11,743 research outputs found
On the striated regularity for the 2D anisotropic Boussinesq system
In this paper, we investigate the global existence and uniqueness of strong
solutions to 2D Boussinesq system with anisotropic thermal diffusion or
anisotropic viscosity and with striated initial data. Using the key idea of
Chemin to solve 2-D vortex patch of ideal fluid, namely the striated regularity
can help to bound the gradient of the velocity, we can prove the global
well-posedness of the Boussinesq system with anisotropic thermal diffusion with
initial vorticity being discontinuous across some smooth interface. In the case
of an anisotropic horizontal viscosity we can study the propagation of the
striated regularity for the smooth temperature patches problem.Comment: 36 page
Isospin breaking, coupled-channel effects, and X(3872)
We re-investigate the possibility of X(3872) as a molecule with
within the framework of both the one-pion-exchange (OPE) model
and the one-boson-exchange (OBE) model. After careful treatment of the S-D wave
mixing, the mass difference between the neutral and charged mesons and
the coupling of the pair to , a loosely bound molecular
state X(3872) emerges quite naturally with large isospin violation in its
flavor wave function. For example, the isovector component is 26.24% if the
binding energy is 0.30 MeV, where the isospin breaking effect is amplified by
the tiny binding energy. After taking into account the phase space difference
and assuming the and come from a virtual omega and rho meson
respectively, we obtain the ratio of these two hidden-charm decay modes:
for the binding
energy being 0.3 MeV, which is consistent with the experimental value.Comment: published in Phys. Rev.
Rain or Shine: Where is the Weather Effect?
Saunders (1993) and Hirshleifer and Shumway (2001) document the effect of weather on stock returns. The proposed explanation in both papers is that investor mood affects cognitive processes and trading decisions. In this paper, we use a database of individual investor accounts to examine the weather effects on traders. Our analysis of the trading activity in five major U.S. cities over a six-year period finds vistually no difference in individuals propensity to buy or sell equities on cloudy days as opposed to sunny days. If the association between cloud cover and stock returns documented for New York and other world cities is indeed caused by investor mood swings, our findings suggest that researchers should focus on the attitudes of market-makers, news providers or other agents physically located in the city hosting the exchange. NYSE spreads widen on cloudy days. When we control for this, the significance of the weather effect is dramatically reduced. We interpret this as evidence that the behavior of market-makers, rather than individual investors, may be responsible for the relation between returns and weather.
Deuteron-like states composed of two doubly charmed baryons
We present a systematic investigation of the possible molecular states
composed of a pair of doubly charmed baryons () or one doubly
charmed baryon and one doubly charmed antibaryon
within the framework of the one-boson-exchange-potential model. For the
spin-triplet systems, we take into account the mixing between the and
channels. For the baryon-baryon system with and , where and represent the group
representation and the isospin of the system, respectively, there exist loosely
bound molecular states. For the baryon-antibaryon system
with , and , there
also exist deuteron-like molecules. The molecular states
may be produced at LHC. The proximity of their masses to the threshold of two
doubly charmed baryons provides a clean clue to identify them.Comment: 18 pages, 8 figure
Highlights of Supersymmetric Hypercharge Triplets
The discovery of a standard model (SM)-like Higgs boson with a relatively
heavy mass and hints of di-photon excess has deep implication to
supersymmetric standard models (SSMs). We consider the SSM extended with
hypercharge triplets, and investigate two scenarios of it: (A) Triplets
significantly couple to the Higgs doublets, which can substantially raise
and simultaneously enhance the Higgs to di-photon rate via light chargino
loops; (B) Oppositely, these couplings are quite weak and thus can not be
raised. But the doubly-charged Higgs bosons, owing to the gauge group
structure, naturally interprets why there is an excess rather than a deficient
of Higgs to di-photon rate. Additionally, the pseudo Dirac triplet fermion is
an inelastic non-thermal dark matter candidate. Light doubly-charged particles,
especially the doubly-charged Higgs boson around 100 GeV in scenario B, are
predicted. We give a preliminary discussion on their search at the LHC.Comment: JHEP version. Typos fixed, comments, references and acknowledge adde
Flavor Violating Transitions of Charged Leptons from a Seesaw Mechanism of Dimension Seven
A mechanism has been suggested recently to generate the neutrino mass out of
a dimension-seven operator. This is expected to relieve the tension between the
occurrence of a tiny neutrino mass and the observability of other physics
effects beyond it. Such a mechanism would inevitably entail lepton flavor
violating effects. We study in this work the radiative and purely leptonic
transitions of the light charged leptons. In so doing we make a systematic
analysis of the flavor structure by providing a convenient parametrization of
the mass matrices in terms of independent physical parameters and diagonalizing
them explicitly. We illustrate our numerical results by sampling over two CP
phases and one Yukawa coupling which are the essential parameters in addition
to the heavy lepton mass. We find that with the stringent constraints coming
from the muon decays and the muon-electron conversion in nuclei taken into
account the decays of the tau lepton are severely suppressed in the majority of
parameter space. There exist, however, small regions in which some tau decays
can reach a level that is about 2 orders of magnitude below their current
bounds.Comment: v1: 25 pages, 8 figures; v2: proofread version for PRD. Included
muon-electron conversion in nuclei at the referee's suggestion and added
relevant refs accordingly; main conclusion not changed but bounds on tau
lepton decays becoming more stringent; linguistic and editing corrections
also mad
Possible hadronic molecules composed of the doubly charmed baryon and nucleon
We perform a systematical investigation of the possible deuteron-like bound
states with configuration , where denotes the
nucleon (anti-nucleon), in the framework of the one-boson-exchange-potential
model. In the spin-triplet sector we take into account both the and
channels due to non-vanishing tensor force. There exist several
candidates of the loosely bound molecular states for the and
systems, which lie below the threshold of
or . We also investigate the
possible loosely bound states with configurations and
. These molecular candidates may be searched for at Belle
II and LHC in the near future.Comment: 14 pages, 5 figure
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