相关论文: Baryon Asymmetry, Supersymmetry and Gravitational …
It has been argued that any primordial B+L asymmetry existing at very high temperatures can be subsequently erased by anomalous electroweak effects. We argue that this is not necessarily the case in the supersymmetric standard model…
Baryogenesis appears to require lepton number violation. This is naturally realized in extensions of the standard model containing right-handed neutrinos. We discuss the generation of a baryon asymmetry by the out-of-equilibrium decay of…
In the presence of anomaly induced sphaleron process, only a B-L asymmetry can be partially converted to the baryon asymmetry while any B+L asymmetry would be completely erased. Thus in any successful baryogenesis theories, B-L is usually…
The presently observed cosmological baryon asymmetry has been finally determined at the time of the electroweak phase transition, when baryon and lepton number violating interactions fell out of thermal equilibrium. We discuss the…
The baryon asymmetry of the universe can be explained by the out-of-equilibrium decays of heavy right-handed neutrinos. We analyse this mechanism in the framework of a supersymmetric extension of the Standard Model and show that lepton…
The baryon asymmetry of the universe can be explained by the out-of-equilibrium decays of heavy right-handed neutrinos. We analyse this mechanism in the framework of a supersymmetric extension of the Standard Model and show that lepton…
Cosmological baryon asymmetry B is studied in supersymmetric standard models, assuming the electroweak reprocessing of B and L. Only when the soft supersymmetry breaking is taken into account, B is proportional to the primordial B-L in the…
Primordial Big-Bang Nucleosynthesis (BBN) tightly constrains the existence of any additional relativistic degrees of freedom at that epoch. However a large asymmetry in electron neutrino number shifts the chemical equilibrium between the…
In this letter, we quantify the challenge of explaining the baryon asymmetry using initial conditions in a universe that undergoes inflation. Contrary to lore, we find that such an explanation is possible if net $B-L$ number is stored in a…
We consider a minimal supersymmetric extension of the Standard Model, with right-handed neutrinos and local B-L, the difference between baryon and lepton number, a symmetry which is spontaneously broken at the scale of grand unification. To…
In theories where $B-L$ is a spontaneously broken local symmetry, the cosmological baryon asymmetry can be generated by the out-of-equilibrium decay of heavy Majorana neutrinos. We study this mechanism assuming a similar pattern of mixings…
We reconsider the GUT-baryogenesis mechanism for generating the baryon asymmetry of the Universe. The baryon asymmetry is produced by the out of equilibrium decay of coloured Higgs bosons at the GUT scale, conserving B-L. If neutrinos are…
Due to sphaleron processes in the high-temperature symmetric phase of the standard model the cosmological baryon asymmetry is related to neutrino properties. For hierarchical neutrino masses, with $B-L$ broken at the unification scale…
The difference between baryon number B and lepton number L is the only anomaly-free global symmetry of the Standard Model, easily promoted to a local symmetry by introducing three right-handed neutrinos, which automatically make neutrinos…
The realisation that the electroweak anomaly can induce significant baryon number violation at high temperature and that the standard models of particle physics and cosmology contain all the ingredients needed for baryogenesis has led to…
The presence of additional neutrino states with masses in the GeV range is allowed by electro-weak precision observables. However, these additional states can lead to lepton number violating interactions which potentially can wash out…
Helical hypermagnetic fields in the primordial Universe can produce the observed amount of baryon asymmetry through the chiral anomaly without any ingredients beyond the standard model of particle physics. While they generate no $B-L$…
We study the cosmology of supersymmetric models in which the supersymmetry breaking effects are mediated by gauge interactions at about the 10^5 GeV scale. We first point out that the gravitino is likely to overclose the Universe in this…
We note that the maximum temperature during reheating can be much greater than the reheating temperature $T_r$ at which the Universe becomes radiation dominated. We show that the Standard Model anomalous $(B+L)$-violating processes can…
Stringent bounds on baryon and lepton number violating interactions have been derived from the requirement that such interactions, together with electroweak instantons, do not destroy a cosmological baryon asymmetry produced at an extremely…