Speaker
Anna Zsigmond
(Wigner RCP, Budapest (HU))
Description
The weak bosons, Z and W, do not participate in the strong interaction, and thus constitute
clean probes of the initial state of nuclear collisions. Detected trough their leptonic decay
channels, they provide constraints on the nuclear parton distribution functions (PDF). In
particular the W boson proves a unique constraint on the sea quark distributions.
We report on CMS measurements of weak boson production in pp, pPb and PbPb. Particular emphasis
is place on measurements of the 35 nb$^{-1}$ of pPb data collected at the beginning of 2013.
This provides access to a Bjorken x region, $10^{-3}$ -- 1, which is lacking precision
experimental measurements needed by nuclear PDF parametrizations.
The Z boson nuclear modification factors as a function of transverse momentum and rapidity will
be shown, together with forward to backward ratios. The W boson yields, charge asymmetries, and
forward to backward ratios in pPb collisions will also be reported. With a production cross
section an order of magnitude larger than the Z, the W allows precise comparisons to theoretical
predictions. Comparisons to PDFs are made for both Z and W measurements
| On behalf of collaboration: | CMS |
|---|
Primary author
Anna Zsigmond
(Wigner RCP, Budapest (HU))
