Filters
Results 1 - 10 of 30
Results 1 - 10 of 30.
Search took: 0.025 seconds
| Sort by: date | relevance |
[en] Antimatter exists, we can produce it in particle accelerators and detect it in cosmic radiations but antimatter stays very rare at the universe scale. The standard model does not explain this asymmetry, the excess of baryons (called also baryogenesis) might be a consequence of unknown particles and interactions that existed during the first moments after the Big-bang. 2 scenarios could explain baryogenesis: the first one is based on the annihilation of the massive particles that gives their tiny mass to the neutrinos through their interaction with the Higgs field. The second scenario is based on a possible separation of the weak interaction from the electromagnetic interaction that could have happened 10-11 s after the Big-bang. This separation could have led to an excess of baryons through processes involving topological features called sphalerons. The existence of sphalerons is not inconsistent with the standard model. The second scenario could be tested at LHC when the accelerator reaches the TeV energy range. (A.C.)
Journal
[en] We compute one loop neutrino masses in the R-parity violating Minimal Supersymmetric Model, including the bilinear Rpv masses in the mass insertion approximation. To the order we calculate, our results are independent of the Higgs-lepton basis choice. We have a variety of perturbative parameters-gauge, yukawa and trilinear couplings, and Rp violating masses. Their relative magnitudes determine which diagrams are relevant for neutrino mass calculations. We find new loop diagrams which can be relevant and have frequently been neglected in the past. For the Grossman-Haber neutral loop contribution to the neutrino mass matrix we obtain explicit analytic results. (author)
Journal
Journal of High Energy Physics (Online); ISSN 1029-8479; 
; v. 05(2000); p. vp
; v. 05(2000); p. vp
[en] We summarize theoretical explanations of the three σ discrepancy between sin2θW measured by NuTeV and predicted by the standard model global fit. Possible new physics explanations (e.g., an unmized Z') are not compelling. The discrepancy would be reduced by a positive momentum asymmetry s- in the strange sea; present experimental estimates of s- are unreliable or incomplete. Upgrading the NuTeV analysis to NLO would alleviate concerns that the discrepancy is a QCD effect
Journal
Journal of Physics. G, Nuclear and Particle Physics; ISSN 0954-3899; ; CODEN JPGPED; v. 29(8); p. 2001-2003
; CODEN JPGPED; v. 29(8); p. 2001-2003
[en] We update the bounds on fermions with electric charge epsilon e and mass mε. For mε lsim me we find 10(-15) lsim ε<1 is excluded by laboratory experiments, astrophysics and cosmology. For larger masses, the limits are less restrictive and depend on mε. For milli-charged neutrinos, the limits are stronger, especially if the different flavors mix as suggested by current experimental evidence. (author)
Journal
Journal of High Energy Physics (Online); ISSN 1029-8479; ; v. 05(2000); p. vp
; v. 05(2000); p. vp
[en] The objective of this research is to measure condensation rates in steam-water flow under various conditions. Such data are needed to develop semi-empirical relations which are required in advanced computer codes for prediction of loss-of-coolant accidents
Source
Reocreux, M.; Katz, G. (eds.); CEA Centre d'Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Surete Nucleaire; Nuclear Energy Agency, 75 - Paris (France); 358 p; ISBN 2-7272-0055-2; ; Feb 1981; v. 2 p. 567-582; Commissariat a l'Energie Atomique; Paris, France; 2. CSNI specialists meeting on transient two-phase flow; Paris, France; 12 - 14 Jun 1978; Available from Dept. de Surete Nucleaire, CEN Fontenay-aux-Roses, B.P. 6, 92260 (France)
; Feb 1981; v. 2 p. 567-582; Commissariat a l'Energie Atomique; Paris, France; 2. CSNI specialists meeting on transient two-phase flow; Paris, France; 12 - 14 Jun 1978; Available from Dept. de Surete Nucleaire, CEN Fontenay-aux-Roses, B.P. 6, 92260 (France)
[en] In recent papers QCD corrections to the decay t→H+b were calculated by two groups with results that disagreed. Using dimensional regularization for both infrared and ultraviolet divergences, we confirm that the QCD corrections to the decay width Γ(t→H+b) are equal to Γ(t→W+b) in the limit of a large t-quark mass
Journal
[en] In November 2018 the General Conference on Weights and Measures (CGPM) will meet and are likely to ratify the revision of the international system of units (SI). This represents a major change to the way the base SI units are defined and realised, a major consequence being that the last of the definitions based on a material artefact, the international prototype of the kilogram, will be “retired” and the “new” kilogram will be realised in terms of the Planck constant via the Kibble balance or X-ray crystal density (XRCD) experiment. While the revision of the SI and the redefinition of the kilogram will almost certainly be endorsed by the CGPM there are issues around the current agreement of the Kibble balance and XRCD experiments. This will mean that in order to implement the kilogram redefinition a consensus value for the “new” kilogram will need to be adopted in order that a consistent value for the SI unit of mass be maintained. In order to maintain this consistency the storage, monitoring and use of current primary mass standards will be critical and this paper outlines ways in which the stability of artefact based mass standards can be optimised by careful storage and monitoring using surface analysis techniques and quartz crystal microbalance technology. (paper)
Journal
Journal of Physics. Conference Series (Online); ISSN 1742-6596; ; v. 1065(4); [4 p.]
; v. 1065(4); [4 p.]
[en] The see-saw mechanism is a very attractive explanation for small neutrino masses, parametrized at the GUT scale by the right-handed Majorana mass matrix, M, and the neutrino Yukawa matrix, Yν. We show that M and Yν can be calculated from the light neutrino masses, the MNS matrix, and Yν† Yν, which enters into the left-handed slepton radiative corrections. This suggests that in principle the GUT-scale inputs of the seesaw can be reconstructed from the neutrino and sneutrino mass matrices. We briefly discuss why this is impractical, but advocate the neutrino and sneutrino mass matrices as an alternative bottom-up parametrization of the seesaw. (author)
Journal
Journal of High Energy Physics; ISSN 1126-6708; ; v. 09(2001); p. vp
; v. 09(2001); p. vp
| 1 | 2 | 3 | Next |