Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Small Cosmological Constant, Grand Unification and Warped Geometry   We explore a mechanism to obtain the observational small value for the
4-dimensional vacuum energy through an exponential warp-factor suppression.
Intriguingly the required suppression scale relates directly to the GUT scale.
We demonstrate the mechanism explicitly in a 5-dimensional brane-world setup
with warped geometry. Upon lifting the setup to 10-dimensional IIB
string-theory, the relevance of the GUT scale becomes clear as the IIB
string-theory description, which is based on D3-brane stacks, gives rise to a
spontaneously broken SU(5) supersymmetric GUT theory with low-energy MSSM
spectrum and Higgs doublet-triplet splitting.

22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat