6,952 research outputs found
A method for determining CP violating phase
A new way of determining the phases of weak amplitudes in charged decays
based on SU(3) symmetry is proposed. The CP violating phase can now be
determined without the previous difficulty associated with electroweak
penguins.Comment: 9 pages plus one figure, Revte
The Rotation of M Dwarfs Observed by the Apache Point Galactic Evolution Experiment
We present the results of a spectroscopic analysis of rotational velocities
in 714 M dwarf stars observed by the SDSS III Apache Point Galactic Evolution
Experiment (APOGEE) survey. We use a template fitting technique to estimate
while simultaneously estimating , ,
and . We conservatively estimate that our detection limit is 8
km s. We compare our results to M dwarf rotation studies in the
literature based on both spectroscopic and photometric measurements. Like other
authors, we find an increase in the fraction of rapid rotators with decreasing
stellar temperature, exemplified by a sharp increase in rotation near the M
transition to fully convective stellar interiors, which is consistent with the
hypothesis that fully convective stars are unable to shed angular momentum as
efficiently as those with radiative cores. We compare a sample of targets
observed both by APOGEE and the MEarth transiting planet survey and find no
cases were the measured and rotation period are physically
inconsistent, requiring . We compare our spectroscopic results to
the fraction of rotators inferred from photometric surveys and find that while
the results are broadly consistent, the photometric surveys exhibit a smaller
fraction of rotators beyond the M transition by a factor of . We
discuss possible reasons for this discrepancy. Given our detection limit, our
results are consistent with a bi-modal distribution in rotation that is seen in
photometric surveys.Comment: 31 pages, 11 figures, 4 tables. Accepted for publication by A
Electroweak Model Independent Tests for SU(3) Symmetry in Hadronic B Decays
We study effects of new physics beyond the Standard Model on SU(3) symmetry
in charmless hadronic two body B decays. It is found that several equalities
for some of the decay amplitudes, such as , , , predicted by SU(3) symmetry in the SM are not affected by new
physics. These relations provide important electroweak model independent tests
for SU(3) symmetry in B decays.Comment: 4 pages, revte
Invisible Higgs boson, continuous mass fields and unHiggs mechanism
We explore the consequences of an electroweak symmetry breaking sector which
exhibits approximately scale invariant dynamics -- i.e., nontrivial fixed point
behavior, as in unparticle models. One can think of an unHiggs as a composite
Higgs boson with a continuous mass distribution. We find it convenient to
represent the unHiggs in terms of a Kallen-Lehmann spectral function, from
which it is simple to verify the generation of gauge boson and fermion masses,
and unitarization of WW scattering. We show that a spectral function with broad
support, which corresponds to approximate fixed point behavior over an extended
range of energy, can lead to an effectively invisible Higgs particle, whose
decays at LEP or LHC could be obscured by background.Comment: 8 page
Hybrid vehicle assessment. Phase 1: Petroleum savings analysis
The results of a comprehensive analysis of near term electric hybrid vehicles are presented, with emphasis on their potential to save significant amounts of petroleum on a national scale in the 1990s. Performance requirements and expected annual usage patterns of these vehicles are first modeled. The projected U.S. fleet composition is estimated, and conceptual hybrid vehicle designs are conceived and analyzed for petroleum use when driven in the expected annual patterns. These petroleum consumption estimates are then compared to similar estimates for projected 1990 conventional vehicles having the same performance and driven in the same patterns. Results are presented in the form of three utility functions and comparisons of sevral conceptual designs are made. The Hybrid Vehicle (HV) design and assessment techniques are discussed and a general method is explained for selecting the optimum energy management strategy for any vehicle mission battery combination. Conclusions and recommendations are presented, and development recommendations are identified
CP Violation in a Multi-Higgs Doublet Model
We study CP violation in a multi-Higgs doublet model based on a horizontal symmetry. We consider two mechanisms for CP violation in this
model: a) CP violation due to complex Yukawa couplings; and b) CP violation due
to scalar-pseudoscalar mixings. We find that the predictions for
, CP violation in B decays and the electric dipole moments
of neutron and electron are different between these two mechanisms. These
predictions are also dramatically different from the minimal Standard Model
predictions.Comment: 17 pages + one figure, Revtex. Talk presented by Deshpande at the
Conference WHEPP-3, December 199
Prospects for Direct CP Violaton in Exclusive and Inclusive Charmless B decays
Within the Standard Model, CP rate asymmetries for could
reach 10%. With strong final state phases, they could go up to 20--30%, even
for mode which would have opposite sign. We can account for
, and rate data with new physics enhanced
color dipole coupling and destructive interference. Asymmetries could reach
40--60% for and modes and are all of the same sign. We are
unable to account for rate. Our inclusive study supports our
exclusive results.Comment: Minor changes, correct a small bug in Fig. 1(b). Version to appear in
Phys. Rev. Let
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