1,155 research outputs found
Signal for CP violation in decays
We analyze the partial rate asymmetry in
decays () which results from the interference of
the nonresonant decay amplitude and the resonant amplitude for followed by the decay . The CP
violating phase can be extracted from the measured asymmetry. We find
that the partial rate asymmetry for is
, while for it amounts .Comment: 3 pages, latex, no figures, Talk given by S. Fajfer at the Hyperons,
Charm and Beauty Hadrons, Genova, Italy, 30 June -3 July 1998, to appear as
proceedings in Nucl. Phys.
High Temperature Symmetry Nonrestoration
This is a short review on the subject of symmetry nonrestoration at high
temperature. Special emphasis is put on experimental discoveries and different
theoretical mechanisms. At the end, possible cosmological applications are
briefly mentioned.Comment: 7 pages; plenary talk at COSMO99, Trieste, Italy, Sep 27 - Oct 2,
1999; to appear in the proceedings; minor text changes and new references
adde
Do internal symmetries get restored in hot and dense SUSY?
I offer some computational details and useful and concise formulae to
calculate the effective potential for a general abelian supersymmetric model at
high temperature and density. It will be shown that such cases are very good
candidates for symmetry nonrestoration at high temperature, providing large
densities are present.Comment: 3 pages, uses sprocl.sty, talk given at the International Workshop
COSMO97 on Particle Physics and the Early Universe, 15-19 September 1997,
Ambleside, Lake District, England, to be published in the Proceeding
Fermion mass relations in a supersymmetric SO(10) theory
Neutrino and charged fermion masses provide important constraints on grand
unified theories. We illustrate this by focusing on a renormalizable,
supersymmetric SO(10) theory proposed long ago, that recently attracted great
interest in view of its minimality. We show how the nature of the light Higgs,
which depends on the GUT scale fields, gets reflected on the precise
predictions for fermion masses and mixings. We exemplify this on the case of
dominant Type II see-saw, which gets severely constrained and is likely to
fail.Comment: Based on talks given by G. Senjanovic in the plenary session of
PASCOS05 Conference and by A. Melfo at the 2005 Gran Sasso Summer Institut
Charged-fermion masses in SO(10): analysis with scalars in 10+120
We consider the scenario in which the mass matrices of the charged fermions
in the SO(10) Grand Unified Theory are generated exclusively by renormalizable
Yukawa couplings to one representation of
scalars. We analyze, partly analytically and partly numerically, this scenario
in the three-generations case. We demonstrate that it leads to unification of
the and masses at the GUT scale. Testing this scenario against the
mass values at the GUT scale, obtained from the renormalization-group evolution
in the minimal SUSY extension of the Standard Model, we find that it is not
viable: either the down-quark mass or the top-quark mass must be
unrealistically low. If we include the CKM mixing angles in the test, then, in
order that the mixing angles are well reproduced, either the top-quark mass or
the strange-quark mass together with the down-quark mass must be very low. We
conclude that, assuming a SUSY SO(10) scenario, charged-fermion mass generation
based exclusively on one representation of
scalars is in contradiction with experiment.Comment: 18 pages, 3 eps figures; references added and corrected. We have also
corrected an error in the code for the CKM matrix; the ensuing results are
sharper at eliminating our scenario. In version 3 we have rectified a
statement concerning Ref.[18] and added one reference and some phrases; final
version for Nucl. Phys.
Pinning down the New Minimal Supersymmetric GUT
We show that generic fits of
fermion masses and mixings, using real superpotential couplings but with
complex `Higgs fractions' leading to complex yukawa couplings in the effective
MSSM, \emph{overdetermine}(by one extra constraint) the superpotential
parameters of the New Minimal Supersymmetric SO(10) GUT\cite{nmsgut}. Therefore
fits should properly be done by generating the 24 generic fit parameters from
the 23 parameters of the NMSGUT superpotential, given as input.
Each numerical fit then \emph{fully specifies} the parameters of the NMSGUT. An
analysis of all its implications, modulo only the residual uncertainty of
supersymmetry breaking parameters, is now feasible. Thus the NMSGUT offers the
possibility of a confrontation between the scale of gauge unification and the
fit to fermion masses due to their extractable common dependence on the NMSGUT
parameters. If and when `smoking gun' discoveries of Supersymmetry and Proton
decay occur they will find the NMSGUT fully vulnerable to falsification.Comment: Minor changes : (1) Abstract : Phrase "complex Higgs doublet vevs"
made more precise and a conjunction deleted (2)References : Umlauts inserted
in an author nam
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