Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraints on the quark mixing matrix with vector-like quarks   While a chiral fourth generation of quarks is almost ruled out from the data
on Higgs boson production and decay at the Large Hadron Collider, vector-like
quarks are still a feasible option to extend the fermionic sector of the
Standard Model. Such an extension does not suffer from any anomalies and easily
passes the constraints coming from oblique electroweak parameters. We consider
such minimal extensions with $SU(2)$ singlet and doublet vector-like quarks
that may mix with one, or at the most two, of the Standard Model quarks.
Constraints on the new mixing angles and phases are obtained from several
$\Delta B = 1$ and $\Delta B = 2$ processes.

26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc