13,554 research outputs found
PSR B1828-11: a precession pulsar torqued by a quark planet?
The pulsar PSR B1828-11 has long-term, highly periodic and correlated
variations in both pulse shape and the rate of slow-down. This phenomenon may
provide evidence for precession of the pulsar as suggested previously within
the framework of free precession as well as forced one. On a presumption of
forced precession, we propose a quark planet model to this precession henomenon
instead, in which the pulsar is torqued by a quark planet. We construct this
model by constraining mass of the pulsar (), mass of the planet
() and orbital radius of the planet (). Five aspects
are considered: derived relation between and ,
movement of the pulsar around the center of mass, ratio of and
, gravitational wave radiation timescale of the planetary system,
and death-line criterion. We also calculate the range of precession period
derivative and gravitational wave strength (at earth) permitted by the model.
Under reasonable parameters, the observed phenomenon can be understood by a
pulsar () with a quark planet
() orbiting it. According to the calculations
presented, the pulsar would be a quark star because of its low mass, which
might eject a lump of quark matter (to become a planet around) during its
birth.Comment: 6 pages, 3 figures, accepted by MNRAS (Letters
Symmetry-preserving Loop Regularization and Renormalization of QFTs
A new symmetry-preserving loop regularization method proposed in \cite{ylw}
is further investigated. It is found that its prescription can be understood by
introducing a regulating distribution function to the proper-time formalism of
irreducible loop integrals. The method simulates in many interesting features
to the momentum cutoff, Pauli-Villars and dimensional regularization. The loop
regularization method is also simple and general for the practical calculations
to higher loop graphs and can be applied to both underlying and effective
quantum field theories including gauge, chiral, supersymmetric and
gravitational ones as the new method does not modify either the lagrangian
formalism or the space-time dimension of original theory. The appearance of
characteristic energy scale and sliding energy scale offers a
systematic way for studying the renormalization-group evolution of gauge
theories in the spirit of Wilson-Kadanoff and for exploring important effects
of higher dimensional interaction terms in the infrared regime.Comment: 13 pages, Revtex, extended modified version, more references adde
associated production at LHC in the general 2HDM with Spontaneous CP Violation
Spontaneous CP violation motivates the introduction of two Higgs doublets in
the electroweak theory. Such a simple extension of the standard model has three
neutral Higgs bosons and a pair charged Higgs, especially it leads to rich
CP-violating sources including the induced Kobayashi-Maskawa CP-violating
phase, the mixing of the neutral Higgs bosons due to the CP-odd Higgs and the
effective complex Yukawa couplings of the charged and neutral Higgs bosons.
Within this model, we present the production of a charged Higgs boson in
association with a W boson at the LHC, and calculate in detail the cross
section and the transverse momentum distribution of the associated W boson.Comment: 16 pages, 6 figures, omitted 3 figures, motivations for Type III 2HDM
with SCPV is emphasized, to be published in PR
Implications of new data in charmless B decays
Based on the latest experimental data of and modes, a
model-independent analytical analysis is presented. The CP-averaged branching
ratio difference in decays with and
is reduced though it remains larger than the prediction from the standard
model(SM) as both measured and are enhanced, which indicates that a
room for new physics becomes smaller. The present data of decay reduce
the ratio from the previous value of to , which is still larger than the theoretical estimations based on
QCD factorization and pQCD. Within SM and flavor SU(3) symmetry, the current
data also diminish the ratio from the previous value to with a large strong phase , while its value remains much larger than the one extracted from
the modes. The direct CP violation is
predicted to be , which is consistent
with the present data. Two kinds of new effects in both strong and weak phases
of the electroweak penguin diagram are considered. It is found that both cases
can reduce the ratio to and lead to roughly the same
predictions for CP violation in .Comment: 13 pages, 4 figure
Charmless decays B->pipi, piK and KK in broken SU(3)symmetry
Charmless B decay modes and aresystematically
investigated with and without flavor SU(3) symmetry. Independent analyses on
and modes both favor a large ratio between color-suppressed
tree () and tree ( diagram, which suggests that they are more likely to
originate from long distance effects. The sizes of QCD penguin diagrams
extracted individually from , and modes are found to
follow a pattern of SU(3) breaking in agreement with the naive factorization
estimates. Global fits to these modes are done under various scenarios of
SU(3)relations. The results show good determinations of weak phase in
consistency with the Standard Model (SM), but a large electro-weak penguin
(P_{\tmop{EW}}) relative to with a large relative strong phase are
favored, which requires an big enhancement of color suppressed electro-weak
penguin (P_{\tmop{EW}}^C) compatible in size but destructively interfering
with P_{\tmop{EW}} within the SM, or implies new physics. Possibility of
sizable contributions from nonfactorizable diagrams such as -exchange (),
annihilation() and penguin-annihilation diagrams() are investigated.
The implications to the branching ratios and CP violations in modes are
discussed.Comment: 27 pages, 9 figures, reference added, to appear in Phy.Rev.
Exclusive Decays and CP Violation in the General two-Higgs-doublet Model
We calculate all the branching ratios and direct CP violations of
decays in a most general two-Higgs-doublet model with spontaneous CP violation.
As the model has rich CP-violating sources, it is shown that the new physics
effects to direct CP violations and branching ratios in some channels can be
significant when adopting the generalized factorization approach to evaluate
the hadronic matrix elements, which provides good signals for probing new
physics beyond the SM in the future B experiments.Comment: 21 page
Calculation of composition distribution of ultrafine ion-H2O-H2SO4 clusters using a modified binary ion nucleation theory
Thomson's ion nucleation theory was modified to include the effects of curvature dependence of the microscopic surface tension of field dependent, nonlinear, dielectric properties of the liquid; and of sulfuric acid hydrate formation in binary mixtures of water and sulfuric acid vapors. The modified theory leads to a broadening of the ion cluster spectrum, and shifts it towards larger numbers of H2O and H2SO4 molecules. Whether there is more shifting towards larger numbers of H2O or H2SO4 molecules depends on the relative humidity and relative acidity of the mixture. Usually, a broadening of the spectrum is accompanied by a lowering of the mean cluster intensity. For fixed values of relative humidity and relative acidity, a similar broadening pattern is observed when the temperature is lowered. These features of the modified theory illustrate that a trace of sulfuric acid can facilitate the formation of ultrafine, stable, prenucleation ion clusters as well as the growth of the prenucleation ion clusters towards the critical saddle point conditions, even with low values of relative humidity and relative acidity
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