electroweak cross-over shifts to lower temperatures with increasing external magnetic field, bringing the onset of the suppression of the baryon number violation with it. When the hypermagnetic field reaches the magitude $B_Y\approx 2T^2$ the cross-over temperature is reduced from $160$ GeV to $145$ GeV. In the broken phase for small magnetic fields the rate behaves quadratically as a function of the magnetic flux. For stronger magnetic fields the rate reaches a linear regime which lasts until the field gets strong enough to restore the electroweak symmetry where the symmetric phase rate is reached.

15 pages, 16 figures, corrected typos, published version

References in corpus (11)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• The Sphaleron Rate in the Minimal Standard Model
• Progress on Cosmological Magnetic Fields
• Baryogenesis from Decaying Magnetic Helicity
• The Sphaleron Rate through the Electroweak Cross-over
• First-order electroweak phase transitions: a nonperturbative update
• On the origin of matter in the Universe
• Baryon isocurvature constraints on the primordial hypermagnetic fields
• Phase structure of electroweak vacuum in a strong magnetic field: the lattice results
• The Electroweak Sphaleron in a strong magnetic field

Cited by in corpus (3)

• Bubble Trouble: a Review on Electroweak Baryogenesis
• Non-perturbative determination of the sphaleron rate for first-order phase transitions
• Baryogenesis in $SU(2{)}_L$ multiplet models