13,386 research outputs found
List version of (,1)-total labellings
The (,1)-total number of a graph is the width of the
smallest range of integers that suffices to label the vertices and the edges of
such that no two adjacent vertices have the same label, no two incident
edges have the same label and the difference between the labels of a vertex and
its incident edges is at least . In this paper we consider the list version.
Let be a list of possible colors for all . Define
to be the smallest integer such that for every list
assignment with for all , has a
(,1)-total labelling such that for all . We call the (,1)-total labelling choosability and
is list -(,1)-total labelable. In this paper, we present a conjecture on
the upper bound of . Furthermore, we study this parameter for paths
and trees in Section 2. We also prove that for
star with in Section 3 and for outerplanar graph with in Section 4.Comment: 11 pages, 2 figure
List (d,1)-total labelling of graphs embedded in surfaces
The (d,1)-total labelling of graphs was introduced by Havet and Yu. In this
paper, we consider the list version of (d,1)-total labelling of graphs. Let G
be a graph embedded in a surface with Euler characteristic whose
maximum degree is sufficiently large. We prove that the (d,1)-total
choosability of is at most .Comment: 6 page
Probing dark matter particles at CEPC
We investigate the capability of the future electron collider CEPC in probing
the parameter space of several dark matter models, including millicharged dark
matter models, portal dark matter models, and effective field theory dark
matter models. In our analysis, the monophoton final state is used as the
primary channel to detect dark matter models at CEPC. To maximize the signal to
background significance, we study the energy and angular distributions of the
monophoton channel arising from dark matter models and from the standard model
to design a set of detector cuts. For the portal dark matter, we also
analyze the boson visible decay channel which is found to be complementary
to the monophoton channel in certain parameter space. The CEPC reach in the
parameter space of dark matter models is also put in comparison with Xenon1T.
We find that CEPC has the unprecedented sensitivity to certain parameter space
for the dark matter models considered; for example, CEPC can improve the limits
on millicharge by one order of magnitude than previous collider experiments for
GeV dark matter.Comment: 21 pages, 31 figure
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