1,364 research outputs found
The Effect of the Sparticle Mass Spectrum on the Conversion of B-L to B
In the context of many leptogenesis and baryogenesis scenarios, B-L (baryon
minus the lepton number) is converted into B (baryon number) by
non-perturbative B+L violating operators in the SU(2)_L sector. We correct a
common misconversion of B-L to B in the literature in the context of
supersymmetry. More specifically, kinematic effects associated with the
sparticle masses can be generically important (typically a factor of 2/3
correction in mSUGRA scenarios), and in some cases, it may even flip the sign
between B-L and B. We give explicit formulae for converting B-L to B for
temperatures approaching the electroweak phase transition temperature from
above. Enhancements of B are also possible, leading to a mild relaxation of the
reheating temperature bounds coming from gravitino constraints.Comment: 17 page
Combined Pricing and Portfolio Option Procurement
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90569/1/poms1255.pd
Lepton-mediated electroweak baryogenesis
We investigate the impact of the tau and bottom Yukawa couplings on the
transport dynamics for electroweak baryogenesis in supersymmetric extensions of
the Standard Model. Although it has generally been assumed in the literature
that all Yukawa interactions except those involving the top quark are
negligible, we find that the tau and bottom Yukawa interaction rates are too
fast to be neglected. We identify an illustrative "lepton-mediated electroweak
baryogenesis" scenario in which the baryon asymmetry is induced mainly through
the presence of a left-handed leptonic charge. We derive analytic formulae for
the computation of the baryon asymmetry that, in light of these effects, are
qualitatively different from those in the established literature. In this
scenario, for fixed CP-violating phases, the baryon asymmetry has opposite sign
compared to that calculated using established formulae.Comment: 26 pages, 5 figure
Does export dependence imply more political support in Sino-Africa relation since 2000?
published_or_final_versionInternational and Public AffairsMasterMaster of International and Public Affair
Supergauge interactions and electroweak baryogenesis
We present a complete treatment of the diffusion processes for supersymmetric
electroweak baryogenesis that characterizes transport dynamics ahead of the
phase transition bubble wall within the symmetric phase. In particular, we
generalize existing approaches to distinguish between chemical potentials of
particles and their superpartners. This allows us to test the assumption of
superequilibrium (equal chemical potentials for particles and sparticles) that
has usually been made in earlier studies. We show that in the Minimal
Supersymmetric Standard Model, superequilibrium is generically maintained --
even in the absence of fast supergauge interactions -- due to the presence of
Yukawa interactions. We provide both analytic arguments as well as illustrative
numerical examples. We also extend the latter to regions where analytical
approximations are not available since down-type Yukawa couplings or supergauge
interactions only incompletely equilibrate. We further comment on cases of
broken superequilibrium wherein a heavy superpartner decouples from the
electroweak plasma, causing a kinematic bottleneck in the chain of
equilibrating reactions. Such situations may be relevant for baryogenesis
within extensions of the MSSM. We also provide a compendium of inputs required
to characterize the symmetric phase transport dynamics.Comment: 49 pages, 9 figure
Datacasting V3.0
Datacasting V3.0 provides an RSSbased feed mechanism for publishing the availability of Earth science data records in real time. It also provides a utility for subscribing to these feeds and sifting through all the items in an automatic manner to identify and download the data records that are required for a specific application. Datacasting is a method by which multiple data providers can publish the availability of new Earth science data and users download those files that meet a predefined need; for example, to only download data files related to a specific earthquake or region on the globe. Datacasting is a server-client architecture. The server-side software is used by data providers to create and publish the metadata about recently available data according to the Datacasting RSS (Really Simple Syndication) specification. The client software subscribes to the Datacasting RSS and other RSS-based feeds. By configuring filters associated with feeds, data consumers can use the client to identify and automatically download files that meet a specific need. On the client side, a Datacasting feed reader monitors the server for new feeds. The feed reader will be tuned by the user, via a graphical user interface (GUI), to examine the content of the feeds and initiate a data pull after some criteria are satisfied. The criteria might be, for example, to download sea surface temperature data for a particular region that has cloud cover less than 50% and during daylight hours. After the granule is downloaded to the client, the user will have the ability to visualize the data in the GUI. Based on the popular concept of podcasting, which gives listeners the capability to download only those MP3 files that match their preference, Earth science Datacasting will give users a method to download only the Earth science data files that are required for a particular application
Apolipoprotein-induced conversion of phosphatidylcholine bilayer vesicles into nanodisks
AbstractApolipoprotein mediated formation of nanodisks was studied in detail using apolipophorin III (apoLp-III), thereby providing insight in apolipoproteinâlipid binding interactions. The spontaneous solubilization of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles occured only in a very narrow temperature range at the gelâliquidâcrystalline phase transition temperature, exhibiting a net exothermic interaction based on isothermal titration calorimetry analysis. The resulting nanodisks were protected from proteolysis by trypsin, endoproteinase Glu-C, chymotrypsin and elastase. DMPC solubilization and the simultaneous formation of nanodisks were promoted by increasing the vesicle diameter, protein to lipid ratio and concentration. Inclusion of cholesterol in DMPC dramatically enhanced the rate of nanodisk formation, presumably by stabilization of lattice defects which form the main insertion sites for apolipoprotein α-helices. The presence of fully saturated acyl chains with a length of 13 or 14 carbons in phosphatidylcholine allowed the spontaneous vesicle solubilization upon apolipoprotein addition. Nanodisks with C13:0-phosphatidylcholine were significantly smaller with a diameter of 11.7±3.1nm compared to 18.5±5.6nm for DMPC nanodisks determined by transmission electron microscopy. Nanodisk formation was not observed when the phosphatidylcholine vesicles contained acyl chains of 15 or 16 carbons. However, using very high concentrations of lipid and protein (>10mg/ml), 1,2,-dipalmitoyl-sn-glycero-3-phosphocholine nanodisks could be produced spontaneously although the efficiency remained low
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