76 research outputs found
Kinetic approach to electroweak baryogenesis
After a short review of baryogenesis mechanisms, we focus on the charge
transport mechanism at the electroweak scale, effective at strong electroweak
phase transitions. Starting from the one-loop Schwinger-Dyson equations for
fermions coupled to bosons, we present a derivation of the relevant kinetic
equations in the on-shell and gradient approximations, relevant for the thick
wall baryogenesis regime. We then discuss the CP-violating source from the
semiclassical force in the flow term, and compare it with the source arising in
the collision term of the kinetic equation. Finally, we summarize the results
concerning the chargino mediated baryogenesis in the Minimal Supersymmetric
Standard Model.Comment: 13 pages, 6 figures. Invited talk at the International Workshop
"Strong and Electroweak Matter 2002", October 2-5, 2002 Heidelberg, German
Quantum Boltzmann equations for electroweak baryogenesis including gauge fields
We review and extend to include the gauge fields our derivation of the
semiclassical limit of the collisionless quantum transport equations for the
fermions in presence of a CP-violating bubble wall at a first order electroweak
phase transition. We show how the (gradient correction modified) Lorenz-force
appears both in the Schwinger-Keldysh approach and in the semiclassical
WKB-treatment. In the latter approach the inclusion of gauge fields removes the
apparent phase reparametrization dependence of the intermediate calculations.
We also discuss setting up the fluid equations for practical calculations in
electroweak baryogenesis including the self-consistent (hyper)electric field
and the anomaly.Comment: 15 pages, talk presented by Kimmo Kainulainen at COSMO-01, Rovaniemi,
Finland, 09/200
Some aspects of collisional sources for electroweak baryogenesis
We consider the dynamics of fermions with a spatially varying mass which
couple to bosons through a Yukawa interaction term and perform a consistent
weak coupling truncation of the relevant kinetic equations. We then use a
gradient expansion and derive the CP-violating source in the collision term for
fermions which appears at first order in gradients. The collisional sources
together with the semiclassical force constitute the CP-violating sources
relevant for baryogenesis at the electroweak scale. We discuss also the absence
of sources at first order in gradients in the scalar equation, and the
limitations of the relaxation time approximation.Comment: 12 pages, 4 figures, talk presented by Tomislav Prokopec at COSMO-01,
Rovaniemi, Finland, 09/2001 references added, minor changes in sections 5.3
and
Boltzmann Collision Term
We derive the Boltzmann equation for scalar fields using the
Schwinger-Keldysh formalism. The focus lies on the derivation of the collision
term. We show that the relevant self-energy diagrams have a factorization
property. The collision term assumes the Boltzmann-like form of scattering
probability times statistical factors for those self-energy diagrams which
correspond to tree level scattering processes. Our proof covers scattering
processes with any number of external particles, which come from self-energy
diagrams with any number of loops.Comment: 17 pages, 4 figure
Transport equations for chiral fermions to order \hbar and electroweak baryogenesis: Part I
This is the first in a series of two papers. We use the Schwinger-Keldysh
formalism to derive semiclassical Boltzmann transport equations for massive
chiral fermions and scalar particles. Our considerations include complex mass
terms and mixing fermion and scalar fields, such that CP-violation is naturally
included, rendering the equations particularly suitable for studies of
baryogenesis at a first order electroweak phase transition. In part II we
discuss the collision terms.Comment: 58 pages, 5 figures; earlier version broken up into two parts, Part
II is hep-ph/0406140; accepted for publication in Annals of Physic
Semiclassical force for electroweak baryogenesis: three-dimensional derivation
We derive a semiclassical transport equation for fermions propagating in the
presence of a CP-violating planar bubble wall at a first order electroweak
phase transition. Starting from the Kadanoff-Baym (KB) equation for the
two-point (Wightman) function we perform an expansion in gradients, or
equivalently in the Planck constant h-bar. We show that to first order in h-bar
the KB equations have a spectral solution, which allows for an on-shell
description of the plasma excitations. The CP-violating force acting on these
excitations is found to be enhanced by a boost factor in comparison with the
1+1-dimensional case studied in a former paper. We find that an identical
semiclassical force can be obtained by the WKB method. Applications to the MSSM
are also mentioned.Comment: 19 page
Polo-like kinase 3 regulates CtIP during DNA double-strand break repair in G1
DNA double-strand breaks (DSBs) are repaired by nonhomologous end joining (NHEJ) or homologous recombination (HR). The C terminal binding proteinâinteracting protein (CtIP) is phosphorylated in G2 by cyclin-dependent kinases to initiate resection and promote HR. CtIP also exerts functions during NHEJ, although the mechanism phosphorylating CtIP in G1 is unknown. In this paper, we identify Plk3 (Polo-like kinase 3) as a novel DSB response factor that phosphorylates CtIP in G1 in a damage-inducible manner and impacts on various cellular processes in G1. First, Plk3 and CtIP enhance the formation of ionizing radiation-induced translocations; second, they promote large-scale genomic deletions from restriction enzyme-induced DSBs; third, they are required for resection and repair of complex DSBs; and finally, they regulate alternative NHEJ processes in Kuâ/â mutants. We show that mutating CtIP at S327 or T847 to nonphosphorylatable alanine phenocopies Plk3 or CtIP loss. Plk3 binds to CtIP phosphorylated at S327 via its Polo box domains, which is necessary for robust damage-induced CtIP phosphorylation at S327 and subsequent CtIP phosphorylation at T847
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