Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Coulomb Effects on the W Line Shape at LEP2   One of the most powerful methods for obtaining a precision measurement of M_W
at LEP2 is from direct reconstruction of the invariant mass distribution of W
bosons produced in e+e- --> W+W-. We investigate the effects on the W line
shape, and in particular on the average invariant mass, of phase-space and
first-order Coulomb corrections. The latter are shown to have a non-negligible
effect on the reconstructed mass, inducing shifts of order -20 MeV at collision
energies above threshold, compared to the Born approximation cross section. The
sign and magnitude of the effect can be understood in a simple model
calculation in which one of the W bosons is assumed to be stable.

29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math