Z and W production in pp, pPb and PbPb collisions with CMS

May 19, 2014, 5:10 PM
helium (darmstadtium)



Schlossgraben 1 64283 Darmstadt Germany
Contributed Talk Electromagnetic Probes Electromagnetic probes


Anna Zsigmond (Wigner RCP, Budapest (HU))


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))

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