26 research outputs found
Current quark mass dependence of nucleon magnetic moments and radii
A calculation of the current-quark-mass-dependence of nucleon static
electromagnetic properties is necessary in order to use observational data as a
means to place constraints on the variation of Nature's fundamental parameters.
A Poincare' covariant Faddeev equation, which describes baryons as composites
of confined-quarks and -nonpointlike-diquarks, is used to calculate this
dependence The results indicate that, like observables dependent on the
nucleons' magnetic moments, quantities sensitive to their magnetic and charge
radii, such as the energy levels and transition frequencies in Hydrogen and
Deuterium, might also provide a tool with which to place limits on the allowed
variation in Nature's constants.Comment: 23 pages, 2 figures, 4 tables, 4 appendice
Charm CP Violation and the Electric Dipole Moments from the Charm Scale
The reported CP asymmetry in D->K^+K^- / pi^+pi^- is argued to be too large
to naturally fit the SM. If so, a new source of CP violation is implied in the
Delta C=1 sector with a milliweak strength. CP-odd interactions in the
flavor-diagonal sector are strongly constrained by the EDMs placing severe
limitations on the underlying theory. While the largest effects usually come
from the New Physics energy scale, they are strongly model-dependent. Yet the
interference of the CP-odd forces manifested in D decays with the conventional
CP-even Delta C=1 weak interaction generates at the charm scale a background
level. It has been argued that the d_n in the SM is largely generated via such
an interference, with mild KM-specific additional suppression. The reported CP
asymmetry is expected to generate d_n of 30 to 100 times larger than in the SM,
or even higher in certain model yet not quite natural examples. In the SM the
charm-induced loop-less |d_n| is expected around 10^{-31}e*cm. On the technical
side, we present a compact Ward-identity--based derivation of the induced
scalar pion-nucleon coupling in the presence of the CP-odd interactions, which
appears once the latter include the right-handed light quarks.Comment: 29pages, 5 figure
A Comprehensive Analysis of Electric Dipole Moment Constraints on CP-violating Phases in the MSSM
We analyze the constraints placed on individual, flavor diagonal CP-violating
phases in the minimal supersymmetric extension of the Standard Model (MSSM) by
current experimental bounds on the electric dipole moments (EDMs) of the
neutron, Thallium, and Mercury atoms. We identify the four CP-violating phases
that are individually highly constrained by current EDM bounds, and we explore
how these phases and correlations among them are constrained by current EDM
limits. We also analyze the prospective implications of the next generation of
EDM experiments. We point out that all other CP-violating phases in the MSSM
are not nearly as tightly constrained by limits on the size of EDMs. We
emphasize that a rich set of phenomenological consequences is potentially
associated with these generically large EDM-allowed phases, ranging from B
physics, electroweak baryogenesis, and signals of CP-violation at the CERN
Large Hadron Collider and at future linear colliders. Our numerical study takes
into account the complete set of contributions from one- and two-loop EDMs of
the electron and quarks, one- and two-loop Chromo-EDMs of quarks, the Weinberg
3-gluon operator, and dominant 4-fermion CP-odd operator contributions,
including contributions which are both included and not included yet in the
CPsuperH2.0 package. We also introduce an open-source numerical package, 2LEDM,
which provides the complete set of two-loop electroweak diagrams contributing
to the electric dipole moments of leptons and quarks.Comment: 23 pages, 11 figures; v2: references added, minor change
The deuteron: structure and form factors
A brief review of the history of the discovery of the deuteron in provided.
The current status of both experiment and theory for the elastic electron
scattering is then presented.Comment: 80 pages, 33 figures, submited to Advances in Nuclear Physic
Varying constants, Gravitation and Cosmology
Fundamental constants are a cornerstone of our physical laws. Any constant
varying in space and/or time would reflect the existence of an almost massless
field that couples to matter. This will induce a violation of the universality
of free fall. It is thus of utmost importance for our understanding of gravity
and of the domain of validity of general relativity to test for their
constancy. We thus detail the relations between the constants, the tests of the
local position invariance and of the universality of free fall. We then review
the main experimental and observational constraints that have been obtained
from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites
dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic
microwave background and big bang nucleosynthesis. At each step we describe the
basics of each system, its dependence with respect to the constants, the known
systematic effects and the most recent constraints that have been obtained. We
then describe the main theoretical frameworks in which the low-energy constants
may actually be varying and we focus on the unification mechanisms and the
relations between the variation of different constants. To finish, we discuss
the more speculative possibility of understanding their numerical values and
the apparent fine-tuning that they confront us with.Comment: 145 pages, 10 figures, Review for Living Reviews in Relativit
An alternative for polarized antiproton beams
The current prevalence of hospital-acquired infections and evolving amplification of bacterial resistance are major public health concerns. A heightened awareness of intraoperative transmission of potentially pathogenic bacterial organisms may lead to implementation of effective preventative measures.Sixty-one operative suites were randomly selected for analysis. Sterile intravenous stopcock sets and two sites on the anesthesia machine were decontaminated and cultured aseptically at baseline and at case completion. The primary outcome was the presence of a positive culture on the previously sterile patient stopcock set. Secondary outcomes were the number of colonies per surface area sampled on the anesthesia machine, species identification, and antibiotic susceptibility of isolated organisms.Bacterial contamination of the anesthesia work area increased significantly at the case conclusion, with a mean difference of 115 colonies per surface area sampled (95% confidence interval [CI], 62-169; P < 0.001). Transmission of bacterial organisms, including vancomycin-resistant enterococcus, to intravenous stopcock sets occurred in 32% (95% CI, 20.6-44.9%) of cases. Highly contaminated work areas increased the odds of stopcock contamination by 4.7 (95% CI, 1.42-15.42; P = 0.011). Contaminated intravenous tubing was associated with a trend toward increased nosocomial infection rates (odds ratio, 3.08; 95% CI, 0.56-17.5; P = 0.11) and with an increase in mortality (95% CI odds ratio, 1.11-infinity; P = 0.0395).Potentially pathogenic, multidrug-resistant bacterial organisms are transmitted during the practice of general anesthesia to both the anesthesia work area and intravenous stopcock sets. Implementation of infection control measures in this area may help to reduce both the evolving problem of increasing bacterial resistance and the development of life-threatening infectious complications