1,072 research outputs found
Renormalization of dimension-six operators relevant for the Higgs decays
The discovery of the Higgs boson has opened a new window to test the SM
through the measurements of its couplings. Of particular interest is the
measured Higgs coupling to photons which arises in the SM at the one-loop
level, and can then be significantly affected by new physics. We calculate the
one-loop renormalization of the dimension-six operators relevant for
, which can be potentially important since
it could, in principle, give log-enhanced contributions from operator mixing.
We find however that there is no mixing from any current-current operator that
could lead to this log-enhanced effect. We show how the right choice of
operator basis can make this calculation simple. We then conclude that
can only be affected by RG mixing from
operators whose Wilson coefficients are expected to be of one-loop size, among
them fermion dipole-moment operators which we have also included.Comment: 21 pages. Improved version with h -> gamma Z results added and
structure of anomalous-dimension matrix determined further. Conclusions
unchange
Numerical evolution of matter in dynamical axisymmetric black hole spacetimes. I. Methods and tests
We have developed a numerical code to study the evolution of self-gravitating
matter in dynamic black hole axisymmetric spacetimes in general relativity. The
matter fields are evolved with a high-resolution shock-capturing scheme that
uses the characteristic information of the general relativistic hydrodynamic
equations to build up a linearized Riemann solver. The spacetime is evolved
with an axisymmetric ADM code designed to evolve a wormhole in full general
relativity. We discuss the numerical and algorithmic issues related to the
effective coupling of the hydrodynamical and spacetime pieces of the code, as
well as the numerical methods and gauge conditions we use to evolve such
spacetimes. The code has been put through a series of tests that verify that it
functions correctly. Particularly, we develop and describe a new set of testbed
calculations and techniques designed to handle dynamically sliced,
self-gravitating matter flows on black holes, and subject the code to these
tests. We make some studies of the spherical and axisymmetric accretion onto a
dynamic black hole, the fully dynamical evolution of imploding shells of dust
with a black hole, the evolution of matter in rotating spacetimes, the
gravitational radiation induced by the presence of the matter fields and the
behavior of apparent horizons through the evolution.Comment: 42 pages, 20 figures, submitted to Phys Rev
Axion interpretation of the PVLAS data?
The PVLAS collaboration has recently reported the observation of a rotation
of the polarization plane of light propagating through a transverse static
magnetic field. Such an effect can arise from the production of a light, m_A ~
meV, pseudoscalar coupled to two photons with coupling strength g_{A\gamma} ~
5x10^{-6} GeV^{-1}. Here, we review these experimental findings, discuss how
astrophysical and helioscope bounds on this coupling can be evaded, and
emphasize some experimental proposals to test the scenario.Comment: 4 pages, 1 figure, jpconf.cls, talk presented at the ninth
International Conference on Topics in Astroparticle and Underground Physics,
TAUP 2005, Zaragoza, Spain, September 10-14, 200
New bounds on millicharged particles from cosmology
Particles with millicharge q and sub-eV mass can be produced in photon-photon
collisions, distorting the energy spectrum of the Cosmic Microwave Background.
We derive the conservative bound q < 10^-7 e (as well as model-dependent bounds
two orders of magnitude stronger), incompatible with proposed interpretations
of the PVLAS anomaly based on millicharged production or on
millicharged-mediated axion-like couplings.Comment: 7 pages, 2 figures. Final versio
HEMATURIA POR ROTURA DE ANEURISMA ILÍACO-URETERAL.
Arch Esp Urol. 2006 Apr;59(3):287-9.
[Hematuria after ureteral-iliac aneurysm rupture]
[Article in Spanish]
Palacios A, Massó P, Osorio L, Oliveira A, Soares J, Marcelo F.
Servicio de Urología, Hospital General de Santo Antonio, Porto, Portugal. [email protected]
Abstract
OBJECTIVE: Ureteral-iliac artery fistula is a rare condition. We perform a bibliographic review and report a case of ureter-iliac artery fistula reviewing its major differential diagnosis.
METHODS: This case-study describes a patient with massive hematuria that presented a ureter-iliac artery fistula secondary to spontaneous rupture of an internal iliac artery aneurysm.
RESULTS: 86 -year-old male patient with history of previous surgery for aneurysm and ureteral catheterization.
CONCLUSIONS: This difficult diagnosis should be thought of in a patient with massive macroscopic hematuria and previous vascular surgery. The treatment is always surgery.
PMID: 16724715 [PubMed - indexed for MEDLIN
Self Interacting Dark Matter in the Solar System
Weakly coupled, almost massless, spin 0 particles have been predicted by many
extensions of the standard model of particle physics. Recently, the PVLAS group
observed a rotation of polarization of electromagnetic waves in vacuum in the
presence of transverse magnetic field. This phenomenon is best explained by the
existence of a weakly coupled light pseudoscalar particle. However, the
coupling required by this experiment is much larger than the conventional
astrophysical limits. Here we consider a hypothetical self-interacting
pseudoscalar particle which couples weakly with visible matter.
Assuming that these pseudoscalars pervade the galaxy, we show that the solar
limits on the pseudoscalar-photon coupling can be evaded.Comment: 17 pages, 2 figure
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