Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New type of beam size effect and the $W$-boson production at
  $\mu^+\mu^-$ colliders   The cross section for the reactions of the type $\mu^-\mu^+ \to e\bar\nu_e X$
can not be calculated by the standard methods due to the $t$--channel
singularity in the physical region. In this letter we show that accounting for
the finite sizes of the colliding beams results in the regularization of this
singularity. The finite cross section, which is obtained in this way, turns out
to be linear proportional to the transverse sizes of the colliding beams. As an
application of the above result, we calculate the cross section of the $W$
boson production at $\mu^+\mu^-$ colliders in the reaction $\mu^- \mu^+ \to
e\bar\nu _e W^+$.

23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg