10,378 research outputs found
Measuring the ratio of and couplings through production
For a generic Higgs boson, measuring the relative sign and magnitude of its
couplings with the and bosons is essential in determining its origin.
Such a test is also indispensable for the 125-GeV Higgs boson. We propose that
the ratio of the and couplings can be directly
determined through the production, where denotes a generic Higgs
boson, owing to the tree-level interference effect. While this is impractical
at the LHC due to the limited sensitivity, it can be done at future
colliders, such as a 500-GeV ILC with the beam polarization
in the and
channels. The discovery potential of a
general ratio and the power to discriminate it from the SM value are studied in
detail. Combining the cross section of with the
measurements of coupling at the HL-LHC, one can further improve the
sensitivity of .Comment: 24 pages, 10 figures, 2 table
Hunting for the X_b via Radiative Decays
In this paper, we study radiative decays of X_b, the counterpart of the
famous X(3872) in the bottomonium-sector as a candidate for meson-meson
molecule, into the \gamma \Upsilon(nS) (n=1, 2, 3). Since it is likely that the
X_b is below the B\bar B^* threshold and the mass difference between the
neutral and charged bottom meson is small compared to the binding energy of the
X_b, the isospin violating decay mode X_b\to \Upsilon (nS)\pi^+\pi^- would be
greatly suppressed. This will promote the importance of the radiative decays.
We use the effective Lagrangian based on the heavy quark symmetry to explore
the rescattering mechanism and calculate the partial widths. Our results show
that the partial widths into \gamma \Upsilon(nS) are about 1 keV, and thus the
branching fractions may be sizeable, considering the fact the total width may
also be smaller than a few MeV like the X(3872). These radiative decay modes
are of great importance in the experimental search for the X_b particularly at
hadron collider. An observation of the X_b will provide a deeper insight into
the exotic hadron spectroscopy and is helpful to unravel the nature of the
states connected by the heavy quark symmetry.Comment: 10 pages, 4 figure
A Light Sterile Neutrino from Friedberg-Lee Symmetry
Light sterile neutrinos of mass about an eV with mixing of a
few percent to active neutrinos may solve some anomalies shown in experimental
data related to neutrino oscillation. How to have light sterile neutrinos is
one of the theoretical problems which have attracted a lot of attentions. In
this article we show that such an eV scale light sterile neutrino candidate can
be obtained in a seesaw model in which the right-handed neutrinos satisfy a
softly-broken Friedberg-Lee (FL) symmetry. In this model a right-handed
neutrino is guaranteed by the FL symmetry to be light comparing with other two
heavy right-handed neutrinos. It can be of eV scale when the FL symmetry is
softly broken and can play the role of eV scale sterile neutrino needed for
explaining the anomalies of experimental data. This model predicts that one of
the active neutrino is massless. We find that this model prefers inverted
hierarchy mass pattern of active neutrinos than normal hierarchy. An
interesting consequence of this model is that realizing relatively large
and relatively small in this model
naturally leads to a relatively small . This interesting
prediction can be tested in future atmospheric or solar neutrino experiments.Comment: 14 pages, references added, version for publication in PL
Modular matrices from universal wave function overlaps in Gutzwiller-projected parton wave functions
We implement the universal wave function overlap (UWFO) method to extract
modular and matrices for topological orders in Gutzwiller-projected
parton wave functions (GPWFs). The modular and matrices generate a
projective representation of on the degenerate-ground-state
Hilbert space on a torus and may fully characterize the 2+1D topological
orders, i.e. the quasi-particle statistics and chiral central charge (up to
bosonic quantum Hall states). We used the variational Monte Carlo method
to computed the and matrices of the chiral spin liquid (CSL)
constructed by the GPWF on the square lattice, and confirm that the CSL carries
the same topological order as the bosonic Laughlin state. We
find that the non-universal exponents in UWFO can be small and direct numerical
computation is able to be applied on relatively large systems. We also discuss
the UWFO method for GPWFs on other Bravais lattices in two and three dimensions
by using the Monte Carlo method. UWFO may be a powerful method to calculate the
topological order in GPWFs.Comment: 5 pages with 3 figure
- β¦